I knew that the “two-thirds” sensor, common in compact SLRs, has a magnifying impact on an image compared to the “full frame” sensor found in the mid-size and pro SLRs, but I’d never seen the effect of this 1.6x magnification with my own eyes until today.
This post compares photos taken on Dave’s Canon 5D with a EF 17-40mmm lens vs my Canon 650D with EF-S 18-200mm lens.
Test 1 – Wide angle
The “two-thirds” (22.3mm) APS-C sensor in my 650D has the effect of magnifying an image by 1.6x compared to the “full frame” (36mm) sensor of the 5D, meaning that at the same focal length my camera can’t fit as much into the image as it’s big brother. Both these shots were taken at each lens’s widest angle (17mm vs 18mm respectively).
Notice, for example, how the bench and flower pots in the foreground are complete in the first image, but cropped in the second one:
Test 2 – 40mm focal length
The next test shows a flower taken at 40mm focal length on both cameras. You can see the magnification effect again on the 650D as less of the house in the background is visible compared to the 5D.
MiniF1 | Photoblog 