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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 :)

Collimation on RED ONE

Shawn Nelson said:
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.
Click to expand...

Hi Shawn,

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

Stephen
 
Reliable test target at infinity

Reliable test target at infinity

Evin Grant said:
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.
Click to expand...

But isn't a real life subject with detail and contrast at >1000 feet a "reliable test target at infinity?
 
Stephen Williams said:
Hi Shawn,

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

Stephen
Click to expand...

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?
 
Mr. White said:
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?
Click to expand...

Hi,

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

Stephen
 
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
 
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?
 
Mr. White said:
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?
Click to expand...

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
 
Move the sensor not shim the mount.

Move the sensor not shim the mount.

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
 
Stephen Williams said:
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
Click to expand...

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..










X_caught!.GIF
 
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

filmmaker's gang said:
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..







X_caught!.GIF
Click to expand...
 
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
 
renting Lens techs and Stephen: a special case question for your formula.

renting Lens techs and Stephen: a special case question for your formula.

Stephen Williams said:
Hi,

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

Stephen
Click to expand...

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.
 
AquaVideoRed206 said:
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.
Click to expand...

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
 
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