During a recent trip to photograph Gannets and Terns in flight, I became frustrated while using my 200-400 on my Nikon D800 as despite tracking the birds well and seeing focus grab in the viewfinder the images on preview were lacking critical focus. I changed to my D3s and things immediately improved with much better sharpness. I generally use my 500m lens for birds and had not calibrated the 200-400 for the D800 or D3s.

I have previously used LensAlign and manually calibrated the lens micro-adjustement by assessing the images in Lightroom but found it a little frustrating due to shot to shot variability. FocusTune software automates this process and generates a graph making the assessment very easy but an update was required after the launch of Mac OSX Mavericks. This was released at the end of 2013 so after getting it updated we were able to proceed with the lens calibration. After setting up the target and lens on tripods we ran the initial calibration series of images taking 5 at each setting  -20, -15, -10, -5, 0, +5, +10, +15, +20 and importing them into FocusTune. While downloading into Lightroom off the memory card it was clear that the lens with D800 was significantly back focussing with the images at -15 and -20 looking visibly better. The graphs from FocusTune clearly confirmed this and also showed that the D3s was spot on with 0 adjustment, confirming why the flight shots with this body had been so much better. Running a second series with the D800 using 5 shots each at -20, -19, -18, -17, -16, -15 showed the sweet spot at -15 so I am looking forward to another opportunity to try it.