I've read one article which used a razor blade to focus the camera.
Something about splitting a star with the razor blade. Believe it was
called the foccult method. Only problem was I couldn't really tell what he
was doing with the razor blade or how he positioned it within the camera
body. I know he had it set on the bulb setting and then placed a razor
(I'll assume a thin double sided blade) "exactly" where the film would be.
The "exactly" is what I didn't understand. Does this mean that the leading
edge of the razor blade is at the focal point of the film? How do you keep
it there? A diagram would really be helpful at this point.

I'll go back and revist the mapug archives.


-----Original Message-----
Date: Friday, July 02, 1999 11:27 PM
Subject: [M]: Re: OAG Focusing....


>Hi, Fred:
>You don't say how you plan to focus the Pentax before "starting to shoot
>away..." Even if the eyepiece happened to be parfocal with the camera, I
>wouldn't trust it: your eye does too much accomodating when checking the
>ordinary viewfinder or eyepiece visually. If you haven't already read up on
>"the focusing problem" checkout the MAPUG archives and Doc Greiner's
>website. Focusing is a nontrivial matter and calls for high magnification
or
>a knife-edge focuser of some type. A parfocal eyepiece is great for getting
>rough focus, your focusing accessory takes over from there.
>Hope this helps...
>Bert
>
>-----Original Message-----
>Date: Friday, 02 July, 1999 3:47 PM
>Subject: [M]: OAG Focusing....
>
>
>>
>>While were on the subject of reducers and OAG's I have a pertinant newbie
>>type question...
>>
>>I also have the Meade off axis guider that I plan on using with my
>Starlight
>>Express CCD in guide mode and a Pentax K1000. Is the mounting of the
>Pentax
>>camera a "no brainer"? i.e. Will the Pentax be in focus with a standard
>>Meade eyepiece? (Speaking of parfocal,,, I've noticed that the Meade
>>12.4mm is NOT parfocal with the standard 26mm. Are they supposed to be
>>parfocal?)
>>
>>Expressed another way: Can I just start shooting away after I mount
>>everything? Or do I have to undergo some type of elaborate focusing
>process
>>for the Pentax? From just a quick look at the Pentax, OAG and T-adapter
it
>>doesn't look like there is much to adjust other than the placement of the
>>eyepiece in the OAG.
>>
>>Fred
>>
>
>

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