This lens was a real surprise with the Canon 20D where it’s test performance was excellent - especially for a relatively old lens bought on ebay for about £ 50 as part of my do I want to change to Canon cheap set of lenses. Although the lens is no heavyweight in comparison to a Canon 28-70 f2.8L it’s performance wasn’t that far behind with the Canon 20D.
Canon 28-70 3.5-4.5 20D Test
Build quality is another matter though - This lens, although solidly built my modern lightweight plastic standards, doesn’t exactly feel nice, with an old style very narrow and scratchy feeling manual focus ring and a zoom action which isn’t silky smooth. On the plus side it does have a metal mount, and, like all older Canon AF non USM lenses the autofocus may be a bit noisy and slow, but it works perfectly well.
With The Canon EOS 5D tests the first thing I look at is the level of vignetting at full aperture, and at 28mm and full aperture the Canon 28-70 f3.5-4.5 has very noticeable darkening in the extreme corners, reducing as you zoom to 35 - 50mm and starting to reappear at 70mm. By f 5.6 things have improved a great deal at 28mm with only slight darkening away from the center of the field. So not bad overall, just avoid full aperture at 28mm.
That’s a shame really as image sharpness even at that setting is very good almost all the way to the corners where there is a very dramatic drop in quality just where the serious vignetting starts. The story at 35mm is much the same but the soft area is even smaller, and by 50mm it’s gone, leaving excellent sharpness even in the extreme corners - at full aperture. I’m impressed - again.
The main improvement in performance at f5.6 is the reduced darkening in the corners - it is still visible at 28mm and 70mm, but on a par with most lenses with the Canon 5D. Image sharpness is now excellent almost right to the very corners of the frame and very good even there.
Once again the Canon EF 28-70 f3.5-4.5 II has performed way beyond expectations. Despite it’s age and the poor feel of it’s controls this is a surprisingly good lens which I’d recommend for any Canon camera, digital or film.