Thermally Stable Lens Mount ( this time around )

[Matt Uhry]

The lens mounts on all the Red 1's I've used shifts as the camera warms up. It's a pretty significant problem on many lenses. On my Cooke 18-100 from warm to cold it shifts a significant amount - 2 or 3 feet at a 10ft distance. On a MP 14mm it's quite nasty, 20ft cold is 30ft warm. Not acceptable guys !

Could you look into not using aluminum on the Epic and instead use Invar or at least Stainless ? It's not so much the mount itself but the standoffs that align the mount and the sensor plane. At least offer it as an upgrade for the cine lens - focus by scale crowd.

Aluminum is pretty much the worst metal ever as far as thermal stability goes.

Matt Uhry
www.mattuhry.com

[sander kamp]

That is so strange since i believe my mount is really solid. I work a lot on the set as a technician for my camera and tend to check every shot for focus and never find there to be a shift when the camera warms up.

In fact, because of your post I just did a check with a cool camera; I focussed it with the 1:1 pixel zoom with a 28mm lens wide open and let it warm up. After the camera got warm to the touch, the fan spinning full and the lens mount hand warm it was still spot on.

[Jannard]

All the reports we have from the field... guys using them everyday for months... have been telling us the mount is rock solid. They check them every day out of precaution, but never need to adjust them.

I'm all ears. If there are real problems we haven't heard about, please let us know. We have been very sensitive to this issue since we changed to the adjustable (and much better) mount.

Jim

[Michael Lindsay]

Hi Matt

Is the temp difference between just turned on and on for hours enough to show the problem? Or do I need to move the camera between 2 temperature locations?

regards

Michael L

[David Didato]

I thought the mount was stainless steel?

[Bob Rudis]

I've been hearing about problems with the mount. Problems with the big Optimo. Not many but some. Also I hear Clairmont is designing their own stainless mount for their red cameras, perhaps this is a rumor.

[Hans von Sonntag]

Matt, I had backfocus shifts with may RedOne and my Cooke. That was in Fabruary/March. The backfocus shifts were sever and a major problem. It happened with all lenses I used.

When the camera was cold all was fine, after half an hour or so the backfocus started to drift. 80 cm were 1m on an 18mm SuperSpeed.

I contacted Red and after some difficulties regarding e-mail/spamfolder etc... we solved the problem by tightening the screws on the mount. Apparently my camera was shipped with a lose mount. The backfocus shift never came back.

Hans

[Matt Uhry]

All the reports we have from the field... guys using them everyday for months... have been telling us the mount is rock solid. They check them every day out of precaution, but never need to adjust them.

I'm all ears. If there are real problems we haven't heard about, please let us know. We have been very sensitive to this issue since we changed to the adjustable (and much better) mount.

Jim

Sorry, but it's really not stable over the cameras warm up. I've tested it carefully several times, while shooting on stage and during a long lighting setups. On my cooke 18-100 @ 18mm A Putora chart set and sharp at 10ft will be focusing at 8.8 to 9ft once the camera warms up. Same thing with wide Ultraprimes and Master Primes.

One has to choose to set the mount to "warm" or "cold". Warm is probably the smart choice here but it's not one I want to have to make.

I think the current camera for the most part is great and like much about the new Epic designs, just pointing out an area that should be improved on the next camera. It's not that strange - aluminum has a poor thermal expansion coefficient and the red heats up quite a bit.

Have a look here for a list of various materials: http://en.wikipedia.org/wiki/Coefficient_of_thermal_expansion

Matt Uhry
www.mattuhry.com

[Matt Uhry]

Matt, I had backfocus shifts with may RedOne and my Cooke. That was in Fabruary/March. The backfocus shifts were sever and a major problem. It happened with all lenses I used.

When the camera was cold all was fine, after half an hour or so the backfocus started to drift. 80 cm were 1m on an 18mm SuperSpeed.

I contacted Red and after some difficulties regarding e-mail/spamfolder etc... we solved the problem by tightening the screws on the mount. Apparently my camera was shipped with a lose mount. The backfocus shift never came back.

Hans

I'll check for proper torque on the mount screws.

Matt Uhry
www.mattuhry.com

[Steve Gal]

I have not had this problem with my cameras. Perhaps that 18-100 has done some warping to the mount due. Sometimes I see AC's using the low bridge support wrong and they actually are pulling the lens downward and that puts alot of stress on the mount.

[Matt Uhry]

I have not had this problem with my cameras. Perhaps that 18-100 has done some warping to the mount due. Sometimes I see AC's using the low bridge support wrong and they actually are pulling the lens downward and that puts alot of stress on the mount.

I've observed the same problem with master and ultra primes. Support situation on 18-100 seems OK.

Matt Uhry
www.mattuhry.com

[Miguel "Macgregor" De Olaso]

I´ve seen this problem with different sets of Superspeeds and different red ones. After some hours, the marks do not match.

[Hans von Sonntag]

I´ve seen this problem with different sets of Superspeeds and different red ones. After some hours, the marks do not match.

Do you have the problem with MPs?

Hans

[Stephen Williams]

I´ve seen this problem with different sets of Superspeeds and different red ones. After some hours, the marks do not match.

Hi,

I have seen it too on a few later cameras, but not on early cameras, did anything change in the production about sn 750?

Best

Stephen

[Finner]

I have definately had this problem. Especially outdoor nights if there is a 10degree or more celsius change the back focus will be way off. I had a night car explosion shot ruined because of this.

[Sanjin Jukic]

IMS PL mount performs a pretty good when RED camera warms up.

[Jannard]

We'll look at this issue again internally if those of you that are having problems double check to make sure the mount is properly tight.

We did have some issues here awhile back with loose mounts. Tightening them solved the problem.

Jim

Jim

[Miguel "Macgregor" De Olaso]

Do you have the problem with MPs?

Hans

I haven´t seen it yet, and no one has reported issues with them. But everytime i´ve shot with the MP it was under good temperature conditions so i can´t really give you a good answer.

[Alex Carr]

I have seen this problem with the 16mm Ultra Prime, All other lenses in the set seem to be fine, except the 16

[Stephen Williams]

I have seen this problem with the 16mm Ultra Prime, All other lenses in the set seem to be fine, except the 16

Hi,

Was 16mm your widest lens? Wide fast lenses are the most critical for FFD.

Stephen

[Michael Lindsay]

Is the 16mm the widest lens you have... is the next lens up a 20mm or a 24mm?

thanks for any info

Michael L

[Brook Willard]

I've run into the issue on cameras from all different generations/batches. Primes, zooms... Even the 12:1. Chalk me down as another... But with dozens of cameras instead of one.

Thanks for re-investigating the issue. Invar is your friend. :)

[Finner]

Thanks for re-investigating the issue. Invar is your friend. :)

Yes please, another vote for Invar.

[Jannard]

The lens mounts on Scarlet and EPIC are quite a bit shorter than the RED ONE... and quite a bit less complicated. Any "expansion" issues should be quite a bit less than a RED ONE. But. Doing mounts in Invar is no big deal. They will certainly cost significantly more, but that is not a problem for you guys. :-) We aim to please...

Jim

[Matt Uhry]

The lens mounts on Scarlet and EPIC are quite a bit shorter than the RED ONE... and quite a bit less complicated. Any "expansion" issues should be quite a bit less than a RED ONE. But. Doing mounts in Invar is no big deal. They will certainly cost significantly more, but that is not a problem for you guys. :-) We aim to please...

Jim

Reasonable additional cost is not a problem. Invar is cool, but even stainless steel has about half the thermal expansion of aluminum and seems to work well enough on other professional digital cinema cameras which don't use invar standoffs to hold the stainless steel PV or PL mounts in place.

I'm not sure why the expansion / contraction of the FFD would be more or less if the materials ( aluminum ) were the same. The mechanical design should not matter. There's formula's out there, but I suck at math. But in concept a 52mm block or a 52mm tube of aluminum will elongate the same amount with the same amount of heat. My Brother in law is a material science PhD and I'll get him to show me how to calculate it correctly and get back with the actual #'s

Matt Uhry
www.mattuhry.com


Matt Uhry
www.mattuhry.com

[Alexis Hanawalt]

We'll look at this issue again internally if those of you that are having problems double check to make sure the mount is properly tight.

We did have some issues here awhile back with loose mounts. Tightening them solved the problem.

Jim

Jim

I've had backfocus shifts too. By making sure the mount isn't loose, you mean all the tiny screws that are swapped out whenever switching from nikon to pl, right? How tight should they be?

[Evin Grant]

So far I've been lucky and haven't seen too much shift but I rarely work at 16mm T2. That being said I heartily endorse the idea of a more stable mount option. Even if it means a little more $.

[Jannard]

Reasonable additional cost is not a problem. Invar is cool, but even stainless steel has about half the thermal expansion of aluminum and seems to work well enough on other professional digital cinema cameras which don't use invar standoffs to hold the stainless steel PV or PL mounts in place.

I'm not sure why the expansion / contraction of the FFD would be more or less if the materials ( aluminum ) were the same. The mechanical design should not matter. There's formula's out there, but I suck at math. But in concept a 52mm block or a 52mm tube of aluminum will elongate the same amount with the same amount of heat. My Brother in law is a material science PhD and I'll get him to show me how to calculate it correctly and get back with the actual #'s

Matt Uhry
www.mattuhry.com


Matt Uhry
www.mattuhry.com

At what point are you OK with thermal expansion? Is stainless OK with you even though it is less stable than invar? There comes a point of practical vs. theoretical. We certainly don't have a problem making anything you guys want, assuming you guys know what that is. There is a price to pay. If you want Zero movement ever (any condition and any lens), we need to make an invar mount that weighs quite a bit and is pretty expensive. No problem with us. If you want a stainless mount that is reasonable in weight, how much expansion can you tolerate and under what conditions. One thing we can't do is make 22 versions of mount materials. Well, I guess we can, actually. Cost is the only factor.

Jim

[Jannard]

After considering our customers wishes, we will make the PL mounts in 3 versions. Aluminum, stainless and Invar. There will be 3 price points. Take your pick. Just consider that stainless and Invar will weigh more and cost more.

Happy Holidays.

Jim

[Irmeli R]

as i understand epic and scarlet (like red one) will not have a hardfront. so even if the plate (with the 4 screws) plus the PL mount is made of invar, the body (made from aluminum) will still expand.

image of a hardfront (invar) where the PL or nikon mount is seated - not connected to the front housing made of aluminum

http://img88.imageshack.us/img88/6070/hardfrontxs2.jpg

[Matt Uhry]

What Nell has pictured is the design change I was getting at not the twisting part of the mount itself. Does Aaton actually use Invar in the hard front ?

Matt Uhry
www.mattuhry.com

[Irmeli R]

no..aaton does not use an invar hard front. in film cameras the use of a hard front has less to do with thermal expansion but with reducing noise from the pull down claw and gears and with keeping tolerances. like in an arri 35BL or an arri 16BL or the new 416 the PL mount, hard front, pulldown mechanism and filmgate are precisely machined and rigidly interconnected..but only connect to the outside body (which is less precise (sand cast or die cast)) through rubber mounted connectors..it's actually more complex than that but that's the general idea.

[Steve Sherrick]

Isn't Invar susceptible to wearing down over time. Are other materials added to strengthen it?

I'm all for a solution that is stable but doesn't send the cost sky high. Once the price/performance ratio gets too out of whack, it might not make sense. Having the option as Jim mentioned might be a good way to compromise. Although, having several mounts could make it confusing out in the field, so they would have to be distinguishable from each other I would think.

[Brook Willard]

After considering our customers wishes, we will make the PL mounts in 3 versions. Aluminum, stainless and Invar. There will be 3 price points. Take your pick. Just consider that stainless and Invar will weigh more and cost more.

Happy Holidays.

Jim

That's pretty cool.

What of the sensor moving mechanism? I already wrote a bit about my concerns on that subject a few weeks ago. Will that mechanism be of similar thermal stability? The same question applies to the rest of the body as Nell mentioned.

Invar is the key word because it was mentioned once upon a time with the RED ONE and - for better or for worse - it has been elevated to "best mount ever" theoretical status in our collective minds. While it does have some awesome thermal characteristics, your point about bang:buck is a good one.

So what of a machined hard front design? Is that outside the realm of engineering based on the aforementioned adjustable sensor plan?

[Irmeli R]

brook..what's the point of machining a hard front if it's not in invar or stainless steel? if it's in aluminum it will expand like the body..so you can leave PL mount attached to the body like we see in the renderings..no difference.

anyway..i think the scarlet and epics will run alot less hot so it might not be necessary.

[Brook Willard]

brook..what's the point of machining a hard front if it's not in invar or stainless steel? if it's in aluminum it will expand like the body..so you can leave PL mount attached to the body like we see in the renderings..no difference.

Trust me, I'm probably the most anti-aluminum mount guy here.

[Albert Malvaez]

Re: the present problem and avoiding what happened to Finner.
Heater with controlling circuitry pulling power from the battery plate D connector. Camera is collimated at X degrees. Heater prevents lens mount assembly from dropping below X degrees. Batteries are cheaper than a reshoot. While I'm thinking about it, Anton Bauer has a hot swappable dual battery plate. Are there any other versions/options of a hot swappable dual battery plate?

[Brook Willard]

Re: the present problem and avoiding what happened to Finner.
Heater with controlling circuitry pulling power from the battery plate D connector. Camera is collimated at X degrees. Heater prevents lens mount assembly from dropping below X degrees. Batteries are cheaper than a reshoot. While I'm thinking about it, Anton Bauer has a hot swappable dual battery plate. Are there any other versions/options?

Yep: build a more stable lens mount. :):wink:

[Finner]

anyway..i think the scarlet and epics will run alot less hot so it might not be necessary.

I have found the heat of the camera has far less effect on the mount as compared to external temperature swings.

[Steve Gibby]

After considering our customers wishes, we will make the PL mounts in 3 versions. Aluminum, stainless and Invar. There will be 3 price points. Take your pick. Just consider that stainless and Invar will weigh more and cost more.

Happy Holidays.

Jim

That's an excellent solution if these guys need/want it. One observation: Everyone on this thread who has complained about thermal expansion of the PL mount is working in crew situations using traditional focusing. Thermal expansion of the mounts has been a non-issue for those of us who mostly sight focus RED One. Even when my crews have used traditional focusing on my RED cameras, with the new mount installed, we haven't experienced any noticeable degree of thermal expansion problems. Our mount screws are torked correctly.

Since you've mentioned three options for PL mount materials, for my PL mounts on the new cameras I'll probably go with stainless, because I use a lot of long heavy lenses (obviously with bottom lens support) but a little extra added weight of stainless won't be a problem. I also use a lot of mid-weight lenses unsupported in hand held configurations, and run a lot with them, so a bit stronger mount in stainless may be a good idea. That said, I've had no problems whatsoever with the new mounts on my cameras, so if I ended up with aluminum, that would probably be fine too. The back focus on the new mounts on my cameras has been rock solid.

-----------------------

Happy Holidays Jim!

[Matt Uhry]

It's not so much the mount that's the issue, it's the 52mm of cast and machined aluminum that holds the mount and the sensor aligned. What's being suggested is that Red not screw the mount onto the body and instead onto a standoff that keeps it aligned with the plane of the senor made of invar or some other thermally stable material of their choosing.

That being said a steel mount front PL is a still good idea. I think invar may be a bit brittle for the actual mount, but I'm not sure of this.

Thanks for your care and attention!.

Matt Uhry
www.mattuhry.com

[David Mullen ASC]

I only had a back-focus problem once on the RED, oddly enough it was just two days after the initial prep where the back-focus had been checked at the rental house where the lenses came from. But by Day Two, I started noticing that one of our RED's seemed off in a wide day exterior shot and it turned out that the back-focus had shifted. But after we set it again, it never was a problem -- so perhaps we had a loose screw or something.

Now this was a movie shot in summer in warm to normal temp locations, never any cold situations.

Even if you focus by eye rather than measurements, a wide-angle wide shot can be hard to get sharp if the back-focus is off. On tighter, longer-lensed shots, sure, focusing by eye usually gets around this problem, or hides it. On the other hand, a lot of eye-focusing involves zooming in tight, focusing, and then zooming back wide, which doesn't work well if the back-focus is off (in fact, that's often how you spot that it is off...)

If you're shooting for projection on a 50' or 75' screen, these little issues become big issues.

In fact, one of the advantages I've found with shooting digitally on cameras like the RED is that I spot certain lens defeats and problems more easily rather than being surprised months later.

[Steve Sherrick]

It's not so much the mount that's the issue, it's the 52mm of cast and machined aluminum that holds the mount and the sensor aligned. What's being suggested is that Red not screw the mount onto the body and instead onto a standoff that keeps it aligned with the plane of the senor made of invar or some other thermally stable material of their choosing.

That being said a steel mount front PL is a still good idea. I think invar may be a bit brittle for the actual mount, but I'm not sure of this.

Thanks for your care and attention!.

Matt Uhry
www.mattuhry.com
Ah, this makes more sense why you guys are suggesting invar. The reason I asked if it would be strong enough is that I thought you were referring to using it for the mount itself, which made me wonder if it would be able to take the wear. This makes sense now.

[Dale Launer]

Any reason titanium isn't being considered as a lens mount?

[Steve Gibby]

On the other hand, a lot of eye-focusing involves zooming in tight, focusing, and then zooming back wide, which doesn't work well if the back-focus is off (in fact, that's often how you spot that it is off...)

In fact, one of the advantages I've found with shooting digitally on cameras like the RED is that I spot certain lens defeats and problems more easily rather than being surprised months later.

Definitely. Eye focusing with zoom lenses on RED does involve a lot of zooming in, hitting 1:1 image magnification (if you have time), racking focus, then pulling back to the framing. Experienced eye focusers get used to picking up nuances of the framings as they change from tight to wider - things like increased softness as you widen out, which tip you off to the possible need to reset back focus. Its obviously much better to notice that at the start of the shooting session, than later on, and have to re-shoot material. Experienced sight focusers will usually spot back focus problems quickly.

The addition of 1:1 image magnification on RED One has really enhanced sight focusing with the camera.

From f4 to more stopped down apertures I really enjoy sight focusing RED One if it works for the workflow and the needs of the shots. As you know, sight focusing obviously becomes much more of a challenge at apertures of 2.8 or wider open, which limits sight focusing to relatively static shots, and shots where subjects are not frequently moving toward or away from the lens.

I guess there is a time and place for everything. Experienced shooters develop an uncanny sense of when to do what, and when not to do what - and when to shift gears and move on to another solution.

[Jarred Land]

I wonder when people that are really worried about this are gonna start using Invar in lenses... The expansion that happens with the metal in most lenses is just as big of an issue as thermal expansion that happens in the mounts. Specially with the bigger zooms, like the big Optimos. People forget about that part. It's why Canon makes their long zooms White.

I guess minimizing the tolerance stacking as much as possible helps though.. which is why, like Jim said, for those that really want it, we will make it :)

[Fredrik Callinggard]

and instead use Invar or at least Stainless ?

Stainless is the only way to go

[Fredrik Callinggard]

I wonder when people that are really worried about this are gonna start using Invar in lenses... The expansion that happens with the metal in most lenses is just as big of an issue as thermal expansion that happens in the mounts. Specially with the bigger zooms, like the big Optimos. People forget about that part. It's why Canon makes their long zooms White.

I guess minimizing the tolerance stacking as much as possible helps though.. which is why, like Jim said, for those that really want it, we will make it :)

Absolutely but RED is infamous by now and one of the points for naysayers so why not go for stainless? It's proven itself to work for years and years.

I would also appreciate if we don't have a self adjustable mount. It has proven itself to be nothing but trouble.

[Steve Gibby]

I would also appreciate if we don't have a self adjustable mount. It has proven itself to be nothing but trouble.

I completely disagree with that. I own several RED One cameras and I've had no problems whatsoever with the new adjustable mounts. The ability for us to adjust back focus ourselves was a major advancement

What has proven itself to be nothing but trouble is the "never satisfied" attitude of some posters here. No matter how many improvement RED has made to RED One, and the excellent proposals for the new cameras, there are some nitpickers who are never satisfied no matter what advancements RED makes.

If you want to go back to mounts that can only be adjusted by a technician and not by the owner or operator, then IMO you should seriously consider buying your cameras from another company.

[Jarred Land]

I'm with Gibby on this one...

The attitude is frustrating. Specially after Jim bends and offers up a solution in this very thread.. people still bitch bitch bitch...

[David Groundwater]

What has proven itself to be nothing but trouble is the "never satisfied" attitude of some posters here. No matter how many improvement RED has made to RED One, and the excellent proposals for the new cameras, there are some nitpickers who are never satisfied no matter what advancements RED makes.

If you want to go back to mounts that can only be adjusted by a technician and not by the owner or operator, then IMO you should seriously consider buying your cameras from another company.

Fair go Gibby.... I'm with Fredrik on this one.

I've seen top notch camera technicians and focus pullers really struggle to set back focus properly - mainly because of the way the focus changes as you tighten the mount.

We all are fans of the camera and want to see that future models are as good as they possibly can be. If we just accepted everything as being as good as it can be, then there would be no progress at all.

[Jorge Díaz-Amador]

I think some of you guys here need some perspective. RED does NOT , in a practical sense, need to make an Invar lens mount. Stainless steel, grade 303 or 416 will do just fine.

If RED can use a material that will control the thermal expansion of the lens mount to within +/- 0.01 mm for a +/- 17º C temperature change, I think that would be a very practical solution, and anything beyond that will be diminishing returns.

So if you calibrate the mount at 52.00 mm @ 20º C and it measures: 51.99 mm at 3º C and 52.01 mm at 37º C, you've got a very big temperature range to work with with no more than +/- 0.01 mm dimensional change.

The steel my gage blocks are made of has a thermal expansion of .0000115 mm per ºC per mm. A 52 mm gage block will expand 0.0006 mm (0.6 µm) per ºC. It takes a 17º C temperature change to for the block to expand 0.01 mm. Most steels are in a similar range.

Chromium Carbide gage blocks would reduce that expansion to 0.00045 mm at a huge increase in cost that I would never be able to recover since everyone will want their focus calibration for the lowest possible cost (or not be willing to pay at all).

Those steel blocks are the standards that my gages are calibrated to, which then calibrate the autocollimator, which then calibrates the test lens, then the test lens and the autocollimator calibrate the FFD of the camera (your RED ONE).

There is no point to making the lens mount on the camera more thermally stable than the tools that are being to used to calibrate the focus of that lens mount.

Especially since every lens that is used on the mount is going to be predominantly made out of aluminum and brass, and will expand way more than the lens mount...

A 52 mm Invar 36 gage block or PL mount expands 0.0000014 in/ºF = 0.000035 mm/ºF. Nice... but Invar is costly, not available from most metal suppliers, and very difficult to machine (wears out cutting tools rapidly).

I'm sure you get the idea... Aluminum mount for the weight conscious and Stainless for production work. Invar? Maybe for the lens projector.

I need to get back to work and actually make some money. Happy Holidays everyone... I'm outta here!

[Harry Clark]

Thanks Jim for considering to offer options.
For me, I'm with Jorge. Stainless has proven itself over time and would be a great option to have. Is it a done deal Jim/Jarred? Will we see that as an option in the store? Or simply contact our reps about getting a new mount?
I also agree with Gibby. The adjustability is a fantastic option over shims. I have actually been pretty lucky and have only had to do it once. It IS a bit tricky when tightening the set screws but way better than shims.
Really great to be a customer of a company that listens!
Anyway, happy holidays all...
Cheers,
Harry

[David Mullen ASC]

If you think professional people can't be just as nitpicky when talking about other companies' products, you'd be wrong. I've been to trade presentations and seen Sony or Kodak reps get grilled for not adding this or that feature, etc.

I can recall a Sony presentation on the in-development F23 over at the ASC clubhouse and boy did those engineers get a grilling. Some comments were useful, some were way offbase. Some were implemented and some were ignored, and some were saved for the F35 years later.

On the other hand, that's the sort of feedback that causes progress to be made. Imagine how useless it would be if all we ever did was thank or praise manufacturers with never one suggestion on what could be better? RED wouldn't even exist if there wasn't some dissatisfaction with other companies' products that they could capitalize on by doing better. And they won't survive if they don't in turn provide better and better products, and the only way that's going to happen is with customer feedback.

Yes, some of the feedback is contradictory because we all have different opinions and different needs, different tastes, which is why it is ultimately up to RED to figure what to implement and what to ignore.

The need or lack of need to be able to set back-focus oneself is a prime example -- one can make excellent arguments either way, so there is no right or wrong answer here. It has its strengths and weaknesses.

Filmmaking, for better or worse, is a job that attracts very focused individuals who are incredibly nitpicky, anal-retentive-types. It's even worse among camera assistants, DIT's, and engineers. Not all are like that, but a high percentage are.

So if you are open to customer feedback, as RED is, it's a bit of Pandora's Box being opened, or a floodgate -- it's hard to control. But don't think that cinematographers aren't as critical of the products of other companies; they are, and given half a chance, they will tell the company... just that the company doesn't give as much of an opportunity for that feedback as RED does. So either RED can embrace the chaos of this relentless feedback as positive, or they can shut the door to it, it's up to them... but the one thing that is hard to do is control the nature of people.

[Mitch Gross]

I'm with Jorge. Stainless Steel or Titanium all the way. Forget about Invar. I don't know anyone who uses it in this industry.

[Steve Gibby]

Fair go Gibby.... I'm with Fredrik on this one.

I've seen top notch camera technicians and focus pullers really struggle to set back focus properly - mainly because of the way the focus changes as you tighten the mount.

We all are fans of the camera and want to see that future models are as good as they possibly can be. If we just accepted everything as being as good as it can be, then there would be no progress at all.

I can just comment on our own experience with the multiple RED One cameras I own - and that is that the new adjustable mount has been rock solid on my cameras, and that the ability to adjust and re-set back focus if needed on location is a major plus in our workflow. For an affirmation of that from another highly experienced shooter, you need go no farther than David Mullen's post #42 on this thread, where only once in his experience with RED One cameras using the new mount did he experience a back focus problem. And what did he/they do to solve it? They went to the self adjusting back focus setup on the new mount, re-adjusted it, and had no further problems.

I use highly experienced camera technicians when I need them, but in doing so I know that there are progressive ones who want to acclimate themselves to emerging technology and procedures - and there are also a lot of them who have a "but we've always done it this other way" attitude.

So I know your background with RED camera, I'd like to ask you a few questions, with added insight into my experience with RED One:

How many RED One cameras do you own? (I own several)

How long have you been using them? (I've owned and extensively used my RED One cameras for over 16 months now)

How many different camera technicians have you used on the RED cameras you own or have used? (I rarely have to use camera technicians for simple things like setting back focus.)

Have you personally ever attempted to adjust the back focus on a RED camera equipped with the new RED mount? (Once set properly with the new mount, I check back focus regularly, and watch for any signs of drift in it, and I haven't had any problems whatsoever)

I'm leaving to go mobile right now and won't have internet access until late tonight at the earliest, but when I get a chance I'll re-visit this thread and review your added input.

Yes, input to RED is and has been critical to the development of the camera. I'm the wrong one to preach to about that. I've been giving extensive field experience input to RED since 2005 when the camera was announced. My style of doing that is different though. I generally send my input directly to RED via email or PM - the most direct and rapid way to have it analyzed, rather than feeling the need to parade my suggestions by the whole RED User board. Once I give RED my input I don't worry much if it is adopted or not. They have a company to run, and I'm sure there is a multitude of factors they have to weigh out in order to get a "yah" or "nah" to a suggestion.

[Jannard]

This is quite a dance we have going on here. We try to listen to everyone's opinion, take the ones we feel are valid and implement them if possible. That has lead to more and more "opinions" from our customers. Some opinions are completely valid and some are completely unreasonable. Some are great suggestions that just can't be done given current technology. Some are easy to do but completely counter-productive.

Sifting through all this stuff is exciting, frustrating, energizing and time-consuming. That is RED.

If we look back at where we were and compare to where we are, I think it is pretty unbelievable. The new modular program is our best solution to giving as many options, updates and upgrades as possible, along with flexibility to expand the system as we go along.

Thanks to all for the contributions. We are all learning here...

Jim

[Michael Lindsay]

...
I would also appreciate if we don't have a self adjustable mount. It has proven itself to be nothing but trouble.

Hi Freddy

Got to disagree... I believe there is only 2 problems (post 1 to 1 zoom) with self adjusting.

1) adjust to what? Not everyone has a 21mm MP (very telecentric) sitting in a box waiting to set mounts. If Red (or third party) can give us a PL device that we set to for less than £1000 there is every reason to keep self adjustment. This should be a piece of cake for somebody to make when you have guaranteed sales of over a 1000.

2) The actually locking of the backfocus is a little tricky. It tend to push it out a tad. You end up guessing the needed compensation. If this is improved I would be doubly delighted!

ADVANTAGES

Back focus can be used creatively.. I shot a whole programme with the backfoucus out. A number of shots couldn't have been achieved in any other way.

Not everyone is geographically and for business reasons connected to hire houses that can shim their mount. These people benefit from being able to do this themselves.

Emergency problems on a shoot where adjusting backfocus gets you a technical workaround.

For me the loss would simply be the loss of a creative option.. I hope this is not what Red needs to do!!

kind regards

Michael L

[Jeff Kilgroe]

Forget about Invar. I don't know anyone who uses it in this industry.

Panavision...

Anyway, I also agree that Invar should probably be left alone. I am with Jorge and everything he has said. I can attest to his point about lens behavior with temperature changes. I shot quite a bit in -15F/-26C cold last sunday. All of the marks on my Cooke zoom were way off, we couldn't measure focus, a total lost cause. In spite of that, the Cooke actually performed admirably. After a brief use of a 14mm Zeiss standard prime, all the Zeiss glass went back in the case. The cold had those lenses so tightened-up that I did not feel comfortable using them and risking damage. I'm sure the mount was off, due to the temperature, the last time back focus was check was the friday before at about 70F room temperature. But I know that the lens was the bigger culprit as it had become much tighter to operate and by how far some of the marks appeared to be off. We did not attempt to adjust the backfocus in the cold. Didn't see much point, if the lens marks were going to be off anyway. All the marks on the lens are spot-on again after returning the lens and the mount to indoor temps and checking them again yesterday.

What Hans said a few posts back about making sure the mount screws are all properly tightened is good advice. I had some focus shifting with my mount last summer in high temps. Or at least I think I did because it was real hot and I had backfocus issues. After re-collimating and making sure that not only the screws on the adjustment collar were tight, but the other mount screws as well, seems to have made all the difference. After the adjustment and screw check, I didn't have any further fluctuations and have not had any until my recent severe cold testing.

Not so sure about a titanium mount either, titanium can probably be left alone. Yes, it's strong and light weight compared to steel, but offers no thermal advantages over stainless and it would be more expensive. Titanium also does not hold up as well as stainless or 707x aluminum when it comes to scraping or galling or other effects that will wear a mount down over time. A stainless mount would be my first choice as it does have better thermal characteristics than aluminum and should theoretically be tougher over continuous wear and tear.

I can't comment about EPIC or Scarlet and their construction, having only seen renders and last year's NAB mock-ups. But with the current RED One, I don't see an invar mount offering any significant advantage. The entire body, front plate and mounting structures that hold the mount and sensor block, are all aluminum and vulnerable to thermal variations.

[Jannard]

We don't see any advantage to Invar in a lens mount as well... but we are kind of tired hearing that we need to do it. So, if our customers think they need it, we'll make them. It is easy to do, just expensive. My bet is that as soon as we make two of them, one will sit on the shelf and ultimately end up in the RED Museum. People ask for stuff here because "they have heard"... if we don't offer it, they continue to NEED it. As soon as it is available, they go silent. That is just human nature.

Jim

[Joel Kaye]

if we don't offer it, they continue to NEED it. As soon as it is available, they go silent. That is just human nature.

Free business advice they probably don't teach you at Harvard in that post.

[Brook Willard]

As far as I can tell, the "invar" obsession is as I posted earlier in this thread. When the RED ONE mount was being developed, somebody from RED posted that the mount would be invar. It eventually became aluminum and was notoriously unstable. The new mount was supposed to be stainless... but became aluminum and is less notorious but still somewhat unstable.

So when many of us thing "thermal stability," we think of "invar" because it was the metal behind the mythical thermally stable lens mount that never was. Ultimately we all aren't thermal engineers... but we sure know that aluminum doesn't quite seem to cut it. So if the word "invar" were replaced with "a thermally stable metal," I think the message behind this thread would probably be clearer. I bet that many of us wouldn't even have thought of invar as a good metal for lens mounts if we hadn't read it on REDuser [or DVXuser] that one day. :)

I suppose the same logic applies to the word "mount". If the mount were rock solid but the sensor block and front of the camera were thermally unstable... the mount is meaningless. The desire is more for a complete hardfront and sensor block made out of some sort of material that is more thermally stable than aluminum. If that material is stainless, awesome. If it's titanium or invar, perfect. If it's aerogel... that's cool too. Ultimately you have more lens building experience than most posters on these forums... and with our feedback in mind, I'm sure you'll find a stable solution for the mount.

As the end users, all we know is that the aluminum mount isn't quite cutting it. You guys have been cool enough to take that feedback... so the best we can do is sit back and wait... right?

Thanks for listening to the feedback. As much as we complain sometimes, we've sure never had to deal with the sensor flexing issues that the old D-20 did in the early days! :) Keep it up.

[Jay A. Kelley]

Jim, Jarred...
I FRIGGIN LOVE YOU GUYS (Don't take that wrong, I don't want to start picking out curtains or anything).

This thread, this one right here is what RED's all about.. And it's so damn fun and exciting to read and experience. Sure there are a couple of pissy people sometimes but what I see are a lot talented people from different parts of this industry speaking to the OWNER OF THE DAMN CAMERA COMPANY and each other about this and that lens mount. Customer feedback at it's best.

Rather than being an arrogant prick like so many other companys Jim says "Hey thanks for this, we're learning" and offers options for those that request it, not weeks or months later, but minutes. Even though you can tell he really doesn't agree with some of what's said his take is "you guys are the customers, and if it's that important to you, we'll get it done".

I really mean it.. This is special. I hope I'm not the only one that sees it.

As for my opinion on the type of lens mount... I have no idea, I'm not knowlegeable about this stuff, but I will keep reading and learn what I can, then depend on Jim to put a mount on Epic/Scarlet that does not cause me trouble later! :)

Jay

[Jens Jakob Thorsen]

Steel it is then? Please!...It has been used for decades and it works! I have had Backfocus issues and I would pay a "little" for anything that works....

[Deanan]

It eventually became aluminum and was notoriously unstable.

You get a very different picture when you dig into every customer issue versus what you hear around town. Almost all of the mount issues from the early days were because of mounts that weren't tightened or set properly. The adjustable mount made it alot easier to do both so there was less room for error.

Even the mounts as early CHE stayed solid through month of shooting and going from an AC'd camera truck to very hot ambient temps and direct sunlight.

"notorious" in no way implies factually correct. :)

[Michael Ragen]

true true. its quite frustrating going on shoots and suddenly all the nasty red rumors start flying around, or one guy on the shoot had a bad experience because someone fucked up and blames it on the camera.

haven't experienced any mount shifts yet, but i only took my camera into the snow for the second time today, and it was only around 30. but i'll still take whatever provides the most stability.

[Matt Uhry]

Yes it's true that lenses will change focus with ambient temp. but the camera has a built in heater in it - the processor. The problems I've experienced have had minimal external temp. swings, like shooting on a stage in El Segundo, during a summer day.

I'd accept some variances a shoot day included a frozen lake and a out of control sauna, but if it's going out of whack on a soundstage just while the camera warms up...

I've picked the brain of my material sciences Phd. brother in law - this is the amount of shift you can expect with the linear expansion of a 52mm piece of aluminum, if you calibrate the 52mm at "room temp" 25 deg C. It's enough of a shift to cause the problems I've been having. Depending on how the sensor is attached to the shell of the body the 52mm distance may be more or less.

Linear thermal expansion / contraction of 52mm of Aluminum:
5 Deg C 51.975
15 Deg C 51.988
25 Deg C 52.000 mm
30 Deg C 52.006
35 Deg C 52.012
45 Deg C 52.024

Using stainless parts to link the sensor plane to the sub mount ( the part we attach the user mount to ) should cut these #'s more or less in half which would probably be good enough for most people including me most of the time. Stainless mounts ( the PL part ) would be the cherry on top.

Matt Uhry
www.mattuhry.com

[Neil Duffy]

This is an excellent thread. Everyone is giving really knowledgeable feedback. This looks like a tricky issue, with the body being aluminum and the mount potentially being another material that has a higher price point. But everyone seems to be helping find a solution.

Very promising for RED's future.

[Brook Willard]

You get a very different picture when you dig into every customer issue versus what you hear around town. Almost all of the mount issues from the early days were because of mounts that weren't tightened or set properly. The adjustable mount made it alot easier to do both so there was less room for error.

Even the mounts as early CHE stayed solid through month of shooting and going from an AC'd camera truck to very hot ambient temps and direct sunlight.

"notorious" in no way implies factually correct. :)

You know, I'm actually glad to hear you say that. While I found the mount difficult in its factory calibration [throat too narrow, up to a dozen shims in the mount, sticky collar, loose screws, etc.], once the mount was milled out and collimated by Clairmont... it stuck as long as we had the mount. While it did shift in a similar manner to the current mount, it didn't explode and fall off like it did out of the box. I remember having Sam Druckerman's camera collimated at Clairmont before the first trip to Dubai... and it was SPOT on until the day he sent it back to get his X body. I've praised the general design of the mount multiple times on the forums... it was the factory collimation, tolerances and material [aluminum is what it is...] that weren't "up to snuff". :wink:

My choice of "notorious" was more relating to the reputation that the mount quickly gained across the industry in those first weeks and months. There were enough shoots and tests that were botched to make the concerns very real... back then. While those rather antiquated concerns certainly have vanished from that absurd oh-no-I-hear-the-RED-kills-your-shoot manner, there are still those little points that I'd love to see fine tuned.

Those points were originally squaring the mount to the sensor, centering the sensor and dealing with the thermal instability. The first two are guaranteed to be fixed by the inherent design of the new lens mount. I believe that this discussion and the work that you guys have no doubt been doing behind closed doors will lead to the third point being solved. :)

[Brent J. Craig]

We won't be happy until the entire camera is made out of unobtainium with mysterium accents.

:-)

[Dale Launer]

Stainless is the only way to go

Why is that? When Invar and titanium expand/contract less than stainless steel?

[Jannard]

Everyone seems to have an opinion on this topic. Why not make them all and let the customer have their choice?

Jim

[Matt Uhry]

Everyone seems to have an opinion on this topic. Why not make them all and let the customer have their choice?

Jim

It's not the mount itself but the material between the sensor plane and the part you bolt the mount to... Bolting 12mm of Invar or Stainless PL ring to 40mm of aluminum camera body is not going to fix the problem. *

I'm totally in for a Stainless PL mount for the gains in strength, stability and stickiness.

Matt Uhry
www.mattuhry.com

* I don't know the Epic's internals, but it looks like the user changeable front mount plates bolts onto the external body. Using a sub-mount that connects to the sensor plane to the front attach points would be one way to solve this. Imagine a squarish table with a rectangular hole cut in the center. That part would be made of something that is reasonably thermally stable.

[chuck colburn]

The advantage a video camera has over a film camera so far as error in the viewing system goes is, that the film plane is the ground glass. Now I know that in itself has it's own inherent problems but at least one does not have to worry if the flange focale depth is the same as the ground glass depth and vicea versa. I believe if the sensor and lens mount be it interchangable or not are mounted in a common machined block of whatever metal you will maintain a flange focale depth at least as accuret as what the lens is capable of. I also think that the lens seat and locking ring on the camera should be stainless even if the rest of the lens mount/sensor mount assembly is aluminum.
Just my two cents...

Another couple of reasons for having an "optical block" type of assembly are that it allows one to align the bore of the lens mount to the center of the aperture and garuntees parallelism of the lens seat to the film plane.

[chuck colburn]

as i understand epic and scarlet (like red one) will not have a hardfront. so even if the plate (with the 4 screws) plus the PL mount is made of invar, the body (made from aluminum) will still expand.

image of a hardfront (invar) where the PL or nikon mount is seated - not connected to the front housing made of aluminum

http://img88.imageshack.us/img88/6070/hardfrontxs2.jpg

Is that the new Aaton 35 camera?

[Jannard]

You know... it is an absolute miracle that anyone is getting good images out of a RED ONE. Really. If you look at it, it just doesn't make any sense. The whole body should technically be Invar, including the mount. Anything else just... well, sucks! If I do the math, the RED ONE, along with every other camera just can't make good images. The laws of science prohibit it.

I'm with you guys. Make an option where everything just can't move one iota. Then we would all be happy and be able to shoot feature films again instead of just fooling around with this other crap.

How many vote for an all Invar camera body and mount? Too heavy and much $$$? How about an all stainless steel body and mount? We are all in. Just tell us what you want and put up your deposit.

Jim

[Jannard]

We will make an optional Invar front body plate (integral with the sensor mount) and lens mount. We will also make an optional stainless steel front plate and lens mount option. Obviously they both will cost more money. But it now puts this thread to rest.

Oh, and you want a titanium set instead? No problem. We'll do that too. We aim to please. God loves a modular system.

Jim

[Fredrik Callinggard]

I here you Jim it's frustrating hearing all this voices, but no one is complaining about the image of RED One. Well, except for now and then :) , but mostly not.

See all this as us trying to be constructive not complaining. After all your learning and so are we. The mount as it is now is functional but it's definitely not perfect. The amount of times I've been standing swearing on set when backfocus been an issue are plenty.

At those times I've not immediately been able to say if it's the lens, the camera or the temperature.

So all we're trying to put in our suggestions in how to make it better. Letting us all sleep better at night, except for you guys who has to put in overtime back at the shop :w00t:

I for example suggested stainless steel, because it's the cheapest that has proven itself to work. Although that is with film and it's more forgiving.

Depending on price I wouldn't be against for example invar.

No ones asking for the whole body to be in invar but BTW didn't you promise that Epic is an all titanium body :innocent:

and as a last word I want to say... that don't think we appreciate your hard work and your crazy idea about a camera for everybody. We just want to chime in so we can pretend we're a part of it.

[Jarred Land]

We will make an optional Invar front body plate (integral with the sensor mount) and lens mount. We will also make an optional stainless steel front plate and lens mount option. Obviously they both will cost more money. But it now puts this thread to rest.
Jim

and with that.. lets close this one down :)