Lens Converters??

  • Thread starter Thread starter gingerweasel
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gingerweasel

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Okay so I keep coming across people talking about converters. From what I can gather these are a cheap way of adding reach to your existing lenses and possibly avoiding the expense of a farther reaching superzoom.

So far I'm with it ...

If I use a 2x converter on a 70-200mm lens then I get 140-400mm.

As with all things in life I'm guessing there are some catches but I haven't been able to find any information on it.
 
With tele converters and extenders there's no free lunch, but it can be quite a tasty one.

They only work well with longer lenses, of very high quality, and at mid-range f/numbers. What they do is magnify the centre part of the image, complete with all it's optical shortcomings, plus they then inevitably add a few of their own. Central sharpness is reduced, and edge sharpness can be quite poor.

While they increase focal length by 1.4x or 2x, you lose one stop of light, or two stops respectively. So if you have a 70-200mm f/4 lens and a 2x converter, it becomes 140-400mm f/8. Remember that if you go higher than f/5.6 you lose AF with most camera bodies which is why 1.4x converters are more popular, plus they are sharper. A 70-200mm f/4 lens then becomes a 98-280mm f/5.6 with a 1.4x converter which retains AF, even if it is a bit slower than without the converter.

Canon and Nikon converters and extenders are good, with the right lens, but expensive. Kenko Pro 1.4x has a decent reputation. Sigma is also okay. Cheap converters are horrible.
 
I use a Canon 2x on a 70-200L F4, and the main downside for me is the loss of autofoucus (using 10d). I believe on certain bodies the autofocus works. The image quality is not just as good as using the lens without the convertor, but in my opinion it is not a significant difference. Using hand held though, with the loss of a stop, on what is now 140-400, the options are limited. Talking everything into account, from my point of view, I don't think they are great value for money.
 
I have various converters by both Canon and Kenko which mostly remain unused, one is on long term loan and I have yet to miss it. I would hesitate to recommend them as the perfect solution but so long as you buy good ones they are a low cost option compared to dedicated lenses with the increased focal length. Yes there are the catches mentioned by others which can put many off bothering.
If you want to make your own judgment then I suggest getting your hands on a Kenko 1.4x Teleplus PRO 300. These retail at around £100 which is a a lot less than the Canon version.
 
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