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08-02-2009, 08:59 AM   #1
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Anything about Vivitar 28/2.5

Sorry, if this thread is in wrong place. Newbie as I am....

I have tried to find out anything about the lens Vivitar 28mm/2.5 (serie 22xx, with K mount) without luck. I am wondering what purpose the A and M possibilities "under the lens" have? What the differences between them (automatic/manual), talking more about in use than theory?

08-02-2009, 09:15 AM   #2
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I got this lens with some other stuff I bought. I ended up selling it with the camera I purchased and kepp the stuff I wanted. It won't fit on a k10d. The A/M settings pertain to aperture, but only for slr's, not dslr's.
08-02-2009, 09:19 AM   #3
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My guess is, If it is like the A/M switches on the Taks, then the A forces the lens wide open for focus... When you switch back to the M it closes the lens down to whatever you have the aperture preset at for metering.


Robin has the most knowledge of the 28mm vivi lenses and posted a link to this info http://photografica.robinparmar.com/vivitar.html

Last edited by Igilligan; 08-02-2009 at 09:29 AM.
08-02-2009, 09:33 AM   #4
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Plus, the thread referred to is here.

That is a Kiron-made lens which should be a decent performer, though it is not one of the variants people rave about.

08-02-2009, 10:43 AM   #5
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QuoteOriginally posted by HeG Quote
Sorry, if this thread is in wrong place. Newbie as I am....

I have tried to find out anything about the lens Vivitar 28mm/2.5 (serie 22xx, with K mount) without luck. I am wondering what purpose the A and M possibilities "under the lens" have? What the differences between them (automatic/manual), talking more about in use than theory?
K-mount with A/M switch? Is it possible that you have a T-mount with a K-mount adapter? In any case, the lens should work fine on any K-mount film or digital SLR. The initials on the A/M switch stand for "Auto" and "Manual" in reference to the aperture diaphragm mechanism. This use of the term "auto" in this context has nothing to do with exposure automation. When in the "A" position, the aperture is wide open to compose and focus and automatically stops down just prior to exposure and automatically opens back up when the exposure is done. In the "M" position, the aperture is fully manual and stays in the position as set by the aperture ring.

The presence of the A/M switch means that your lens is particularly useful on a Pentax dSLR. In the "M" position, it allows you to shoot in Av mode without having to rely on the green button to determine appropriate exposure. Alternatively, you can put it in the "A" position and use the green button in M mode and have the benefit of open aperture viewing. The best of both worlds!

Steve
08-05-2009, 04:36 AM   #6
HeG
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QuoteOriginally posted by stevebrot Quote
K-mount with A/M switch? Is it possible that you have a T-mount with a K-mount adapter? In any case, the lens should work fine on any K-mount film or digital SLR. The initials on the A/M switch stand for "Auto" and "Manual" in reference to the aperture diaphragm mechanism. This use of the term "auto" in this context has nothing to do with exposure automation. When in the "A" position, the aperture is wide open to compose and focus and automatically stops down just prior to exposure and automatically opens back up when the exposure is done. In the "M" position, the aperture is fully manual and stays in the position as set by the aperture ring.

The presence of the A/M switch means that your lens is particularly useful on a Pentax dSLR. In the "M" position, it allows you to shoot in Av mode without having to rely on the green button to determine appropriate exposure. Alternatively, you can put it in the "A" position and use the green button in M mode and have the benefit of open aperture viewing. The best of both worlds!

Steve
Thanx for all answers. Especially to Steve, to whom I also have some follow-up-questions. As I mentioned, I just started with photographing and knows about nothing, especially then with film cameras/manual lenses.

I have no clue what kind of mount or/and adapter the lens have. If I have the time tomorrow I could take a photo of it and post it here for you. (I know, I donīt have to, but I want to do it just out of curiousity.)

Then... I am so confused because I donīt understand a word of what you tried to explain, Steve.
The aperture diaphragm mechanism, whatīs that?
I became confused when you, Steve, talked about how to use the lens in A and M mode. Sorry!

Have I understood it right; I can use the lens in both A and M, but to get the right exposure I have to do different things in A and M? What things? Since I until now havenīt used the "green button"-funtion, Iīm having a little bit difficulties to understand the benefit of it with my lens.

Is it just my lens or is it typical for "this kind of lenses" that when it is in M-mode itīs darker and harder to see what Iīm focusing on, and the focusing isnīt working? And in the A mode itīs lighter and the focusing works (it peeps and blinking when it is focused)?

Can I use the A mode eventhough I use M-mode (not Av, Tva, etc)? I havenīt come som far that I would use more Av than M...

Okey, hope you (steve) understand what I am after, if not, ask me. Because youīre the only one - so far - that have explained the lens really well.

Thanx!
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