Re: [OM] Long Focus vs. Mirror Lens

Subject: Re: [OM] Long Focus vs. Mirror Lens
From: "tOM Trottier" <Tom@xxxxxxxxxxxxx>
Date: Fri, 1 Feb 2002 13:14:55 -0500
On Friday, February 01, 2002 at 12:48, frieder.faig@xxxxxxxxxxxx-
stuttgart.de <olympus@xxxxxxxxxxxxxxx>
wrote re "Re: [OM] Long Focus vs. Mirror Lens" saying:

> On Thu, Jan 31, 2002 at 01:34:36PM -0700, Daniel J. Mitchell wrote:
> >  Also, how awkward _is_ this? f8's a reasonable aperture, I guess, but
> > do you end up needing a lot of ND filters or something in practise?
> What is the speed of the film? Remember the sunny F-16 rule. This is the
> usual brightness of sunlit scenes. There are not too much cases, when you`ve 
> to
> deal with a lot more light. (double amount = a lot more, but just one stop!)
> 100 ASA -> ~ F16+1/125s -> F8+1/500s
> 400 ASA -> ~ F16+1/500s -> F8+1/2000s
> I´ve no experience with mirror lenses. But I´d guess one ND-2 filter would 
> help
> in most cases.

Don't forget that mirror lenses lose about a stop to the middle mirror, so
you wouldn't need an Neutral Density filter in daylight unless your ASA was
over 400, even with 1/1000.

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