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

[Kirk Carbo <kcarbo@lobosservices.com>]

Wei-Hao

That's very interesting.  I have thought about doing more wide field shots
with my view camera and slide film.  I was thinking a 4x5 slide is so large,
it wouldn't even need to be printed.  It would look beautiful on a light
box.  Are the on films being pushed needing 2 hour exposure or one hour?

Kirk Carbo

>-----Original Message-----
>From: Wei-Hao Wang [mailto:wang@IfA.Hawaii.Edu]
>Sent: Thursday, May 06, 2004 4:40 PM
>To: Discussion of Film Astrophotography
>Subject: RE: [APML] 4x5 astrocamera (again?)
>
>
>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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