Canon EF 300mm f/4 L IS USM + 2.0x III Extender

[KoiErik]

Has anybody or is anybody using this combination?

[brogan]

Hi Erik,

I have tried out the 300 F4 IS with a 1.4X TC MK II and III and was not happy with the results, the 2X will have more of an impact on image quality than the 1.4 X though. I would not go this route as you will also loose AF, unless you mount it on a pro spec 1D body. if you are looking for that sort of focal length, in the same sort of cost bracket rather look at the 400 F/5.6 L /100-400 l . Otherwise you will need to look at the X-500 Sigma lenses. I got a chance to shoot with a 150-500 OS Sigma last week in Kruger (Nikon Mount) and the OS takes for ever to start up, the AF is slow (slower than 100-400) although it was accurate.

To go back to your question, no I have not tried this combo, nor will I. For the reasons I stated above, I am assuming, there have been no posts to your question by other Forumites.

[camerasaurusrex]

I know a lot of birders who take excellent pictures with the 300mm F/4 and a 1.4x converter. This is quite a popular combination. I agree that the 2x converter is not a good idea.