Test results: MTF (Sharpness)

Our MTF tests are conducted using Applied Imaging charts and software. We’ve tested the Sony Zeiss Distagon T* 35mm f/1.4 ZA on the Sony Alpha 7R, which has a 36MP full frame sensor and no optical low-pass filter.

Our tests reveal a lens that is impressively sharp in the centre wide open, however the corners are somewhat soft. Stop down to f/2.8 and the centre sharpness up a little, but the edges stay much the same. Much bigger improvements follow, though, with the very best results from f/5.6 to f/11. At the minimum aperture of f/16, diffraction slightly softens the image.

Central sharpness is high at f/1.4, but the edges lag some way behind

Stop down to f/2.8 and the centre sharpens up further, but edges are still soft

Very best results are obtained at f/8 (and a stop either side)

Diffraction slightly softens the image at the lens’s minimum aperture of f/16