Testing the Canon 300mm f/4 lens with a 2X Teleconverter

Sometimes I just don’t want to carry around my Canon 500mm f/4 lens with a big, sturdy tripod, but I still want to be able to photograph wildlife and birds.  The Canon 500mm f/4 is a terrific lens but it can be difficult to travel with this big lens.  Flying on small planes is not possible and shipping the lens to your destination can be expensive.  So what are the options for a smaller, lighter lens that can still be used for wildlife and bird photography?

The Canon 300mm f/4 is a sharp lens.  Also, Canon recently released firmware upgrades for the Canon 5D Mark iii and Canon 1D X that allows the center focus point to autofocus at a maximum aperture of f/8 when a lens and teleconverter are used together.  This means that the Canon 300mm f/4 lens can be used with a 2X teleconverter and still autofocus.

I recently tested the Canon 5D Mark III, Canon 300mm f/4 lens, and the Canon EF 2.0X III Telephoto Extender out while photographing birds.  This was a test prior to leaving for an Alaskan cruise.  It wouldn’t be possible to bring the Canon 500 f/4 lens on the cruise so I wanted to see if the Canon 300mm f/4 and 2X teleconverter would be an acceptable replacement.  Check back on the blog to see how this combination performed on my Alaskan Cruise.

I was surprised with the image quality of the pair.  All the photos in this blog post were taken with the 300mm and 2x teleconverter. 

Drawbacks of using the Canon 300mm f/4 lens and 2.0X Teleconverter Combination

• The widest aperture for the pairing is f/8.  This could cause problems in low light situations.
• Autofocus is a lot slower than with only the Canon 300mm attached to the camera.  This is especially true in AI Server mode when trying to photograph a moving object.
• There were more soft photos than without the 2.0X teleconverter attached.  However, I did get some sharp images even of a blackbird in flight.

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