There has been a lot of talk among wildlife shooters about the new III series teleconverters from Canon. Perhaps the most important stated advantages are improved auto-focus and image quality. My friends Doug Brown and Keith Bauer had a chance to do some test shots the other day to compare the image quality between the older series II converters and the new series III converters. Thanks to their images and an online collaboration, we’ve been able to produce this review for my blog.
My thanks to Doug and Keith for doing all of the work in taking the test images. Please visit their websites to see some of their great nature photography. In addition to being great nature photographers, Doug and Keith are excellent workshop instructors and super nice guys to boot. They are both based in New Mexico so if you are looking for a workshop when you visit Bosque del Apache, be sure to contact them.
If you liked this review and are in the market for new photo gear, please consider making your purchases at B and H Photo Video through the links below, the B and H logo at the bottom of this page, or through any of the links on my Rainforest Photography Gear Guide page. You pay the same, and I get a little something to buy food for the kids, the tanagers, and the hummingbirds
All images were shot with the Canon Mark IV camera body, the Canon 500 mm f4 L IS lens, Canon 580 EX II Speedlite flash, mirror lockup, and a Gitzo tripod with the Wimberley gimbal head. Images were shot in RAW, imported into Lightroom 3, and then output to PNG files via screen capture (the Mac’s screen capture utility apparently defaults to PNG for the output file format). Upon receiving the files, I renamed them for organizational purposes and output 100% quality jpegs to post here. No post-processing or sharpening has been applied, and all of the images represent 200% crops from the center of the image. Auto-focus was used and double-checked with Live View. The same focus point was used for all of the comparison images.
We don’t want to get into long arguments over the merits of different testing methodologies but simply wanted to share the results and our interpretation of them. Though I do have a sales commission affiliation with B and H through this blog, we really don’t have any stake in saying the new TCs are good or bad. Indeed, you’ll notice that we are very objective in our interpretations.
Clicking on the images below will open a new window displaying a larger version of the image so that you can make your own decisions.
At the widest available aperture with the 500 mm f4 L IS lens, we don’t find any major differences. If anything, while the new version appears a bit more contrasty, the previous version appears to be a bit sharper.
Again here, no major differences are apparent. When closing the aperture one stop from wide open, the new 1.4x converter doesn’t seem to offer much if any advantage over the Series II version. I think that the previous version of the 1.4x still looks slightly cripser here, while Doug thinks the new version offers a slight improvement in sharpness and contrast. Despite these opinions, these are really minor observations, and we’re all in agreement that there is no major difference here.
Comparing the new 1.4x at different apertures does show a difference. The new converter clearly shows an improvement in contrast and sharpness when stopping down from wide open, as would be expected.
Here things start to get interesting. The new 2x clearly shows improved contrast and sharpness over the older version, even wide open.
This is the most striking comparison image. The new 2x TC improves remarkably when stopping down one stop from wide open. The difference in sharpness and contrast between the two aperture settings is huge!
So, what to make of the test images presented here? To our eyes, it’s clear that the new 2x TC offers a substantial advantage over the older version in terms of image quality when used with the current generation of telephoto lenses (we’ll have to assume that the TC performance with the 500 mm f4 is representative of how the TC will behave with the other current super teles). The contrast and sharpness are notably improved. Stopping down a bit will really let the new 2x TC shine. Even if you do not plan to upgrade to one of the new super teles when they come out, the new series III 2x TC looks like it will be worth the extra money if you need critical sharpness in your images.
The new 1.4x TC, on the other hand, seems to offer image quality very similar to that of the current version when used with the current generation of Canon super telephoto lenses. Based on image quality alone then, we would question whether the new 1.4 TC is worth the extra $200 or so if intended to be used with one of the current super teles.
It remains to be seen, of course, how the new teleconverters will behave with the new generation of super telephoto lenses that are on the horizon. Since the new teleconverters were designed in conjunction with the new super teles, Canon claims that the new TCs will really come into their own with these new lenses. Indeed, Canon’s Chuck Westfall wrote that the "Extenders EF 1.4X III and EF 2X III have been newly developed in conjunction with the new Series II Image Stabilizer EF super-telephoto lenses. They can also be used with all previously announced extender-compatible EF lenses, but maximum performance is achieved when they are used with the new 300mm, 400mm, 500mm and 600mm lenses." If Canon wants to send us new 300 mm, 400 mm, 500 mm, and 600 mm lenses, we will be happy to conduct a thorough test though it would be necessary for us to keep the lenses to ensure that the test results remain constant over time
This review also does not touch on the autofocus capabilities of the new teleconverters (again, reported to be maximized with the new super tele lenses), so that is an issue for another day.
Stay tuned for a real world evaluation of the new teleconverters. Doug and I will be testing them out in the field during our tropical bird photography workshop here in Costa Rica with the current versions of the Canon 500 mm f4 and 300 mm f2.8 super telephotos at the end of this month. We’ll report our impressions here at the end of February. We also will be adding some test shots and impressions of the corner sharpness of the Series III TCs on full-frame sensor bodies.