My $0.02.
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When doing macro with two lenses stacked, the guidelines are:
1) EXPERIMENT WITH WHAT YOU HAVE. Don't avoid a two lens combination because someone says it will not work. Excellent results may be possible with unexpected combinations of lenses.
THAT SAID
2) generally it's better to have the longer focal length lens mounted directly to the camera.
3) as with normal photography, on the average, SFL lenses give better results than zooms, BUT EXPERIMENT WITH WHAT YOU HAVE.
4) devoted macro lenses don't seem to work as well as non-macros in stacked lens systems
5) short mount, 100mm bellows lenses have a good reputation for use as the second lens (the one reversed).
6) there is debate on which lens to stop down at the moment of exposure. Personally, I always go with the auto-diaphragm of the lens directly attached to the camera, but some expert macro photographers insist that stopping down the reversed lens gives sharper results.
7) 90% or more of my macros taken with flash are sharper and more satisfactory than those taken with ambient light only, even with the camera on a relatively massive tripod.
Another suggestion for low magnification macros (less than 1:1). Canon still makes two element, achromatic close-up lenses in a range of filter sizes and two different strength (lower magnification designated "500," higher designated "250"). These, like the Raynox, can give very good results and are very convenient for travel. I got some good close-ups with a Canon 250 mounted on a Pentax 55-300. Nikon once made achromatic close up lenses (occasionally available used on EBAY, B&H, KEH) in 52mm (designated 3T and 4T, lower/higher magnification) and 62mm (5T & 6T). I have several of these, and again, they are useful when traveling and can give very good results. These two-element filters work best on moderate telephotos (about 70~200mm), although I carry a big Canon unit to use on my 300 f4, for unapproachable small creatures.
NOTE ADDED: I find two-element close up lenses more satisfactory than extension tube(s) on zoom lenses because once focussed on the subject, the focus is maintained very closely when the lens is zoomed. With an extension tube, once the subject is in focus, if you zoom, the subject will go wildly out of focus. This is because as with a series of SFL lenses, the focal distance with a given extension tube is much shorter with a short focal length lens than with a long lens. So a zoom set at 80mm with extension tube, in focus at 15 inches, zoom to 135mm, now the correct in-focus distance is 24 inches.
A Canon "250" close-up lenses sets the in-focus distance to about 250mm when the lens is set to "infinity" regardless of the focal length of the lens, therefore regardless of the zoom setting of the lens.
Last edited by WPRESTO; 08-05-2014 at 06:19 AM.