What is the issue? The 12-24mm is a DX lens. The field of view will be like 18-36mm when the D600 is put in DX crop mode. If you don't put the D600 in auto DX mode you will get a lot of vignetting. That's normal.
To: Leonard 62 and ZDude Thank you very much for the reply, though, my post was published for amateurs alike me, having Nikkor 12-24 lens, but Professors quick to eliminate illiteracy. Of course we all read the documents listed below and know that setting Nikkor 12-24 on camera D600 ripe for trouble but I wanted to check it out. My sin is curiosity. Yet, the truth is I have found out myself: the lens works great on the camera D600 in the range of 24-20mm. As for my emotional comment "Back to D200" it caused by random setting Nikkor 12-24 at the end value of f12mm. Concerning your reminder about the DX Crop Mode I should admit: it is not very practical. We get this opportunity for account of Nikon who tries to grasp the immensity. Reference: AF-S DX Zoom-Nikkor ED 12-24mm f/4G IF Nikon Instruction Manual: ....these lenses can be attached to film based 35mm SLR, but will not work properly due to reduction size of the image circle. Adorama: Nikon 12-24mm F/4G ED-IF DX Zoom Lens DX Nikkor is designed exclusively for use with Nikon Digital SLR models. Design enables a combination of wider angle-of-view with optical characteristics that are optimized for Nikon digital SLR camera sensors. Comparable to that of an 18-36mm lens on 35mm size sensor format. B&H: AF-S DX Zoom-Nikkor ED 12-24mm f/4G IF Overview: Note! DX lenses are NOT recommended for use with 35mm, "full-frame" digital, or APS SLR cameras. Specification: Format Compatibility; Nikon DX; FX in DX Crop Mode davidben33
Philip, just to add. I have a zoom Nkkor 35-70mm 1: 2.8 D. So with a zoom 12-24 f4 DX in range of 20-24mm, I consider not to buy others. Though with telephoto lens for D600, the problem do exist. Thanks again, davidben33
Please do not try to put one's joke in my old head, better set that lens on your D600 and make some shots in range of f/24 to 20mm, then please tell me if you find some flaws. I did not find ones. "Break the rules, if you capable" D. Benyukhis