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04-01-2019, 09:59 AM   #1
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KP and Tamron 90mm macro

Nothing wrong as such. Bought a Tamron 90 mm macro to go with my KP and the aperture ring sits so far back on the lens that it goes under the overhang of the pentaprism.
This makes changing the aperture setting quite difficult especially with chubby fingers as the aperture release button is just in the wrong place!. Just a heads up for anyone interested.

04-01-2019, 10:28 AM   #2
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why would you not just leave the lens on the 'A' setting and change it with the camera's e-dial?
04-01-2019, 10:54 AM - 1 Like   #3
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QuoteOriginally posted by pepperberry farm Quote
why would you not just leave the lens on the 'A' setting and change it with the camera's e-dial?
I shouldn't answer for the OP, but the main benefit of the aperture ring on a macro lens is to use it with extension tubes for greater magnification; although the extension tube(s) should move the aperture ring far enough away from the camera body to effectively eliminate the OP's problem. But I agree, for any of my uses for the Tamron, I don't need the aperture ring (even when I used it on my old film cameras).
04-01-2019, 10:57 AM   #4
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QuoteOriginally posted by RGlasel Quote
I shouldn't answer for the OP, but the main benefit of the aperture ring on a macro lens is to use it with extension tubes for greater magnification; although the extension tube(s) should move the aperture ring far enough away from the camera body to effectively eliminate the OP's problem. But I agree, for any of my uses for the Tamron, I don't need the aperture ring (even when I used it on my old film cameras).

I considered the use if tubes also, but as stated, even a small tube would push the lens far enough out from aperture ring to be more accessible...

04-01-2019, 11:19 AM   #5
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I assumed there was an old Tamron macro that was full manual? But yeah, for me the aperture ring is mainly something I have to avoid touching.
04-01-2019, 05:54 PM   #6
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I have the old Tamron adaptall (the A version), f2.5 lens. It is my wife's lens, but she no longer uses it. It's a very nice, sharp lens.
04-02-2019, 05:44 AM   #7
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Thanks for the responses. I do leave the aperture setting on A. I was simply posting that if anyone should want to manually control aperture from the lens it isn't easy. Can someone answer this. Is there is a situation when you would change aperture manually on this lens and if not why have the ability to do so?

04-02-2019, 07:14 AM   #8
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QuoteOriginally posted by David Cook Quote
Is there is a situation when you would change aperture manually on this lens and if not why have the ability to do so?
Any time there is something between the lens and the camera body that does not permit the aperture lever to be activated. Extension tubes (hollow tubes with the required mounts on each end) to increase the magnification by moving the lens away from the camera are the only examples I can think of, as far as I know, compatible tele-convertors have the necessary linkage. If you have a Pentax film camera that isn't capable of automatically setting aperture (say a K1000) then only lenses with aperture rings will work and even with cameras such as the Program Plus, if you want to manually set the aperture, you have to do it with the aperture ring (those cameras open up the aperture for metering, but close it down to the set aperture when the shutter is released).
04-03-2019, 02:20 AM   #9
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Thanks for your reply, RGlasel. I must have been having a senior moment when I asked the question because I have a set of extension tubes. I only used them a couple of times though with my K10D. They are lurking somewhere in the bottom of a camera bag.
04-03-2019, 02:31 AM   #10
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The ring can be nice with cameras with one control wheel. Shutter with camera and aperture with lens. With duel wheels one could set them for iso and shutter and still have aperture on the lens.
What's more they work on older cameras.
04-05-2019, 01:14 AM   #11
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I have the same (272E?) lens for my KP, it is excellent, always in my bag or on my camera. As you mentioned the ring is narrow and hard to grip. I leave the ring in the A position and use the front dial on the KP to select aperture. My fingers must be smaller, I can press the tiny button on top of the ring to move it out of the A position, then it can be gripped and rotated from the sides, and it can be rotated back in to the A position without pressing the tiny button. But the camera will not know what the aperture setting is. You can also take aperture ring out of the A position before mounting it on the camera. To answer the other part of your question, I don't know why one would ever need to do that, unless you just wanted to make sure the aperture did not change. Sometimes as I am fiddling with the knobs and settings, then go back to take a shot all of my previous exposure settings have changed, so fixing the aperture would be one less variable that could change. (I am stretching here for a reason to do so.)

Last edited by tljensen; 04-05-2019 at 01:27 AM. Reason: to answer rest of question.
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