7D on a 500mm Lens

This question has probably been asked before, but I will ask it again in view of the upcoming 7DII. I just purchased a Canon 500mm f4 II and will be using it for wildlife photography, including birds. I did not want a longer lens in view of the increased weight. The 1.6 crop factor will take this lens to 800mm. Can I anticipate that the image quality will be the same as using my 5DIII? Will the image quality be as good or better than the 500mm and 5DIII with a 1.4 teleconverter? Am I comparing apples and oranges? Thanks.

I have no actual experience, but my hunch is that the IQ will be about the same at low ISO. But extenders do infact make AF somewhat sluggish, so I would bet on more keepers with the 7D2 + 500mm combination.

I am also jelly of your super tele's.

FF with a 1.4x TC will yield either slightly better results or nearly identical to the 7D using the same lens, IMO. I have tried that with my Sigma 500mm (in no way close to the 500mm prime for IQ), and the 5D3 with TC was very close, if not a tiny bit better, than the 7D without.

Also since you will shooting at f5.6 on the 5D3 with that combo, you will lose a stop of ISO, so even the ISO performance would be somewhat close, with the edge going to the 5D3.

So in summary, if you already have the 5D3, just get a TC first, and try it out. If it works for what you want, then great, else you can decide on whether you want to get a used 7D. You will need to be a bit more attuned to processing the files though, good exposure, good raw converter and good post to get the most out of the 7D.

I recently picked up a good used 500 f4L verson1. I have only been out a few times with it and I have used it on my 1D MKIV and 7D both with good results. What I have noticed under good lighting conditions, max 800 ISO, the 7d is holding up better, if and when I need to crop then the MKIV. The MKIV is better when everything is filling the frame. My solution thus far is I use the 7d when shooting small birds or far off subjects that I know I will want to crop. I use my MKIV for the larger birds and deer and more close up stuff like Eagles fishing or anytime I need to push the ISO. I think the 7d II will be the body I go to for wildlife if there is a vast improvement in noise at higher ISO settings. I had a 5D MKIII for a while but I wanted more frames per second for BIF and I always had an extender the 5DIII on my lenses for the extra reach. Also I feel the 1.4 extender definately slowed down the autofocus on my 300 2.8 IS. I will say the 5DIII produced some fantastics shots though.

cerett wrote in post #17191344
This question has probably been asked before, but I will ask it again in view of the upcoming 7DII. I just purchased a Canon 500mm f4 II and will be using it for wildlife photography, including birds. I did not want a longer lens in view of the increased weight. The 1.6 crop factor will take this lens to 800mm. Can I anticipate that the image quality will be the same as using my 5DIII? Will the image quality be as good or better than the 500mm and 5DIII with a 1.4 teleconverter? Am I comparing apples and oranges? Thanks.

Any Canon camera will give it's best images on a lens like yours! It is even better than the Mk1, which is superb.
Most of my photography is with long lenses (300 F2.8 and 800 F5.6) so here are a couple of my observations - for what they are worth.
For medium to large mammals then the AF is not critical, it needs to be accurate, but even my 5D Mk1 was quite fast enough. For smaller birds and birds in flight then the fastest and most accurate AF system you can afford is the best choice.
ISO performance is very important to me as many wildlife species are active when the light is not at it's strongest/best - Canon's full frame (and 1D4) are better than the APSC models in this respect.
Extenders. I don't like using extenders but there are times when they are the only way to get the framing that you want. You will loose some AF performance and a stop or two of light. Given that you have a Mk2 lens then Mk3 extenders and a 5D3 or 1DX will give the best AF performance and ISO, the 1D4 does pretty well too.
You mention that "The 1.6 crop factor will take this lens to 800mm" well sorry it won't - trust me I have one! You will get the field of view of an 800mm lens but not the focal length. The APSC sensor will give you more "Reach" than a larger sensor but, in practice, the difference is nothing like the 1.6 crop factor would suggest.
Personally I prefer larger sensors even for subjects like songbirds/kingfishers etc as their ISO and IQ advantages more than make up for the small loss of reach in my experience. We don't know, yet, how the 7D2 will perform in the real world but I suspect the ISO performance (from the samples I have seen) will be it's limiting factor - but only time will tell.
I would suggest that, at the moment, the ultimate solution would be the Canon 1DX. In theory you do loose reach but it at least equals the 1.3 crop of the 1D4 and the AF and ISO are in a different league - it is also the best performer with extenders. Unfortunately it is a heavy beast but your wallet would be lighter to compensate!

I wouldn't anticipate the IQ to be the same due to the AF capabilities of the 5D3 with the new II lenses. If Canon put the same AF in the 7D2 they'd be killing themselves.

Actually they are putting a more potent AF system in the 7D2... based on specs.

Try the extender. The 1D IV / 500 f/4 II /1.4X focuses fast enough for BIFs but the 2X more often requires a support IMO. I use the 1.4X quite a bit on my 500.