Canon 20mm


Canon 20mm lens review

canon 20mm

Canon 20mm f/2.8 lens review
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Official name

Canon EF 20mm f/2.8 USM

Canon 20mm specification

Release date: 1992
Minimal focus distance:0.25m
Aperture: f/2.8
Max reproduction ration: 1:7
Aperture blades: 5
Filter size: 72mm
Weight: 405g (0.8 lb 14.28 oz.)
Optical formula: 11 elements in 9 groups
Hood: not included – EW-75 II (petal shaped not the one on the picture)
Size: 78x71mm
Af: USM silent focusing
Constant physical size
Internal focusing
Non rotating front element
Full time manual focus override
Floating lens elements for close focus correction


Canon FF and Aps-c sensored cameras

Category Canon 20mm

This is not a top of the line product. I would say a good budget option for full frame if you really need it.

About ultra wide angle lenses – Canon 20mm

If you want to use this lens to the full of it’s potential (on Full Frame camera) the details will be quite small on screen size. To use such a lens is not so automatic, I find myself harder to make the images I would like to do with this lenses than with normal focal length (24-70mm) lenses. It is very important where you place the camera and which direction you make the picture, and how close you go. With ultra wide angle lenses you must go closer the subject in order to make the best images, with the best detail, and a small thing like the cigarette or a plastic bottle easily run your photo.

Canon 20mm range

On Full frame cameras it is an ultra wide angle lens, on Aps-C a good wide angle for landscapes or street photography.

Canon 20mm optical quality

canon 20mm
Canon 30d Canon 20mm f/5.6 ISO 100 1/250s cropped no sharpening


At the center the lens is very sharp around f/4, even on a 8Mp Aps-C camera, at the edges are softer, but not so bad. Some sharpening helps in post-processing.

Contrast – Canon 20mm

The contrast is good, but don’t think in superlatives. The 50mm lenses has better contrast for example.


The colors are nice but not so good than some other Canon lenses with special glass elements (ED, fluorite).
canon 20mm 3

Distortion, chromatic aberration, vignetting, flare

There is a small barrel distortion(1-2%), here is where the lens is better than zoom lenses. There is some vignetting (darker corners) even on Aps-C cameras (1.3 EV wide open, 0.4 EV at f/4, after smaller). Chromatic aberration not really visible.
canon 20mm 8 I shoot directly in the afternoon sun.

Canon 10-22 build quality

The lens has a reasonably good build quality,


The autofocus is an USM focus, and surprisingly quick for such an old lens. The sound of the focus is very quiet. Some may think this is an ultra wide angle lens there are everything in focus. It is not so simple. If you want to make dramatic looking shots you need to be very close and needs very precise focusing.


The lens has no stabilizer. I thought not needed so high shutter speed like other lenses, but for critically sharp shot the faster shutter speed is preferred.


The lens has only one switch to switch between manual and autofocus.

Sweet spot

The sweet spot or sharpest aperture setting is at f/4-f/5.6 of the Canon 20mm lens.


It is very hard to produce a bokeh with this lens, this.

Price/performance ratio

As this is an old lens, one can have it very cheaply. Compare to the used price it is not a bad lens, especially on Full frame cameras.

Compare to/rivals

Not many rivals are around, especially at this price range. This lens has very good USM focus, little distortion, and moderate price. Usual wide angle zoom lenses has much bigger distortion but some of them are better. Seems Canon struggle in this area. Canon has a 14mm lenses for much higher price, Samyang has 14 and 24mm lenses with much higher distortion, and better sharpness, but perhaps similar colors and contrast. Canon 17-40 and the Canon 16-35 are the other options, the 16-35 much more expensive and has two versions. The Canon 17-40 is perhaps similar but more versatile option. If you want better quality perhaps the Zeiss 21mm or the Nikon 14-24mm (can be used on Canon with adapter) are the best options. These lenses are in different leage than the Canon 20mm, pricewise also.


The Canon 20mm is decent lens, with good optical qualities, but nothing to write home about like the Canon telephoto L primes, Sigma 35mm 1.4 or 18-35mm f/1.8 or the Tamron 17-50. The center sharpness is very good at f/4, at wider apertures the corners are not so sharp even on crop sensor cameras. Vignetting is high wide open even on crop sensored cameras.

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