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Difference between Macro extender & 2x teleconverter

Sorin Varzaru , Jun 28, 2000; 05:17 p.m.

Can somebody please explain what is the difference between a macro converter (the second lens that came with my macro lens, that makes it a 1:1) and a 2x teleconverter. I noticed they have the same effect. Do I miss anything? I have a Kenko-Tokina 2x Teleconverter.


Joseph Moniz , Jun 28, 2000; 06:05 p.m.

A macro extender, or extension tube, will allow a lens to focus closer. You will sacrifice infinity focus to do so.

A Teleconverter/teleextender will increase the focal length of your lens, but (usually) wlll NOT allow your lens to focus closer.

Both items will cause a loss in light transmission to your film. If you do not have TTL metering you will have to experiment to find the correct compensation to adjust for this loss of light.

David Goldfarb , Jun 28, 2000; 06:16 p.m.

If your macro lens has a magnification of 1:2 without the extender, it might be the case that what the manufacturer is calling a "Macro Extender" is in fact a 2x teleconverter, since the teleconverter doubles the magnification without changing the near-focus distance of the lens. The Tamron SP 90mm/f:2.5 macro lens, for instance, is designed to work in this way with its own flat-field teleconverter. If there are lenses inside the "Macro Extender," then this is most likely the case. If the "Macro Extender" is just an empty tube, then it is just an extension tube that allows you to focus closer.

If the "Macro Extender" is a 2x converter and it came with the macro lens, then it might be optically matched to that lens, and if so, should produce better results with that particular lens than an unmatched teleconverter.

Chuck Fan , Jun 28, 2000; 06:19 p.m.

In addition to what Joseph said, many marco lenses are designed with matched extension tube in mind. Their optical performance suffers less when used used with a extension tube than with a typical teleconverter. However, 2X teleconverter gives you more than twice the working distance, which is of great help if you photgraph insects or use sophisticated lighting arrangements.

kurt heintzelman , Jun 28, 2000; 07:12 p.m.

I don't know the details, but within the Canon EOS line, there is the 1:1 "Life size convertor EF" (~$230.00), which is claimed by Canon to be for "exclusive" use with their 50/2.5 Compact Macro (~$355.00). This converter contains glass elements, so it's not merely an extension tube. Do the math, figure in the inconvenience of the converter, and the conclusion will likely be that the EOS 100/2.8 macro (non-USM, or even USM) may be a better purchase.

Robert Edwards , Jun 28, 2000; 08:51 p.m.

Hi Sorin

The Kenko 2x Teleplus is a regular 2x teleconverter which doubles your focal length. It has an extra feature where you twist the barrel and it also acts like an extention tube.

I used one a few years ago on a 50mm f1.4 lens and the Kenko made it into a 100mm f2.8 macro lens capable of 1:1 reproduction. The 7 element Kenko (known as Glanz in some parts) is the highest quality after-market teleconverter available. I used mine to photograph insects on the wing with flash at f11 with a 50mm and the results were fantastic.

Bare in mind what you compromise. As a 2x converter you lose 2 f-stops and after "zooming" the extension out fully you lose another stop, a total of 3 f-stops. That makes my 50mm f1.4 a 100mm f4 when shooting at 1:1. You should also close down a couple of stops when using any teleconverter for the best quality.

Robin Sibson , Jun 29, 2000; 04:09 a.m.

The Canon Life Size Converter is a combination of a 1.5x teleconverter and an _extra_ 8.3mm of extension, and thus converts the basic focus range of the Canon EF 50/2.5 macro lens from (x0 to x0.5) to (x0.25 to x1). Its optical performance is excellent with the lens for which it is designed. There is no physical barrier to using it with other EF lenses (unlike the Canon Extenders which project at the front) but performance may be poor (chromatic aberration, mainly) and infinity focus is nominally unavailable (although it is possible to take advantage of the fact that many long lenses focus beyond infinity). With the converter, the 50/2.5 becomes a 75mm lens and reports itself as f/3.2 (surprising - I would have expected f/3.5). The new internal-focus 100mm USM macro probably has a very similar focal length in extreme close-up, whereas the old non-USM version does not change its focal length. Obviously it is convenient to be able to focus to x1 without interruption, but 50mm is in my experience a good focal length for botanical work and I find the converter to be readily useable in the field.

Sorin Varzaru , Jun 29, 2000; 10:23 a.m.

Thank you everybody for the answers. This is the reason I asked. I have a Tokina ATX 90mm macro with it's own macro extender. My camera (N80) does not provide any metering for non-cpu lens like this one. So I was thinking to pay some guy $80 to add a "cpu" to this lens. I don't really need AF for macro so that would make it perfect. However, I would loose the ability to use the macro extender since it doen's have contacts for the cpu. I do however have a 2x Kenko teleconverter with contacts. So, the question is, should I modify the AI mount on the this macro (to get metering) and use it with the kenko teleconverter or I'm loosing quality due to the fact that the kenko was not designed for this specific lens.

Or sell the macro and get an AF-D mount? Speaking of that, can anybody tell me how much better is the flash photography with 3D matrix metering (with nikon D mount) compared with regular matrix metering. Is it worth the money?

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