I am having a big focusing issue with my D3s when it comes to focusing in low light, with some lenses its worse than with others, for instance the worst lens on my D3s to focus with is my 8mm5 1.4 lens.
I do wedding photography 90% of the time and I have a super hard time focusing when it comes to the dancing pictures when the lights are dimmed... once the actual dancing starts and the lights go down even more my D3s is almost useless.
Is it me ? what can I do for it to focus better ??
I cannot say that I had the same problem that you have though we share the same camera/lens combination. I POSSIBLY avoided that problem as a side effect to an other discomfort I had when I bought the 85mm 1.4…
When I first tested my new lens, I noticed that I had a sharpness issue. A friend of mine told me that he also had the same not "so sharp results" higher then ƒ3.5. He said that going through the AF-Fine Tune of the D3S solve the problem and that the camera was performing great at night (what he did most at that time).
Actually, my sons and I were shooting a small country circus show yesterday where no flash was allowed. The D3S (with the 85/ f1.4) was in charge of the low lights shots of the second fire joggler.
>So the D4 is really that much better in low light when it >comes to focusing ??
I find the D4's autofocus to be pretty amazing. My only gripe with my D3 was low light autofocus. Not that it was terrible, but I did miss shots with it when light levels got low. I skipped the D3S since it had the same autofocus performance. My D4 will focus if I have enough light to compose.
I went the same route as Luke. The D4 is better at focusing in low light. I bought mine from a friend and compared the two cameras in his bathroom with the lights off. The D3S never locked focus. The D4 focused without hesitation. I bought the D4.
When shooting in the low light conditions you've mentioned, what are your camera settings? It is my opinion that the D4 is not a huge upgrade from the D3S. In low light conditions I generally start with the following settings:
AFC-9 Auto-ISO SPOT Metering Manual mode with a minimum shutter speed of 1/160 I may add +.7 to +1.00 exposure depending on the situation
If I was going to use my 85mm 1.4G my aperture would be anywhere from 1.8-2.0. Again, these are the general settings I tend to use with both my D800 & D4.