Sat 03-Nov-12 07:10 PM | edited Sat 03-Nov-12 07:15 PM by nrothschild
I think we have both ends of the choir sufficiently preaching at each other .
I generally use Bill Claff's charts to work out the relative noise performance. According to his numbers The D300 and D300s are identical, the D700 adds about 1.3 stops, and the D600 further improves the D600 performance by about 0.9 stops, for a total of about 2.2 stops between where you are and where you want to go.
Personally I found the D700 to be a phenomenal game changer upgrade over the D300, in terms of noise and to a lesser extent dynamic range even at base ISO. The difference, psychologically, was more than the 1.3 stops his charts suggest. And the charts suggest that the dynamic range at around the base ISO has been significantly improved in a way I cannot envision because the D700 is just so good in that way, and amazing in its own right.
I cannot imagine jumping from the D300 to D600, partly because I don't have one to shoot. But mainly because that extra ~1 stop has to be huge.
I found Auto-ISO to be far more useful on the D700 simply because of the extra stop or two of ISO range that I am comfortable shooting while the camera is in ISO autopilot mode. For street shooting and similar I run the camera in "Manual Exposure" Auto-ISO mode, usually with the max ISO at 3200.
On the D300 I am not usually comfortable with more than 800, which is quite limiting. With a D600 you could probably use 6400 and be very happy with the results. That's a lot of exposure latitude (6 stops from 100-6400) and makes street shooting much easier.
If you like the idea of the 28/1.8 you might want to keep an eye out for a 28/2 Ai and maybe the 28/2.8 Ai-S. They are an interesting pair. The 28/2.8 focuses down to 0.2m, which is closer than the new 28G lens.
On a relative basis I think the 28/2 is the best of my MF Nikkors wide open, partly because it is fundamentally very excellent wide open but partly because f/2 at 28mm usually renders a sane depth of field to work with, compared to 50 at f/1.2 or 35 at 1.4.
If you like the mechanical feel of the older Ai era lenses you might especially like the 28/2. The 28/2.8 is also well built, especially compared to the loose focusing feel of most modern lenses (the 70-200 excepted, and maybe a few others but usually on the very long end). But the 28/2.8 Ai-S is a far lighter lens so doesn't and probably can't have the feel I'm talking about regarding the 28/2.
I think Bjorn Rorslett's reviews of my 28's cover them very well. I'm sure you've been there once or twice. I mention the 28/2 Ai because that is what I own and know. I don't think there is much if any difference, optically, between that and the Ai-S version. The focus throws are the same, but the Ai-S focuses down to 0.25m verses the 0.3m of my Ai version. I didn't worry about that because I had the 0.2m 28/2.8 Ai-S before I got the f/2 and got a very nice nearly unused sample for about $254 a few years ago.
At closest focus I'm not sure how useful I would find f/2 because the DOF is amazingly and often frustratingly small.
In the f/2.8 version only the Ai-S version focuses to 0.2m verses 0.3m for the Ai version, so most people go for the Ai-S only. But they seem to be cheap and plentiful, even now after some prices have risen significantly the past few years.
I use my 28/2.8 Ai-S for document reproduction. I have an occasional need to shoot very old documents that are too fragile to scan. I use it where my 60 Af Micro is too long for my copy stand (larger documents, usually well over 8"x10"). And I do that at even f/5.6; the lens is that good and that flat.
I think it would be interesting to compare those older lenses with the modern f/1.8. The f/1.8 would probably make a better low light street shooter, just because of the AF, and as I understand it, it is quite sharp wide open and has the newer Nano Coatings. Although interestingly, the older 28/2 may be just as or even more flare resistant. It would be fun to have that trifecta and figure all this out for sure .
Back when I bought my 28/2 there was a huge spread in prices on Ebay where I eventually found mine. And I still see it when I occasionally check up on price trends. If that interests you it could take a while to find the right sample at the right price.
I find these and similar primes much more interesting on FX
Edit: my comments about document repro and the flat field of the 28/2.8 Ai-S is solely in the context of DX because in the situations where I've done that I usually have the D300 on a copy stand doing mostly macro work with a 105/2.8 Micro AF-D and the D700 shooting candid portraiture. It's a bizarre environment . I've just never tried any document repro on FX. I should, just to push that envelope a bit to see what it can do.