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Old Jun 12, 2010, 6:14 PM   #21
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The magnification ratio doesn't depend on the focal length. It depends on the ratio of the focal length to the minimum focusing distance. Nikon's 60/2.8 1:1 has a minimum focusing distance of 8.6", the 105/2.8 1:1 has a minimum focusing distance of 12", and the 200/4.0 1:1 has a minimum focusing distance of 19". Nikon's 400/2.8 would need a minimum focusing distance of about 30" to have a 1:1 magnification ratio, but has a minimum focusing distance of 114", so it has a magnification ratio of 1:6.25.
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Old Jun 16, 2010, 12:40 AM   #22
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Is it just my imagination or are macro lenses all sharper than most other types (e.g. zooms, wide-angle, telephoto, primes...etc.)? Whether wise open or at their sweet spots and beyond. My new Nikon 105mm f/2.8 VR Micro looks to be noticeably sharper then most of my lenses if not all. Are most macro lenses sharper than the others by design?
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Old Jun 16, 2010, 6:07 AM   #23
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In general, macro lenses are sharper than any other category of lens. There are no bad macro lenses. You can't say that about telephoto zooms, for instance.

But that's MACRO lenses we're talking about, not "macro" lenses. The 1:3 or 1:2 "macro" zoom lenses don't count.
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Old Jun 16, 2010, 7:16 AM   #24
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Ok thanks TCav. I definitely do feel I can see that my 105 is noticeably sharper than any lens I have in my collection (from my 50 and 85mm primes, 17-55 f/2.8 wide, 70-300 zoom...good lenses but not as obviously tack sharp as my new 105 is even at f/5.6 or f/8...never mind @ f/32, f/36 using a tripod). Glad I bought it.
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Old Jun 16, 2010, 8:58 AM   #25
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Originally Posted by BDD View Post
...good lenses but not as obviously tack sharp as my new 105 is even at f/5.6 or f/8...never mind @ f/32, f/36 using a tripod).
Once you get down to about f/22, you reach the diffration limited aperture, and the image starts getting softer. You can go smaller, but you've past the peak sharpness.
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Old Jun 16, 2010, 10:55 AM   #26
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Where did you find this information about f/22 being the peak of sharpness for my 105? Curious.

All I can say is that from the series of test images I took yesterday (had my camera mounted on a tripod...aperture priority mode...took an image at each f-stop starting from f/8 to f/36) the images (or more of the image) kept getting sharper and in-focus as I dialed down the aperture past f/22. I didn't notice the images getting soft.

No matter. The fact is this is a great lens. That and there is a reason why it's recommended to use the max aperture (smallest) for macro photography while using a tripod.
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Old Jun 16, 2010, 12:30 PM   #27
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Where did you find this information about f/22 being the peak of sharpness for my 105? Curious.

All I can say is that from the series of test images I took yesterday (had my camera mounted on a tripod...aperture priority mode...took an image at each f-stop starting from f/8 to f/36) the images (or more of the image) kept getting sharper and in-focus as I dialed down the aperture past f/22. I didn't notice the images getting soft.
See http://diglloyd.com/articles/Diffrac...Challenge.html

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No matter. The fact is this is a great lens.
Without question.
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Old Jun 17, 2010, 8:55 AM   #28
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Thanks for the link TCav. Interesting read. The companion articles as well.

I knew the sweet spot for my 105 would be between f/4-f/8. I did look at reviews from other websites that confirm this. But as I said...as I stopped down beyond f/8 the images just kept becoming more in-focus. Which I suppose doesn't necessarily mean it's a better image.

Yet, it's recommended that we use the max aperture (smallest) for macro photography. Which for my 105 is f/36. I suppose you'd have to be pixel peeping to spot the difference in image quality as you stop down.

In the comparison examples provided by that article what you echoed was obvious. Perhaps easier to see using a "BLACK resolution" page as the subject with groupings of lines and text...versus looking at a series of test photos of some object.

I do intend to mostly use my 105 as a portrait lens any how. Shooting in the aperture range of f/4-f/8 whether shooting portraits and certain macro shots hand-held. On a tripod in other circumstances (low light macro images or type of shot desired) at max aperture.

Last edited by BDD; Jun 17, 2010 at 9:03 AM.
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