Nikon D750 and AF-S 70-200mm F2.8 lens
The Nikon D750 is popular choice when on a budget that can't stretch to the Nikon D850. The Nikkor AF-S 70-200mm F2.8 lens is a very popular choice to combine with the D750 by wedding photographers and portrait photographers.
The optical quality of the lens and the technical functionality of the camera make a fine pair. However there is a 'but' coming here. Remember the D850, being similar in functionality, but more expensive? What's on the D850 that isn't on the D750 to make it more expensive? We have found one expenditure. Once you know you can amend the handling of your gear to prevent any problem. If not it could get problematic........
A while back one of our customers was experiencing focusing issues when using their AF-S 70-200mm F2.8 lens with their D750 body - the right hand side of the image showed obvious signs of back focus - in fact it was totally out of focus. We popped the camera and lens on the calibration rig and ran the diagnostics programme. Unfortunately it told us very little more that what was so plainly obvious. Considerable back focussing on one side of the image.
We asked the customer to demonstrate the process he went through to take a shot. From switch on to click the shutter. In fact we didn't need to get as far as the shutter click. All weight bearing handling was on the camera body with minimal support handling of the lens.
Continuous use like this is likely to put stress on the lens mount and cause damage.
We sent the camera to our repairers who after checking (and extracting the mount) found it to be warped. The video shows this degree of damage...
Moral of the story - if using long heavy lenses like Nikon AF-S 24-70mm, AF-S 70-200mm F2.8, any of the longer Sigma Art series primes i.e 85mm or 135mm it is advisable to pick up and hold the camera / lens combo by the lens NOT by the camera.
Now that applies to any camera body with a heavy lens. So why is it even more important on the Nikon D750 and not the D850? The two lens mounts look identical but are actually made out of different materials. The Nikon D850 lens mount is made out of a strong magnesium alloy whereas the Nikon D750 lens mount is made of a weaker carbon composite.