sigma 28-300mm over exposing?

kauaiguy · 09-18-2008, 12:32 PM

greetings! first post, hope it's in the right place:

I've got a Sigma 28-300 3.5-6.3 zoom that i've been using for a few years. over the past few months, it's images have become more over-exposed. I suspected it was just some setting on the K10d, and have played and learned a lot from that, but the problem remains. Recently I acquired an FA 50mm 1.4, and (wow, what a lens!) all it's images are perfectly exposed. change back to the sigma, over-exposed. In all shooting modes, all metering and focusing modes.

One other possibly telling piece of info, for awhile, when the first attached, the camera would ask for the focal length of the lens. I've gently cleaned the contacts, and that problem went away. But possibly some info isn't getting from that lens to the camera?

Another related question: does the camera store any user data on the lens used? In other words, if i'd set some menu item while one lens was attached, then swapped lenses and set it another way, would the camera remember when the first lens was reattached and change those settings for that lens?

Thanks in advance for your kind help.

Marc Sabatella · 09-18-2008, 02:03 PM

Could be that the aperture blades have become slow. Does this happen when shooting wide open? If not, that's my bet.

kauaiguy · 09-18-2008, 05:30 PM

Originally posted by Marc Sabatella

Could be that the aperture blades have become slow. Does this happen when shooting wide open? If not, that's my bet.

Marc, tried it wide open, same results. weird, eh?

09-18-2008, 12:32 PM	#1
kauaiguy Forum Member Join Date: Sep 2008 Location: hawaii Photos: Gallery Posts: 62	sigma 28-300mm over exposing? greetings! first post, hope it's in the right place: I've got a Sigma 28-300 3.5-6.3 zoom that i've been using for a few years. over the past few months, it's images have become more over-exposed. I suspected it was just some setting on the K10d, and have played and learned a lot from that, but the problem remains. Recently I acquired an FA 50mm 1.4, and (wow, what a lens!) all it's images are perfectly exposed. change back to the sigma, over-exposed. In all shooting modes, all metering and focusing modes. One other possibly telling piece of info, for awhile, when the first attached, the camera would ask for the focal length of the lens. I've gently cleaned the contacts, and that problem went away. But possibly some info isn't getting from that lens to the camera? Another related question: does the camera store any user data on the lens used? In other words, if i'd set some menu item while one lens was attached, then swapped lenses and set it another way, would the camera remember when the first lens was reattached and change those settings for that lens? Thanks in advance for your kind help.

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09-18-2008, 02:03 PM	#2
Marc Sabatella Veteran Member Join Date: Sep 2006 Location: Denver, CO Photos: Gallery Posts: 10,685	Could be that the aperture blades have become slow. Does this happen when shooting wide open? If not, that's my bet.

09-18-2008, 05:30 PM	#3
kauaiguy Forum Member Join Date: Sep 2008 Location: hawaii Photos: Gallery Posts: 62 Original Poster	Originally posted by Marc Sabatella Could be that the aperture blades have become slow. Does this happen when shooting wide open? If not, that's my bet. Marc, tried it wide open, same results. weird, eh?

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