Sharpness at 500mm

Our sharpness tests were conducted using a 36.3-megapixel Nikon D810 body and a sturdy tripod. The camera’s shutter release was also set with a two-second exposure delay timer to avoid camera shake from pressing the shutter release and any vibration from the mirror. The test subject was shot using ambient lighting, hence some colour and contrast variation is to be expected between apertures.

The full frame at 500mm

Sharpness in the centre of frame is consistently high from f/4 through to the f/22 minimum aperture. Some slight camera shake has caused minor ghosting at f/5.6, but the lens was not at fault. At f/22 diffraction has caused a negligible sharpness reduction.

Moving to the corners of frame and we can see that sharpness is noticeably reduced at f/4, though it’s almost back to full centre clarity at f/5.6. Maximum corner sharpness is reached at f/8 through to f/16, with f22 again appearing very slightly softer due to diffraction. However, corner sharpness on a lens of this nature isn’t necessarily crucial, as it’s likely to be focussed on a bird or athlete occupying the centre of frame, with the corners being out of focus and already blurred.

Aperture	Centre Crop	Edge Crop
f/4
f/5.6
f/8
f/11
f/16
f/22