I have a Nikon 24-70mm f/2.8 (without VR) and the pictures taken with it are not sharp and crisp as I think they should be. I use it with a Nikon D7200 that works perfectly with a Nikon 70-200mm f/2.8 VRII and a Nikon 18-140mm f/3.5-5.6 VR. I made some home tests and provide the results below. In addition to back-focus, what is happening? Which is the reason for the lack of detail ? Is this normal?
I did some tests with basic material. I used My D7200, D3100, the kit lens 18-140mm f/3.5-5.6, the 70-200mm f/2.8 and the 24-70, with Live View, Manual Focus, a tripod with a level in the camera and the settings below. I used a diagonal test chart and a perpendicular one which you can see here or download here. The JPGs are the conversion in Darktable of the NEFs without any adjustment. There are also the NEFs in the link.
- Diagonal test chart
- 1A _ 24-70mm f/2.8 _ 70mm, f/2.8, 1/500, ISO 100
- 1B _ 24-70mm f/2.8 _ 70mm, f/2.8, 1/500, ISO 100 _ +20 AF Fine tune
- 1C _ 18-140mm f/3.5-5.6 VR _ 70mm, f/5, 1/125, ISO 100
- 1D _ 70-200mm f/2.8 VRII _ 70mm, f/2.8, 1/250, ISO 100
- 2A _ 24-70mm f/2.8 _ 70mm, f/2.8, 1/800, ISO 400
- 2B _ 18-140mm f/3.5-5.6 VR _ 75mm, f/5, 1/250, ISO 400
- Perpendicular test chart
- 3A _ 24-70mm f/2.8 _ 70mm, f/2.8, 1/125, ISO 400
- 3B _ 24-70mm f/2.8 _ 70mm, f/4, 1/60, ISO 400 (this for a bigger depth of fild)
It also has a back-focus issue that I tried to fix without success. One of the tests is purposely +20 and presents no difference.