Canon 500mm f/4 L IS vs. 300mm f/4 L IS

[SLRUser]

I have been trying out a Canon 500mm f/4 L IS and comparing it to a 300mm f/4 L IS on a 7D.

Both of these images are 100% centre crops and taken wide open with a Canon 1.4x II teleconverter attached from the same position only moments apart. Not exactly a very good test subject but I couldn't get a bird to sit still long enough for me to change lenses.

Much more contrast and no CA around the bolts. What is your impression?

300mm f/4 L IS with 1.4x TC (420mm equivalent) @ f5.6, ISO 100

500mm f/4 L IS with 1.4x TC (700mm equivalent) @ f5.6, ISO 100

 

[scottthehat]

id be happy with both, but the 500 look better.

 

[lost]

It's difficult because you have the leaves in the one image which could have affected the exposure slightly a fairer test would be an object against a mid tone grey background both lenses mounted on a tripod then you may find they are closer than they look here.
With the 2 images you have posted the 500mm looks better
Regards
Richard

 

[da_nige]

I have both the 300 f4 IS and 500 f4 IS and in real world shooting find the 500 to be superior but with its price tag that can be expected.

I used the 300 before I could afford the 500 and won't sell it. Its too useful for close up work.

Neil