Canon EF 17-40mm f/4.0 L USM Lens Review

Because it is a very high quality but moderately-priced ultra wide angle zoom lens, the Canon EF 17-40mm f/4.0 L USM Lens is one of Canon's best selling lenses.

The 17-40 f/4 L fills out the bottom focal length range of Canon's f/4 L zoom lens series. It is the lightest L lens currently made (1.1 lbs / 475g) and is the smallest L zoom lens currently produced (3.3" x 3.8" / 83.5mm x 96.8mm - DxL). As you expect from an "L" lens, the 17-40's build quality is very high. This is an easy-to-take-with-you lens - It handles very nicely as well.

Utilizing Ring USM, the Canon EF 17-40mm f/4.0 L USM Lens focuses very fast, quietly and accurately. The focus and zoom rings are nicely sized, turn smoothly and are nicely damped. This lens does not extend with a very small exception - the objective end lens elements move in/out slightly inside the lens barrel during focusing. The movement is 100% behind the filter threads. If you have a filter installed, you will have no external movement. Since the filter attaches to the fixed lens barrel - the filter also does not rotate. Circular Polarizing Filter and split neutral density filter users will care about this. The common 77mm filter threads make sharing filters with many of Canon's complementing lenses easy. The Canon EF 17-40mm f/4.0 L USM Lens is weather-sealed but requires a UV Filter to complete the sealing.

Wide open center of the frame sharpness ranges from great on the wide end to good on the long end. Corner sharpness is the reverse - ranging from good at 40mm to soft in the full frame corners at 17mm. Stopping the 17-40 L down to f/5.6 levels sharpness to very good across the frame. Both of the 17-40 L lenses I've owned have yielded better sharpness at short distances than at long distances.

The Canon EF 17-40mm f/4.0 L USM Lens resists flare very well. Colors and contrast are very good. Expect some CA in the full frame corners below 24mm. Distortion ranges from moderately strong barrel distortion at 17mm to mild pincushion at 40mm with 24mm being the approximate point of no distortion. As usual, closer distances resulted in stronger distortion and significantly less distortion will be noticeable on 1.6x FOVCF bodies. You will likely notice the barrel distortion in the full-frame 17mm ISO 12233 resolution chart sample crops.

A 7-blade circular aperture delivers excellent OOF (Out of Focus) blur quality. But, unless you have a close subject and a wide aperture, do not expect a diffusely blurred background with this ultra-wide angle focal length range and moderate maximum aperture opening.

Vignetting will be a non-issue when the 17-40 L is mounted on 1.6x FOVCF bodies. Full frame body users will see vignetting ranging from very strong at 17mm f/4 to not too bad at 40mm f/4 and 17mm f/8. A standard thickness UV filter shows little or no additional vignetting regardless of the camera body being used. However, you will likely want a slim circular polarizing filter.

Although not as fast as the Canon EF 16-35mm f/2.8 L lens, the Canon EF 17-40mm f/4.0 L USM Lens is a comparable lens in terms of image quality. The biggest difference between the 17-40 and the similar-focal-length-covering 16-36 L is price. The 17-40 is much less expensive - practically half the price. But of course, the 16-35 is able to let in twice as much light.

Canon Zoom Lens Size Comparison

The above size comparison photo includes from left to right the Canon EF 17-40mm f/4 L USM Lens, Canon EF 24-105mm f/4 L IS USM Lens, Canon EF-S 17-55mm f/2.8 IS USM Lens and Canon EF 24-70mm f/2.8 L USM Lens. The same lenses are show fully extended below.

Canon Zoom Lens Size Comparison- - All Lens Shown Fully Extended

At its closest-focusing-distance of .92' (.28m), the Canon EF 17-40mm f/4.0 L USM Lens delivers its maximum magnification of .24x at 40mm (a decent value). Zooming out to 17mm at this distance will yield a dramatic perspective. Adding extension tubes to the equation shortens the closest focusing distance and delivers significant (macro-realm) .83x and 1.02x maximum magnifications for 12mm and 25mm tubes respectively.

The Canon EF 17-40mm f/4.0 L USM Lens ships with a Canon EW-83E lens hood and a Canon LP1319 soft lens pouch. The shape of the hood (very wide and very short) makes one question whether it actually helps. It does almost nothing for lens protection - and probably nothing for image quality when used on a 1.6x FOVCF body. It also makes storage inefficient. With the hood removed, the 17-40 easily fits in a relatively small Lowepro Lens Case 1W. To accommodate the diameter of the hood installed, the 17-40 requires a relatively large Lowepro Lens Case 4S.

Since 1.6x camera bodies do not need all of the image this lens presents, a more-light-reducing lens hood can be used. Friends of the site have reported that the Canon EF 24mm f/1.4 L Lens' EW-83DII lens hood and the Canon EF 24-105mm f/4 L IS Lens' EW-83H work well as alternatives for these bodies. I tested the EW-83J from the Canon EF-S 17-55mm f/2.8 IS Lens and it seems to work fine on the 17-40. It fits and does not cause vignetting at 17mm and f/4. It looks a lot better as well. :)

Canon Wide Angle L Series Zoom Lenses

Shown above are the Canon EF 17-40mm f/4 L USM Lens, Canon EF 16-35mm f/2.8 L USM Lens, Canon EF 16-35mm f/2.8 L II USM Lens and Canon EF 24-70mm f/2.8 L USM Lens. The same lenses minus the 24-70 L are shown below with their included lens hoods.

Canon Wide Angle L Series Zoom Lenses with Lens Hoods

Be sure to read my Canon EF 16-35mm f/2.8 L II USM lens review to determine which of these two Canon Ultra Wide Angle lenses is right for you. In brief - If you are going to shoot primarily with narrow apertures or your budget is restricted, the decision is easy - get the Canon EF 17-40mm f/4.0 L USM Lens. If you need to shoot in low light conditions such as indoors without a flash or tripod, then the 16-35 L II is for you (you need at least f/2.8 - or image stabilization for motionless subjects). If you do not need full-frame compatibility, rugged build quality or environmental sealing, the newer Canon EF-S 17-55mm f/2.8 IS USM is another great solution.

I frequently recommend the Canon EF 17-40mm f/4.0 L USM Lens as a general purpose lens for those with a 1.6x FOVCF (field of view crop factor) camera that want the best image quality for a reasonable price. The focal length range of this lens is not big, but on a 1.6x body, the full-frame equivalent 27.2-64mm lens can handle many general purpose needs. Good full-frame compatibility and performance make the 17-40 L an especially good lens for those thinking of upgrading to such a body in the future.

Wide landscape photography is a very popular use for this lens Use wide angles to emphasize an object in the foreground against an attractive (and mostly in-focus) background. Or use it to simply take in a very wide field of view. Shoot your garden landscape, the lake, large mountains ...

Architecture and real estate photography often have large subjects that require wide angle lenses. These are more good uses for the Canon EF 17-40mm f/4.0 L USM Lens. You may need to remove the barrel distortion from 17mm shots during post-processing.

Other situations that require you to work in a tight space may be right for the 17-40 L.

Although the Canon EF 17-40mm f/4.0 L USM Lens can be a good people lens, it is not a good short-distance people lens. A head shot from this lens will emphasize the subject's nose more than the subject will want. The 17-40mm focal length range is great for group pictures, environmental portraits and full body pictures. Stand back and make a person part of a wide landscape shot. If tighter portraits are your interest, look for a lens that gives you at least an 85mm - 135mm equivalent focal length. The captures of your important subject will be more pleasing.

Of course, that closeup wide angle portrait look is fun to use sometimes. Just don't overdo it.

As with any other general purpose/ultra wide angle lens, this lens has far more uses than I am going to think of. But if you want a great wide angle lens for an attractive price, the Canon EF 17-40mm f/4.0 L USM Lens is a very good choice.

Canon EF 17-40mm f/4.0 L USM Lens Sample Pictures ...

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