Ophrys Photography

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Kent UK- Wildlife and nature photography- High-quality wildlife prints & stock images

Canon recently released mkIII versions of their teleconverters (converters) which are primarily designed to go with the new generation of mkII supertelephoto lenses. There are mixed reports on the internet as to whether the new converters also offer an improvement when coupled to existing telephotos.

I replaced my mkII 1.4x teleconverter with a mkIII model a few months back and was disappointed that I could see no improvement in image quality in the new converter whatsoever when used on a 70-200 f2.8 L IS mkII or 300mm f2.8 L IS lens. In fact the only improvement that I could determine at all was that the lens locking mechanism appears to have been improved with a wider catch which removes the need to jiggle with the switch to get it to lock properly. Contact with the lens and camera appears to be better.All my previous converters started life OK but all developed the annoying need to wiggle the catch to get it to lock after a a short period of time.

Having been disappointed in the 1.4x mkIII converter I was about to also dismiss the 2x mkIII converter as well, but having read some very positive comments from respected bird photographer, Art Morris when using the mkIII with a 70-200 f2.8L IS mkII, and also from other photographers on the Bird Photographers.net and Fred Miranda forums I was persuaded to change my mind and purchase the 2x mkIII converter to accompany my 70-200 f2.8 mkII, 500mm f4 and 300mm f2.8.

Here are my findings:

Test conditions

For the 300mm and 500mm tests I used a 1DmkIV camera, but conducted the 70-200 tests on a different occasion using a 5DmkII camera. I also changed camera to target distance between lenses as the longest lens had far more reach than the shortest. I don't feel that these inconsistencies matter, as what is important is the comparisons between the two 2x converters in each case. All combinations were lens- micro adjusted using the Hazeghi tethered method and I used a gitzo tripod/markins head, mirror lock-up and a remote release was throughout. Target was my usual banknote taped to a metal angle bracket. The widest aperture that each lens/converter permitted was employed.

Results

500mm f4 Lens with mkII and mkIII 2x converters

Starting image

100% crop - 2x mkII converter



100% crop - 2x mkIII converter




300mm f2.8 L IS mkI USM lens with mkII and mkIII 2x converters

100% crop - 2x mkII converter

100% crop - 2x mkIII converter

70-200 f2.8 L IS mkII USM lens set to 200mm with mkII and mkIII 2x converters

Starting image

100% crop - 2x mkII converter

100% crop - 2x mkIII converter




Conclusions

Despite being a new design, the 2x MkIII converter appears to offer absolutely no difference in image quality over the mkII design when used with any of the three lenses I used. Hopefully the new converters will perform at another level when coupled to the new mkII generation of 300mm, 400mm, 500mm and 600mm super telephoto lenses. In the meantime I do not agree with the findings of some others that the mkIII 2x converter offers any improvement in image quality from the mkII converters with the current generation of 300mm and 500mm lenses or the latest 70-200mm f2.8 mkII.

I have not tested the converters for edge sharpness or chromatic abberation, so there could be some improvements here, but as it stands I cannot recommend purchasing either mkIII converter if you already own a mkII.