kgs Posted May 26, 2007 Share #1 Posted May 26, 2007 Advertisement (gone after registration) Hi all, I observed that all pictures taken with M8 (28,35,50 mm) and SF24D are aprox. 2/3 to 1 f-stop underexposed. Adding the Leica IR-filter everything is OK. Without flash there is no difference in the exposures with and without filter. Lens Detection was set according epuipment used, but there is no impact of this setting on that effect. How is it possible? Has somebody an explanation? Regards George Link to post Share on other sites More sharing options...
Advertisement Posted May 26, 2007 Posted May 26, 2007 Hi kgs, Take a look here M8, SF24D & IR-filter. I'm sure you'll find what you were looking for!
Shootist Posted May 26, 2007 Share #2 Posted May 26, 2007 I see a drop in exposure reading when using the IR filters. Say I have a 50mm lens with no filter and I set the f/stop to 4. I get a shutter speed of 1/250. I then put the filter on with the same f/stop and same lighting and now get a shutter speed of 1/180-1/125. Don't own the Leica flash so I can't comment on that part of it. Link to post Share on other sites More sharing options...
gravastar Posted May 26, 2007 Share #3 Posted May 26, 2007 I think you will find both the camera and flash exposure meters are sensitive to some infra red as well as daylight. Without the UV-IR filter the scene you are photographing appears brighter than with the filter because of the infra red contribution. The effect is very noticeable with tungsten illumination. Bob. Link to post Share on other sites More sharing options...
marknorton Posted May 26, 2007 Share #4 Posted May 26, 2007 Which mode are you using for the SF-24D - Auto or GNC? I agree with Bob, the two flash sensors either side of the main metering cell in the base of the camera lens throat are probably sensitive to IR and are throwing off the exposure. I expect the main metering cell is much more sensitive and will have its own built in IR filter. Link to post Share on other sites More sharing options...
barjohn Posted May 26, 2007 Share #5 Posted May 26, 2007 I was doing some testing yesterday with a GretagMacbeth color checker to generate M8 profiles and I noticed a couple of things. The camera seems to be about 1/2 to 3/4 stop over exposing in bright sunlight with a UVIR filter. I didn't try it without a filter. I have noticed in the past that the SF-24D flash in GNC will overexpose the image by at least 1 stop and if you are close to the subject by as much as 2 stops, even when I use a diffuser from Leica goodies. It is a little frustrating. Maybe I am doing something wrong and I just haven't figured it out. Link to post Share on other sites More sharing options...
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