Collimator devices and the like.

[Michael Epple]

I have noticed a lot of products for setting your back focus to the ?micron, but as I recall back focus adjustment was set for the lenses. Has that changed? I remember a year ago that people were setting the back focus specifically for different lenses, yet now things like the Red null and others make it sound like one size fits all. What have people found? Since I don't own one of these I always check back focus with the widest lens in a set on any new project.

 

[Michael Epple]

I guess nobody remembers those days.

 

[Dustin Cross]

Red Null is for calibrating the camera. You also need to make sure each lens is properly calibrated.


Dusty

 

[Jacek Zakowicz]

lens back focus

lens back focus

I have noticed a lot of products for setting your back focus to the ?micron, but as I recall back focus adjustment was set for the lenses. Has that changed? I remember a year ago that people were setting the back focus specifically for different lenses, yet now things like the Red null and others make it sound like one size fits all. What have people found? Since I don't own one of these I always check back focus with the widest lens in a set on any new project.

You can still adjust the camera to each lens, if you use widest lens to set the camera, you have the best chance of success. But you cannot be sure about the settings if your lenses are not checked and verified on collimator for proper back focus adjustment. Checking and changing back focus (actually it's the Flange Depth on camera) for each lens on set is not very accurate or practical, depending on your style or genre.
With the Optimator you can adjust the camera Flange Depth and knowing that that's correct check and adjust your lenses accordingly. If you are careful and with some practice it should not be a major hurdle. The checking part that is. The adjustments to lenses should be done by a qualified tech unless you are confident that you can handle the job of removing lens mount and shimming lenses, which requires whole new set of skills. All that should be done during the first prep of a camera/lens setup and shouldn'change for the duration of job if lenses and camera are not bumped, dropped etc. Then you would just do a quick Flange check on camera between setups to be sure.
Jim mentioned a while back that there will be a "lens test mode" on the RedOne for that purpose as well. That would certainly help to put things in place. I hope this helps to explain the procedures....

 

[Steve Sherrick]

Jim mentioned a while back that there will be a "lens test mode" on the RedOne for that purpose as well. That would certainly help to put things in place. I hope this helps to explain the procedures....

Do you mean Epic?

 

[Jacek Zakowicz]

RedOne lens test mode

RedOne lens test mode

Do you mean Epic?

It sounded like a firmware/software feature so it was a possibility on REdOne.
All necessary hardware is there already. If anything it's easier to implement on RedOne because of the FPGA flexibility. Once they go ASIC they lose the flexibility, or at least some of it. Some core features just have to be baked in...

 

[Michael Epple]

As I recall, people found differences between lens sets on their red, even though the lenses were properly collimated. I don't know if it is because of something else, or the IR + OLPF filters. Maybe I'm wrong. I'm just asking. When I rent a lens set, I've just prepped the camera like a normal 35mm package and use an HD monitor and charts. I always reset the flange depth right away, unless the same set was used last time and all the lenses match the tape. I would love the Optimator, Red Null and other products to be the quickest, easiest check.

 

[Jacek Zakowicz]

Back focus variations

Back focus variations

The only setup issues that I'm aware off is with some Master Primes, 27mm and 40mm. But that's not a common setup- the MPs are very pricy. And also a bit of controversy as Pavel puts his life on the line for MPs.
Don't forget that aside of cleaning optics back focus issues are by far the biggest task of rental house lens techs. They shim lenses all the time to match ACs requirements. And this is in traditional film production. REdOne is a very high resolution camera so it may even be more critical than film cameras..
What I'm saying is that rumors that lenses are off on RedOne can't be taken at face value and need more testing and verification. But who has the time...

 

[Steve Sherrick]

It sounded like a firmware/software feature so it was a possibility on REdOne.
All necessary hardware is there already. If anything it's easier to implement on RedOne because of the FPGA flexibility. Once they go ASIC they lose the flexibility, or at least some of it. Some core features just have to be baked in...

Interesting, I think I missed that one. What would the lens test consist of?

 

[Jacek Zakowicz]

lens test mode

lens test mode

Interesting, I think I missed that one. What would the lens test consist of?

I don't even know if it's still on the list, things changing and all. I know what I would put there but I don't work for Red.
I am planning a software module for the Optimator system but that would test sensor and DSP not lenses.

 

[Fredrik Callinggard]

The only setup issues that I'm aware off is with some Master Primes, 27mm and 40mm.

????? Never heard of this problem. Would you mind to elaborate?

 

[Mitch Gross]

I heard stories of a mythic issue on certain focal lengths of Master Primes as well as at certain distances on particular zooms. What I can tell you is that it is not true based on physics, it is only true based on the condition and setting o particular lenses. In the case of the primes we discovered a couple of lenses that were correct at infinity but when set to different focus distances were consistently off. This was because of an improper re-assembly of certain parts within the lens when someone had performed some service. The error was corrected and the lenses tracked focus perfectly. In the case of a particular zoom we found that the lens actually had to go back to the factory for service. But there is no reason for a properly functioning lens to not work correctly on a RED camera, given that both are set to the correct depth.

Get all your lenses set to correct depth. Get a NULL Lens, Optimator or other lens mount depth-checking device and check your camera on a regular basis. You will be just fine.

 

[Jacek Zakowicz]

You have to check yourself

You have to check yourself

????? Never heard of this problem. Would you mind to elaborate?

I heard it from experienced rental house lens tech.
Both 27 and 40 when setup on collimator and checked footage marks on projector were visibly off on Red just looking at monitor. 6, 10ft etc.
Then when adjusted to match footage marks on Red they were off on collimator and projector. All other lenses in the set were fine. He called me to double check- he'd never seen that before and thought he was doing something wrong. We went over procedures on the phone and everything seemed right to me...
Correction:
it looks like it was only urban legend- I just spoke with him again and he said he needed to tweak back focus on Red and all lenses matched.
Sorry about the confusion.

 

[Peter Repich]

I have noticed a lot of products for setting your back focus to the ?micron, but as I recall back focus adjustment was set for the lenses. Has that changed? I remember a year ago that people were setting the back focus specifically for different lenses, yet now things like the Red null and others make it sound like one size fits all. What have people found? Since I don't own one of these I always check back focus with the widest lens in a set on any new project.

.

Michael,

you are absolutely right. Back focus is a term for setting the lens collimation to the correct specification (PL mounted lenses have 52 mm back focus setting via PL mount shims). Cameras have Flange Focus Distance adjustment (FFD). Currently, only the RED ONE and Sony F35 have customer capable FFD adjustement not requiring shimming. Others like Arri D-21 require shims. All film cinema cameras are shimmed. Uniqoptics makes a focusable Diascope to perform cinema grade FFD adjustment in a very siple way. See www.uniQoptics.com.

Peter Repich

 

[Jacek Zakowicz]

new Optimator video

new Optimator video

Please check out this link if you are interested in the OptiTek Optimator:
http://www.youtube.com/watch?v=p5tJIDtWzh8
This is first cut but it has all the information about basic operation and touches on the advanced features as well.
Comments and questions very welcome
Merry Christmas and Happy Holidays to all!!!!