Tag Archives: flower

The magnifying effect: full-frame vs two-thirds sensors

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:

Anyas Garden (5D)
Canon 5D with 17-40mm lens at 17mm focal length

Anya's Garden (650D)
Canon 650D with 18-200mm lens at 18mm focal length

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.

Bee on echinacea (5D)
Canon 5D at 40mm focal length (f11, 1/1000th, ISO-1000)

Bee on echinacea (650D)
Canon 650D at 40mm focal length (f14, 1/40th, ISO-400, -0.3 step)
I guess I’ll no longer brag about how my 18-200mm lens is a ‘wide angle’ lens any more then!