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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

chuck colburn said:
http://www.chamblesscineequip.com/catalog/Richter 102.htm

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

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

Here's the taking off:

Emanuel said:
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.





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

Hi,

I googled lenses MTF! this may help you.

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

Stephen
 
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.
 
Stephen Williams said:
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
Click to expand...

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.
 
Very important hint!

Very important hint!

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


Emanuel said:
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.





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»
Click to expand...
 
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