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05-16-2008, 11:39 AM   #1
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Aperture Ring on Screwmount Vivitar...Please Help

I just received my Vivitar 28/2.5 (Kiron). The lens looks like it is in nice shape, but when I turn the aperture ring, there are no positive stops. I do not have a screwmount body yet to which to mount the lens. Is this correct? Should there be no stops when turning the ring (when not attcahed to a body)? The seller described the lens as having "precise and positive" aperture function.

05-16-2008, 11:44 AM   #2
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QuoteOriginally posted by zx-m Quote
I just received my Vivitar 28/2.5 (Kiron). The lens looks like it is in nice shape, but when I turn the aperture ring, there are no positive stops. I do not have a screwmount body yet to which to mount the lens. Is this correct? Should there be no stops when turning the ring (when not attcahed to a body)? The seller described the lens as having "precise and positive" aperture function.
Some use stops some dont. Does it close and open properly? Does it have an M/A switch? Or a button? If not it could have been made that easy to move for fast opening to focus and fast closing to take the picture.
05-16-2008, 11:51 AM   #3
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I thank you for the prompt response, Zewrak, as I was initially puzzled by this lens.

Your comments were very helpful, as I think I have figured out the matter. Yes, it does have a switch, marked "A," and when I switch it to the A side, the lens closes down (or opens up) properly. Actually, there are stops either way, but they are different than stops on more modern lenses...less distinct.

Regards,
Glen
05-16-2008, 12:01 PM   #4
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QuoteOriginally posted by zx-m Quote
I thank you for the prompt response, Zewrak, as I was initially puzzled by this lens.

Your comments were very helpful, as I think I have figured out the matter. Yes, it does have a switch, marked "A," and when I switch it to the A side, the lens closes down (or opens up) properly. Actually, there are stops either way, but they are different than stops on more modern lenses...less distinct.

Regards,
Glen
Well I don't know that particular lens. But I suppose that if you are in manual mode you want it to move quickly and easily, since you will turn it while having it on the camera. Because focus can be hard to achieve at high aperture, since the image gets dark. So therefor you focus first wide open and then turn the aperture down.

On one of my lenses (Helios 44-2) for example there are two rings, one that sets the aperture and one that opens and closes the lens to the aperture you set with the first ring. The second ring has no resistence at all.

If you have "A" set, it means that the lens should be wide open while you focus and close down when you hit the shutter release button. When you have the "M" mode it should close down even if the lens is not mounted to a camera (the pin in the mount should not have any function when in M mode). Test it by setting the A setting and close the aperture as much as possible and then push the pin in the back, then it should close.

05-16-2008, 12:53 PM   #5
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Thanks...

I just looked over the lens' optics. The front and rear elements look nice, just a few cleaning marks here and there. Inside, though, I see some type of small fragment. It is fairly thin and about 2mm or 3mm in length. It is not in the center, but a bit beyond midway out (from the middle). Does this sound like it would be troublesome, or do you think I should get good prints out of this lens?
05-16-2008, 12:56 PM   #6
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QuoteOriginally posted by zx-m Quote
Thanks...

I just looked over the lens' optics. The front and rear elements look nice, just a few cleaning marks here and there. Inside, though, I see some type of small fragment. It is fairly thin and about 2mm or 3mm in length. It is not in the center, but a bit beyond midway out (from the middle). Does this sound like it would be troublesome, or do you think I should get good prints out of this lens?
Could you take a photo of it? And some stuff don't matter at all. If you are unlucky it might be fungus and that means you need to clean it off, because it can grow over time, if you have moisture air around where you live. Fungus is evil, but can be controlled, not cured though, without opening the lense up and clean it properly. And when I say properly I mean properly, with strong chemicals that kill everything it touches.

But don't panic, it's not sure its fungus. A picture would be great.
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