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01-03-2010, 02:54 PM   #1
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Tokina MF, K-mt stays wide open on k-7

I just acquired an immaculate, manual focus, k-mount Tokina 80-200mm F4.5 lens for $10. Everything works great, the lens looks and feels new, but it stays at the widest aperture no matter what I do. It does not have an "A" setting on the aperture ring. Usually allof my older pentax lenses work well at any setting, so long as I have the camera on Av. Any ideas?

01-03-2010, 03:41 PM   #2
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Are you using M mode with the green button, or are you just looking visually at the lens while mounted on the camera? The camera will keep the lens in the wide-open position while mounted, no matter what aperture you have the lens set to. This is for wide-open metering. However, when in M mode, the green button will stop down the aperture to get a light metering. A non-KA or newer lens will not operate (well) outside of M mode. Do you notice no difference when you do this with the lens set at f/16? Are your images coming out overexposed or underexposed?
01-03-2010, 04:17 PM   #3
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Thanks!

Thanks for the info. It works just fine on M and green button. This is the only lens that I have which only works on M+Green
01-03-2010, 04:39 PM   #4
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what are your other lenses, all K mounts only stop down on pentax DSLRs in M mode.

A Mode fires wide open always.

M42 lenses work in Av Mode because they stop down all the time manually

01-03-2010, 05:49 PM   #5
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My most common lens is a 17 - 70 Sigma (AF). I also have a couple of old M42 Takumars 300/F4and 55/1.8. Plus a 70-210 F, 28-300 Tamron AF, 90mm Tamron AF 2.8 1:1 macro, 35-135 Pentax F, M-135/3.5 , M 200/f4. The last two are recently acquired and I haven't had a chance to test them out. The 28-300 Tamron is not a great lens by any standards and I seldom usi it now. Same for the 35 - 135 which I'm selling. The old Takumar 300 is also probaly sold - it is a little too awkward to use hand held and is very front heavy on a tripod since the tripod mount has to be removed from the lens to fit the K-7. The Tak 55/1.8 came with the first SV i bought around 1966 and still produces great photos. I'll probably pick up a couple more M42's. I found that if I take the spring out of the adapter it stays on the lens all the time and it becomes a semi-permanent K-mount.
01-03-2010, 06:20 PM   #6
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your lens list and explanation of what you have not yet used says it all.

ALl the K Mount lenses, specifically the M 135 and M 200 will behave the same way as the tokina 80-200.

You can use manual only.

except for the takumars, all others are "A" lenses or newer which means the camera controls the aperture.
01-03-2010, 10:27 PM   #7
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QuoteOriginally posted by Lowell Goudge Quote
your lens list and explanation of what you have not yet used says it all.

ALl the K Mount lenses, specifically the M 135 and M 200 will behave the same way as the tokina 80-200.

You can use manual only.

except for the takumars, all others are "A" lenses or newer which means the camera controls the aperture.
What he said...

Steve

(This stuff is hidden deep in the back pages of your camera manual...)
01-04-2010, 11:05 AM   #8
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... but explained quite clearly in the sticky thread on using manual lenses at the top of the Beginner's forum here!

01-04-2010, 11:11 AM   #9
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QuoteOriginally posted by Marc Sabatella Quote
... but explained quite clearly in the sticky thread on using manual lenses at the top of the Beginner's forum here!
and still amazingly reliant it seems on people being willing to read
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