Full frame extenders?

[cloudhunter]

Hi,

For full frame if i added one of these 1.7x or 2x extenders what negatives are there of using one?

For instance would a 500mm lens give the equivalent of 1000mm (using the 2x extender) with the same quality as if i was using a 1000m lens?

Matt

 

[Kaouthia]

You will lose some quality. To what degree really depends on your body, the lens in question, and the brand/quality of teleconverter used. You will also use 2 stops of light on a 2x TC, so a 500mm f/4, for example, would become a 1000mm f/8.

This would probably also affect the "sweet spot" aperture of your lens. Again, using a random brand 500mm f/4, it may have a sweet spot of f/8 to get the best quality of sharpness. With a 2xTC, this could become f/16 or even slower.