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03-04-2013, 05:45 AM   #1
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Removed aperture control lever

I just bought a M*300 with removed aperture control lever. Will the lens be able to meter in Av mode? My M50 1.7 and M135 3.5 meter just fine in Av but they both have the lever. Yes, i know i should have asked before buying.

03-04-2013, 06:07 AM   #2
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Yes it will work in Av mode.

Without the prescence of the lever the aperture will always be stopped down to the value set on the aperture ring. You may want to open up during focusing and then stop down when taking the shot.
03-04-2013, 06:22 AM   #3
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Original Poster
Thank you for the response. So, as I understand your response, the problem is that since the aperture is closed higher f settings will darken the screen making focusing difficult. In low light I would have to put to largest aperture for focusing, then set the f number I want to use for the shot.
03-04-2013, 07:52 AM   #4
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It will meter in Av mode even when stopped down but will probably only give accurate exposures when wide open. You'll have to run a series of exposure tests at different f-stops to determine what exposure compensation is needed.

I hate it when people mangle K-mount lenses and then sell it without informing the buyers. Many times the lever can be removed in a reversible manner. It's a crime if it is a KA type lens.

03-04-2013, 11:37 AM   #5
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To be completely clear about legacy lenses and Av mode

K mount lenses with an aperture lever but no aperture contacts (I.e. not KA lenses) will meter in Av mode but only operate wide open, the lens will never stop down while shooting.

k mount lenses with the aperture lever removed, and m42 lenses will stop down as you turn. The aperture ring, and meter at all apertures, but it is a little difficult some times to focus as the image darkens, so you end up focusing wide open then stopping down manually to shoot.

KA and newer lenses will meter wide open in AV mode and stop down to the camera set aperture when shooting providing the aperture ring is in the A position, otherwise they behave like K mount lenses and only shoot wide open in AV mode.

Also, any legacy lens, when shooting in Av mode may have errors compared to a KA or later lens because of metering errors s a function of actual aperture. This point h been discussed since the introduction of the K10D . You may need to test each lens or at least understand how errrors modify the metering as a function of aperture to get it right consistently

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