Canon EF 400mm f/2.8L IS USM

Yes, slight improvements when stopping down with with TCs is normal. Although it should be useful wide-open

OK, need further testing then Thanks.

I should mention that I don't own this lens nor TC's myself. The above statement is taken from several reviews and tests I've read

with 2x TC III...the IQ gets improved a LOT!

silvex wrote in post #15786887
with 2x TC III...the IQ gets improved a LOT!

Really? That goes against what Canon told us

silvex wrote in post #15786887
with 2x TC III...the IQ gets improved a LOT!

I've not tried the 2x TC III, but have used the 1.4x TC II & III.
Yes the mkIII is a little better but it's barely noticable and certainly not a "night and day" experience. If I A/B two simular shots, I can just discern a difference. If I just use them both the difference is so slight it's neglidgeable.

I would suppose the 2x II and III is a simular experiance.

Neilyb wrote in post #15789266
Really? That goes against what Canon told us

I've used 1.4/2.x MkIII with 70-200 MkII and 400 f/2.8 MkI/MKII and works much better than version II. The IQ is better than with older converters. It does not improve the IQ of the lens it self...it actually degrades a bit...

Well to be honest I will not use either the 1.4 III or 2x II wide open, the images are watery. Stopped down = amazing but wide open is a no go. May just stick to my original plan and sell it . I do like the flexibility of 400-800mm though.

If you want to sell yours, please send me a PM, I might wanna buy it instead of the 300mm

Postage to Denmark would cost like a flight!

Neilyb wrote in post #15792805
Well to be honest I will not use either the 1.4 III or 2x II wide open, the images are watery. Stopped down = amazing but wide open is a no go. May just stick to my original plan and sell it . I do like the flexibility of 400-800mm though.

The extender, camera and lens must be fine tune, else the extender will just amplify the any focusing problems with the lens and/or camera.

Neilyb wrote in post #15793169
Postage to Denmark would cost like a flight!

Yeah, I know, but the prices here are so expensive that it will ve in my favor if the price is right.

You will be first on my list should I sell it

silvex wrote in post #15793810
The extender, camera and lens must be fine tune, else the extender will just amplify the any focusing problems with the lens and/or camera.

Well, when I asked to have my 300 2.8 calibrated with my 1.4 and 2x extenders and then 5D the Canon place here in Munich said they don't do that. One reason I do not want to take it, I do not trust them to do it right, nothing came from there better than it went in.

Neilyb wrote in post #15794337
You will be first on my list should I sell it

Thanks