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things seem to be getting lost in the d400 discussions, AF and other speed stuff

Started Dec 27, 2013 | Discussions thread
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Kerry Pierce
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things seem to be getting lost in the d400 discussions, AF and other speed stuff
Dec 27, 2013

There are a number of "hidden" features of an anticipated d400, that I don't recall having seen mentioned. Among those features are mirror blackout times, supporting electronics for both the AF and other areas where speed is important.

One of the issues with the d7100 is that there are consistent complaints about the AF not being quite as good as it was in the d300/s, d700, d800. Well, it isn't likely that all of the supporting electronics have been upgraded from that which was utilized for the CAM 4800. That could mean slower acquisition or difficulty in tracking, for the CAM 3500 module that is now used in the d7100.

I can recall when the d300 and d3 came out, there was a lot of discussion about the d3 being faster, more accurate, and better tracking. At first, nobody wanted to believe that the d300 was lacking, after all, it was the same AF module. But, in time, it became clear that there are solid differences, with the d3 being better. Many people, myself included, thought that the differences were due to the power that was being delivered to the camera by the big honkin battery of the d3. Marianne Oelund did a bunch of tests that seemed to prove that the battery had nothing to do with it.

Marianne has written a number of articles on AF that you might wish to read. She knows her stuff and she can present it well.

http://www.dpreview.com/forums/post/34713361 on why tracking a subject moving toward you is difficult for the camera.

http://www.dpreview.com/forums/post/34489608 on testing and AF consistency

http://www.dpreview.com/forums/post/33834563 brief comparison of d3 - d3s, some general info on the difficulty of testing AF

http://www.dpreview.com/forums/post/33601363 the thread is a very good one, mandatory reading if you want to know what's going on with the AF differences of d3x, d3, d700, and d300. I would advise reading the entire thread for fun, but if you simply start at this link and then follow Marianne's posts throughout, you'll see some great info.

http://www.dpreview.com/forums/post/33601209 Marianne flatly states that the battery size/type doesn't affect AF.

http://www.dpreview.com/forums/post/33646010 Important general data about Marianne's tests

http://www.dpreview.com/forums/post/33609657 talks about the d3 vs d700 vs d300 when using screwdriver lenses and the speed of the AF motors in the body.

http://www.dpreview.com/forums/post/33646010 brief synopsis of Marianne's findings. Some critical info here, but no raw test data

http://www.dpreview.com/forums/post/33660055 test data for all 4 cameras, initial acquisition in set light level ( I'm not aware of any tests done by Marianne on AF tracking, but she does talk about her, very extensive, experiences in the various posts).

http://www.dpreview.com/forums/post/33679637 specific post on battery tests of el3 vs el4a, where no difference in AF capability was found.

http://www.dpreview.com/forums/post/32694307 brief summation of some tests that Marianne did, which talks about 3 things affecting AF, lens drive speed, AF processing delays, mechanical shutter delay.

(The AF processing issues are what I am mainly concerned about when one is trying weigh the AF capabilities of the d7100, d300 (s). A d400 should be better than any d7xxx, due to the differences in blackout times, shutter delays, supporting electronics and AF processing.)

http://www.dpreview.com/forums/post/50834242 shows the difference between the d3 and d7000, driving the 200-400 from closest focus to infinity. The d7k times are slower, which demonstrates that supporting electronics can make significant differences. The differences would be cumulative, for the different things that involve AF and its speed/accuracy, which could lead to really serious differences in AF performance.

Marianne is a very good source for factual information on the actual use/workings of cameras. I couldn't find all of the relevant posts that she has put out, so there are likely other posts that have very good info in them that I've missed. Even so, I think that we've got enough material to work with now, that we can hash it out without too much difficulty.

If someone has a link to reliable data on the performance stats (blackout times, shutter times, etc) on all of Nikon's enthusiast and up cameras, I'd appreciate it if you'd post that info here with source info.

Lastly, here are a couple of other links to good info that Marianne has posted, that might have significance to the discussion.

http://www.dpreview.com/forums/post/33735350 not about AF, but good info on sensor MPs

http://www.dpreview.com/forums/post/33762648 talking about crop modes vs TC, which also applies to the FX vs DX argument that some like to put forth.


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