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02-20-2013, 03:12 PM   #1
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Aperture ring on 645 45mm A lens?

Hi,

I have kind of a silly question. i just received a 645 SMC-A 45mm lens to use with a Mirex T/S adapter. While I was checking the lens out I was changing the aperture manually (without the lens being mounted to anything) and the aperture wasn't changing. This is the first 645 lens I've ever held in my hand. Do I need to actuate any of the levers on the lens to see the aperture open & close? On any 35mm A lenses I have owned the aperture moved as I changed the ring without doing anything else. I do not have an adapter to use this lens on my K20 & I do not have the Mirex yet. I wanted to make sure the lens arrived safely & the mechanics were operating properly.

Any thoughts or help would be appreciated.

Thanks,

George

02-20-2013, 03:59 PM   #2
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QuoteOriginally posted by gsrokmix Quote
Hi,

I have kind of a silly question. i just received a 645 SMC-A 45mm lens to use with a Mirex T/S adapter. While I was checking the lens out I was changing the aperture manually (without the lens being mounted to anything) and the aperture wasn't changing. This is the first 645 lens I've ever held in my hand. Do I need to actuate any of the levers on the lens to see the aperture open & close? On any 35mm A lenses I have owned the aperture moved as I changed the ring without doing anything else. I do not have an adapter to use this lens on my K20 & I do not have the Mirex yet. I wanted to make sure the lens arrived safely & the mechanics were operating properly.

Any thoughts or help would be appreciated.

Thanks,

George
Without the adapter mounted, it should stop down as you turn the aperture ring as long as it's not mounted on a camera.

Adam
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02-20-2013, 04:29 PM   #3
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Hi Adam,

Thanks for the reply. The lens only stops down to the selected aperture if I slide one of the levers. One of the levers moves pretty easily, and the other doesn't seem to move at all no matter where the aperture ring is set. I'm assuming it's something I'm doing (or not) because the lens is in pristine shape.

Thanks again,

George
02-20-2013, 04:37 PM   #4
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If I recall correctly what you are facing is completely normal with a 645 lens. The adapter should have a small peg on it that puts tension on the aperture lever as you stop it down. I can remember asking myself the same question while waiting for my cheap ebay adapter to arrive in the post. Unfortunately I have sold my 645 kit now, so I can't be 100% sure.
Either way, you have an excellent lens there. I was always impressed by the quality and sharpness of my 645 lenses.

02-20-2013, 04:50 PM   #5
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Thanks Joe, that's reassuring. Hopefully the Mirex will arrive shortly & I can verify that the lens functions as it should. I'm excited to try this combo. I think I may look for a 75mm to use with the Mirex next if I like the setup. I agonized over this setup as it was kind of pricey so I hope it provides good results.

George
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