p.1 #1 · Zoom Lens for Scanning? Judge for Yourself.
Hello everyone — first post here, hope it's useful.
This is for anyone tempted to use a zoom lens for camera scanning. While "don't do it" is the common answer on scanning forums, many folks still need convincing — so I ran a simple experiment with a Canon EF-S 55–250mm zoom and extension rings to maintain frame coverage on an APS-C Canon R7. The full image set is in this Google Drive folder. All crops shown are from the upper-left corner — this is where aberrations become most pronounced. For comparison I included a shot taken with the Sigma 50mm f/2.8 Macro, a well-regarded lens in the scanning community and not terribly expensive — around US$150 on eBay.
All shots were taken against a 35mm Vlad's calibration test target at f/9, across four focal lengths: 55mm, 79mm, 84mm, and 109mm.
One important caveat: pretty much all zoom lenses — even those marked as macro — exhibit similar aberration characteristics when used at 1:1 or 1:1.6 reproduction ratios. HTH
