comparing autofocus speed and quality on D700, D3, D3s

bluewaterjon · Feb 3, 2010

What is the difference in the method that the camera uses to autofocus on the D700, D300, and D3s, and is the speed and quality of autofocus on the D3s better than the D3, and is the D3 better than the D700?
I shoot for magazines- large fish jumping erratically with a 28-70 and a 70-200 from a moving boat. Once in a while I get lucky like this:

Problem is the fish are often not in high contrast to the water- they blend in. So I need the very best autocusing system ( more tack shark shots means the difference between a possible usable cover or a useless photo) and I am interested in someone with actual knowledge of how these cameras differ mechanically. I have read all the promo specs and literature and I am wondering if there is really any difference in the autofusing mechanism of the D700 to the D3, or D3s. I only use the D300 with my extra 70-200 for the extra reach, but my go to camera is a D700 with an MBD10 grip giving me a high RAW frame rate.
If there is no real difference- and improvement- in the speed and quality of the autofocusing mechanism on the D3 or D3s over the D700, I will just stick with my 700's because with the battery pack I get most of what I need.
Just as an FYI normally I try to shoot between f5.6 and f8 with a max ISO of 400 and a shutter speed of 1/1200 to 1/2000. Once in awhile I will bump up the ISO to 600.
I feel kind of silly in a way using cameras that my sister uses when she is shooting her kids on the playground ( D700), because I am investing a lot of money in travel to get to these spots ( I am a freelancer) and I think maybe I should be spending the 5k on the new Nikon D3s. Then again, maybe I don't need it. I have gotten good results with the D700, but I am wondering if I would be getting a higher percentage of shots in sharp focus with the D3 or D3s. If the answer is yes, I should do it, because I would make a lot more money. If not it would be a waste.
Thanks in advance everyone
Jon Schwartz
Travel Articles and Photography
www.bluewaterjon.com
Blog: Jon Schwartz's Blog: Fishing Articles, Photography, and Travel

Derrel · Feb 3, 2010

Here you go: D3 AF vs D700 AF [Page 1]: Nikon D3 - D1 / D700 Forum: Digital Photography Review

Data is Served - Come and Get It!: Nikon D3 - D1 / D700 Forum: Digital Photography Review

One thing to note from the D2x series: when the LCD's after-shot image review is set to the OFF position, the shutter lag is reduced an addition 18 milliseconds or so, as compared with leaving the LCD set to show the last image shot in a burst automatically after the burst has been shot. It might be possible that the D3 and D700 bodies also share this same characteristic. I know that isn't about autofocus, but about how fast the camera responds once the shutter release has been pressed, which is shutter lag time.

You might look into other factors besides just the autofocusing speed, like "latency" and mirror blackout times; in practice, those two factors are critical. Also, when shooting sequential action, the faster the camera is firing, the more times per second the mirror returns to the "down" or viewing position; only when the mirror is in the DOWN position, can the AF sensors receive new focusing data, so the faster the firing rate the camera is set to, the more times per second the autofocusing data is collected, processed, and acted upon. This is one reason why the mirror return time is so critical for really high-speed sports/action cameras; it is not just so one can machine gun a burst and hope to pick a lucky shot--it's a simple physical fact that once the mirror goes up, the AF data stops coming in, so you want the camera to have the shortest latency time AND the fastest mirror blackout times possible. Most people do not stop to consider that Continuous High means that the AF system will update and refresh the AF data as fast as is mechanically possible, while anything slower dialed into the frame rate means the AF system will "update" with new information fewer times per second. This is according to Nikon expert Thom Hogan.

Using the focus limiter can also speed up the AF process a bit on some lenses, since the system has a narrower range of data it will work with.

Shutter lag time, mirror blackout time, and latency (ie the time between shots) are all some of the minor differences that make the flagship-level Nikons so much easier to shoot action with than the consumer cameras.
If you've spent any time over at sportsshooter.com, you will read from the top shooters that there is a feeling that the D3s has slightly improved AF routines that seem to make it focus just a little bit faster than the now 2-year-old D3. Most also feel that the D300s has had its AF algorithms "tweaked" a bit for faster initial focus acquisition.

djacobox372 · Feb 3, 2010

All three of those cameras have nearly identical autofocus systems (if not completely identical).

With AFS lenses, the focus speed has more to do with the lens then the camera. Since speed is so important to you, you won't be shooting with af lenses.

bluewaterjon · Feb 4, 2010

Derrel, you touched on a lot and I followed up on it. I saw what you were talking about. I am still sitting on the fence and because my next shoot is important I decided to go whole hog in the meantime and rent a D3s. The buffer size is the thing that made me want to have it, because often the fish is spazzing out and I fill the buffer up and have to miss a portion of the acrobatics- and the worst portion to miss too, because it's probably the latter stages of the jumping that my camera is just starting to get dialed in with focus.
Anyway, here is my question: would you recommend for fastest autofocus results that I use Dynamic AF, 21 points? I am thinking this because I seem to have most of my shots centered correctly, and if the fish was to appear on the edge of the frame, I likely could make much use of the shot anyway.
So would you suggest that, Dynamic AF 21 points? or would you recommend something else? And would it follow that the Auto-area AF is necessarilly slower?
Thanks!
Jon Schwartz
Fishing Photography, Articles, and Travel
www.bluewaterjon.com
Blog: Jon Schwartz's Blog: Fishing Articles, Photography, and Travel