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02-24-2012, 12:53 PM   #1
Jonathan Mac's Avatar

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Location: Madrid, Spain
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Sigma 24mm f/2.8 - overexposure on film?

Hi all.

I have the above lens (the AF version) and have used it on my K200D, where it exposes about a half stop brighter than my other lenses. I believe this is a common phenomenon with this lens.

On digital it's easy to work with, but I have recently started using it with an MX, so I won't see the results for a while, until I process the film. Does anyone know if this lens will over-expose on the MX? I don't want to ruin all my super-wide shots on this first roll of film.

02-24-2012, 02:24 PM   #2
johnyates's Avatar

Join Date: Aug 2011
Location: Saskatoon, SK
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Suggestion: go out and shoot. Take notes. Bracket.
Slight overexposure is not fatal on negative film. There's plenty of latitude. You might even appreciate that extra shadow detail. Unless you do your own printing, it's likely you won't even notice the difference between two exposures bracketed by half a stop.
02-25-2012, 04:17 AM   #3
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wlachan's Avatar

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1/2 stops is within "K mount" tolerance based on my experience. The problem is that every K mount body and lens were calibrated with certain tolerance, and each sample is different. Certain combination can be off by as much as 1/2 stops. You can recalibrate that Sigma matching your K200D to your taste, but you might be surprised again with the next body upgrade. Still, you can disassemble the lens mount and bent the metal piece guiding the rear lever inside slightly. Kind of ugly design but that's Sigma.
02-25-2012, 04:58 AM   #4
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You can do a test by putting beside the two cameras and then see how different is the shutter speed at the same ISO and aperture. My guess is that the old MX will measure correctly since it doesn't have an aperture pin, but it simply measures the availible light.


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