Digital Zoom and Cropping: In-Camera Options for Sony α6700 and Nikon Z8

First, Distinguish Between Lens Zoom and In-Camera Enlargement

Optical zoom changes the field of view through the lens's optical system; in-camera image zoom and cropping are handled/recorded by the camera in different ways. Terminology, available ranges, and effects on image quality vary by model. Below, the manufacturer manuals of the Sony α6700 and Nikon Z8 are used as specific examples.

Sony α6700: Distinguishing Clear Image Zoom from Digital Zoom

The Zoom Range menu on the α6700 allows selection of Optical zoom only, Clear Image Zoom, or Digital Zoom. Sony describes Clear Image Zoom as enlargement beyond the optical zoom range using image processing, with less degradation; beyond the Clear Image Zoom range, Digital Zoom continues to enlarge, and the manual notes that image quality will decline. Sony also suggests that if you want to enlarge while staying within an undiminished quality range, you can set Optical zoom only. This is a description of the α6700's functionality and does not guarantee that the same-named feature will perform the same on different models.〔G-ZOOM-01, G-ZOOM-02〕

Nikon Z8: FX and DX Are Image Area Selections

The Z8's image area menu allows selection of FX (36×24) and DX (24×16) regions. The manual explains that when DX is selected, the 35mm equivalent focal length is approximately calculated by multiplying the lens focal length by 1.5; this is a conversion of field of view/image area, not an actual change in lens focal length. The recorded pixel count also changes with the image area: on the Z8, in Large mode, FX is 8256×5504, and DX is 5392×3592.〔G-ZOOM-03, G-ZOOM-04〕

How to Choose

When variable field of view is needed, first check whether the lens has the required optical zoom range. If you only want to change the composition, you can compare the camera's image area cropping with in-camera image zoom options and verify the output image size and format limitations. If image quality is critical, shoot test samples according to the specific body, lens, resolution, and target output size; do not interpret a model's "less degradation" description as lossless, and do not mistake the cropped equivalent field of view for a change in lens focal length.