Exposure compensation with a IIIb centre filter

[ptd81]

Hi there, I was lucky enough to recently pick up a second hand Ebony SW45 with a Schneider 58mm XL for a fantastic price. Now comes the fun part of actually getting to learn how to get great pictures from it! :)

Just a quick question regarding centre filters... the lens is fitted with a Schneider IIIb centre filter and I was wondering what sort of exposure compensation I need to apply from a metered reading (my favourite way of working is to get the shot with my D300 then apply the exposure settings to the film camera - but a bit unsure of how i need to adjust my exposure set up).

Am looking forward to giving this awesome camera a good field test, am planning a trip to the wilds of Tasmania, can't wait!!

[Patrik Roseen]

Hello and welcome to this forum, I hope you will enjoy it here.

The information you are looking for can be found in the bottom of the last page of this pdf-file from Schneider.

http://www.schneiderkreuznach.com/archiv/pdf/an_su_1995.pdf

For maximum compensating effect of these Center Filters the lens should be stopped
down one or two stops depending on the image circle diameter being used. In order
to achieve the best results and definition the exposure time should be increased by a
factor 3.

I have learned that one needs to stop down for the lens to see the filter.
The reason to increase the time of exposure is that the centre of the filter darkens this area with 1.5 stops (aligning it with the fall off on the outside areas)

good luck!

[ptd81]

Thanks for the help, much appreciated!!