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09-19-2007, 04:35 PM   #46
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QuoteOriginally posted by jeffkrol Quote
I'm curious to see your results.....
here is a sample of the linearity test, done on a K mount lens modified to KA mount.

in order to do the test, you need to select an ISO setting that insures at maximum apature, no more than 1/3200 second shutter speed to insure you are always in the control range.

Also, for K mount lenses, the best camera performance is with the exposure set to .5ev increments, as this will match the mechanical .5 ev increments in most apature control rings perfectly. The result iw you will always have the same error, all else being equal, with the camera.


Last edited by Lowell Goudge; 03-02-2008 at 10:58 AM.
11-07-2007, 03:43 PM   #47
sft
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Well, I talked to the person back in the US who is receiving my lens from Pentax US for me and I am little p*ssed. First of all they said that 1/3EV underexposure stopped down vs wide open is normal and within spec - I disagree but whatever - thats not the end of the world but they are saying my lens is performing fine and focusing fine and that I have to send my camera in for focus calibration. This is a major hassle as I am no longer in the US. Also my camera focuses just fine with every other lens I own (albeit none are SDM). Now I don't know all the technical stuff of how this all works but if they calibrate my camera to work correctly for the DA* and if this will affect all non-SDM focusing as-well then all my other lenses will be way off - if they can tweak both so it only affects SDM focusing then I guess it will be OK. I'm feeling a little skeptical about all this and sending my camera to them.

I wish I never bought the DA*, or at least shouldn't have bought it so early on in the life cycle and this whole DA* experience has me dissapointed in Pentax anyways.

Now I have to contemplate whether to send my body to the US or get my lens back and try to get it repaired at a contracted service center in Turkey after dealing with Pentax US to get the international warranty card (and I doubt the service company in Turkey will be able to fix it).

I wouldn't mind sending my camera to them if Pentax could do service like every other company and fix the tihng in a week but a whole month without camera is unacceptable as I plan to travel soon. This sucks and right now I am wishing I was a Nikon user instead as this whole thing would already be over with if I had a problem with one of their products.
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