 BetterPhoto Member |
Macro lens I have Canon Elan7 and I would like to buy a macro lens for it. I need help in understanding a few issues that would let me make a decision. First, what is the difference between 50mm and 100mm macro lenses? Canon 50mm macro lens requires 1:1 lifesize converter; does it change the maximum f-stop of the lens? There is $300 difference between Vivitar macro 100mm lens ($150) and Canon 100mm ($450). Is Vivitar sufficiently good? Are there any other less expensive good macro lenses by Sigma or Tamron that you could recommend? And finally, how would 50mm or 100mm macro lens work on digital Rebel? Thank you in advance, Marianna
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doug Nelson |
A 100mm macro allows twice the working distance between camera and subject that a 50 would. A disadvantage might be less depth of field with a 100, but at distances that close, the difference in DOF may be negligible. Extension of half the lens' focal length Canon's EOS 100mm f2.8 is very highly rated. So is Canon's 50 macro. Put the money in the glass and don't look back. You'll get a 1.6x multiplication factor with a digital SLR. A 50 acts like about an 80. A heads-up if you want to go digital-the new Olympus E-1 has lenses designed especially for digital, including a 50mm macro f2. IF money is an issue, look for the excellent manual focus Canon FD 50mm macro and Life Size adapter, cheap and plentiful on auctions. OR, look for the Vivitar Series 1, Tokina or Tamron 90 f2.5's from the 70s-80's. Just get a manual focus body to fit the lens, and you'd have a dedicated macro set-up for minimal cost.
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doug Nelson |
Look at this: http://www.photo.net/equipment/canon/can-tam-macro/ The writer prefers the Tamron; the Canon looks better to me. The writer says that the depth of field difference between a 100 and a shorter focal length IS significant; so I defer to him. It's interesting, too that autofocus is of little use with a macro, unless, as he says, a bug or something is moving.
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Jon Close |
Depth of Field is a function of magnification and f-number. When set to the same f-number and focused to provide the same magnification (say 1:1), the depth of field will be the same for the 50mm and the 100mm lens. The longer focal length lens will provide more distance between the camera and subject. Independent tests, particularly http://www.photodo.com/nav/prodindex.html rate the Cosina-made Vivitar 100 f/3.5 Macro pretty good optically, but not as good as the Canon EF 100 f/2.8 Macro. The extra cost of the Canon lens goes to better optics (including 2/3 stop faster maximum aperture), fast/silent USM focus motor with nicely damped full-time manual focus, and all around better build quality, and of course a premium for the Canon brand. Other alternatives between the cheap Vivitar and the expensive Canon include the well-regarded Tamron 90 f/2.8 Macro and Sigma 105 f/2.8 EX Macro. Used on the Digital Rebel, the lenses would perform the same. Magnification, focus distance, aperture, DoF are unchanged. Because the digital sensor is smaller than the 35mm film frame (15.1mm x 22.7mm instead of 24mm x 36mm), it creates a crop of the image, so that you get the narrower angle of view of a lens 1.6x longer.
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