thephotographynut wrote in post #14557458
I have not used both lenses but I do own the 17-40.
You didn't mention if you are using a FF or a CF. If you are using a CF, you may also want to consider the EF-S 15-85mm f/3.5-5.6 USM IS.
Both the 15-85 and the 17-40 cost about the same. There are both pros and cons to both lenses but overall, for sharpness and color quality, the 15-85mm takes the cake. The 15-85mm's quality is so good that it has replaced my desire / need to use my 17-40 and I use it is professionally all the time.
- Near L quality build (it is plastic but feels like a brick)
- Sharper and better color then the 17-40 f/4L.
- Has IS and which works very well. Advertised is 4 stops but it easily does 3 stops with perfect results.
- is wider then the 17-40 and has more then double the reach.
- 1/3 Stop faster at 15mm
- Same wide-open f value at 40mm as the 17-40
- Full time manual focus.
- Lens hood does a great job of keeping the sun off the glass.
- One stop slower then the 17-40 at 85mm.
- Variable aperture makes it not ideal for video.
- No lens hood. Must buy separately.
- Can't be used on FF.
- A little Lens-creep at 85mm and pointed straight up / down.
- Slight vignette at 85mm but is easily fixed in ACR
- Slight CA wide open at 15mm but easily fixed in ACR
- Lens gets longer as you zoom in.
EF 17-40 f/4L
- L quality build (feels like a brick).
- Comes with hood and lens pouch.
- Consistent aperture across full focal length range. (Good for video)
- Lens does not grow longer as it zooms in and out. (Although front element does jut out a bit when zooming - see cons)
- Softer then the 15-85mm when wide.
- Slightly less CA then the 15-85 but not by much.
- Color is less vibrant then the 15-85.
- Half the focal length of the 15-85.
- Using some filters causes the lens element to press against the filter when zooming since the front element moves in and out a bit. This is a slight design flaw that is either on all copies out there or at least on some of the newer versions as many have reported this problem and my copy suffers from it too.
- Lens hood does little to shield the sun. Because the hood is so small when shooting at an angle to the sun, it does nothing.
- No IS
- Only produces a field of view equal to a 28mm lens when used on a Crop Frame.