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11-11-2019, 03:03 PM   #1
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SMC 28mm Aperture ring misalignment!??

I recently got a lovely condition SMC 28mm lens with hood etc.

I noticed the aperture ring doesn't line up with the marker...I know it doesn't affect it's function, but quite annoying. I've attached a photo showing the lens set to it's widest and narrowest apertures.

Not sure if this was like this from new...anyone else had any experience with this?

Is it fixable without having to take the entire thing to pieces?

Adam

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11-11-2019, 03:21 PM   #2
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I dount it was like rhat out of the box, Most likely it was serviced to correct sticky aperture blades and not correctly re-assembled.

You should be able to find a disassembly guide to this or similar Takumar lens in the database or on youtube:

Pentax Lens Disassembly Database - PentaxForums.com

Provided you have the tools, skills and experience a DIY adjustment should not be that difficult unless something is broken in the lens. With this vintage lens you should not need JIS cross drivers.
11-11-2019, 03:21 PM   #3
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That's a Takumar. Yes someone has dismantled it and not quite re-assembled it correctly.
11-11-2019, 03:36 PM   #4
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QuoteOriginally posted by Not a Number Quote
I dount it was like rhat out of the box, Most likely it was serviced to correct sticky aperture blades and not correctly re-assembled.

You should be able to find a disassembly guide to this or similar Takumar lens in the database or on youtube:

Pentax Lens Disassembly Database - PentaxForums.com

Provided you have the tools, skills and experience a DIY adjustment should not be that difficult unless something is broken in the lens. With this vintage lens you should not need JIS cross drivers.
I was hoping I could slip it off the back and put it back on correctly but I found one on that list and he takes the whole thing to pieces!

11-11-2019, 05:26 PM   #5
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QuoteOriginally posted by pschlute Quote
That's a Takumar. Yes someone has dismantled it and not quite re-assembled it correctly.
Or perhaps they were so disappointed with how the lens performed at f/3.5 they decided to make it an f/4.5 lens.
11-11-2019, 06:36 PM   #6
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I own a copy of that lens and no, it is not supposed to be aligned that way. If this is a recent purchase, you might want to negotiate a return for full refund including shipping both ways. A repair would be expensive and not within the skill set of most of us.

The aperture mechanism on S-M-C/SMC Takumar lenses is complex and easily damaged by misuse (e.g. A/M switch actuated with the interlock pin extended) or botched repair/modification attempts (e.g. conversion to click-less).


Steve
11-11-2019, 11:35 PM - 1 Like   #7
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The indicator is NOT supposed to be at the top. There are three set screws that hold this indicator in place. Set the lens at 3.5. Using a 1.2mm screw driver loosen the set screws on the indicator ring and shift it so the indicator points at the "." in 3.5. Be careful not to remove the set screws. The Infinity mark should should also align with the infinity indicator mark. Yashica M42 lenses have the indicator on the top. Maybe someone tried to "fix" where the indicator was.
11-12-2019, 01:29 AM - 2 Likes   #8
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QuoteOriginally posted by pentaxus Quote
The indicator is NOT supposed to be at the top. There are three set screws that hold this indicator in place. Set the lens at 3.5. Using a 1.2mm screw driver loosen the set screws on the indicator ring and shift it so the indicator points at the "." in 3.5. Be careful not to remove the set screws. The Infinity mark should should also align with the infinity indicator mark. Yashica M42 lenses have the indicator on the top. Maybe someone tried to "fix" where the indicator was.
Thanks! Thats sorted it! You were right the infinity mark didn't line up either...now it does!! So glad it turned out to be an easy fix! Makes it a real bargain. I got the lens/hood and original cases (including Pentax plastic bag) for 60.

Thanks all the for the help. Here it is on my black Spotmatic.

Adam

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11-12-2019, 08:38 AM   #9
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Excellent! I was thinking along those lines because the meter/foot scale is glued on and often the glue dries out with age and slips off alignment. Or won't turn with the barrel.

Depending on the lens and adapter the indicator mark will align to the 12 o'clock position. I have two lenses that will line up on top with one of my 3 adapters. The same lenses will not line up to 12 o'clock with the other adapters, bellows or extension tubes.
11-12-2019, 09:05 AM   #10
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Wow, that's great you got it fixed.
Kudos to pentaxus for his help
This is the best photo forum ever
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