In my previous blog about Bird Photography Equipment, I reviewed the Canon EF 300 f/4 lens with the teleconverter Kenko C-AF 2X Teleplus Pro 300 DGX.  I have had a couple of weeks of testing this configuration and further testing revealed some additional amazing results that I did not expect.

The new surprise is that this lens, when used in a cropped body, like a 7D or even a t3i (600D), and the Kenko 2X teleconverter, can also be used as an amazing long distance macro of 300 x 2 x 1.6 (crop factor) = 960 mm !!!!  I came across this while testing the 300 with kenko 2X TC and there we no birds to shoot. So I started shooting some butterflies and small flowers without expecting great results.  One of the nice things about the 300 f/4 is the minimum focus distance of 1.5 meters which makes for a good long-distance macro.  Now add a 2X teleconverter and all of a sudden all those small flowers, insects, etc. are 2X closer to you and the image quality is still very good.  Additionally the minimum focus distance does not change with the TC so you definitely see an improvement in the macro side of the lens!

I have gone as far as comparing this arrangement with the legendary canon 180 mm f/3.5 macro with the following examples. Maybe you think I am crazy but look at these pictures please..

This first set of photos compare the 300 vs the 300 with the 2X TC

Canon EF 300mm f/4 with and without Kenko 2X

As you can see the 2X definitely helps the macro shots.

This second set of photos compare the 300 vs the 180.  To do this I have gotten both lenses as close as possible to the subject which means the 300 is 1.25 meters away from the subject and the 180 mm is 0.4 meters away.  To test both lenses as optimal conditions and at ISO 100 I used a 580EX and the 7D in manual mode f/18 and speed 1/200.

Comparison of 180mm macro with the EF 300mm plus Kenko 2X TC

The image quality of the 180 mm macro is only a little better.  I would have expected a bigger difference but at optimal optical conditions there is not a big difference.   Here is the uncropped image of the 300 mm f/4 with the “X TC


Uncropped 300mm at f/18 ISO 100

The next set of photos compare the 300 vs the 180 without flash under shadow. In this case the 7D has been set in manual, f/18, speed 1/100, ISO between 2000 and 3200. Some exposure adjustment was done afterwards.

300mm vs 180 mm without Flash

Again we see improvement of the image when the 2X TC is added to the 300 mm lens. The 180 mm macro does a little better but I think the image of the 300 is very good.

The last set of photos compare the EF 100-400 f/5.6 at 100mm plus a Hoya macro lens with the 300 f/4 plus the Kenko 2X TC and the 180 macro. In this test the camera has been brought as close a possible to the subject. For the 100-400 lens at 100 plus a Hoya +4 Macro ring that distance is 25 cm.


Comparison with 100-400 f/5.6 at 100mm with Hoya +4 macro adapter

The macro image quality for the 100-400 with the Hoya is better than the 300 with the Kenko 2X.  It looks almost as good as the 180mm macro. Which is another plus for the 100-400mm.

Conclusion: My conclusion is that the performance of the Canon EF 300mm f/4 L IS is significantly improved using the Kenko 2X for macro shots when the light conditions are adequate.  In addition the performance is also improved significantly on the telephoto applications as presented on my previous post: Bird Photography Equipment – Teleconverters for 7D and 5D MIII  For these reasons I am now birding more and more with the EF 300mm and keno 2X combo making it a better telephoto and a better macro all in one lens!


Written by Renato
Renato was born in Quito, Ecuador and quickly flew to the USA to learn all about engineering and climbing company ladders. After getting his engineering degree from the University of Minnesota he worked in the Standard-American-Rat-Race-Company for fifteen years. After climbing the ladder to where he could no longer see the ground, he decided to jump off the ladder and migrate south like all normal birds do. To his surprise home did not look like it did when he left as a young fledgling; the towns were bigger, most of his friends had nests of their own, and the countryside was changed. Shocked by all the change he searched for a new life and a new wife. He stumbled across a vivacious young chick who would accompany him inside a volcanic crater to set up a love nest. So, after eight years of nesting inside the crater a new love for nature and birds has sprung a career in environmental conservation and birding tours. Finally this bird has come home to roost!