March of the prototypes...

[Evin Grant]

http://www.evingrant.com/pics/FOR_IS35.jpg
http://www.evingrant.com/pics/UO_FPL.jpg
http://www.evingrant.com/pics/R_RRP.jpg

I've now seen all the new glass in it's prototype form.
Since I gave a preview of the Zeiss Compact primes I thought it only fair to do the same for the rest of our options...

A few notes first, these are just first impressions so I'm not really going to be negative on anything. I'll make some observations based on what I think won't change on the final production lens, but that's about it. For more detailed critiques you'll have to wait for SALT.

I'm going in order of the pictures...

1: Focus Optics Ruby
I am a little biased here because I consulted on the development of this lens . Focus action is super smooth with no backlash. The optics are from the 14-24 Nikkor and we all know they are superb, they look great on the Red. Good size and a weight as well. The barrel finish is a nice flat black. Solid construction.

2: Illumina S35 primes
Very solidly built. They have that Russian image character that I find quite appealing in Lomo lenses. Very sharp on the projector, even at T1.3.
Traditional focus (barrels move) not internal focus.

3:Unique Optics
T1.9 very nice looking barrels, modern internal focus design. Very little breathing (in a directors finder). No 18mm yet, but coming soon.

4: Fujinon 18-85 T2
Other than the back focus adjustment which I found amusing, these seem like serious top line lenses poised to go head to head with the Optimo line, both in performance and price. They look superb on an F35, we'll see how they look on a Red at SALT.

5. IB/e Rebel Primes
These are the first lenses I've seen with a tele-centric design, on a finder they didn't breathe at all and seemed to have a nice fall off. The barrels are a complete departure from what I'm used too but I imagine they should be fine in use. They are not internal focus but are rear focus, as in the entire barrel moves forward from the mount. It doesn't move much though so I doubt it will be problematic. Only 25, 50 and 95mm For now.
There was also a mockup of the Supreme Prime 14mm which looked great but it's hard to tell anything from a mockup.

6: Red Pro Primes
The RRPs are impressive, both physically and optically. The projection test proved pretty much exactly what Jim has said all along about their performance. Seeing them through a Red was also very enlightening,
practically no breathing, very pleasant Bokeh and OOF highlight rendering (I much prefer the 7 blade iris pattern to the star pattern from S4s).
The focusing seemed smooth and repeatable with no backlash. Finish was a very sexy flat black. One issue though is weight, these are big lenses (4lbs), this seems to be the current trend as well as the trade off for high performance lenses.

I know there is a time crunch here for many of us (including me) but these impressions are the best I can do for now with such limited exposure to all these lenses. I'm trying my best to get everyone to the SALT within the next few weeks, but it may be hard. I hope this helps.

[Shawn Nelson]

Thanks Evin! Also remember the flare test on the RPP did pretty well for an ad-hoc test.

[Evin Grant]

True, but it wasn't a controlled enough test for me to mention.

[Phil Jordan]

I saw the Ruby Series zoom on a RED ONE outside the tent and it looked very nice but the focus rotation was very short and made for difficult critical focus and it had pretty severe breathing.

[Mike Prevette]

Moar!@@

[lensmaster]

I spoke to the IBE lens designer. These lenses are not 100% telecentric. Telecentric means chief ray angle at film plane of zero. That is the definition.

He also told me they were basically a set of machine vision lenses they modified to be cine lenses.

Just be careful calling these telecentric. You can tell how close to telecentric a lens is by looking at the size of the rear elements (especially on the wide angles).

I saw most of the lenses at NAB and was surprised how small the rear element on the IBE was since they were claiming telecentricity. Discussions with them told me that although these had less steep angles at the sensor they are not purely telecentric by definition.

The Zeiss lenses also had really small rear elements. Remember a real telecentric lens needs a rear element larger than the image circle. How much larger depends on the T-stop.

I did not see this on the IBE lenses. These were not from the ground up designs like I expected (hoped). They are modified machine vision optics.

Alot of the other sets were much more exciting to me.

[Kwan Khan]

Interesting ... thanks evin

[Mitch Gross]

To be fair, a modified machine vision lens is not necessarily a bad thing. It's a lens already designed to cover an electronic sensor the same size as the one in a RED. And let's call it "largely telecentric" rather than "fully telecentric." At a certain point the PL lens mount becomes a limiting factor in telecentricity.

[Jeff Kieffer]

...

2: Illumina S35 primes
Very solidly built. They have that Russian image character that I find quite appealing in Lomo lenses. Very sharp on the projector, even at T1.3.
Traditional focus (barrels move) not internal focus.

...

6: Red Pro Primes
The RRPs are impressive, both physically and optically. The projection test proved pretty much exactly what Jim has said all along about their performance. Seeing them through a Red was also very enlightening,
practically no breathing, very pleasant Bokeh and OOF highlight rendering (I much prefer the 7 blade iris pattern to the star pattern from S4s).
The focusing seemed smooth and repeatable with no backlash. Finish was a very sexy flat black. One issue though is weight, these are big lenses (4lbs), this seems to be the current trend as well as the trade off for high performance lenses.



Hi Evin,

What about the breathing and the weight and the size of the Lomos, compared to the RRPs?

Jeff

[JD Holloway]

deleted

[I Bloom]

Evin,

How do the Illumina Lenses compare to Zeiss Superspeeds?

Ian

[Charles Pickel]

Just want want to clarify Evin's description of the Illumina S35's as "not internal focus". True, they are not sealed units like Cooke S4's. More similar to Zeiss mechanism in that the front and rear are coupled by internal guides. This means that your focus gear does NOT move, but the front of the lens and its iris gear do track in and out, but they DO NOT ROTATE. Constant 95mm front diameters assure ease of use with matte boxes and clamp on lens accessories.

They have a feel and function that will be familiar to users of fine cinema lenses.

Thanks to Evin for making the rounds !

[Frank Weeks]

Here's a few shots from the Luma tech suite. Evin checking out the lenses.

[Evin Grant]

Hi Evin,

What about the breathing and the weight and the size of the Lomos, compared to the RRPs?

Jeff

The Illuminas are a little bit bigger than Zeiss Super speeds so much smaller and lighter than RRPs. As far as breathing I think it was there but very minimal, there was a tiny amount of breathing near infinity on the RRPs too.


Evin,

How do the Illumina Lenses compare to Zeiss Superspeeds?

Ian

They compared very well, it's hard to make a judgement from the limited time I had but I wouldn't hesitate to take a set out Illuminas out instead of Super Speeds. SALT is coming soon and lots more will come to light.

[Tim Naylor]

Can someone explain "telecentric" design. I went to their website and after reading for a few minutes, I still didn't get it. I need pictures or a clearer more brief explanation. I got a headache trying to really understand what it is.

Mitch? In plain English anyone.

[Tim Naylor]

Will the Illuminas cover 30mm / 5k?

[Andrew Walker]

I'm really looking forward to the SALT test Evin. But even with all these other lens options that came up at this years NAB I still think the RPP's seem to be the best deal for what they offer. But of course I really only got to see the RPP's tested on a camera. The other thing to think about is what if something happens to one of your lenses. Who do you think is going to have the best customer service?

[OptiTek]

Hi Tim,
First let me explain we are talking here about image side telecentric design as they are the only type useful for creative imaging. It simply means that all rays exit the lens at or close to 0 degrees angle to it's optical axis and, therefore , reach the pixels at the right angle to the sensor(or close to it)
That property mainly improves the off axis illumination on the image side as the extreme rays travel the same distance as the center rays. The other reason this property improves even illumination is minimized pixel shading phenomenon when the rays coming at steep angles are partially blocked by the eddge of the "bucket" containing pixels on the sensor.
I hope this helps, Jacek Zakowicz, optiTek.org:thumbsup:

[Mitch Gross]

Jacek explains it very well; let me try in different phrasing in case it still is not clear. Think of the sensor as a flat surface. It kinda is, but actually it's a bunch of little cups, with the light sensitive surface at the bottom. Light coming straight into the cup will hit the bottom. Light coming in at an extreme angle will not. A telecentric lens sends the light straight down the cup or close to it. This is not as important for a film camera as it is a digital one. But it can also improve color fringing and other artifacts.

Hey everyone, Tim's camera was the very first client RED to be officially checked with a Red Null. Yesterday I was shooting the blog video on the Red Null when his came in to have the backfocus checked. I handed the Red Null to our tech to try out. He nailed it right away, and then proceded to go through all his standard checks to confirm because he wanted to be prudent. In the end he could have done it in two minutes because that's all it took using the Red Null.

[Charles Pickel]

The LOMO factory informs us that the image diagonal (image circle) for the Illumina S35 T1.3 primes is approx. 33.5mm. This is approximate for two reasons:

1) Not all lenses are in their final form yet.

2) Image circle varies as a function of focal length. Longer lenses will have the largest coverage area.

We understand that none of the lenses will have less than a 33mm image circle. So future digital formats (e.g. 5K) will be covererd.

We expect to have production lenses by August/Sept. and will have sets to deliver in quantity by November.

Hope this is clear.

[Paul Leeming]

Hey everyone, Tim's camera was the very first client RED to be officially checked with a Red Null. Yesterday I was shooting the blog video on the Red Null when his came in to have the backfocus checked. I handed the Red Null to our tech to try out. He nailed it right away, and then proceded to go through all his standard checks to confirm because he wanted to be prudent. In the end he could have done it in two minutes because that's all it took using the Red Null.
Could you post a new thread about this lens as well as a picture? You're saying it functions as a normal lens too? I'm keen to know more about this as Japan is a nightmare with backfocus, since no one seems to conform to the STANDARD!! :angry:

It's why Fuji lenses etc have a separate backfocus ring ON the lens! Because the trend here is simply to set the lens to the particular camera, not 52mm precisely. Frustrating as hell....

Cheers,

Paul

[AIO Films]

I'm really looking forward to the SALT test Evin. But even with all these other lens options that came up at this years NAB I still think the RPP's seem to be the best deal for what they offer. But of course I really only got to see the RPP's tested on a camera. The other thing to think about is what if something happens to one of your lenses. Who do you think is going to have the best customer service?

I have ordered a set of RPP but is still contemplating on the Illuminar S35 lenses for it's faster speed, light weight and much smaller bulk. Too bad, I missed the projector demo but managed to hold the three lenses on my hands the last minute before Luma Tech people left their hotel room. So I have a pretty good idea of their physical properties.

In fact, there is no alternative for the speed and physical size combination on the market today. Now that Zeiss has discontinued their Super Speed series, do we really have a choice, at any price?

"Horses for courses" was what I have been hearing all over NAB this year.

Maybe Charles should reiterate their early reservation discount and the generous refund policy on this board for others to make a purchase decision before it's too late.

[Andrew Walker]

I have ordered a set of RPP but is still contemplating on the Illuminar S35 lenses for it's faster speed, light weight and much smaller bulk. Too bad, I missed the projector demo but managed to hold the three lenses on my hands the last minute before Luma Tech people left their hotel room. So I have a pretty good idea of their physical properties.

In fact, there is no alternative for the speed and physical size combination on the market today. Now that Zeiss has discontinued their Super Speed series, do we really have a choice, at any price?

"Horses for courses" was what I have been hearing all over NAB this year.

Maybe Charles should reiterate their early reservation discount and the generous refund policy on this board for others to make a purchase decision before it's too late.

I haven't dismissed the Illuminar S35 lenses. They seem like some awesome lenses. But I believe I would get more use out of the RPP's and I got a chance to see how those worked. I could see renting the Illuminar for those really low light shots that I need to get. But for my kit and my future Epic X I think the RPP's will be the best fit.

[Tim Naylor]

Hey everyone, Tim's camera was the very first client RED to be officially checked with a Red Null. Yesterday I was shooting the blog video on the Red Null when his came in to have the backfocus checked. I handed the Red Null to our tech to try out. He nailed it right away, and then proceded to go through all his standard checks to confirm because he wanted to be prudent. In the end he could have done it in two minutes because that's all it took using the Red Null.

Thanks for the explanation. If this tech thing doesn't work out, you should write manuals. Very clear. Cups O' light. I like that.

Also, I want to thank you for saving my ass. I was DP'ing a spot for Grey Advertising and try as we may we couldn't get the back focus spot on. It got progressively worse to the point where we couldn't get it at all. All three of us failed (AC, Tech and myself). Client wondering what's up. If my tech didn't have a body (Emron) in midtown, I would've been royally screwed that day (well actually I probably would've grabbed one from Abel). The next day, Mitch and Company turned my camera around early morning. This was the Production Company's first RED shoot. Lives were saved.

Now what I need to know is what did we do procedurally wrong that didn't allow our ring to turn anymore (in the direction we needed to go) as well as get worse the more we tried. Before that job I had messed with the back focus to properly fit a Nikon mount and then went back to PL. That's when it all went pear shaped.

Please PM me, Mitch.

Again, thanks a million.

[Mitch Gross]

The name was changed from Illumina to Luma Tech, the American importer. Personally I think they missed the boat by passing up the opportunity to run with the Illuminati.

[Tim Naylor]

The LOMO factory informs us that the image diagonal (image circle) for the Illumina S35 T1.3 primes is approx. 33.5mm. This is approximate for two reasons:

1) Not all lenses are in their final form yet.

2) Image circle varies as a function of focal length. Longer lenses will have the largest coverage area.

We understand that none of the lenses will have less than a 33mm image circle. So future digital formats (e.g. 5K) will be covererd.

We expect to have production lenses by August/Sept. and will have sets to deliver in quantity by November.

Hope this is clear.

Great news. Thanks.

[Andrew Walker]

The name was changed from Illumina to Luma Tech, the American importer. Personally I think they missed the boat by passing up the opportunity to run with the Illuminati.

Mitch, can you can you talk a little more about this magical back focus device you guys have. Would be kind of nice to go into the Able right by my house and have them get it spot on.

[Mitch Gross]

Hey Tim,

Don't know exactly what you were doing wrong but I have my suspicions. It's an easy enough mistake that it's worth me posting here for everyone rather than a PM. And it's nothing to be ashamed of for privacy.

On the RED, the backfocus ring with the two hexbolts is a clamp, nothing more. The ring that adjusts the wormgear for moving the mount in & out from the sensor is located underneath it. The idea is to loosen the hexbolts just barely enough to be able to move the outer ring, which will then move the inner ring via contact friction. What happens often is that people will loosen the hexbolts far too much, separating the outer ring from the inner ring. At that point turning the outer ring will have little to no effect. Or you might be able to move it one way but not the other, getting the mount further & further out of depth.

The first time it happened to me induced a lot of sweat.

Another trick I found is that it can really matter which screw you tighten first once you found correct depth. The definition of frustration is to find perfect depth and then discover that the act of tightening the mount in place shifts the mount back out of focus! Think of the backfocus adjustment as a big screw. By definition there has to be a bit of play front and back between the threads, otherwise they would not turn. When we're talking about a system measured in microns this is a pretty tight tolerance. So turning the screw one direction would put metal to metal contact against one side with air space on the other. Rotate in the opposite direction and the metal to metal contact occurs on the opposite side. YMMV, but I find that -- facing into the lens port -- if I finish my adjustment by rotating CLOCKWISE then I should tighten the REAR hexblot first (just enough so it catches, then tighten the other one). If I end turning COUNTERCLOCKWISE then tighten the FRONT hexbolt first.

It's vital to do this with a decent-sized monitor and the pixel-to-pixel zoom switched on. Otherwise you could be totally soft and have no idea. When you make the adjustment and then lock down you'll see in an instant if anything is going wrong.

Especially if you use the new Red Null, coming soon! ;-)

[Harry Clark]

Mitch,
Nice tip on the "which hex bolt to tighten first". I have only had to do this once but it was a tricky process to retighten and not throw the backfocus out again.
Cheers,
Harry

[Mitch Gross]

Mitch, can you can you talk a little more about this magical back focus device you guys have. Would be kind of nice to go into the Able right by my house and have them get it spot on.

The Red Null is a fabulous little gadget that everyone really should get for their kit. We're finalizing details now with the manufacturer so we know the price and delivery schedule. I've already shot a demo video for our blog that we'll have up in a few days, at which point we'll have other info up on our website and I'll provide detailed info here on REDuser as well. It is extremely simple to use and highly accurate.

The Red Null is a special hyper-wide lens that has tons of depth of field in front of the lens but an incredibly small depth of focus behind it. It is locked to infinity and a very fast aperture with an incredibly tight single-purpose tolerance. Put the Red Null on the camera and point it at anything 100' or so away. Loosen the mount and adjust until the image is sharp. It will pop into focus at the correct depth and be obviously soft when not. It is accurate to five microns, which is pretty much as accurate as you're gonna get.

As soon as we can roll this out we want to get it in people's hands. This is a tool that every RED user using PL mount should have and use often. We're trying to keep it priced at a reasonable cost so that lots of people buy it, because whether you use this or some other variant that are in the works I firmly believe that backfocus is something that should be checked often and easily and on set.

We currently have the prototype in our office in NY and expect them to be available to the world soon. As soon as I have more I'll let everyone know.

[Frank Weeks]

I have ordered a set of RPP but is still contemplating on the Illuminar S35 lenses for it's faster speed, light weight and much smaller bulk. Too bad, I missed the projector demo but managed to hold the three lenses on my hands the last minute before Luma Tech people left their hotel room. So I have a pretty good idea of their physical properties.

In fact, there is no alternative for the speed and physical size combination on the market today.

I feel the same. The only two lens sets I considered were the Luma Tech (Lomos) and RPPs. I was willing to spend more for the speed. Charles showed me the 85mm and 50mm on the projector. They were sharp to the edges. I can't say matched the RPPs but they were better than the lenses that red used to compare the RPPs with. They also look very clean on the camera.

They were amazing for prototypes. Not perfect. Slight pincushion on the 85 but they were well aware and working to resolve it.

My main concerns were
1. Would they cover 5k? (it now appears they will)
2. Realistic delivery date?

I often shoot alone or with a small crew. The extra speed of the Lomos would have been welcomed.

Charles was very professional and straight forward about his lenses. I believe they will perform very well at salt and be a popular choice for Red users.

For me, there's no looking back.

[Andrew Walker]

The Red Null is a fabulous little gadget that everyone really should get for their kit. We're finalizing details now with the manufacturer so we know the price and delivery schedule. I've already shot a demo video for our blog that we'll have up in a few days, at which point we'll have other info up on our website and I'll provide detailed info here on REDuser as well. It is extremely simple to use and highly accurate.

The Red Null is a special hyper-wide lens that has tons of depth of field in front of the lens but an incredibly small depth of focus behind it. It is locked to infinity and a very fast aperture with an incredibly tight single-purpose tolerance. Put the Red Null on the camera and point it at anything 100' or so away. Loosen the mount and adjust until the image is sharp. It will pop into focus at the correct depth and be obviously soft when not. It is accurate to five microns, which is pretty much as accurate as you're gonna get.

As soon as we can roll this out we want to get it in people's hands. This is a tool that every RED user using PL mount should have and use often. We're trying to keep it priced at a reasonable cost so that lots of people buy it, because whether you use this or some other variant that are in the works I firmly believe that backfocus is something that should be checked often and easily and on set.

We currently have the prototype in our office in NY and expect them to be available to the world soon. As soon as I have more I'll let everyone know.

Thanks Mitch, I look forward to seeing that video on your blog. Should be a very valuable tool to have in a kit. Right up there with a sensor loop and cleaning kit.

[Mike Prevette]

Mitch,

Does the Red Null take into account the OLPF/ IR combo in the optical path?

I'm still convinced that this filter in the optical path is why some "Perfect" lenses will come up bang on and others will not. As physics of light tells us this offset seems to effect longer lenses more.

EDIT: I got this backwards I meant effect it less.

I typically start a prep with a nice wide on the camera (14 or 16) set the flange depth, then step up the range of lenses. Without fail by the time you get to the longer lenses the marks will creep a bit. Then throw in a couple zooms and your life becomes a nightmare. I used to think it was just maladjusted lenses, but every time I'd get they were just projected and came up perfect. This could be coincidence, but the more I see it the more I tend to think it is the filter.

[Tim Naylor]

Hey Tim,

Don't know exactly what you were doing wrong but I have my suspicions. It's an easy enough mistake that it's worth me posting here for everyone rather than a PM. And it's nothing to be ashamed of for privacy.

On the RED, the backfocus ring with the two hexbolts is a clamp, nothing more. The ring that adjusts the wormgear for moving the mount in & out from the sensor is located underneath it. The idea is to loosen the hexbolts just barely enough to be able to move the outer ring, which will then move the inner ring via contact friction. What happens often is that people will loosen the hexbolts far too much, separating the outer ring from the inner ring. At that point turning the outer ring will have little to no effect. Or you might be able to move it one way but not the other, getting the mount further & further out of depth.

The first time it happened to me induced a lot of sweat.

Another trick I found is that it can really matter which screw you tighten first once you found correct depth. The definition of frustration is to find perfect depth and then discover that the act of tightening the mount in place shifts the mount back out of focus! Think of the backfocus adjustment as a big screw. By definition there has to be a bit of play front and back between the threads, otherwise they would not turn. When we're talking about a system measured in microns this is a pretty tight tolerance. So turning the screw one direction would put metal to metal contact against one side with air space on the other. Rotate in the opposite direction and the metal to metal contact occurs on the opposite side. YMMV, but I find that -- facing into the lens port -- if I finish my adjustment by rotating CLOCKWISE then I should tighten the REAR hexblot first (just enough so it catches, then tighten the other one). If I end turning COUNTERCLOCKWISE then tighten the FRONT hexbolt first.

It's vital to do this with a decent-sized monitor and the pixel-to-pixel zoom switched on. Otherwise you could be totally soft and have no idea. When you make the adjustment and then lock down you'll see in an instant if anything is going wrong.

Especially if you use the new Red Null, coming soon! ;-)

My shame has been lifted. Ignorance is murder. Thanks for the excellent answer - your answer should be a sticky. You pointed out exactly what we went through. Being used to 2/3" back focus I thought it would be a matter of loosen, turn, tighten and shoot. Not the delicate business you pointed out. Hopefully, RED either gives careful instructions on how to do this right or design it differently in the next iteration.

Thanks again.

[Mitch Gross]

Mike,

Sorry but you have your physics off a bit. We work with digital sensor cameras with OLPFs every day. Phantom, RED, SI-2K, some stills, etc. This is a non-issue.

One of the many tests we performed with the Red Null was to mount an Optimo 24-290 after setting the camera with the device. The focus tracked perfectly as expected. I even did this on the NAB floor just to check things on Day three after moving the camera around a bunch and moving the camera from our NY office to FedEx (freezing in airplane cargo hold) to Las Vegas shipping container (100+ heat beating down in the desert to set-up/strip down each day with a 26lbs. lens hanging off the front. The mount had definitely shifted over time, but the Red Null snapped it right back to where it belonged and the zoom test bore that out.

That's why y'all need to own one so you can double-check backfocus on a regular basis. We do it with every single camera of any manufacture on every rental at Abel. That goes for film or video. Check all the lenses as well. Every rental.

[Mike Prevette]

Hmm, I was under the impression that you always have to compensate or 1/3 (as a general rule) the thickness of any optical flat behind the lens in the image path. It's always been true in the past, why is it different now? Also why would Jim make a specific point about how the RPP's are tuned for the OLPF/IR filter specific to the Red. Also last I checked none of those cameras you cited had their filter offset from the chip as far as the Reds.

http://books.google.com/books?id=r4LgHiMTMZ8C&pg=PA185&lpg=PA185&dq=behind+the+lens+filters+and+flange+depth&source=bl&ots=W_RZE97lFv&sig=k2IgrdbtLhy5Nv86do1S_cLTb40&hl=en&ei=Lhj5SfSmK8vJtgeWqoCfDw&sa=X&oi=book_result&ct=result&resnum=1

http://books.google.com/books?id=fY98hmhWp58C&pg=PA1205&lpg=PA1205&dq=optical+flat+affecting+Flange+depth&source=bl&ots=_97vZsvtSv&sig=Rgumek8aOpH1nRBmfGzP1uwLAfU&hl=en&ei=oxf5SYygBdmJtgfV0PDsDw&sa=X&oi=book_result&ct=result&resnum=7

http://en.wikipedia.org/wiki/Depth_of_focus

And since Red has moved the IR filter off the chip the light passing through it has to travel at a steeper angle through the glass (in a non telecentric design), therefore offsetting the depth to a greater degree around the outer edges.

My point is I'm trying to rationalize oddisms I've been observing for the past year and a half. At this point I have come to the conclusion that there is no one single flange depth that will work with all lenses of all varieties (even assuming they are perfectly tuned).


http://www.freedomfromgravity.com/red/olpf.gif

[Mitch Gross]

Once the OLPF is in place the offset in flange depth it causes is a constant based on its thickness and refraction index. It does not matter what lens is placed in front of it. So a lens set to infinity and then focused onto the sensor through the OLPF will be correct, as will any other properly set lens. That's the physics and it has always played out for the work we do.

[Ken Hale]

Hello Mitch,
I need a little clarification on this OLPF issue that you are very experienced with. From the picture above, the light from lens "2" passes at a different angle than lens "1" and so the light travels a longer distance through the OLPF. Does this not bring the sensor edges in closer to the lens, focussing the lens farther than the sensor? If so, then is there a rule of thumb for various wide angle primes focal lengths? Or, do I just set all lenses to be used on a camera with an OLPF at exactly 52mm and be done with it?
Thank you in advance for helping me wrap my head around this one.