Everything you'll ever need to know about using a 1.4x or 2x extender or teleconverter on your lens. Will it degrade the image? How can you prevent this?
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The Ultimate Guide To Extenders Or Teleconverters, 50% OFF
Canon EF Extenders - Teleconverters
The Ultimate Guide To Extenders Or Teleconverters
Teleconvertor vs Extension tubes
Should you buy a Teleconverter?
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Pros and cons of teleconverters for macro photography