Sharpness at 15mm

For this test, the Fujinon XC 15-45mm f/3.5-5.6 OIS PZ lens was attached to a Fuji X-A5 body, which in turn was mounted on a sturdy tripod. Exposure delay mode was activated and focus is set to the middle of the frame. Tonal and colour variances across the crops are due to changes in natural light during the session.

The full frame at 15mm

Centre sharpness is excellent at all apertures, even including f/3.5. The smallest f/22 aperture is the softest, being affected by diffraction. However, it’s immediately clear how sharp images are. 

Between f/4 and f/11 you’ll get the optimum performance. Look at real world images and the lens is able to handle intricate detail with amazing clarity. 

To a degree, detail is slightly softer and there is less contrast at f/3.5 and f/16. However, images at these apertures, even f/22 which is softer still, are still impressively sharp. 

Get to the corners of the frame and image sharpness is by and large maintained. Sharpness does depend on the point of focus and depth of field. We’ve focused in the middle of the frame, so some softness at f/3.5 is more because it’s out-of-focus (there is less depth-of-field). 

So in regards to depth of field, the optimum f/8 and f/11 apertures remain the sharpest in the corners because these are the sharpest settings with greater depth of field. Diffraction is more evident at f/22 when looking in the corners of the frame. In general, we’d avoid f/22.

Aperture	Centre Crop	Edge Crop
f/3.5
f/4
f/5.6
f/8
f/11
f/16
f/22