Tuesday, July 17, 2007

Using a 70-200 F4 L for closeup photography

Violet Darter series 2007_4-6
Originally uploaded by Dalantech.
Most telephoto lenses are soft at the minimum focusing distance of the lens -by design. The primary use for a telephoto is to take images of distant subjects, so they are built to be sharp when focused toward infinity.

If you're finding it difficult to get sharp images of critters close to the lens then it might not be your technique, it may just be the glass.

One way around the limitation is to use a diopter (like the 500D) since it will fix the focus at about 1/2 of a meter (approximately 18 inches) from the front of the lens. Since the focus is fixed (the focus ring will only change the area of sharp focus by about a centimeter or ½ inch) you can set the focus ring toward infinity and the resulting images are pretty sharp. The focal length of the lens changes the magnification, so to get “closer” to the subject all you have to do is zoom in.

The image with this post was taken with Canon’s 70-200 F4 L and a 500D diopter. Notice how smooth the background is –another advantage to using the diopter is that it improves the bokeh of a lens.

I have a 500D on my 100mm macro lens all the time just for the bokeh…
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