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07-28-2009, 12:23 PM   #1
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Extension tubes

Any thoughts about extension tubes or close up lens sets. I have an ist DS with 18-55 and 75-300 lenses. Thanks... Charles:l

07-28-2009, 05:31 PM   #2
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QuoteOriginally posted by Charles1 Quote
Any thoughts about extension tubes or close up lens sets. I have an ist DS with 18-55 and 75-300 lenses. Thanks... Charles:l
Hi Charles 1,

I shoot mainly 35mm film with a variety of "venerable" cameras and I too have been exploring -in a small way- the notion of extension tubes, close-up lenses and Macro lenses.

Close-up lenses: can be used with any existing lenses and do not lose "light", i.e. do not alter exposure, but affect image quality. They come as simple meniscus lenses (chromatic aberation) or as doublets (more expensive, but corrected for CA). I have tried a cheap set and, sure they work, but it looks like a shot using a toy camera with a plastic lens.

Extension tubes: simple, cheap, turn your fixed focal length primes into "instant macros", with corresponding light loss (affect exsposure). I have tried both an "Auto" set and a "plain" set. Both work. The TTL metering on your camera takes care of the exposure metering issues automatically with both types, just that, with the plain type, you have to meter and compose your shot in the (dimmer) stopped-down mode. These work quite well but there can be a considerable amount of somewhat tedious tube changing involved. You also lose infinity focusing.

I also have some 50mm and a 100mm "Macro" lenses. These work very well, giving a range of magnifications each (up to their individual designed limit). You can also attach them to extension tubes or close-up lenses, or both for more magnification.

Of course, all this results in severe loss of depth of field: a big bugbear.

You can also get similar effects to extension tubes using a tele-converter: that will lose light (affect exposure) but maintain the minimum focusing distance of the original lens.

Check out this link:

http://www.apug.org/forums/forum206/59211-extension-rings-vs-teleconverter.html
07-29-2009, 02:22 PM   #3
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Thanks for the follow up... Charles1
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