Re: [APML] question on exposure times for E200

Yes always push the E200 at least one stop. A few will push 2 stops but additional grain will show at questionable sensitivity gains. However a one stop push will not increase grain hardley any. E200 is a very fine-grained film and has excellent Ha sensitivity. You'll find it not quite as good in recording OIII and reflection nebulosity.

Bobby Middleton

From: Richard Crisp

To: Stuart Heggie ; Discussion of Film Astrophotography

Sent: Saturday, July 10, 2004 2:30 PM

Subject: Re: [APML] question on exposure times for E200

thanks Stuart.

I guess I have to ask the film processing people to push it one stop, right? That's not an exposure parameter from what I remember, it is a processing parameter, right?

I wonder if I will have fogging problems going so long?

----- Original Message -----

From: Stuart Heggie

To: Richard Crisp ; Discussion of Film Astrophotography

Sent: Saturday, July 10, 2004 12:13 PM

Subject: Re: [APML] question on exposure times for E200

Richard, you could go 2 hours with that film f-ratio combo. I go 40 min at f/4 with 400 speed film from my rural skies. My math says the square of your f-ratio divided by mine * 40 min is about 2 hours so if you push the E200 one stop you get 2 hours. You could probably get away with less but I bet that would work.

Beauty in things exists in the mind that contemplates them.

Stuart
http://www3.sympatico.ca/stuart.j.heggie/Stuart.J.Heggie/
Flesherton, Ontario, Canada

----- Original Message -----

From: Richard Crisp

To: Discussion of Film Astrophotography

Sent: Saturday, July 10, 2004 3:03 PM

Subject: [APML] question on exposure times for E200

Hi gang

I want to do some prime focus film shots tonight in the Saggittarius region using my Pentax 6x7 and some E200 film.

I am really excited about doing this.

I want to mount the camera on my AP180EDT with both the 0.75x telecompressor and the AP field flattener. That gives a focal ratio of f/6.75

My question is what exposure time should I use for something like M20?

If I got no answers from the list, I'd probably go with 45 minutes, but you folks are the experts, so I'd like to hear some other opinions.

Thanks and best regards

Richard

_______________________________________________
Astro-Photo mailing list
Astro-Photo@seds.org
http://seds.org/mailman/listinfo/astro-photo

_______________________________________________
Astro-Photo mailing list
Astro-Photo@seds.org
http://seds.org/mailman/listinfo/astro-photo