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11-17-2011, 08:06 PM   #1
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Help with tamron Model 472D

Hi I just purchased this Tamron 70-300mm Lens on Ebay and seems to be nice.
However it's supposed to work as a macro lens as well. There is no switch on it to get it into macro, and I can't rotate the past the stop as in my f-35-70 lens.
Any suggestions? thanks!
Jake

11-17-2011, 08:41 PM   #2
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Doesn't it just focus closer at longer FL's? That's how most AF lenses handle it.

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11-17-2011, 09:05 PM   #3
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Tamron lenses use two methods to achieve close-focus. Your lens simply continuously focuses via internal extension to achieve an MFD of 59 inches (which is quite close for a conventional 300mm lens). The "macro switch" you refer to merely limits the focusing freedom, it doesn't "allow" macro operation.

The only downside to this convenient configuration is that there's no mechanical focus limiter to prevent the auto focus system from "hunting" throughout the full "macro" focal range of the lens when having difficulty locking on a distant subject.

H2

Last edited by pacerr; 11-17-2011 at 09:33 PM.
11-17-2011, 09:44 PM   #4
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Thanks for the responses. I had assumed that the way to acheive macro is the ability to move in closer. That's what my other lens does. If I understand you correctly is that I have the ability to zoom in at longer focal lengths at a shorter distance than non-macro modes. Is that right?
Thanks again Jake
Also sorry for my ignorance, but what is "MFD of 59 inches "
I need close to five feet to be able to focus!

11-17-2011, 10:40 PM   #5
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MFD = Minimum Focus Distance
11-18-2011, 09:45 AM   #6
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I believe that you'll find that at 300mm you'll focus on an area about the size of a deck of cards at about 4 1/2 ft (59 inches) distance. This isn't true macro (roughly a 1:4 magnification ratio) but it's very much closer than a "non-macro" tele-zoom lens would achieve.

If you'd like more magnification (and closer focus distance) add 25 - 50mm of extension rings to the lens. If you can find a cheap PK/A-capable TC that will allow you to unscrew the optic element you can make yourself a very effective close-up (but not true macro) rig that retains the auto exposure functionality of the lens.

You can explore this effect very easily: Zoom to 300mm and select minimum focus distance on the lens. With it detached from the camera, hold the lens stead about one inch in front of the body with your cupped hand and approach the subject until it's in focus at about 2-3 ft.

This is essentially what your "macro" ( = close(er) focusing) tele-zoom lens does with a longer internal focusing sleeve than "normal" lenses.

H2
11-18-2011, 12:30 PM   #7
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Thanks so much for your responses!
Jake
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