rjk55425 Offline Image Upload: Off
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I am a recent convert to Nikon and use a D700. Over the years, I have I run a standard series of tests with all my lenses, shooting wide open and one stop down at the wide and telephoto ends of the lens. I have seen something with the 28-70 that I have never seen before in any other lens tested and not sure if its a major concern since its most visible when viewing at 100%. The lens is sharp enough wide open at both ends but when I photograph small print, the color of the font is not right at f2.8, kind of purple, at high contrast edges.
Everything looks as I would expect at 28mm, here are 2 shots at f2.8 and f4.0:


But the results are very different at 70mm, these 2 shots are also at f2.8 and 4.0. You don't see this problem as dramatically in the larger text above the small print put there is a faint purple edge around the text. It does improve when stopping down but is definitely visible in shots at 2.8:


Now in this series of shots, you can see the purple fringing around the Nikon letters but it disappears at f4:


And when I shoot larger text, its less noticeable (again f2.8, then f4):


I was hoping this issue would be less noticeable with real world shots but it is visible at 100% viewing, this is f2.8 at 70mm:

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