In this review, I do a review of the Canon Extender 1.4x III teleconverter. I rented this from along with a Canon EF 400mm f/5.6L lens and the 2x III teleconverter hoping to get some amazing bird photos. After over 1000 shots with the lens alone, the 1.4x and the 2x teleconverters, my sad conclusion is that the lens alone probably gave me the best results.

Sure the 1.4x and 2x teleconverters do zoom in the image by 1.4x and 2x respectively, but they also deteriorate the image quality by a good amount, so taking a photo without the teleconverter and cropping it down usually gave very similar results without many of the inconveniences that comes from using a teleconverter (lost of 1-2 stops of light which sometimes disables autofocus on some lens/camera combinations).

All photos in this video are as-is .jpgs coming right out of the camera with no post-processing. Definitely some post-processing would improve some of these, but I want to show the files as they come, not after spending hours refining a RAW file. I first show the full image, then I zoom in 1:1.