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Old 12/22/2009, 02:22 PM   #1
BlueCorn
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Now that I've got a DSLR, which macro lens should I buy?

UPS just dropped off your new DSLR, you've charged the battery and started shooting like crazy at the stuff in your tank. After downloading the pictures onto your computer you realize that they look nothing like the close-up shots so often seen in this forum and elsewhere on the board. Now what?

With the kit lens, most consumer DSLR cameras are just expensive point and shoot cameras. The ability to adapt the lens to a particular shooting situation is the primary reason to go that route. The next question is which lens to buy.

Macro photography, strictly speaking starts at 1:1 magnification. The 1 to 1 ratio means that the image that gets projected onto your camera sensor is the same size as the object in real life. Anything less than 1:1 isn't truly macro but rather a "closeup."

A number of zoom lenses include the word macro in their titles and descriptions but that's mostly marketing. Any true macro lens will be a fixed focal length; i.e. 100mm not 28-300mm. Macro lenses can also be used for non-closeup work. What distinguishes them from non-macro lenses of the same focal length is their minimum focusing distance. For example, a non macro lens of 100mm focal length has a minimum focus distance of about 5-6'. The macro version about 1'. The magnification is due to the camera being closer to the subject. We call that working distance.

There are a bunch of 1:1 macro lenses from 60-200mm. They are all capable of the same magnification but the longer the focal length, the farther you can be from your subject and still get 1:1. For most aquariums, the 100mm range is a pretty good fit. It's a good trade off of value vs working distance. (If you shoot Olympus, you'll want to be looking at their 35mm, with their 2x crop factor it's functionally equivalent.) Some lenses, like the Canon MP-E 65 can go all the way to 5:1 magnification but it's a very specialized lens.

You can't go wrong Nikon and Canon's 100mm macro lenses but there are other options if you'd like to save some money. Tamron makes a 90mm and Sigma a 105mm that are both very sharp lenses. The only drawback, to both, is they are external focusing. External means the lens barrel extends during focusing. In your garden it isn't a big deal but if you're up against the aquarium glass it can be a real hassle.

Extension tubes, and screw on adapters can be useful but don't replace the functionality of a true macro lens.


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Last edited by BlueCorn; 12/24/2009 at 11:36 PM.
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