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03-23-2010, 09:49 PM   #1
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Takumar under-exposure problem

I have some takumar that i bought to play with, and i am really astounded to their quality and sharpness. The problem is that in my K-m they underexpose a lot (around 2.5 stops for the 200/4 200/3.5 28/3.5 and 1.5 stops for the 55/1.8) so I'm wondering if they would underexpose in my MX in the same amount? Would I need to compensate still or is there no problem with it (or some other film cameras for that matter)?

03-23-2010, 10:03 PM   #2
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When I was shooting Pentax digital I always had that problem, however I was shooting the K100D. However, since I was shooting in full manual it didn't mater much.
Some people said that shorting the contacts with tinfoil helps, so I tried it.... and sure enough it did.
However I don't recommend being the first one to try it, with your camera model

I've never had those problems while shooting with the same lenses on film cameras, or my Sigma.

I haven't the faintest idea what would be causing it on Pentax digitals
03-23-2010, 11:09 PM   #3
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Same here

I have Super Tak 200 f4 that is almost exactly 2.5 stops under exposed shooting Av!

Does not leave much room for exposure comp - I usually end up in manual.

Interesting about the contacts.
03-24-2010, 04:49 AM   #4
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I typically find that M42 mount lenses require about 1 stop of over exposure in the exposure compensation.

Note also that on the later cameras and especially K10D and K20D exposure is a problem with manual aperture lenses due to the focusing screen used on those cameras. this causes exposure to change a lot as a function of F stop.

the K7 is better but in my opinion, the *istD is the best metering body out there in terms of exposure linearity with aperture.

Putting a split image into the k10D helps substantially except for the need for exposure compensation,

I have posted results before on this

03-24-2010, 04:49 AM   #5
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I also mostly use old Pentax primes on my K100s and find that shooting in manual is the best way to obtain perfect exposure.
03-24-2010, 06:39 AM   #6
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On my kx, the readings are totally different between M and Av, with Av way underexposing. M is correct 90% of the time. (Of course, lenses vary.)

I don't understand this at all, because the same light is entering the lens in both modes, but the camera only understands one of them.
03-24-2010, 07:37 AM   #7
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I use the tinfoil trick - no problem with anything, really. If you think about it, all your "K" lenses short out those contacts since they have metal mounts
03-24-2010, 10:22 AM   #8
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My eyes, my eyes!!

I shoot many M42's and other manuals on my katzeye-equipped K20D. Often the exposures are dead-on, whether in Av or M. Some M42's on a Bowers-type adapter have contact-shorting tape, and some don't. Lately I've been using the flanged adapter a lot, which shorts all contacts. The only pattern I see is that shadowed scenes with small bright areas (patches of sun amidst thick forest, etc) tend to correctly expose with a PK-A lens, and underexpose with an adaptered lens, whether in Av or M. I should try hand-metering and compare results.


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