EF 70-200mm f/2.8L IS II USM with 1.4 TC III or EF 300mm f/4 -- image quality

[contrastny]

I currently have the EF 300mm f/4L IS and I am thinking about getting the EF 70-200mm f/2.8L IS II USM. In terms of image quality is the 70 - 200 with a 1.4 TC better than the 300mm f/4 without a TC?

Maybe I'll keep the 300mm f/4 for when I have 2 bodies 300 on one and the 70 - 200 on another for wildlife work.

[neuroanatomist]

Although the zoom without an extender beats the prime (meaning it's a very good zoom!), the 300/4 is slightly better than the 70-200/2.8 IS II + 1.4x, both with the MkII and MkIII versions of the extender (links are to TDP's ISO 12233 comparisons). 

[neuroanatomist]

I should add - I have the 100-400, but I occasionally use the 70-200 II + 1.4x II on my 7D.  The latter combo is weather-sealed when used on my 7D, whereas the 100-400 is not, nor is the 300/4. 

This shot was taken with the 7D with 70-200 + 1.4x II in the rain:


EOS 7D, EF 70-200mm f/2.8L II IS USM + EF 1.4x II Extender @ 280mm, 1/2000 s, f/6.3, ISO 3200

[Harv]

I own both of those lenses and considered disposing of the 300/4L IS and using my 1.4xTC II on my 70-200/2.8L IS II when I needed the extra reach.  For the record, I shoot them on a 1D Mark IV but I suspect the relative performance would hold true on any body.

The 70-200/2.8L IS II is an outstanding lens but with the 1.4xTC behind it, the 300/4L IS outperforms it for sharpness, colour and contrast as well as AF speed.  Remember that Canon states the TC will slow AF by approximately 50%.  This was done by design to provide the most accurate AF.

Also, if you already have the 1.4xTC, keeping the 300 gives you a 420/5.6 lens as well.  That can be a pretty good combination.  Here is a shot I took hand held with the 300/4 + 1.4xTC a couple of weeks ago.  It's about a 50% crop.

Be certain to click on the image to bring it up full size.



I'm keeping both.   

Hope this helps.

Harv

[contrastny]

Thanks for the comments, looks like I will keep my 300 f/4 as well.