Canon 2x teleconverter review

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Introduction

I often use teleconverters. The converters are multiply the ‘mother lens‘ magnification, this way allows tighter view of a distant subject. Mostly used my Soligor 2x converter before, that is similar to Kenko earlier model. Some info about converters/extenders in general:

Basics of converters

1. The 1.4 converter are much better optically, than the 2x ones, even wide open.

2. The converters works best with bright prime lenses from 135 mm focal length, and canon ‘L’ zooms started from 70mm focal length.

3. The 1.4 converters lost 1 stop light, 2x converters 2 stop of light. What does this means? 1.4 converters shutter speed is half than the lens without the converter. 2x converters shutter speed is 1/4 than the original lens shutter speed at same aperture.

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4. With a bad, not sharp lens, the converter can make awful image quality. The converter simply magnifies the lens aberrations.

5. Autofocus not works ”normally” with canon converters with consumer or prosumer bodies(10,20,30,40,50,60D or 300,450,500,600d, etc) above f5.6, with I Mark bodies above f8. This means that an f5.6 lens normally not autofocuses with an 1.4 converter, but autofocuses with an I series canon body (For example Canon 1d MKII. An f2.8 lens normally autofocuses even with a 2x extender on a consumer body as well. My experience with a canon 200 2.8L, that some copies of the canon 2x converter focuses better, other copies of the same converter is very slowly autofocuses. This means better check first before buy, and read the same about the ‘mighty’ 300 f2.8 lens.

2x Converters available in the market

Canon has 3 double converters: Mark I, II, and III. All different a little bit. Between mark II, and III the difference is a little better contrast, and little better chromatic aberration, and better autofocus operation. The shapness between the two not really different. I don’t see much difference also between the Mk I and MK II modell as well. The new Mk III works better with newer lenses, the MkI and Mk II ones works better with older lenses.

It is said that 2x converters are ‘soft’, unlike the 1.4 ones. But in some situation the longer reach is preferred even with less optical quality. Earlier I used a cheap Soligor converter which is identical with an earlier Kenko modell. I don’t like the colours of that converter. The canons colours much superior, sharpness also a bit better. The canon also much better wide open. I recommend this converter just for the sharpest lenses: 200 f2, f2.8, 300f2.8, 400 f2.8 or other exotics. The 2x converters degrade image quality considerably even with the best lenses, and also reduce brightness and shutter speed considerably, this is why so many on used markets. The 1.4-s is much better selled.