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Close-Up Diopters
One of the simplest and most cost-effective ways to get into the realm of macro photography is though the use of two-element close-up diopters, also known as an achromats. These handy lens accessories essentially are nothing more than high-quality magnifying glasses you screw onto the front of your lens that allow you to get closer. Before you rush right out and buy one though, there are a few things you ought to know.
First off, you want to be sure you get one of the ones made with two lens elements as they are highly corrected and can work quite well, A number of manufacturers such as Hoya, Tiffen and even Nikon and Canon also make cheaper single-element ones that are best avoided.
They also come in multiple sizes and strengths. Sizes are easy to understand since, just like a filter, you want to get one that fits the thread diameter of the lens you intend to use it on. They tend to work best on moderate telephoto lenses. Either prime of zoom lenses will work well, but if you use one on a zoom lens, you will need to refocus after zooming. Not really a problem, but something to be aware of. Diopter strength is measured in units aptly known as diopters. The diopter strength of a more powerful close-up lens is a higher number than that of a weaker one. Generally, you are better off starting with a weaker one and later getting a stronger one if you still want to get greater magnification.
The actual diopter rating is determined by taking the focal length of the close-up lens and dividing it into 1000. As such, an achromat with a focal length of 500mm would have a diopter strength of 2 (1000 divided by 500).
As to what is available, Nikon makes them in two sizes, 52mm and 62mm and in two strengths, 1.4 and 2.9 diopters. Canon makes two-element close-up lenses with a strength of 2.0 in 52mm, 58mm, 72mm and 77mm size, as well as 4.0 strength diopters in 52mm and 58mm sizes. How either company determined what to offer is beyond me. I am not aware of any other comparable quality diopters from any other company. The following table summarizes what is available:
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The Good Ones:
| Manufacturer |
Product |
Diopter Strength |
Sizes Available |
| Nikon |
3T |
1.5 |
52mm |
| Nikon |
4T |
2.9 |
52mm |
| Nikon |
5T |
1.5 |
62mm |
| Nikon |
6T |
2.9 |
62mm |
| Canon |
500D |
2.0 |
52mm, 58mm, 72m, 77mm |
| Canon |
250D |
4.0 |
52mm, 58mm |
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The Not So Good Ones (single element):
| Manufacturer |
Product |
| Nikon |
#0, #1, #2 |
| Canon |
#500 (without the "D") |
| Tiffen, Hoya, B+W, others |
Any |
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You needn't be concerned with getting Nikon ones for Nikon lenses or Canon for Canon any more than you should fret that Minolta or Pentax don't make any if you shoot those brands. Simply get the ones that fit your lens just as you would with a regular filter.
When you are working at high magnification such as this, be aware that your working distance (the distance from the front of your lens to the subject) can be quite small. Don't be alarmed that you won't be able to focus on objects on the other side of the room. It may take you a little while to get used to the fact that you may only be an inch or two from what you are photographing. Depth of field will also be quite shallow so it is important that you optimize your camera position so that the film plane is parallel to the plane of the subject.
These little guys are definitely your best entry point into the world of macro photography. Image quality can be quite good. A true macro lens may be slightly better, but images taken with the quality close-up lenses such as the 5T or 6T can be quite publishable.
Update 11/15/2003: I have recently found that there is one third party alternative for multiple element close-up lenses. Century Optics makes achromat accessory lenses in +2, +4 and +7 diopter strengths, but only in 58mm thread size. While designed for video cameras, they are reported to work well with film cameras as well, assuming they are not too small to fit on your lens.
Update 05/23/2004: For completeness, here's another possible alternative: Olympus makes the MCON-35 two-element close-up lens for their E-10 and E-20 digital cameras. I have not actually seen one, but they have a 62mm thread size and a focal length of 350mm (about +2.9 diopters) and are reportedly of good quality. The excellent quality Nikon 6T is essentially the same strength though and cheaper by a good margin.
Update 06/30/2004: How about a 52mm-threaded 12-diopter "ultra high-performance aspherical close-up lens?" Well, there is such a thing. The Zörk Makroscope / Type I may be just the ticket.
Update 09/08/2004: One more update from a reader. The Sony VCLM3358 is a 58mm-threaded two-element diopter with a strength of somewhere around +3.3 diopters.
Update 03/05/2006: There are strong rumors that Nikon has discontinued the 6T, leaving only the 3T, 4T and 5T. If you want one, better get it now.
If you know of other 2-element achromats, please let me know and I will add them here.
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