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08-29-2014, 10:23 PM   #1
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Tamron 28-75mm reverse ring macro experiment

I'm pretty happy with my lens collection, but occasionally I find myself wishing I had a macro lens. My Tamron 28-75mm f/2.8 can focus pretty close, but it's not a true macro, so sometimes it just doesn't do the job. I've got enough in the piggy bank for a nice macro, but I'm kind of paralyzed since I'm torn between that, the new Sigma 18-35mm f/1.8, and the desire to upgrade my Sony RX100-II to the Mark III.

Sooooo, in the meantime I thought I would try the reverse-adapter trick on my Tamron 28-75mm. The ring got here today, but I only had about half an hour to play with it. I have some studio strobes, but I didn't have time to mess with them, so I just used a tripod and shot some test pictures near a window with indirect late afternoon light.

The pictures are pretty mundane (i.e. bad), since I have no experience with macro photography, and I didn't have the time to do anything other than photograph the first few small objects I could find. But I wasn't trying to make art, I just wanted to see how well the lens worked, in terms of magnification and image quality. (The pictures of the camera/lens are courtesy of my RX100-II).




I was pretty surprised with the results. The lens focused far closer than I ever would have expected. In fact, I would say that it probably focuses way too close to be useful for me in most situations. In the pictures below, the little toy girl whose head more than fills the frame is a Lego figurine that is only about an inch tall. So I guess the head is mabye 1/4 inch tall? And I was surprised that zooming the lens did not seem to have any noticeable effect on focal length/field of view. It seemed like zooming the lens just changed how closely the lens focused.

The pictures were mostly shot between f16 and f22. Image quality was okay, but not great. Viewed at 100%, the images aren't that sharp, but when down-rezzed a bit or printed they would appear plenty sharp. (It's also possible that some of the softness could be attributed to technique/lack of experience at macro). Contrast was also not that great, but a boost in contrast in Photoshop pretty much took care of it. I wonder if the lack of a lens hood was the cause of the contrast problem?

Anyway, here are the pictures. They are all full-crops, and you can click on them to view the full-size image. If you notice the line on the pencil shot, that was actually a strand of hair that my 5-yoa daughter graciously loaned me. And if you notice the green areas on the dime shot, that was actually a reflection from the Lego pieces that the dime was propped up on.


















Last edited by Edgar_in_Indy; 08-29-2014 at 10:46 PM.
08-30-2014, 05:48 AM   #2
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These look really good. As you discovered, the main effect of zooming a reversed lens is to change the magnification (and hence the focusing distance). A short focal reversed gives very high magnification; you're probably past 2:1 in some of these shots. As you say, too much magnification for a lot of subjects. As a rule, reversed lenses are for when you want to go well past 1:1. As for sharpness at 100%, one effect you're certainly seeing is diffraction softening. As you increase magnification you also increase the effective f-number by a factor of 1 plus the magnification. So 2:1 magnification means the effective f-number is triple the nominal setting.

To fill the gap between normal magnifications and this extreme macro, you might look into a Raynox if you have a suitable telephoto zoom.
08-30-2014, 10:41 AM   #3
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That's quite a bulky macro, but results are impressive good job!

I'm between macro lenses other than a 1:2 zoom right now, but yesterday I visited a random-tech resale store & came out with a like-new Vivitar 2x macro TC for $40. Whoopee!
08-30-2014, 11:50 AM   #4
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QuoteOriginally posted by jimr-pdx Quote
I visited a random-tech resale store & came out with a like-new Vivitar 2x macro TC for $40. Whoopee!
Sounds like we're both ready for the big-time!

08-31-2014, 11:44 AM   #5
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A reversing ring makes sense if you only do macro occasionally. One thing to consider is protecting the rear element while shooting with the lens reversed. Knocking the center out of a rear lens cap works as a pseudo hood/rear element protection device for reversed lenses.
08-31-2014, 11:59 AM   #6
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QuoteOriginally posted by bimjo Quote
A reversing ring makes sense if you only do macro occasionally. One thing to consider is protecting the rear element while shooting with the lens reversed. Knocking the center out of a rear lens cap works as a pseudo hood/rear element protection device for reversed lenses.
I only need macro occasionally, for close up shots. But what I got with the reverse ring is basically a microscope. It's too close for what I need. So while it was interesting to play with, I don't see myself getting much use out of it.

Good idea about the rear lens cap.
09-01-2014, 10:09 AM   #7
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QuoteOriginally posted by Edgar_in_Indy Quote
I only need macro occasionally, for close up shots. But what I got with the reverse ring is basically a microscope. It's too close for what I need. So while it was interesting to play with, I don't see myself getting much use out of it.

Good idea about the rear lens cap.
A short extension tube might suit your needs better then. A 10mm tube will bring the min focus distance down without getting into crazy magnification ratios.

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