Re: [APML]: PPF400 exposure time

[byen@ix.netcom.com]

byen@ix.netcom.com wrote:
> 
> 
> Hi Robert,
> 
>   I also use a Celestron 8" f1.5 Schmidt Camera, both color & TP films.
> I typically use 4 min on Hyp 2415 and Fuji Super HG400.  This weekend
> will be my 1st try at using PPF400 color film, on Hale-Bopp.  I'm
> guessing around 2 min for exposure time, and will bracket around this.
> Have you used this film & "zeroed" in on an exposure time?  Do you use a
> roll film holder (I don't).
> 
>   I found your homepage informative.  See mine at
> http://www.primenet.com/~boobyen - there are some Schmidt shots there.
> 
>  Many yrs ago, I used a Meade 8" SC as a guide scope.  Now, my 8" (or
> 5.5") rides piggyback on my AP 5" f8 EDT refractor (guidescope), on a
> G11 mount.
> 
>    There was some guy Mike Sisk (I think), who had a photo with a 16"
> (?) Schmidt camera in Deep Sky, few yrs ago.  He's in Oklahoma (?).
> Know of any bigger Schmidt cameras available?
> 
> Bob Yen

Oops.. This was meant as private e-mail to Robert Reeves.

  Anyway, may as well ask everyone out there.  Question is for unhypered 
Kodak PPF400 & telephoto lenses (unobstructed optics), what exposure 
times for various f ratios - f4, f2.8, f2, f1.4?

I've heard reports of 15 min & 20 min for f4.  Roughly this would 
translate to:
   7.5 - 10 min for f2.8
   3.6-5 min for f2
   1.8-2.5 min for f1.4  

Jerry Lodriguss recently did a test using a 85mm/1.4 stopped to f2.8 - 
went 5 min.  Was this adequate?
Jerry: did the PJM-2 (Ektapress 640 multispeed) show similar exposure 
characteristics as PPF400?  I may also try it (if I can get a hold of a 
roll)..

For Fuji 800, I've been going 6 min @f2, 12 min @f2.8.  If Jerry's test 
exposures @f2.8 for 5 min are "adequate", then I've been going too long! 


Bob Yen