Re: [APML] Pentax 6X7

[Matt BenDaniel <matt@starmatt.com>]

Dean,

If are building a fast telescope for AP with wide illumination, you will probably not be happy with a Pentax 67 or any other standard medium format camera. The mounting flange vignettes significantly, even at f/7. I go to quite a bit of effort in Photoshop to compensate for that vignetting. Otherwise, I think the Pentax 67 works great.

Will your telescope have correcting optics near the film plane? Take a look at the new Traveler field flattener. It locates the rear element very close to the mounting flange, thereby minimizing vignetting with a standard Pentax 67. It still vignettes slightly, but it is better than any other commercial scope of similar focal length for a Pentax 67.

You could make a camera yourself, or buy one from Schmidling. 

At 06:34 AM 10/31/2001 -0700, Dean Ketelsen wrote:

>Hello All-
>        I am in the process of constructing a telescope for astrophotography
>that is capable of providing a large flat field and am interested in 
>feedback concerning a camera to design it around.  The Pentax 6X7 seems
>to be in popular use amoung many of you and the use of a medium format
>camera one can use for non-astronomy applications is a draw over a devoted
>system for this telescope.  I see many of you use yours at F/5 to F/6 -
>is there vignetting at these speeds caused by adaptors or the mounting
>flange?  There would certainly be some at the F/3.6 to F/4 of the system
>I'm envisioning.  I'd be interested in hearing any comments regarding
>the Pentax camera or if you would have other recommendations, either on
>list or off.  Thanks in advance.

--
Matt BenDaniel
http://starmatt.com


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