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Vivitar 24-48mm Zoom Mounting Woes
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PostPosted: Mon Apr 26, 2021 5:24 pm    Post subject: Vivitar 24-48mm Zoom Mounting Woes Reply with quote

Hi Everyone: I bought a Vivitar 24-48mm Auto Zoom on EBay. But when I tried to mount it to an MD-NEX adapter, I was able to turn it but it wouldn't lock. I used the same adapter on a Minolta MD Zoom 35-70mm and the adapter worked perfectly. Interestingly, the two lenses had identical appearing mounts, except the pins were shaped a little differently. A friend of mine suggested that he remembered that "some extension tubes and lenses didn't fit because of the fixed MD tab on certain lenses. If that is the case filing down the MD tab may be an option." Is that what people would recommend? Any other suggestions? I don't have the tools to start messing with the mechanics, but if that is the only way.

Thanks,

-Charles

Here are some images:


#1 The Adapter


#2 Vivitar


#3: Vivitar


#4: Vivitar


PostPosted: Mon Apr 26, 2021 6:04 pm    Post subject: Re: Vivitar 24-48mm Zoom Mounting Woes Reply with quote

charley5 wrote:
Hi Everyone: I bought a Vivitar 24-48mm Auto Zoom on EBay. But when I tried to mount it to an MD-NEX adapter, I was able to turn it but it wouldn't lock.

I have two (nominally) identical "Prost MD-NEX" adapters - one of them locks perfectly on any lens, the other one sometimes on some lenses makes problems. If you put your adapter onto the MD 35-70mm (without mounting it to the camera) you can look into the rear side of the adapter/lens combination while pushing and relaxing the knob on the adapter itself. Then you'll see the little lever moving and locking/unlocking the lens. Then do the same thing with your 24-48mm lens, and you'll see what's wrong. I'd guess the small dent or slit for coupling is slightly too narrow ... If so, you might either make the dent (slit) on the 24-48mm a bit broader, or you might take the adapter apart and make the lever slightly narrower.

charley5 wrote:
I used the same adapter on a Minolta MD Zoom 35-70mm and the adapter worked perfectly. Interestingly, the two lenses had identical appearing mounts, except the pins were shaped a little differently. A friend of mine suggested that he remembered that "some extension tubes and lenses didn't fit because of the fixed MD tab on certain lenses. If that is the case filing down the MD tab may be an option." Is that what people would recommend?

In fact some adapters are designed only for MC lenses, and the MD pin if MD lenses scratches badly on the adapter, kind of blocking the aperture ring. That's not the case here, though, since you successfully have used your MD 35-70mm!


PostPosted: Tue Apr 27, 2021 3:12 pm    Post subject: Re: Vivitar 24-48mm Zoom Mounting Woes Reply with quote

stevemark wrote:
charley5 wrote:
Hi Everyone: I bought a Vivitar 24-48mm Auto Zoom on EBay. But when I tried to mount it to an MD-NEX adapter, I was able to turn it but it wouldn't lock.

I have two (nominally) identical "Prost MD-NEX" adapters - one of them locks perfectly on any lens, the other one sometimes on some lenses makes problems. If you put your adapter onto the MD 35-70mm (without mounting it to the camera) you can look into the rear side of the adapter/lens combination while pushing and relaxing the knob on the adapter itself. Then you'll see the little lever moving and locking/unlocking the lens. Then do the same thing with your 24-48mm lens, and you'll see what's wrong. I'd guess the small dent or slit for coupling is slightly too narrow ... If so, you might either make the dent (slit) on the 24-48mm a bit broader, or you might take the adapter apart and make the lever slightly narrower.

charley5 wrote:
I used the same adapter on a Minolta MD Zoom 35-70mm and the adapter worked perfectly. Interestingly, the two lenses had identical appearing mounts, except the pins were shaped a little differently. A friend of mine suggested that he remembered that "some extension tubes and lenses didn't fit because of the fixed MD tab on certain lenses. If that is the case filing down the MD tab may be an option." Is that what people would recommend?

In fact some adapters are designed only for MC lenses, and the MD pin if MD lenses scratches badly on the adapter, kind of blocking the aperture ring. That's not the case here, though, since you successfully have used your MD 35-70mm!


Excellent. Thank you so much. I shall follow your suggestion!

-Charles


PostPosted: Tue Apr 27, 2021 3:23 pm    Post subject: Re: Vivitar 24-48mm Zoom Mounting Woes Reply with quote

You're welcome Wink

S