Collimation on RED ONE

[Emanuel A.]

Actually, I'm not the right person to ask this. Although I'd say that Stephen is the right person to answer on this.

I've been in touch with a very cool person from the industry in hollywood. He has worked with names like Spielberg, etc. I just won't disclose his name here though I can tell you he's the most well knowledgeable person that I could know on these days. Same level than our Stephen.

And he asked me a relevant question:

How would I collimate using a digital sensor camera since it's not the same than a film capture device?

[Kevin Halverson]

I guess I don't really understand your concern. Setting back focus is a common task and really not difficult at all. In the case of the RED, it might be based upon shims, or it might be a bit easier, I don't know that these details have been released yet. I am confident that they have designed a scheme that won't be excessively complicated.

[Brook Willard]

It could just be that this person isn't 100% sure of how the sensor works. People who are used to 3CCD cameras often don't realize that a Bayer sensor can be effectively treated just like a film camera with regards to collimation. The PL-mount flange focal distance is 52.00mm... just collimate like you would with a film camera. No magic 3CCD trickery required.

That said, I'm sure the cameras will be collimated from the factory.

[Emanuel A.]

Thanks for the answers. As I said, I'm not the best man for this doubt. Actually, I've suggested to him in order to put both (plus Stephen) in touch. My concern is regarding to the changing mounts. I can't invest on the Birger's mount, for example, if I haven't a back guarantee about avoiding future problems on field.

As I said, this person is very knowledgeable about every issues on the motion picture technologies related. I have learnt a lot with him and he has been very helpful in order to give me some lights on my glass purchases.

I couldn't imagine the secrets beyond the PL compatibility as far as the PL mount adapters is concerned. BE CAREFUL with this! NOT ALL the lenses are compatible with a PL mount. No matters if you have or not the right PL mount adapter to the job...

I believe this question is so valid that this thread is open. As matter of fact, I invited him to our forum. This would be a great resource for this community. I hope he may accept it. We wait and see.

Other thoughts?

[Emanuel A.]

Here's morning. I could check my email and had got mail sent six hours ago from the same person. Very nice and friendly human being. I'd add, already a friend. I had asked him his input in order to proceed with my inquiry.

Here goes his question:

«HI Emanuel, the question I have is, how do you use the auto collimator on the Red One Camera? When you use an Auto Collimator with a film camera the procedure is generally as follows:



1) A precision first surface mirror is fit onto the film camera so that its mirrored surface is resting flush and flat on the side rails that the film emulsion would ride on when the film is being exposed in the camera.

2) A taking lens is fit on the lens mount of the film camera, the focus ring on the lens is set to infinity, the iris ring is set in the full open position and the camera shutter is moved so that it is not in the light path between the lens and the film plain.

3) The auto collimator is placed in front of the taking lens so that the reticule image that the collimator generates is projected through the taking lens and is then reflected off the first surface mirror that was installed in the camera aperture and back into the collimator.

4) If the lens is calibrated correctly at infinity, and the cameras flange focal depth (the distance from the lens mounting surface to the film plain) is correct, the collimator reticule image should be sharp when seen through the collimators eye piece.

5) See attached sketch.

http://img337.imageshack.us/img337/273/untitled2mi0.jpg (http://imageshack.us)



This test tells you three possible things.



1) All is adjusted correctly.

2) The lens needs adjusting.

3) The flange focal depth is incorrect.



So my question on the Red One camera is how you put a precision reflective surface at the image sensor position in order to check the collimation. Can you put a first surface mirror in the image sensors position? Is the front surface of the sensor flat enough and reflective enough to reflect the collimators reticule image back to the collimator? Are there any optical surfaces between the lens mount and the image sensor that would interfere with the collimation of the optical system? I’m sure someone will have the answer to my question.



Best Regards,

RB»

[Stephen Williams]

Hi Emmanuel,

I asked the same question in October 2006.
http://www.cinematography.com/forum2004/index.php?showtopic=17540

Stephen

[Mr. Paul White]

Alright but what's the conclusion?

[Kevin Halverson]

Again, I still don't see the concern. There is no practical difference if you use an optical device to set the FFD, or any other method, as long as the method results in a correct distance between the rear element and the sensor surface. That is all that is being adjusted and more importantly, all that matters.

[Don King]

??

Sorry, this is very confusing. Two professionals with film background are doing the same question so...

On the other hand, Mr. Williams has been very proactive about collimation so he should have had any conclusion or am I missing something there too?

[Stephen Williams]

Again, I still don't see the concern. There is no practical difference if you use an optical device to set the FFD, or any other method, as long as the method results in a correct distance between the rear element and the sensor surface. That is all that is being adjusted and more importantly, all that matters.

Hi,

The only question is will it work with a Red one? I haven't myself had a chance to test it so......

Stephen

[Kevin Halverson]

Hi,

The only question is will it work with a Red one? I haven't myself had a chance to test it so......

Stephen

Will what "work"?

Are you asking about using an optical collimator or a depth gage?

The reflective properties of the imager surface should result in an 'OK' image for optical collimation, but since no one has had access to a RED One, we can't be certain. Using a depth gage might result in a correct distance, but it seems that you really risk damaging the imager, so I don't "think" this would be a good approach.

I can think of a number of other approaches that would be fine too. One might be a situation where you have a lens that is known to be correct, then it could be used to confirm the flange to imager distance by comparison to a know correctly setup camera. Verification of the focus distance against a know correct lens is another valid approach. Really, there are a number of ways to accomplish the task.

What matters is getting the distance correct, anything that results in that goal should be just fine.

[Stephen Williams]

??

Sorry, this is very confusing. Two professionals with film background are doing the same question so...

On the other hand, Mr. Williams has been very proactive about collimation so he should have had any conclusion or am I missing something there too?

Hi,

Does any body know how Panavision Collimates the Genesis?

A collimator will provide an image at infinity, by enlarging the output of a Red one can see if a lens set at infinity is in correct focus, however how do you calculate how many microns to adjust if it not, experience will put you in the ballpark. An autocollimator allows you to look back through the lens onto the film plane seeing the image from the collimator, the 'auto' part may or may not help, until somebody tries with a Red One we are guessing!

Stephen

[Stephen Williams]

Will what "work"?

Are you asking about using an optical collimator or a depth gage?

The reflective properties of the imager surface should result in an 'OK' image for optical collimation,

What matters is getting the distance correct, anything that results in that goal should be just fine.

Hi,

Is the 'OK' image that you see in the right place, or could it be wrong by a few microns? I think you can forget a depth gauge!

Stephen

[Kevin Halverson]

Hi,

Is the 'OK' image that you see in the right place, or could it be wrong by a few microns? I think you can forget a depth gauge!

Stephen


If you think about it, a front surface mirror doesn't precisely emulate the properties of pan chromatic film by much more than a few microns! All these methods only get "close" in reality. How close is close enough is really a bit subjective.

I do fully agree, I ain't letting anyone with a depth gage anywhere near one of these cameras!

[Dexter Gregoire]

What he's talking about is the Collimation do not lend themselves to exact theoretical understanding, because they are composed of many flange focal depths but but are not large enough to be accurately described as dynamic. They are held together by strong interactions like the lens, sensor, etc... and are on the order of 1 % of their relativistic rest with errors usually smaller than those from other approximations.:clown2:

The conclusion, being in focus is very important and I believe the REDONE being like a digital DSLR has it's own way of telling you that you are in focus.

The REDONE is proving itself and I'm sure the Birger mount will do the same-(fingers crossed).

[Stephen Williams]

If you think about it, a front surface mirror doesn't precisely emulate the properties of pan chromatic film by much more than a few microns! All these methods only get "close" in reality. How close is close enough is really a bit subjective.



Hi,

When using a autocollimator with a film camera, I don't use a mirror, I use film and have the camera running. That gives me more information than a static image, also the changes that occur when the camera runs at different speeds .

Stephen

[Stephen Williams]

What he's talking about is the Collimation do not lend themselves to exact theoretical understanding, because they are composed of many flange focal depths but but are not large enough to be accurately described as dynamic. They are held together by strong interactions like the lens, sensor, etc... and are on the order of 1 % of their relativistic rest with errors usually smaller than those from other approximations.:clown2:

The conclusion, being in focus is very important and I believe the REDONE being like a digital DSLR has it's own way of telling you that you are in focus.

The REDONE is proving itself and I'm sure the Birger mount will do the same-(fingers crossed).

Hi,

Having an image focused at infinity is useful to check lenses. Focus pullers have to use the marks on lenses, by the time you see the image is soft on monitor it's too late!

Stephen

[Kevin Halverson]

Hi,

When using a autocollimator with a film camera, I don't use a mirror, I use film and have the camera running. That gives me more information than a static image, also the changes that occur when the camera runs at different speeds .

Stephen

Even this approach is still subjective and only very "close" as the image that you see is from the boundary between the anti-halation layer and the emulsion layer's and is therefore not "exactly" representative. Also consider the effect of different wavelength of light.

At some point in time, we are getting down to point where the ability to "observe" a process without influencing it in some, unintended way, becomes a factor. Luckily, this point is beyond what we need to achieve for good results.

[Stephen Williams]

Even this approach is still subjective and only very "close" as the image that you see is from the boundary between the anti-halation layer and the emulsion layer's and is therefore not "exactly" representative. Also consider the effect of different wavelength of light.



Hi,

Thats why one normally uses a depth gauge to measure the FDD, & put lenses on a collimator. Using just an autocollimator is not accurate enough as several errors could cancel out each other. Quite what effect this will have when changing Red lens mounts in a hotel room or worse on location remains to be seen!

Stephen

[Kevin Halverson]

Hi,

Thats why one normally uses a depth gauge to measure the FDD, & put lenses on a collimator. Using just an autocollimator is not accurate enough as several errors could cancel out each other. Quite what effect this will have when changing Red lens mounts in a hotel room or worse on location remains to be seen!

Stephen


I couldn't agree more.

Really, unless we are talking about PL mount glass, I don't think this applies. Individuals that try to use still camera mount versions can't expect repeatability (lens to lens) that justifies this level of concern. Even with just one of these types of lenses I doubt you could mount and then remount it twice and achieve the same results. Again, its all speculation until we see what provisions RED has made for this.

[Stephen Williams]

I couldn't agree more.

Really, unless we are talking about PL mount glass, I don't think this applies. Individuals that try to use still camera mount versions can't expect repeatability (lens to lens) that justifies this level of concern. Even with just one of these types of lenses I doubt you could mount and then remount it twice and achieve the same results. Again, its all speculation until we see what provisions RED has made for this.

Hi,

I have used Nikon lenses on motion control (with bellows focusing) & the lenses can be remounted & focus remains perfect. However the mount must be made very 'tight'.

Stephen

[Matt Uhry]

Really, unless we are talking about PL mount glass, I don't think this applies. Individuals that try to use still camera mount versions can't expect repeatability (lens to lens) that justifies this level of concern. Even with just one of these types of lenses I doubt you could mount and then remount it twice and achieve the same results.

True !

I did a quick test on my Nikon DSLR with my autocollimator and it's much harder to get a good image on a sensor than it is on a piece of film. The low pass filter gives a stronger return than the sensor, and the sensor is not as reflective as a piece of film. You can see a faint grid like pattern on the sensor but the collimator target does not resolve very well.

Obviously anything involving a depth gauge is a bad idea and wouldn't work anyway.

I think the best use of it is more like the way the zeiss sharpmax is used. That is as a target that gives a reliable infinity that you verify from a hi-res monitor.

Matt Uhry
www.mattuhry.com

[Kevin Halverson]

I have used Nikon lenses on motion control (with bellows focusing) & the lenses can be remounted & focus remains perfect. However the mount must be made very 'tight'.

"perfect"? Unlikely.

Good enough not to be noticeable? That seems much more possible.

I am curious, how did you achieve the "tight" mount?

[Stephen Williams]

"perfect"? Unlikely.

Good enough not to be noticeable? That seems much more possible.

I am curious, how did you achieve the "tight" mount?

Hi,

Good enough to be repeatable, tape the lenses at infinity measure the focus distance, put distance in computer & shoot. Works wide open! However as Nikon lenses are not accurately collimated infinity has to be set on the bellows focus the first time the lens is used. Focus is determined from just the infinity focus & lens focal length.

I made the base of the Nikon mount thicker than normal, so it's tight!

Stephen

[Evin Grant]

I think the best use of it is more like the way the zeiss sharpmax is used. That is as a target that gives a reliable infinity that you verify from a hi-res monitor.

Matt Uhry
www.mattuhry.com

I think this is the best approach, Matt do you know how the Sharpmax achieves infinity, could this be duplicated on the cheap?

This is basically the same product, no?
http://www.schneideroptics.com/ecommerce/CatalogItemDetail.aspx?CID=1098&IID=1069
Schneider/Century HD Collimator
http://www.schneideroptics.com/Ecommerce/site/images/Photo2/0HD-C150-00.jpg

[Stephen Williams]

Hi Evin,

Cheap Collimator's have been built, there was a camera engineering selling them on Ebay for $180 but he retired.

http://www.trioptics.com/test_equipment/collimators/description.php

Explains how it works.

Stephen


I think this is the best approach, Matt do you know how the Sharpmax achieves infinity, could this be duplicated on the cheap?

This is basically the same product, no?
http://www.schneideroptics.com/ecommerce/CatalogItemDetail.aspx?CID=1098&IID=1069
Schneider/Century HD Collimator
http://www.schneideroptics.com/Ecommerce/site/images/Photo2/0HD-C150-00.jpg

[John Fairstein]

With film cameras, the mirror at the film plane is needed for collimation because film doesn't generate an image in real time. But the digital sensor delivers an image in real time. So could we simply project the image of the reticle at infinity onto the sensor, and use a high quality monitor to show the image off the sensor to make back focus adjustments. Alternately, for those of us without a collimator, could we simply point the camera at an object at infinity, and using a high quality monitor, make the back focus adjustments? A suitable object at infinity might be a distant stand of bare trees -- objects with complex detail and good contrast.

[Evin Grant]

That's what the Sharpmax and Century HD Collimator allow you to do. The monitor is not the problem, getting a reliable test target at infinity is.

[Mr. Paul White]

Now that's my turn to say that I am who is confused.

[Don King]

Ditto.

[Emanuel A.]

Could a bargain tip on this newly released laser collimator help?

http://www.olivonoptics.com/ProductImages/OLC01.jpg

http://www.olivonoptics.com/index.asp?PageAction=VIEWPROD&ProdID=93

[Evin Grant]

Doubt it, the laser would reflect off the Low Pass filter instead of the sensor.

I see why some of you are confused...
With any HD or D-cinema camera you have the option of viewing the image from the sensor, with Red you could use the (1080P HD-SDI out and probably be OK). The trick is geting the lens to focus on a point that is at infinity and high enough contrast and sharpness to reliably judge the plane of focus, and determine if the mount is poperly aligned. The Sharpmax/HD Collimator uses optics and a test target to achieve this.

[Shawn Nelson]

Ouch! I'd hate to have to also buy a $3500 Collimator, but a few hundred I could swallow easily.

Evin, I like where you're going with using the 1080p HD-SDI out for collimation assistance. What sort of low-cost tool could be used in conjunction with that?

[Don King]

Yes, between $3,500.00 and EUR 6,250.00...

http://www.filmfoto.info/forums/viewtopic.php?p=45

I doubt that there will be so many Red One customers changing mounts to PL lenses from their own B4 or SLR glass. If there will not be a reasonable solution for this, there will be less people trading new glass.

[Evin Grant]

Ouch! I'd hate to have to also buy a $3500 Collimator, but a few hundred I could swallow easily.

Evin, I like where you're going with using the 1080p HD-SDI out for collimation assistance. What sort of low-cost tool could be used in conjunction with that?

Not sure there is one yet. Sound like a job for Red or Curt. What kind of optics are needed to create infinity focus on a small target?

[Matt Uhry]

Don't shoot lasers at your sensor !

Nothing inherently expensive about a collimator. It's a light source, a reticle, and a long focal length lens permanently focused at infinity. you probably could score all the parts for a few hundred bucks. a useful reticle is probably the hardest thing to find on the cheap.


Matt Uhry
www.mattuhry.com

[Evin Grant]

Yea but if the sensor isn't a very good reflector what good does it do? Could you adjust it for the height of the OLPF?

[Don King]

Nothing inherently expensive about a collimator. It's a light source, a reticle, and a long focal length lens permanently focused at infinity. you probably could score all the parts for a few hundred bucks. a useful reticle is probably the hardest thing to find on the cheap.Okay but how much would it be? Who could it provide? People like you for example? Or Mr. Grant?

[Matt Uhry]

Hey Evin,
I'm talking about a sharpmax like device - no eyepiece or beamsplitter.

Hey Don,
I'm having a lot of fun being a D.P. Hacking optics is a hobby, sometimes there are useful results. I'm probably not going to get into making and selling equipment. If I come up with a good design, I'll probably share it with you.

Matt Uhry
www.mattuhry

[Shawn Nelson]

I want to be able to switch mounts from the Birger EF to the Red PL quite freely. Not necessarily on the same project, but from day to day I'd like to make a decision without worrying about screwing everything up.

[Stephen Williams]

I want to be able to switch mounts from the Birger EF to the Red PL quite freely. Not necessarily on the same project, but from day to day I'd like to make a decision without worrying about screwing everything up.

Hi Shawn,

Buy your local camera tech a drink, it will be the cheapest route IMHO.

Stephen

[John Fairstein]

That's what the Sharpmax and Century HD Collimator allow you to do. The monitor is not the problem, getting a reliable test target at infinity is.

But isn't a real life subject with detail and contrast at >1000 feet a "reliable test target at infinity?

[Stephen Williams]

But isn't a real life subject with detail and contrast at >1000 feet a "reliable test target at infinity?

Hi,

Stars are better!

Stephen

[Mr. Paul White]

Hi Shawn,

Buy your local camera tech a drink, it will be the cheapest route IMHO.

Stephen

I do not understand.

If there's no solution or only tough ones, how could it be easy for a local camera tech? Yet, where are they, being Red and all this new digital cinema camera thing, an entirely new product?

[Stephen Williams]

I do not understand.

If there's no solution or only tough ones, how could it be easy for a local camera tech? Yet, where are they, being Red and all this new digital cinema camera thing, an entirely new product?

Hi,

Camera tech's have the necessary skill's to collimate camera mounts & lenses, most people don't.

Stephen

[Stephen Williams]

Hi,

If you can't find a friendly lens tech the following formula will help assuming the lens is correctly collimated:-

(d = f squared divided by a-f ) will give you the distance the lens is out of the mount when the lens is focused at infinity. d = displacement of lens out of mount at infinity. f = focal length of lens. a = distance of sharp focused object. You can use inches or metric measures. Note, d = 0 when a = infinity. Example: for a 50 mm lens (2 inch) set to infinity but is focusing at 10 feet. 2" squared/ 10x12"-2 =4/120"-2"=4/118"=.034" so the lens mount is .034" too far out of the mount. Shorten the mount by .034". Better yet, try .030 and check again.

Stephen

[Mr. Paul White]

Are you a camera technician, Mr. Williams?

I just cannot understand why so much doubts around this subject on Red and a digital sensor. And suddenly, everything is easy if you go to a local camera technician... Where are they?

[Stephen Williams]

Are you a camera technician, Mr. Williams?

I just cannot understand why so much doubts around this subject on Red and a digital sensor. And suddenly, everything is easy if you go to a local camera technician... Where are they?

Hi,

I am a DOP, I have changed mounts myself but would only do so it if the tech was too busy, I would however use his tools in his workshop!

Every rental house will have a tech, who as part of his job has checked every camera & lens before each rental every day since he started working there.

Changing lenses & mounts on motion pictures cameras is nothing new, the technology improved upto the Mitchell BNCR mount which is the strongest mount ever made, Panavision mount is similar.

Stephen

[Michael Brennan]

As mentioned in the discussion about ND and filter wheels, a Toshiba 3 chip industrial camera had user variable sensor position adjusted with a low greared screw arrangement.
When introduced this was one of the first c mount 1/2 inch camera with 3 ccd and back focus compatability with wide angle lenses was an issue due to physical proximity of sensor/IR filter to rear lens elements.

They figured that being able to adjust backfocus on the sensor would ease the pain of using c mount zoom lenses that lacked a backfocus adjustment

In theory this concept would work with large sensors and consign shimming to the history books.



Mike Brennan

[Roberto B]

Every rental house will have a tech, who as part of his job has checked every camera & lens before each rental every day since he started working there.

Stephen

your only fault.. or maybe not.. you didn't understand yet that red is a new concept.. completely new.. where the democratization is a fact.. not only a dream in your hands..

most of the red customers don't rent.. didn't you remember?..

http://www.reduser.net/forum/showthread.php?t=2767

93.10% against 6.90%.. you can ever change your vote stephen.. otherwise, you'll be in minority.. each day you'll be far away..










http://clicksmilies.com/s1106/spezial/misterX/X_caught!.GIF

[Stephen Williams]

Hi,

Just because you own something does not mean that it will require no maintenance.

If you don't like the idea of 'renting' a camera tech as required, you may have to employ one full time as in most of the world owning people is illegal.

Stephen


your only fault.. or maybe not.. you didn't understand yet that red is a new concept.. completely new.. where the democratization is a fact.. not only a dream in your hands..

most of the red customers don't rent.. didn't you remember?..

http://www.reduser.net/forum/showthread.php?t=2767

93.10% against 6.90%.. you can ever change your vote stephen.. otherwise, you'll be in minority.. each day you'll be far away..







http://clicksmilies.com/s1106/spezial/misterX/X_caught!.GIF

[Roberto B]

ah ah ah.. you amuse us.. your world is changing stephen.. you should move yourself for hollywood.. there maybe you'll have place for your fees.. or maybe you can change your skills on a new job.. camera tech.. why not?

so try to guarantee we'll all need your beloved collimation..

maybe you'll convince jim on this..

if he wouldn't lose new sales on his lenses.. our warranty.. ehehehehe

[chuck colburn]

Could a bargain tip on this newly released laser collimator help?

http://www.olivonoptics.com/ProductImages/OLC01.jpg

http://www.olivonoptics.com/index.asp?PageAction=VIEWPROD&ProdID=93

That device is used to align the primary mirror to the secondary one in reflective telescopes. It has nothing to do with providing an infinity focus source of light. Mr. Grants response describes what an optical autocollimator is.

[Mr. Paul White]

Thus, do you have any affordable idea?

[chuck colburn]

http://www.chamblesscineequip.com/catalog/Richter%20102.htm

http://www.reduser.net/forum/private.php?do=showpm&pmid=9344

[Michael Hastings]

Hi,

If you can't find a friendly lens tech the following formula will help assuming the lens is correctly collimated:-

Stephen

Stephen, I don't know what ***'s (user ID redacted) problem is - one of the first things I will do when I get my RED #206 is get to know the tech at my local rental house better. I will own my RED, but will need experienced people to help me get the most of it. Further, I'm hoping my local rental house will subrent my RED to their clients for me. Not to mention I will look to them as a source for cine lenses, and any other support my soon to come feature producers will need. In other words, as primarily a video guy in the past, I've never spent much with them before, but as I use my RED to move into the cine realm as well, I see a much closer relationship. If some RED owners see their RED purchase as a way to put their local rental house out of business, instead of making them a partner in their future, I think they are fools.

On to another subject. I am working on underwater housings for RED. I was wondering about using shims instead of diopters to refocus the lens range to compensate for the dome refocusing. A dome acts as a negative diopter when it contacts water, infinity is at 3 times the radius of the dome, so the standard 6" dome puts infinity at 9" in front of the dome (or 12" in front of the lens since it sits at the nodal point of the dome.

Can I use your formula to get the thickness of the shim I would need? In other words for a 10mm lens:

10mm/25.4= 0.3937007874 or .4" Focal length in inches

.4" / 1ftx12" -2 = .4/10 = .040" thick shim?

and since we are actually planning to use a Canon EF-s 10-22mm zoom it changes when we zoom (i.e. .087" @ 22mm)? So if we are planning to use the zoom we need to pick a compromise position not perfect for any of them or go back to the diopter?

Question? Does someone sell a variety of shims or do we need to make our own. (this is more a question for regular shimming for the RED, I would probably have to make my own for the underwater use.)

How are pl mounts normally adjusted? Do they use shims, or is there an adjustment mechanism? Do we know the method of adjustment for RED? Sensor adjustment seems ideal but is that it?

Thanks for all your input.

[Stephen Williams]

On to another subject. I am working on underwater housings for RED. I was wondering about using shims instead of diopters to refocus the lens range to compensate for the dome refocusing. A dome acts as a negative diopter when it contacts water, infinity is at 3 times the radius of the dome, so the standard 6" dome puts infinity at 9" in front of the dome (or 12" in front of the lens since it sits at the nodal point of the dome.

Can I use your formula to get the thickness of the shim I would need? In other words for a 10mm lens:

10mm/25.4= 0.3937007874 or .4" Focal length in inches

.4" / 1ftx12" -2 = .4/10 = .040" thick shim?

and since we are actually planning to use a Canon EF-s 10-22mm zoom it changes when we zoom (i.e. .087" @ 22mm)? So if we are planning to use the zoom we need to pick a compromise position not perfect for any of them or go back to the diopter?

Question? Does someone sell a variety of shims or do we need to make our own. (this is more a question for regular shimming for the RED, I would probably have to make my own for the underwater use.)

How are pl mounts normally adjusted? Do they use shims, or is there an adjustment mechanism? Do we know the method of adjustment for RED? Sensor adjustment seems ideal but is that it?

Thanks for all your input.

Hi,

I would test that shimming idea with an old Nikon still camera.

Shims are sold, I have some from a motion control gearbox project that are fine used for cameras. PL mounts have shims behind the mount. In theory you could shim a Red behind the mount or where the mounting plate joins the camera. For mount swappers without tools behind the mount makes more sense, but behind the mounting plate would be quicker if something was not flat.

Having a good relationship with a rental house can save you a fortune, they don't bill you for small items & let you have equipment free for tests & pitches.

Stephen

[martinnoweck]

Thus, do you have any affordable idea?

thanks to chuck i am working on a solution and will post the results.

martin

[Stephen Williams]

Hi,

I just did a search for shims, mrshims.com can provide what you need, hopefully custom cut ones will be available from Red?

http://www.solarstop.net/mrshims/shims.asp

Stephen

[Mr. Paul White]

http://www.reduser.net/forum/private.php?do=showpm&pmid=9344

I'm sorry but the link doesn't work at all!

[Emanuel A.]

http://www.chamblesscineequip.com/catalog/Richter%20102.htm

http://www.reduser.net/forum/private.php?do=showpm&pmid=9344

You surely couldn't guess but this link was precisely that one which originated this thread...

Here's the taking off:


Here's morning. I could check my email and had got mail sent six hours ago from the same person. Very nice and friendly human being. I'd add, already a friend. I had asked him his input in order to proceed with my inquiry.

Here goes his question:

«HI Emanuel, the question I have is, how do you use the auto collimator on the Red One Camera? When you use an Auto Collimator with a film camera the procedure is generally as follows:



1) A precision first surface mirror is fit onto the film camera so that its mirrored surface is resting flush and flat on the side rails that the film emulsion would ride on when the film is being exposed in the camera.

2) A taking lens is fit on the lens mount of the film camera, the focus ring on the lens is set to infinity, the iris ring is set in the full open position and the camera shutter is moved so that it is not in the light path between the lens and the film plain.

3) The auto collimator is placed in front of the taking lens so that the reticule image that the collimator generates is projected through the taking lens and is then reflected off the first surface mirror that was installed in the camera aperture and back into the collimator.

4) If the lens is calibrated correctly at infinity, and the cameras flange focal depth (the distance from the lens mounting surface to the film plain) is correct, the collimator reticule image should be sharp when seen through the collimators eye piece.

5) See attached sketch.

http://img337.imageshack.us/img337/273/untitled2mi0.jpg (http://imageshack.us)



This test tells you three possible things.



1) All is adjusted correctly.

2) The lens needs adjusting.

3) The flange focal depth is incorrect.



So my question on the Red One camera is how you put a precision reflective surface at the image sensor position in order to check the collimation. Can you put a first surface mirror in the image sensors position? Is the front surface of the sensor flat enough and reflective enough to reflect the collimators reticule image back to the collimator? Are there any optical surfaces between the lens mount and the image sensor that would interfere with the collimation of the optical system? I’m sure someone will have the answer to my question.



Best Regards,

RB»

[chuck colburn]

Mr. White,

Sorry about that. I guess I can't copy one of my private messages back to the forum. What it was about was a question Martinnoweck had about the construction of a Sharpmax type of device. Seems he's working on it. Could be a good thing for those not waning to spend a few grand on the Century or Zeiss units.

Chuck

[Emanuel A.]

But you could copy --> paste, don't you Chuck?

It would be especially interesting...

I would and shall give to RB all the information we have in order to ask him all the help he may give us -- he's very knowledgeable indeed! That man is a live encyclopaedia on cinema gear. I hope to have his interest to join us here beyond his film background field. His stuff is Hollywood. And his speciality the visual effects -- did anybody know that Spielberg had used only Nikkor glass for the visual effects (where the selective focus was not a requirement) on the Close Encounters of the Third Kind?

He's used to work not so below, on the indie side. But he's very friendly and it would be a great resource for us. A sort of Mitch Gross but IMHO, tops.

[chuck colburn]

Emanuel,

This is what the basic conversation was about.

http://www.reduser.net/forum/newreply.php?do=newreply&p=45059


And no, I didn't know Close Encounters was shot with still camera lenses. Or did you mean the plate cameras? Mayby he used the ILM VistaVision eight perf (Empireflex) cameras for those shots.

Chuck

[Emanuel A.]

Thanks Chuck.

Don't ask me this 'cause I'm out. But he can answer you if he'll wish since he worked there. Nikkor glass was his information when I had asked him on shooting with still camera lenses. Deep DOF had allowed its use, he said. Sharpness was what they had looked for, I think. From what I could extract from our nice talk.

E.

[David Mullen ASC]

The main production cameras for "Close Encounters" were 35mm Panaflexes with anamorphic lenses -- the efx plates were shot in 65mm with spherical lenses. It wasn't unusual back then for efx people buying 65mm and VistaVision cameras to adapt still camera lenses for them. To some extent, when your negative is twice as big, the MTF of the lens doesn't have to be as good as it has to on a smaller format.

I remember someone at Panavision telling me that after running some MTF tests of the best lenses made for 35mm and HD, for fun they put an old lens with a much lower MTF on a 65mm camera and found that the final image still had more resolution, simply because they were recording it on twice as large a negative.

[Evin Grant]

Most of those older Panavison Anamorphics were rebuilt Nikon lenses.
http://www.reduser.net/forum/showthread.php?t=1230

[Stephen Williams]

Most of those older Panavison Anamorphics were rebuilt Nikon lenses.
http://www.reduser.net/forum/showthread.php?t=1230

Hi Evan,

Are you saying Panavisions 1958 Scientific or Technical Award (Academy Plaque) For the design and development of the Auto Panatar anamorphic photographic lens for 35mm CinemaScope photography were just rebuilt Nikons?

Stephen

[Mr. Paul White]

What the hell does MTF mean? Modulation Transfer Function??!

Sorry, but there are other professionals from other fields, reading you. I have been hiring and paying... lol ...for several years.
Renting 35 mm motion picture gear and I have no clue on this MTF... I'm sorry.

[Stephen Williams]

What the hell does MTF mean? Modulation Transfer Function??!

Sorry, but there are other professionals from other fields, reading you. I have more than a decade and a half hiring and paying. lol
Renting 35 mm motion picture gear and I have no clue on this MTF... I'm sorry.

Hi,

I googled lenses MTF! this may help you.

http://www.normankoren.com/Tutorials/MTF1A.html

Stephen

[Mr. Paul White]

Message received.

Don't think I had no googled before. The producer's best friend. If not, from where it had came that "Modulation Transfer Function"? We simply don't talk the same language.

Thanks on your tip. Be welcome with your care.

[Evin Grant]

Hi Evan,

Are you saying Panavisions 1958 Scientific or Technical Award (Academy Plaque) For the design and development of the Auto Panatar anamorphic photographic lens for 35mm CinemaScope photography were just rebuilt Nikons?

Stephen

Yes, this is pretty widely known. And it doesn't mean that it wasn't a great achievement either. It's very resourceful of Pany's enginers to use the best available lenses of the day as a starting point for thier Anamorphics. It still took quite a bit of optical wizardry to get those lenses to where they ended up.

[Don King]

These sort of sketches are very important to us also for a good understanding on subject.



Here's morning. I could check my email and had got mail sent six hours ago from the same person. Very nice and friendly human being. I'd add, already a friend. I had asked him his input in order to proceed with my inquiry.

Here goes his question:

«HI Emanuel, the question I have is, how do you use the auto collimator on the Red One Camera? When you use an Auto Collimator with a film camera the procedure is generally as follows:



1) A precision first surface mirror is fit onto the film camera so that its mirrored surface is resting flush and flat on the side rails that the film emulsion would ride on when the film is being exposed in the camera.

2) A taking lens is fit on the lens mount of the film camera, the focus ring on the lens is set to infinity, the iris ring is set in the full open position and the camera shutter is moved so that it is not in the light path between the lens and the film plain.

3) The auto collimator is placed in front of the taking lens so that the reticule image that the collimator generates is projected through the taking lens and is then reflected off the first surface mirror that was installed in the camera aperture and back into the collimator.

4) If the lens is calibrated correctly at infinity, and the cameras flange focal depth (the distance from the lens mounting surface to the film plain) is correct, the collimator reticule image should be sharp when seen through the collimators eye piece.

5) See attached sketch.

http://img337.imageshack.us/img337/273/untitled2mi0.jpg (http://imageshack.us)



This test tells you three possible things.



1) All is adjusted correctly.

2) The lens needs adjusting.

3) The flange focal depth is incorrect.



So my question on the Red One camera is how you put a precision reflective surface at the image sensor position in order to check the collimation. Can you put a first surface mirror in the image sensors position? Is the front surface of the sensor flat enough and reflective enough to reflect the collimators reticule image back to the collimator? Are there any optical surfaces between the lens mount and the image sensor that would interfere with the collimation of the optical system? I’m sure someone will have the answer to my question.



Best Regards,

RB»