Re: [Leica] UV filter for Noctilux-measurable light loss??

[John Collier <jbcollier@home.com>]

Tina,

Are you using the meter as a reflected meter or an incident meter? If you
are using it as an incident meter, you may be shading the dome slightly with
the filter rim and your hand. I just repeated your experiment with the same
meter in reflective mode, ISO 3200 and the speed set at 125th (f stop was
1.4 and 4/10ths). The UV filter reduces light by 1/10 of a stop. I tried two
different types of B+W UV filter, one single coated and one multicoated and
got the same results both times.

Now none of this is to encourage you to use UV filters! I do not use them
(except in salt spray or in sandy wind). Nor is this intended as
instruction!! I do would never give you, Ted, Jim, Mike and others
advice!!!!!!!!!!! I only continue to subscribe so I can get the pearls of
photographic wisdom that you Olympian Photographers pass on to us mere
mortals

Humbly yours,

John Collier

> From: Tina Manley <images@InfoAve.Net>
> 
> At 11:43 AM 11/17/00 +0000, you wrote:
> 
>> An aside to Tina: What instrument do you use to measure darkness? ;-)
>> Nick.
> 
> 
> O.K., Nick.  I tried it again.  I am using a Minolta IV F Auto Meter.  I've
> entered 3200 as the ISO and 1/125 as the time.  In room light, without the
> UV filter in front of the meter I get an f number of 2.89.  With the UV
> filter, I get an f number of 2.86.  Not much difference, it's true, but
> enough to matter when you are taking pictures in the dark!  In my dark
> hallway, with an ISO of 3200 and 1/30, I get a reading of 1.0 without the
> filter and a reading of "under" with the UV filter.
> 
>