Re: [APML] Exposure Question

["Brian Larmay" <astrobri@ameritech.net>]

>
> Each f-stop will approximately double your exposure time.  Reciprocity
> failure on E200 is pretty low, so to a single f-stop, doubling is a
> pretty good estimate.  Remember that anything less than a factor of 2
> generally doesn't matter much, so if you want to double and then
> "round" to 15 minutes, it isn't going to show much of a difference
> from must doubling to 14 minutes.

Ill do this next time out ... Ill try between 13 min, and 15 min exposures
and see what comes out the best @ 5.6


>     Brian> Will this sharpen my images noticably vs @ f/4?
>
> Yes, it should, assuming both are focussed as best you can get.

Isnt it always infinity with wide lenses, or am I missing something?

>     Brian> Will this reduce Vignette and help me to create mosaics
>     Brian> alot easier?
>
> Yes, vignetting should be reduced.

Excellente'

>
>     Brian> All exposures are made using Kodak E200 tonight.
>
> I'm quite suprised you get away with only 7 minutes at f/4.  My first
> shot of Cygnus was pretty mediocre with 4 minutes at f/4, but I was
> clueless about what to try.  From my dark sky site (which is not
> exactly pristine since we are talking about the northeast US), I can
> go 20--60 minutes at f/4 depending on the altitude of what I'm
> shooting.  For stuff near the zenith, 60 minutes is about it.  For
> stuff down around 30-degrees up, 20 minutes is pushing it.  This is
> with normal development.  Also, I don't have a "real" film scanner, I
> have one of those flatbeds that doubles as a slide scanner (the Epson
> 2450).  It needs a well exposed negative to give good results.
>
> Do you push you film?  What do you use to scan it?  I'm just having
> trouble figuring out how 7 minutes works for you.
>
> regards,
>
> roland

I dont push my film because I dont want to deal with added grain.
I wonder if there is something technically dif with my photo labs and their
processing techniques ... I dont understand why you guys expose for so long,
and I expose for so short and get almost the same results.
Might this be due to the 1 hr processing?
I am going to take notes next time I go to the lab and se what they do dif.
How bout my camera as I seen no one else use a Nikon FG here before.

Anyone wanna come to Wi? Shoot some astrophotos under our magical skies??
<grin>

As far as my scanner goes, I use a Kodak RFS 3600 which does a great job
along with the silverfast hardware.

Brian

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