Re: [APML] Exposure Question

["William R. Mattil" <wrmattil@ix.netcom.com>]

Brian Larmay wrote:
> 
> Bill, that is an incredible shot of cygnus!

Thanks Brian. Even a blind squirrel (me) gets lucky once in a while :^)

> Ok... I never really read about large format but have an idea thereof..

Well its medium format but I'm picking nits <laughs>

> So what Im seeing in this photo is one frame at 105mm?
> Is this what the lens sees and records for that FOV?

Yes. 105mm lens with a 6x7 is roughly equivalent to a 50mm lens on a
35mm body. There are plenty of regulars here that can expound on the
medium format far better than I. I am a very recent convert :^)

But the point is that even with 35mm, say 105mm @ f/2.8 1 hour on E200
works well. And a few will even push it a little during processing.
Though that may be more at f/6 and above.
 
> I have to get me one of those if thats the case!

<laughs> Astrophotography is a sickness ... there is no cure. Prices are
coming down with the advent of CCD Cameras so 6x7 isn't all that
expensive. Of course after you get one you will need a AP traveller with
field flattener, or a AP155 .... Or a 12,5" Ritchey or ..... heck you
get the idea

BTW the night I shot that image I actually shot 4. All 60 minutes and I
am curious what it would look like stacked ? Also

http://www.celestial-images.com/Cygnus.html

Was my first light image with this camera. Same subject but framed
differently and it includes IC1396 in Cephus. Also 1 hour. There is no
substitute for dark skies.

Pentax 6x7's show up on Astromart and Ebay all the time.


Regards

Bill

-- 
William R. Mattil	|                              
wrmattil@ix.netcom.com	| http://celestial-images.com      
(972) 399-4106		|
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