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03-10-2010, 06:32 PM   #1
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Cosina 1.2 - Will only mount wide open?

So I just got a Cosina 1.2 off of ebay and whenever I mount it to my k-x, it immediately goes to 1.2 and no matter what I put the aperture ring on it remains at 1.2 while mounted.

But, if I unmount it, it immediately goes to whichever aperture it's set to on the ring.

Any help would be appreciated, otherwise I'll be returning this asap.

03-10-2010, 06:39 PM   #2
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Yup. It will stay at wide-open at all times until you take a photo, at which time it stops down only momentarily while the shot is taken.

This way when you compose through the viewfinder, you always get the brightest possible image.

Use it in "M" mode only. I'm a K20D user, so I don't know exactly how you take a meter reading to set an exposure semi-automatically using one of these lenses on the K-x, but hopefully someone can chime in on that point.
03-10-2010, 06:46 PM   #3
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QuoteOriginally posted by Quicksand Quote
Yup. It will stay at wide-open at all times until you take a photo, at which time it stops down only momentarily while the shot is taken.

This way when you compose through the viewfinder, you always get the brightest possible image.

Use it in "M" mode only. I'm a K20D user, so I don't know exactly how you take a meter reading to set an exposure semi-automatically using one of these lenses on the K-x, but hopefully someone can chime in on that point.
Well, now I feel dumb. I think I just became extra paranoid because the glass came covered in finger prints which took a while to get off.
03-10-2010, 06:48 PM   #4
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QuoteOriginally posted by Quicksand Quote
Use it in "M" mode only. I'm a K20D user, so I don't know exactly how you take a meter reading to set an exposure semi-automatically using one of these lenses on the K-x, but hopefully someone can chime in on that point.
If by semi-automatic you mean green button, then he can use the K-x green button, only it HAS to be set to act as a green button (it can be costumized to act as other things such as DOF preview or Crossprocess filter)

03-10-2010, 06:49 PM   #5
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QuoteOriginally posted by Cedromar Quote
Well, now I feel dumb. I think I just became extra paranoid because the glass came covered in finger prints which took a while to get off.
Don't sweat it. Using an "M-class" lens is different from using an "A-class" lens, which is different from using an autofocus lens, which is different from using a screwmount lens. They all have their operational quirks.
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