Any comments on the 300mm f2.8 IS mk1 and 2x mk3 TC?

[GuyF]

Have any of you tried the above combo?

I currently have the Kenko 2x Pro 300 DG (red dot) which is okay for the money (cost about £110) but images aren't quite as crisp as I'd like so I don't use it that often. Can any of you comment on the sharpness of the 300mm with the mk3 converter or post images? Also, is the AF speed still acceptable to you? I'd be using the combo for airshows or birds in flight etc.

Whilst I'd rather have the 500mm f4, I'm thinking of the cheaper option first! If I got the mk3 TC I'd probably also buy a Wimberly Gimbal head too.

Any suggestions are appreciated.

Body is a 5D3.

[Jim Saunders]

On a 5D2, SOOC, no AFMA:

[LetTheRightLensIn]

Have any of you tried the above combo?

I currently have the Kenko 2x Pro 300 DG (red dot) which is okay for the money (cost about £110) but images aren't quite as crisp as I'd like so I don't use it that often. Can any of you comment on the sharpness of the 300mm with the mk3 converter or post images? Also, is the AF speed still acceptable to you? I'd be using the combo for airshows or birds in flight etc.

Whilst I'd rather have the 500mm f4, I'm thinking of the cheaper option first! If I got the mk3 TC I'd probably also buy a Wimberly Gimbal head too.

Any suggestions are appreciated.

Body is a 5D3.

Softer than the bare lens or using it with a 1.4x TC III certainly, but plenty usable, maybe same quality as a bare Tamron 70-300 VC or so??

AF is like 75% slower than with no TC. For quick locks onto stuff at distant distances or trick situations to lock on it can be slow but, for example, for surfing where distance doesn't change much shot to shot it tracked very well on my 5D3.

[GuyF]

Thanks for the replies. I was looking at the test results over at The Digital Picture and the results really don't convince me the mk3 TC would be significantly better than the Kenko. The 2x is only really used in an "emergency" so I may have to look at the more (much more) expensive options.

Now to try and sell the 300mm and justify a 500mm f4.....

Regards.