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08-23-2013, 11:04 AM   #1
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innivus's Avatar

Join Date: Dec 2011
Location: Bronx NY
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67 100mm macro life size adapter substitute

Hey all, I just wanted to share a quick experience and then see if anyone can confirm my belief or tell me I'm off my rocker. I had a 100mm macro lens that was bought without the life size adapter. It was a great lens that could still go to a 1:2 magnification, but I predominantly used it for non-macro work. I then was able to borrow another 100 macro w/ the adapter, and after some work, I found that if I stacked three old Kenko 49mm close-up filters (px1, px2 and px3), I could achieve almost the exact same magnification as the life size adapter! In fact, I took the two and put them up my eyes and it was like a set of binoculars - the magnification factor was that similar (and yes, my wife made fun of me when I did this). It makes a bit of sense, given that the adapter supposedly has 3 elements. Sadly, I do not have pictures to back this up (nor do I have a scanner capable of differentiating the two). I've also searched the web and found nothing on the subject, which is surprising given the disparity between a lens with the adapter and one without it.

I'd like to hear others' opinions about this; I am sure the OEM 67 adapter is of a better quality, but not by that much.

Anybody know anything about this, or want to confirm or deny whether this is an adequate substitute?

08-23-2013, 11:14 AM   #2
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Join Date: Oct 2008
Location: Vancouver, Canada
Posts: 5,121
If you do not have the 100/4 LSC then I would use the 6x7 extension tubes, before I would use close-up filters.

Regardless the 67 100/4 macro was designed around the LSC, so there will be no substitution that will equal it for 1:1 magnification.

Check KEH as I have seen the LSC for sale on its own.

Phil.
08-25-2013, 11:07 AM   #3
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Join Date: Feb 2009
Location: Arizona
Posts: 867
Any time you add lens elements into an existing optical group, they must be corrected for aberrations, whether it be a rear converter or a close up filter. A single element up front will not be able to correct enough of the aberrations for a great image. Adding two more similar elements that were not designed to work together will only add to the unsharpness. The three element attachment for the 100 macro was designed to correct the major aberrations. It appears to be an apochromat (corrected for 3 colors). Using 3 stacked close up filters could work if the lens were stopped to f/32. That way the diaphragm would truncate the poorly corrected rays.
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