With 24 mm effective focal length at its wide end and 136 mm at its tele end the EF-S 15-85mm f/3.5-5.6 IS USM is an ideal companion for a variety of shots from groups of people to individual portraits, landscapes, plants, buildings, general travel etc.. If you are on a trip and don't know exactly what you are going to photograph take a general purpose lens like this one with you to make sure you have plenty of options. Note that there is a big difference between 24 mm and the 29 mm (effective) that e.g. the kit lens EF-S 18-55mm f/3.5-5.6 IS II and other lenses have at its wide end. 24 mm will be wide enough for all but dramatic ultra wide angle shots where speciality lenses like the EF-S 10-22mm f/3.5-4.5 USM are needed.
The lens's aperture range is nothing to be excited about (unlike say the EF-S 17-55mm f/2.8 IS USM) but is good enough for most purposes.
Weight and Dimensionstop
At 20 oz the EF-S 15-85mm f/3.5-5.6 IS USM is rather heavy for a standard zoom lens but because of its compact size you don't notice the weight that much. Since I personally am used to lenses that are 4 times as heavy I don't even consider weight for a lens like this.
|Canon EF-S 15-85mm f/3.5-5.6 IS USM||20|
Compare with the weight of other lenses:
Handling and Build Qualitytop
The EF-S 15-85mm f/3.5-5.6 IS USM is built of very high-quality plastics and has a solid feel to it. The lens mount is all metal and thus a lot less prone to wear than conventional plastic mounts. The lens is not sealed against dust or moisture and no accessories (other than the lens cap and dust cap) are included. But a nice lens hood is available for purchase and it does have the same nice high-end looks. Its petal shape is convenient to allow access to filters that need to be rotated individually such as circular polarizers or graded filters (the fact that the lens's front element doesn't rotate while focussing or zooming helps with that as well).
In regard to the lens's size and weight it really depends on what you compare it with. There are lighter and smaller lenses that offer similar focal lengths but not at the same level of image quality (which inevitable needs more / heavier glass). On the other hand if you compare it to its full-frame "equivalent" (the EF 24-105mm f/4L IS USM) it is of course lighter and smaller - but that's not a fair comparison either. I have taken this lens on many trips and never thought it was too big or heavy.
The knobs and rings are firm and while the zoom ring is generously sized the focusing ring is a little on the small side (0.3 "). I had to get used to it and while I don't really have a problem focusing with it I would have liked a slightly larger ring. The lens does not have a zoom lock switch and doesn't need one because the zoom has just the right friction to resist gravity zoom extension while allowing precise operation.
Autofocus and Image Stabilization
The EF-S 15-85mm f/3.5-5.6 IS USM features a modern ultra sound type autofocus motor that's quick, acurate and quiet. Without the need to switch over to MF mode it allows you to manually override the autofocus operation at any time (you'll have to be in One-Shot-AF mode for this to be useful). The modern image stabilizer offers shutter speeds 4 times lower than usual (e.g. 1/8 s rather than 1/120 s) which is particularly useful for long focal lengths. For short focal lengths even longer shutter times will likely result in motion blur from subject movement (rather than camera shake) and thus are more of a theoretical benefit and are only useful for some special applications. The image stabilizer cannot detect a tripod so switching it off is recommended by Canon when a tripod is used. It does however detect panning shots automatically and will cleverly stabilize either just the horizontal or just the vertical camera movement.
The maximum magnification of 0.21 x as offered by the EF-S 15-85mm f/3.5-5.6 IS USM is good enough for regular closeup work but of course not good enough for serious macro photography. Let's take a look at the lens's image quality next.