Basketball, as good a test for any camera's autofocus and sensor. Poor lighting and FAST players make for a difficult mix, not only that, the players aren't just fast, their movements are far less regular than, say, football or rugby players, and that's exasperated by using a medium length zoom rather than a nice flattening 3/400 prime on a long pitch.
The first thing you notice with the Nikon D4s, is that it fits the hand brilliantly. It's so much nicer to hold for a length of time than the D3s, and the controls are excellently positioned. I have noticed however that I seem to be able to press some of the back buttons with my nose, and I have a little nose, not one shaped like a finger! There were several times that I looked down, noticing out of the corner of my eye that the screen was on. I probably just need to train my nose to stay out of the way. It's funny, but the camera seems (in use) to feel much lighter than the D3s; not, however, lightweight like the D800 (with MB-D12). It also feels like the weight is distributed differently on the inside, which, if true, probably goes some way towards making it feel better in the hand.
I'm only going to touch on this, because it's early days, but the auto white balance seems to perform like magic. The lighting at the basketball was really very (photographically) poor. It was a typical old sports hall, with low-pressure sodium bulbs, only punctuated with a smidge of bright tungsten from a spot light. I did a test shot, expecting to have to dial in my own WB, but was so impressed, I left it alone. A quick test shot on the D3s showed just how much better it was.
OK, if you're reading this, you probably want to know what the AF, sensor and 'motor drive' were like.
In a word, bloody ACE! Ok, that's two words.
I tried the AF on various modes, 3D tracking, Auto-area AF, Group area and 9-point dynamic-area AF. Although the D4s's instruction book recommends 3D tracking for 'erratically moving subjects' it became confused my the mass of moving bodies it was presented with. Perhaps basketball isn't its 'game', it might fare much better where the subject is more clearly defined against the background, tennis perhaps.
Auto area AF is amazing to watch work, but not so great in use, at least with basketball. Here you look through the viewfinder, and instead of choosing a focus point, the camera does it for you. I find this a very strange idea... why would you want the camera to decide what you're going to have sharp? As you look through the camera, the red focus square jumps at an amazing pace from subject to subject, doing its best to understand what's going on in front of it, and what's the most prudent thing to focus on. As before, it might well work brilliantly with a clean background, for example if your model is running down the beach towards you. I'll find something to try this on later, so stay tuned.
Group area setting fares much better with tribulations of basketball. Here you are presented with a cross of four focus squares, this reduces the risk of the subject leaving the focus area, resulting in a nice sharp background. Generally it seemed to do very well, better I'd say with the 70-200 2.8 Vr2 than the 24-70 2.8. I could image this as very helpful for birds in flight as it gives you a bigger 'focus target' to place over the subject. I did have my concerns about it's limitations in basketball though, this is because as the players charge this way and that, they stoop forwards, here you could find yourself with the top focus point on the players face, but the lower point on his chest...which does the camera choose? * if you are in AF-S mode, it'll chose a face, but you'd only ever be using AF-C in sport.
9-point dynamic focus mode (21 and 51 are also available) is amazing. If you have the focus point on the subject, it's going to be sharp. Simple as that, and for the most of the time, it'll stay that way too. Moving from the D3s (which was very good) there is a marked improvement, not only that, it magically seems to hold focus even though the mirror is -all be it delicately- clattering away at a rate of knots.
Ah yes.... the shutter release/motor drive. All I can say is wow! The whole camera feels like it's chomping at the bit to get going. This is a proper thoroughbred in your hand that'll rear up, snort, and be charging along at full gallop before you know what's happened, It actually made me grin on more than one occasion and I thought that novelty had been lost to time some years ago. OK, some people are going to say, 'yeah, but who uses 11FPS every day?' And...I'd agree, to a point. I generally use my D3s on 'continuous low' , for most things, that's quite adequate, hell, I've even had it on 'single' sometimes! BUT, with the D4s the speed is there when you need it, not just for sport and alike, but for everything. You can feel the camera recycle to ready in a breath, ready for you to shoot the next frame when YOU are ready, and when you're shooting for a living, you need to capture exactly 'the' moment, and with the D4s you can.
Finally... the sensor. Well, I kinda want to hold back on that one at the minute, get used to the camera, and the results, that way I'll be ably to give you a more considered opinion. You can however look at the some of the basketball pics. They were all shot RAW and processed in Adobe RAW 8.4 (which by the way is a pre-release 'lab' version). Some noise reduction has been added, as has some sharpening. The colours are 'real'. Most of the pictures are full frame, two are cropped, these are obvious by their file name. The levels have been tweaked a little, but only a little. Notice how good the blacks look...full and noise free. All were shot at 8000 ASA ( I never used to take the D3s past 4000). Most of them are sharp, it's a fairly representative selection of what was taken. I'd say that 95% were easily sharp enough for newsprint, and probably 85% sharp enough on closer inspection to use in fine print. The first couple of frames were shot in almost total darkness, the subject lit with a soft red light and a spot light. The exposure was guessed, sorry, estimated.