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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Resolution, softness and back focus...

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as i know this is physics experimental theory ..:shifty:
if test works fine . is it will proof correct collimation ..?:pinch: ?
or what it will proof ? :devil:
 
RedCamp & User manual

RedCamp & User manual

Elizabeth said:
I agree that it would great to have all the purely technical information culled out of all the opinion and conversation and joke and philosophy threads on this site and posted it in one technical thread ... it would make everything so much easier. This WOULD take one or two people stepping forward to volunteer make this happen (I would be interested in helping, but would need direction and training in forum management).

However, I really do not think that it is RED's responsibility to train every person who has purchased their camera as to how to use it.
Give them a break! Let them build the equipment.
It is OUR job as professionals to get the training we need to function as professionals, not RED's

Although, I have been thinking that a RED BOOT CAMP is greatly needed. It would be invaluable to be able to get instruction from the RED masters.
I would be interested in opening discussions on making this happen.

I could offer to host it at a 160 acre cabin facility in the Tahoe National Forest in the Sierra Mountains. Anybody interested?
Click to expand...



Happy Holidays Everyone !

Some great points here. Every user will need a "routine" for shooting, and yes many RedCam owners will need to forget some of the DV style shooting tactics in favor of more standard practices.

Above all we need to understand that this is a very different camera, (Brilliant) and adapt our routine around the technology. Pick up a copy of Photo shop to understand how the images captured by this camera can be used and transformed. Lossless Compression, Wavelet based compression, Motion JPEG are all great ways to process and preserve our HD images..Cheers Jim!

I will work on a User manual similar to the "Cook" Manuals when I receive my cameras...1st quarter of 2008.. or sooner I hope!..(Fingers crossed). Nothing under my tree Tuesday Morning!
We are also putting together a series of two Day RedCamp retreats...Elizabeth E-mail me with some Details, we can get some great images in the mountains !

Redrentals@aol.com
 
Before one can do any calibration of the Camera's FFD, as you can not measure the FFD as is done on a film camera, this can only be done optically. to do this, you have to ensure the lens is 100% correct, and the datum lines on the lens line up.

To acheive this on Cine prime and zoom lenses, the back focus is set using an autocollimator and a focal plane micrometer for measuring any error which there may be. Such as made by Richter Cine Equipment. If there is any error, it is then removed with the use of shims either adding or removing to bring the lens in focus at infinity.

The next step is to project the lens using a lens projector such as made by Chrosziel or Century, (there may be others) to check the lens for any errors at various distances, 6' 10' 15 ft etc... you will be looking for any problems with resolution, breathing, datum line alignment, if a zoom, tracking errors, focus shifts through the zoom curve etc as well.

Also bearing in mind the lens manufacturer has specifications for their lens at a particular T-stop. All the calibration must be done at this setting to ensure proper adjustment of the lens to spec. Just because it goes to t1.9, does not mean you will have a proper image there. Look at your image with the lens wide open then stop down to say 2.8, you will notice an improvement in image quality.

Once you are confident the lens is spot on, I.E. your chart at 10 feet is in perfect focus, good resolution and the datum line is on the 10' mark not above or below, If the marks don't line up.. correct the lens before proceeding. Close enough does NOT work here, only then, can the lens be put on the camera.

Once you have the lens PERFECT, you can then adjust the FFD of the camera, by whatever method developed by the camera manufacturer, in this case RED has a new adjustable mount.

The above is only an overview of what is required for Cine lenes which do not have back focus adjustments. This is also not something for someone without the proper equipment and training should attempt. Leave it to the professionals. I'm sure as more cameras are released, there will be rental houses that for a fee, may check and adjust the FFD of your camera. You should be able to put any range of PL mounted lenses on your camera, and shoot with confidence. Remembering your focus puller HAS to trust the marks on the lens. They don't see the same as what you do, they are looking at the barrel of the lens and the distance of the object from the camera.

Again, since you can not physically measure the FFD of digital cameras to the focal plane, it must be done optically. An auto collimator will not work on the camera as the image will be reflected off the OLPF giving you a false reading.

Once the lens is calibrated, and the FFD checked and set with what ever tooling / equipmment RED is developing, you should have some pretty darned nice images produced.


Just my thoughts on the subject.
 
Pana-tech,

I'm not so sure you can't use an autocollimator with the RED camera. The OLPF is now (I read) 8mm from the film plane. And even if it was closer the quality of the reflected image would not appear the same from the sensor as it would from a piece of plano glass (the filter). It might take a tech a few trys to learn what the proper reflected image should look like from the sensor but I'm thinking it could be done if he/she used a quantified lens that they were sure was set up for proper infinity focus. But I might be missing something here as I've never tried it. lol
 
chuck colburn said:
I'm not so sure you can't use an autocollimator with the RED camera. The OLPF is now (I read) 8mm from the film plane. And even if it was closer the quality of the reflected image would not appear the same from the sensor as it would from a piece of plano glass (the filter).
Click to expand...

The Auto collimator projects the image onto the film plane which is then reflected back to the collimator optic block. The lens is set to Infinity, the collimator is calibrated to infinity. This process is also used to check the Ground Glass height which can not be physically measured, to ensure it is at the same distance as the film plane. If the GG height is off by .001" you will see it and the image will be out of focus, resulting in a difference between tape and eye focus.

With the OLPF being 8mm in front of the focal plane, I don't see a way to get an image in focus at the focal plane, as the reflected image is coming from the OLPF. Yes, one could guestimate, but again close enough is NOT good enough.
 
Yeah it will work. We use to check for parallelism of the lens mount seat to the film plane by putting a first surface mirror in the gate and an optical flat on the lens seating surface of the mount. Both images would bounce back through the eyepiece of the Richter and any slight diviation of parallelism would show up as to seperate images of the resoution target in the collimator.
There is even a formula for calculating the angular diviation by reading the error of overlap of the two images. You can use this test to check filters also. Hell you could use to check for parallelism error of the OLPF to the sensor plane. All this with out any lens at all. So what I'm saying is that since the OLPF is so far from the film plane that a lens focused at infinity will not even present a bounce back to the eyepiece of the collimator from the OLPF. I use to set up infinity focus on lens with cameras that had behind the lens filters (gels) and they no way interfered with the collimation of the lens.

Let me just add here that all the above only holds true if the autocollimator itself is in proper calibration. But that's easier to check then a lens itself.
 
jim,

the (very sharp) footage you already sent to us from your own redone, is it sharpened in the post or native from camera?
 
Correct... any RAW .r3d file has NOT been sharpened. Where trouble begins is when our footage is compared in tests against cameras that DO HAVE in camera sharpening. As long as you know it is apples to oranges, it is OK.

If we had it to do over again, we would always choose to NOT sharpen in camera. The RAW non-sharpened look is great. And the user has all the controls if he wants to "snap it up" a bit.

Jim
 
Jannard said:
Correct... any RAW .r3d file has NOT been sharpened. Where trouble begins is when our footage is compared in tests against cameras that DO HAVE in camera sharpening. As long as you know it is apples to oranges, it is OK.

If we had it to do over again, we would always choose to NOT sharpen in camera. The RAW non-sharpened look is great. And the user has all the controls if he wants to "snap it up" a bit.

Jim
Click to expand...

PERFECT
 
and since the sharpening amount and style are all variables of the OUTPUT format they will be very different for a SD broadcast VS a theatrical presentation. This has become a common practice among still photographers when creating presentation prints. A 4x5" print needs totally different sharpening than a 16x20". So it indeed makes the most sense to do it in post.
 
Again a vast number of RAW still photographers use a two step sharpening routine: Input and output sharpening.

Input sharpening is done to make the image seem sharp after capture and is the only sharpening done before archiving the final image.

Output sharpening is done just before delivery for the specific target media and image size.
 
red made the very right decision.
 
If you're downsampling, the down filter should be designed to provide optimum sharpening without ringing or halos in the lower resolution.

Input sharpening should be very subtle...

Graeme
 
Jim,

Is there a difference in the new cameras, because of the placement or type of OLPF, that might affect the percieved sharpness of untouched .R3D files? Or should we be expecting about the same as the original cameras.

And also, is the .6, 300% formula you suggested something that you discovered through trial and error or something that is sort of a scientific match for the OLPF.

Ian
 
ibloom said:
Jim,

Is there a difference in the new cameras, because of the placement or type of OLPF, that might affect the percieved sharpness of untouched .R3D files? Or should we be expecting about the same as the original cameras.

And also, is the .6, 300% formula you suggested something that you discovered through trial and error or something that is sort of a scientific match for the OLPF.

Ian
Click to expand...

i missed this formula, and my question is where in redcine i should add .6 and 300 %...thanks
 
OLPFs don't really change their effect on change of distance. It's more to make any dust less visible and to deal better with flare I think.

Graeme
 
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