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05-06-2011, 01:00 PM   #1
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Takumar Bayonet 28 f2.8 "shifts" during stop-down metering

I recently got a Takumar Bayonet 28 f.28 lens for next to nothing. Cosmetically it is in perfect shape, but I've noticed that when stop down metering (or any time the aperture lever is released) the image in the viewfinder shifts up noticeably. It seems like the entire optical assembly has a bit of wobble, which happens when pressing down on the aperture lever. It doesn't seem to affect the quality of my pictures, but I'm guessing that the final image is very slightly different due to the shift.

Has anyone ever noticed something like this with this or any other lens? I did a search and couldn't find anything on "wobbly" lenses. I did try taking it apart (curse you JIS screws and thread lock!) but saw no way to tighten up the assembly.

I've seen this lens gets fairly average reviews due to the lack of SMC coating and being a budget lens, but the IQ is pretty good:



OTOH, I have a chance to pick up a Pentax-FA 28 2.8 for $160. Would it be worthwhile (strictly with regards to IQ) replacing the Tak with that?

05-06-2011, 01:31 PM   #2
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QuoteOriginally posted by donutman_2000 Quote
I've seen this lens gets fairly average reviews due to the lack of SMC coating and being a budget lens, but the IQ is pretty good:
Wow, that is a nice pic! I have one of these lenses and have never had any of the issues you have mentioned...
05-06-2011, 01:37 PM - 1 Like   #3
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QuoteOriginally posted by donutman_2000 Quote
...OTOH, I have a chance to pick up a Pentax-FA 28 2.8 for $160. Would it be worthwhile (strictly with regards to IQ) replacing the Tak with that?
Definitely do that. The coatings are superior at least. You can compare and easily sell the FA for the same or more if you don't like it.

I think the Takumar is the same optical formula as the M28/2.8 version 2, A28/2.8 and F28/2.8, a pretty good formula. It has the same inferior coatings as the rest of the Takumar Bayonet line, though. So if you test, make sure you compare flare and contrast too. I've never had either of these lenses but a lot of people seem surprised by how decent the Takumar Bayonet is. I wouldn't be shocked if it was competitive on sharpness.

Besides optical formulas, it might share the same problem as some Pentax-A 28/2.8s. The front lens group gets loose. The group is in a threaded carrier and you can tighten it with two fingers on the fromt element. It won't look wrong and you can miss it looking for something obvious, like the barrel or focus ring or mount. With the front trim ring off, you can access spanner slots and properly tighten the group.
05-06-2011, 02:13 PM   #4
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QuoteOriginally posted by Just1MoreDave Quote
Definitely do that.
+1. Great lens, and it has the same FOV as the coveted FA 43 does on film "true normal". I found it a very useful lens... and I only had the measly A version .

05-06-2011, 04:45 PM   #5
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QuoteOriginally posted by joe.penn Quote
Wow, that is a nice pic!
Thanks Joe!

QuoteOriginally posted by Just1MoreDave Quote
Besides optical formulas, it might share the same problem as some Pentax-A 28/2.8s. The front lens group gets loose.
I did notice the rear element was a little loose and I tightened that but I never checked the front. Great advice!

Thanks for the responses everyone! I think I will go for that FA 28/2.8 too, and do some comparisons.
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