Tom Reichner wrote in post #16746434
Eric,
It does seem that the lens provides good sharpness, based on the resolution of the feather detail. However, the max aperture of f6.3 is quite telling; the business of that background would have been smoothed out beautifully with an f4 lens.
Is the focus tracking in AI Servo good with birds in flight? That's something that some folks are complaining about - people say that it works well on some bodies, but not as well with the 7D or the 1D Mk4. I see you're using a 7D, so I am very curious to know how well the AF tracks fast moving subjects in difficult lighting conditions with the body you're using.
I agree that an f/4 lens would certainly have rendered that background better, Tom, but it also wouldn't have only cost $1069, either. Sure you give up a few things, but for a consumer grade ZOOM that goes to 600mm, there's really nothing to complain about.
As far as AF tracking, I've had limited ability to use it for BiF; but the times I *have* used it with enough time to acquire a subject, it's performed well enough:
IMAGE LINK: http://www.flickr.com …s/snydremark/12665883275/ Reifel BEagles-0429 by
Guideon72, on Flickr
I most certainly wouldn't attempt to use this thing as a dedicated BiF lens, but for "incidental" work it's not bad. Most of the problems that are reported for the 7D (which I have run into) are things that are negligible under most, normal shooting circumstances.
@Jeremy: I don't have resized crops or anything, and there is a fair bit of variation in the following exposures, but maybe it will help (click through for better renditions, and to see larger on my Flickr):
100-400 @ 400mm:
IMAGE LINK: http://www.flickr.com …s/snydremark/12666332714/ Reifel Sandhills_400-0673 by
Guideon72, on Flickr
Tammy @ 400mm:
IMAGE LINK: http://www.flickr.com …s/snydremark/12665989583/ Reifel Sandhill-0580 by
Guideon72, on Flickr
Tammy @ 483mm:
IMAGE LINK: http://www.flickr.com …s/snydremark/12665990913/ Reifel Sandhill-0567 by
Guideon72, on Flickr
My big problem with everyone's desire to see crops of 400s vs the 600 is just how much of the image one has to remove to get an equivalent crop; you're throwing out somewhere between a 1/3 and 1/2 of your overall data to get the same framing/view at that point, which you'd then have to upsize in post to wind up with the same image. Below are UNcropped 400 and 600mm shots of the same bird, from the same distance, for reference (not IQ comparison).
400mm:
600:
Unless you are shooting one of the big guns, you're likely going to kill any "IQ" advantage that you might have at 400 by having to crop and resize the image.
Bottom line is, though, it's not an 'L'/is never going BE an 'L' but you can't get anything else for an equivalent price that is going to perform so well at 600mm. <shrug> The next cheapest "600" you're going to get is a 300 f/4 + 2x TC which is going to be at f/8 and only going to work on 1D series or a 5DIII body; whereas, even though it's somewhat slow, this one works on anything from a 20D to a 1Dx.
