An online book of Common Sense Photography, by Rhett Stuart

Close Up Filters

19/27

This is the best choice if you want to move quickly around and not have to use a tripod. You don't even need a macro lens! Get one that has two elements of glass bonded together! They cost about triple what a good UV filter is but are really worth it. (The older close up filters had only one element and didn't work that well, they produced fuzziness). You simply take off your UV filter if you have one, and screw on the close up filter. Now you can take photographs much closer, with no loss of light! This produces high quality photos that can be used commercially. Canon and Nikon both make 2 element close up filters. This is the most economical way to get into macro photography with really good results.

Canon makes the 500d (the d stands for dual glass elements). Canon also has a 250d for lenses less then 70mm in focal length lenses for use with wide angle lenses.

Nikon makes the 5t and 6t. It doesn't matter which brand you get since they both have the same screw type filter attachment. Two element close up filters are about double the weight of a standard filter. However, they are much more compact and lighter to carry in the field than a macro lens! Especially when hauling my equipment for long distances! Sometimes I don't have room for a macro lens, but carrying one of these filters gives me a little insurance in case I suddenly need to do a really close up photograph. The disadvantage is that infinity focus is lost when the close up filters are attached. A close up filter is easier to add on then an extension tube or multiplier.

A dual-element lens cemented together controls chromatic and spherical aberrations (color and image distortion). Dual-element close-up lenses are usually recommended for use with telephoto lenses since they need extra-low dispersion elements to reduce the chromatic aberrations. What all this means is they work a lot better than the single element close up filters. For a rough guess on the magnification benefit to your lens, figure you will get about 30% to 50% more magnification.

Below is a list of dual element close up filters with their magnification strengths.

Focal Length Filter Apx. Magnification
70mm 5T 0.20
70mm 500D 0.40
70mm 6T 0.30
 
200mm 5T 0.50
200mm 500D 0.60
200mm 6T 0.80


Canon makes a 500 (without the D) but this is a single element filter. Don't get it. It's fuzzy. It has chromatic and spherical aberrations.

The 500 stands for the millimeter of working distance available when the master lens is set to infinity focus; however, this working distance is reduced to about 330 mm when I have my 70-200mm lens set for the closest focusing distance. The d signifies that it is a dual-element achromatic lens.

A Canon 100mm f/2.8 macro lens is normally 1X. With the 500D the magnification is increased to 1.3X! For the Canon 180mm macro lens the magnification is increased from 1x to 1.5X.

The Canon 70-200 f/2.8 L zoom lens gives up to 1:4 (0.33X) magnification at 200 mm and the closest focus I can get. By adding a Canon 500D, I can get everything to about 1:1.5 (0.60X) with no light loss.

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