I was having a terrible time with my 7D II not giving me sharp images with my 400 f5.6 lens. I tried a 1DsIII , 5DIII and borrowed a friends 1DX and they seem to work fine . For some reason the old 400 is very inconsistent with my 7D II. Well I found a used 1DIV at a good price and boy does it work well with my lens. Of course Murphy's law showed up and it rained all weekend so I only got to shoot close small birds at high iso. I am very happy with the results so far. I cant wait to get some good light and give it a good workout.
_D4_89651 by Stuart Edwards, on Flickr
_D4_88051 by Stuart Edwards, on Flickr