Hi Jim, I know what you mean about 24 - 70 sounding pretty short. However, in jandq's prior experience the 18-55 on the D2H, the pictures were just fine. Also, English Mastiffs are one of the larger dog breeds. They can be as large as people (although this is not common). That's why I asked about how the images from the 18-55 lens turned out and if the 55 end, was the most used. If jandq used mainly the 55 range and 18 was barley touched, I am thinking that something like the 24 to 70 range might be a bit better. The short end for some closeups when the dogs are very close, and 70 would give a little reach, especially for puppies. Also, possibly something like 35 to 100 would provide more flexiability, though possibly impossible to find.
The other item that went into this, was that the usual shooting range was 8 to 12 yards or usually about 36 feet for a dog that could be 4 to 5 feet long. So using a 1.5x focal length multipler, with a distance at 36 feet, the horizontal field of view for some focal lengths would be:
focal length horizontal field of view (@36') (@24 feet)
24mm 36 feet 24 feet
35mm 24 feet 16 feet
50mm 17 feet 11 feet
70mm 12 feet 8 feet
80mm 10 feet 7 feet
So based on this, I thought that, trim a bit off the 18 end and add it to the 55 end of the lens that appeared to work pretty well might produce something that would work a bit better. Especially for the larger dogs. The other thing was that jandq wrote ....
A split second the perfect pose is there and then it's gone. I'm not speaking of a dog stacked at crufts so much, but in that situation even their they are looking around and you might have 3 seconds to fire off several pictures and maybe one might work.
... so it appears that a fully body shot is probably the primary need, either as an individual or in a small group of dogs. The other item that may be important here is just not the burst speed of say 3 to 5 fps, but the substained ability to take burst shots of 3 to 5+ seconds long so as to maximize the take of the moment. So that would cover the memory write speed (My 3 year old Pentax falls down here, so that is why I bring it up).
If jandq were to go back an look at the exif data on the D2H images that turned out well, that would be valuable in selecting a lens range that would fit the need pretty well.
The other thing is that even for the large events (dog shows), the individual rings tend to be well defined, reasonably small, and the audience is within the 30 to 40 foot range at most. In Scottsdale there is a dog show that attracts 20,000+ dogs across 5 days. It is out side, about 20 show rings and you are no more than say 30 feet away at the worst, or 40 on a diagonal. It's the extremely large shows like Westminister in NYC that are held in very large arenas (on TV), that the audience is really far away (thus the need for a much longer lens - 200 or 300mm). These are the few exceptions (maybe once or twice a year - if you get invited). Most of the time, when the show is indoors, your still pretty close to the dogs in the ring, still in the 30 foot range.
I agree with the need for a f2.8. If your going to spend $2K for a camera setup, it would probably pay to get a better lens and skimp (ever so slightly) on the body (but that's allocating $1K for each - body and lens, which should buy some pretty good capability). I did a quick look for Nikon 18-55 lenses to see what aperatures ran and only came up with f3.5 - 5.6 and that appeared to do the job pretty well. So, a constant 2.8 should pretty easily cover just about all the needs.