I really like to take pictures of insects, close up...get their eyes, their hair, or the texture on my bearded dragons toenails, etc.

I've used a 28-135 (on a canon 7d) at 135 and just gotten as close as possible to the subject. This has mostly worked.
Is a macro lens a better tool for me? What does it do that my current method doesn't do? And if I'm standing super close to the subject, does the 100mm macro just zoom closer than the 40mm macro? Or am I really just looking at the speed of the lens at that point?

  • \$\begingroup\$ Also - while this site is simply RIPE with brilliant math folks, help in layman's terms would be better than formulas. Though all will be appreciated. \$\endgroup\$
    – Seth
    Jan 24, 2013 at 21:01

4 Answers 4


If you own a Canon camera, then to really do macro photography like that you probably want the MP-E 65mm f/2.8 1-5x Zoom Macro lens. Unlike most macro lenses which max out at a 1:1 reproduction ratio, which is usually not quite enough to get close-up shots of bug parts, the MP-E 65mm macro is a zoom macro. It supports a magnification ratio between as low as 1:1 and as high as 5:1, or 5x magnification. With the MP-E, which BTW is a lens entirely unique to Canon, you'll be able to get those amazing super-close macro shots of insect eyes, "hair", etc.

Alternatively, you want to get at least a "true macro" lens. The lens you have now is not a macro, which means you cannot even get a 1:1 magnification. Your lens is limited to less (probably much less) than 1:1 ratio, which greatly reduces the amount of detail you can get onto the sensor. Canon offers several macro lenses, including the EF 100mm f/2.8 Macro USM, the EF 100mm f/2.8 L IS Macro USM, and the EF 180mm f/3.5 L Macro, all of which support a true 1:1 magnification.


Okay, simple answer: yes, you need a macro lens. The lens you are using has a 1:4 magnification at its closest focusing distance. You note that you're getting as close as possible to the subject, which is exactly right, but all lenses have a minimum focus distance. A "true" macro lens has a closer-than-normal focusing distance, allowing the objects you're photographing appear at 1:1 on the sensor.

Longer focal length macro lenses generally have similar magnification, with the primary difference being that you don't have to be as close to your subject.

You can also experiment with alternative techniques like reversal rings and extension tubes — we have a collection of information on these: What macro techniques offer an alternative to expensive optics?

If you have the budget and are really into it, you may check out the specialist Canon MP-E 65mm — see this review on the site blog. But, this is a thousand-dollar lens, and unlike macro lenses is only useful for macro, so that will depend on your level of commitment.


Generally, a dedicated macro lens will let you focus close enough that the subject appears on the sensor the same size as it is in real life; that is, a 25mm x 10mm object will take up 25mm x 10mm on the sensor. This is typically as close as a macro lens will go, though there is at least one specialist lens that magnifies up to five times.

Macro lenes of different focal lengths will all let you get 1:1 magnification in this way, the difference being that a longer lens will allow you to set up the camera further from the subject to get the same magnification, and you will also get the narrower depth of field and compressed perspective inherent in longer focal length lenses.


For extreme macro shots, a very limiting factor tends to be depth of field. To get around that limitation, you need to work with small apertures. Those imply diffraction that can be offset to some degree computationally (using deconvolution as a sharpening mechanism in raw processing software, for example). Diffraction also limits the usefulness of high pixel counts as a basis to crop from: if your image information is already smeared over several pixels, subdividing those pixels does not help all that much.

To deal with the respective small apertures, you also need light. Like, a whole lot of light. Get used to the idea of working with various kinds of flash.

Note that screw-in-between teleconverters achieve their magnification at the cost of aperture. Generally a downside because of the loss of light and bokeh, for macro photography that is an advantage because of depth of field. So consider adding a good teleconverter behind your macro lens. It will enlarge the image at the same ratio as it enlarges the diffraction patterns and consequently is as good as cropping (apart from the loss of light) while retaining a higher resolution. Basically it is the same kind of limited advantage that a higher resolution sensor would provide in the presence of significant diffraction.


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