RE: [APML] 4x5 astrocamera (again?)

[Wei-Hao Wang <wang@IfA.Hawaii.Edu>]

Hi,

I would say, 1 to 2 hours.  4x5 astrophotography is extremely common
in Japan.  (Some of them are quite crazy.)  Sometimes I even wonder 
if 4x5 (instead of 120) is the normal mode of Japanese astrophoto.
People use F5-F8 lenses or telescopes with either E100S or Provia
100F (velvia 100F is a new one).  Their exposure times are usually 
between 1 and 2 hours and the results look nice.

The three films I mentioned all have low ISO speed.  However, they
have low reciprocity too.  In addition, they all can be pushed by
at least 2 stops.  Pushing will make the image contrasty, which is 
not a bad thing as long as the film is not overexposed.

Wei-Hao



On Thu, 6 May 2004, Kirk Carbo wrote:

> What kind of exposure would it take for films that slow.  I made a couple of
> exposures at TSP last year. One hour each on  Ilford HP5 400asa with the
> lense wide open at f5.6 and it needed at least another 30 minutes.  The lens
> needs to be stopped down too, so that would put me at 3 hours for one
> exposure, which is consistent with the exposure times that Wallace and
> Provin were using with hypered Techpan in an AP155 refractor.
> 
> Kirk Carbo
> 
> >-----Original Message-----
> >From: Wei-Hao Wang [mailto:wang@IfA.Hawaii.Edu]
> >Sent: Thursday, May 06, 2004 4:11 PM
> >To: Discussion of Film Astrophotography
> >Subject: RE: [APML] 4x5 astrocamera (again?)
> >
> >
> >Hi,
> >
> >There are at least three 4x5 color films OK for astrophotography.
> >Fuji Provia 100F, Velvia 100F, and Kodak E100S, which is still 
> >available at B&H.  If I shoot 4x5, I will definitely buy lots of 
> >E100S and put them in frig.
> >
> >Cheers,
> >
> >Wei-Hao
> >
> >______________________________________________________________________
> >Wei-Hao Wang  :)
> >
> >Institute for Astronomy at University of Hawaii
> >
> >Address:                       Phone: 808-956-9867                  
> >2680 Woodlawn Drive            Personal Website:
> >Honolulu, HI 96822             http://www.ifa.hawaii.edu/~wang
> >______________________________________________________________________
> >
> >
> >
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