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Forum: Repairs and Warranty Service 05-20-2017, 04:41 PM  
K30 Aperture failure advice
Posted By Owltown
Replies: 29
Views: 3,496
On further careful study, I see that my K30 does have the aperture block failure. Any lens with a fully auto diaphragm (any KA series for example) stops down to its smallest opening regardless of light conditions or camera mode setting. I can see this by looking right into the lens and firing the shutter under different light conditions. The reason I can shoot with my old SMC-M lenses is that the lens mechanically limits stopping down to the opening I manually preset. So now I gotta buy a K3, I guess....
Forum: Repairs and Warranty Service 05-14-2017, 05:14 PM  
K30 Aperture failure advice
Posted By Owltown
Replies: 29
Views: 3,496
Thank you -- I will try that in daylight tomorrow.
Forum: Repairs and Warranty Service 05-14-2017, 04:14 PM  
K30 Aperture failure advice
Posted By Owltown
Replies: 29
Views: 3,496
I wonder if the problem I'm having is related to the aperture block issue. I use a K30 with a K-mount SMC-M 50mm f4 macro lens. I use AV mode in a studio environment, shooting tabletop images with constant lighting. The K30 body was purchased new and now has a shutter count around 20,000. Recently I noted that the shutter speed does not change as the aperture is adjusted. I've looked into the lens when shooting, and the aperture is indeed stopping down correctly throughout the lens's full range. But I cannot get proper exposure other than at a single f-stop setting. Changing ISO has no effect.

Just as a test, I mounted a SMC-DA 18-55mm "kit" lens and shot in AV mode. The problem was unresolved: Correct exposure in AV mode at only one f-stop setting, In P and AutoPict modes, the lens aperture can be seen closing down, but the images are consistently 4 to 5 stops under-exposed.

This is not a show-stopper for the kind of photography I'm doing, but I'm limited to shooting everything at f5.6 to get correct exposure, and using the +/- adjustment simply to correct the equivalent of an f-stop or two, for unusually dark or bright subjects. Any ideas or suggestions? Thanks!
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