I have around $1,200 in my new lens budget and am debating between these two lenses. I'd like to purchase in the next month or so as we plan to take a vacation to Alaska in June and I really need a longer lens for wildlife shots. After the AK vacation, I would use the lens primarily for wildlife closer to home (wild turkeys, bears, deer, maybe a few birds, etc.) and some limited outdoor sports like baseball and soccer.
For the applications you mentioned IQ matters. I attached three pictures with my EF 5.6 400 (EDIT: All taken with EOS 40D) which I bought primarily for condensed landscape shots etc.
First attached image:
- Sharpness/contrast close up (meaning 4m distance) and wide open is phenomenal. It is a 100% crop taken with 40D - not a pixel monster but pixel size is close to 5Diii
- landscape through a lot of atmosphere: This is NO ART FILTER of some software like gimp or photoshop, it is a straight image ... The weather was cloudy but with intense sun so you have a lot of turbulence in the atmosphere.
- Moderate agricultural action shot where I had to place things attractively (more or less) without the chance to get the whole apparatus on the photo - here a ZOOM HAD BEEN VERY HELPFUL
My conclusion is:
- in the close focus or nearer range (<= e.g. 200m) the IQ is dominated by the lens
- depending on weather conditions for distances of e.g. 200m or more the quality of the atmosphere dominates (or select a weather of stable temperatures, then atmosphere has good optical quality)
- a zoom is helpful if you cannot change your position or you have no time to do so. This is a very common statement but it applies perhaps to your scenery very often.
My other tele lens is a 70-200 2.8 II and I have a 2xIII extender. This lens is still really good even with the 2x extender, so maybe I should continue with this combo and save my money toward an 85 1.2 II?
I have used the 4.0 70-200 non IS with the 2x TC mark i - a good combo at f/8, better at f/11 (with TC), but the long exposure times give much more smearing for long distance shots so f/5.6 with the EF 5.6 400 is a large benefit.http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=278&Camera=453&Sample=0&FLI=0&API=0&LensComp=104&CameraComp=453&SampleComp=0&FLIComp=6&APIComp=2
The CAs introduced by the teleconverter are handled well with DPP or DxO and they improve the IQ substantially.
I think your 70-200 lens with 2x TC is quite a good alternative which gives you acceptable IQ combined with flexibility and no additional cost. Just here correcting CAs will help a bit.http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=278&Camera=453&Sample=0&FLI=0&API=0&LensComp=687&CameraComp=453&SampleComp=0&FLIComp=7&APIComp=0
From reading reviews and looking at the lens sharpness tool at TDP, it appears the 400 is sharper overall. But it of course lacks the zooms flexibility and vibration control. At this point, I'm leaning a little toward the 400 5.6 as I expect I would use the zoom primarily at 400+.
If the EF 4.5-5.6 100-400 would exist as a mark ii version with 4 stop IS and equal IQ @ f/5.6 and 400mm like the EF 5.6 400 for 2300 $ I would think: The 1000 $ premium compared to the prime is well invested and that lens would replace my 4.0 70-200 AND the 5.6 400 - so if you can live with your lens-TC combo do that and wait for some development.
Think about renting a 5.6 400 and run your own checks. Lenses are not only about IQ but also about handling, AF speed, mass, size, haptics etc. and the 5.6 400 handles very well.
Just my thoughts - Michael