First off, i wanted to ask you, if maybe you would know. Is the "dust problem" with the D600 solved/fixed already in newer batches? and how to know whether new batches or not? I'm asking about this because I read about it online and it's quite a problem especially if you are a landscape shooter (using small apertures). I thought "OK THIS IS JUST A SMALL PROBLEM" but it happened to my close friend who bought it maybe 4 months ago (not sure exactly when) and it was a big problem as shooting at even f/5.6 already shows the problematic dust bunnies on your images. Wonder what will happen at f8 or f16... and for some reason after he send it for cleaning the AF just stopped working and need to send it again for a 2nd time (the AF thing was maybe a fluke, not sure)
Secondly, I had the AFS 28 1.8G Nano for about 2 months. Read about the reviews online before buying. The good thing - the price is good and it's very light. Now to the bad thing - Basically the main problem most people are talking about the lens is that it has focus shift problems (you can read about it online for more details). Some say the problem is really pronounced and some say it just doesn't exist and it the cameraman's fault.
I used the 28G on mostly on a D3s and sometimes on a D7000. I used the 28G for several wedding shoots. This is what happened :
1. When shooting and viewing it on the camera's LCD it is okay and has good bokeh and colors.
2. When I got back home and checked in on my Adobe Camera Raw I was like "what daaafuuuu~~" The focus shift that some people are talking about really exist and it's not my fault! I do understand that with big apertures I need to be aware & careful of my focusing, but the thing is - my wide open shots at f/1.8 was fine and my f/4 & especially f/5.6 shots was making me crazy mad and worried to use the lens ever again!!!
3. The problem with this lens is focus shift, which most primes have to a certain extend but the thing that makes this lens especially heartbreaking is that is has a FOCUS SHIFT + FIELD CURVATURE. Double the trouble!
At f/1.8 and f/2 the focus is nice and the field curvature problem is not pronounced and most of the time you dont even know it has it. Going down to f4 and f5.6 you get serious problems here, the focus shift + field curvature problem is very pronounced.
EXAMPLE 1 : I was shooting a bride & groom next to each on a malay pelamin (bridal bed) and the background was the flower decoration on several images at f1.8, 2.8 all towards f4. Guess what? The bride & groom is sometimes in focus (not sharpest) and sometimes not in focus but the weird thing is that the decoration at the back has perfectly sharp focus like I was purposely focusing at the decoration. At first I thought I wrongly focused at the back OR the lens has backfocus problems but it turns out that ONLY my f/1.8 shots were fine and the focus field was as I would expect. At other smaller apertures it went backfocus.
EXAMPLE 2 : I was taking a picture of a bride & groom sitting by each other on a bed. I was kneeling straight 90 degrees towards them and using f/2.8 at around 1 meter from the couple. Yes their faces are really close like 10cm from each other & it was a wide shot & NOT a tight close up shot.Guess what? The focus on the bride is just barely okay and the groom just beside her is just like @#%^&! it's not in focus. People might think the lens is not sharp but the thing is that the bed/decoration behind the groom is really sharp and in perfect focus.. i was like WTH? THE SOLUTION : I SOLD THE LENS AND GOT A 16-35 VR. IT WORKS!
This is what i mean:
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I had the D700 for quite some time and was satisfied by the performance. I tested out the D600 and was disappointed. The focus speed of d300/d700 was faster and more so in lowlight. 1/4000s on d600? Yeah.. that's why the initial price d600 was the same as the last price of d700 which is around 6k. The initial price of the d700 was 8-9k if im not mistaken. Again this is your choice if you are okay with the D600. I am not okay with it personally.
I had the 28G and really really really hated it because of that focus shift problem. It does not show (at least in my testing it) on DX but it does show this particular problem on FX. It would be a great lens with the Nano coating, decent price, colour, image quality and lightweight but it's not because of what I experienced. I say this : For environmental portraits (only one subject) shooting wide open (f1.8 or f2) this lens is really great and you don't notice the problem. For couple/group/family shots, basically if you have more than one subject and shoot at this aperture "f2.8-f5.6" forget this lens.
The other options like the AFD 20mm, 24mm & 28mm (all f/2.8) does not have the wide open sharpness & colour rendition of the 28G but these lenses work. FORGET the sigma equivalent it's much worse.
If you are on a limited budget I recommend this :
D600 + AFD 28 or AFD 35 + SB900
I got the similar experience with you.
28G with D700 got some focus shift issue.
Sold it after 2 weeks.
Yes, D600 AF is not as good as I expect.
Nikon give quite a lot of points, but all clustered at the centre.
D700 is a much more reliable when comes to AF performance.