Canon EF zoom lens - 28 mm - 135 mm F/3.5-5.6

Overview
-------------
I bought this lens as part of a package with my previous body, a 20D.

It is a good general purpose lens that covers a wide range of situations but is geared more towards 35mm film use than digital users.

Build Quality
------------------
The EF 28-135 IS USM falls into the mid-range bracket of lenses in that it is a "proper" lens. Unlike the cheapie kit lenses which have all plastic contruction, even the mount, this lens has the metal mount ring and a proper USM AF motor, not the USM micro motor or worse the ordinary motor. It focusses silently and quickly.

Build qulity is good but not great (compared to old Pentax lenses I own and Canon's own L Series professional lenses). The body of this lens extends when zooming and the action feels a little stiff at the wide end where it has to push out a sectional barrel.

The barrels feel a bit loose when its closed but this doesn't translate into any imaging problems, just that there isn't the completely solid feel of the L Series.

You can switch the AF and IS features on and off and unusally for a standard EF lens, the manual focus ring is full-time, so you can adjust it with the AF on. Lots of others can't because the focus ring is geared to the motor directly.

Performance
-------------------
In use, I noticed that the image could shift a tiny bit (up, down, left or right, not round!) when the AF is twitching between shutter button presses. This is generally not a problem but noticable, again a feature of some looser tolerance in the gearing of the optics of the zoom mechanism.

Images are sharp in the middle portion of the image but are a bit soft in the corners with some mild colour fringing. Nothing serious and certainly not noticable in normal viewing and "normal" photos. I was comparing the 28-135 with a EF 24-105 f4 L IS, using close-up photos of print and graphics from a magazine. In fact, the sharpness of the two lenses was comparable in the central region, only the corners are noticably better on the L Series.

One area that I did have problems with on the 28-135 was shooting into light where it suffered much more from a kind of misting flare than the L Series lenses that have additional measures to control stray light leakage in the path and around the mount interface to the body.

Even with a cheaper lens, it's worth spending a the extra Pounds on a top quality protection or UV filter that has anti-reflective coatings and this adds another £45 to the price as it uses a quite large 72mm filter.

The 135mm long end is useful for landscape photography and large animal shots from near distance but a bit short for true telephoto use for sports or wildlife shots from a distance. When I upgraded to the EF 24-105 f4 L IS the problem got worse and I missed the extra 30mm of range. This only got more pronounced when I upgraded to the 5D body. For APS sensor body users (20D, 30D, 40D, 350D, 400D), the telephoto range extends to a very handy 216mm but the wide angle end increases to a not very useful 45mm. That's why I also ended up buying a EF 17-40 f4 L.

This was one of the first lenses to feature the image stabiliser and it works very well. The system enages when you press the shutter to focus and runs on for a few seconds after you let go of the button or fire it. On this lens it makes a noticable whirring noise while doing its job but it's not obtrusive. Obviously it eats battery doing so but I did not suffer any shortage of juice in all the time I used the lens with my 20D body. The 5D uses more power but still I've not run out in a day when using this lens.

Conclusion
-----------------
At the more expensive end of the mid-range sector of Canon's lenses this is a bit of a mixed bag. Build is pretty good but not great. Performance is pretty good but not great and its full frame range of 28-135mm sits somewhat uncomfortably with the target market of APS sensor sized bodies (unless you actually wanted a 45-216mm lens).

It's a much better lens than the cheapie kit lenses that come with the 350D and 400D bundles. It will serve users of APS sensor users better than full frame bodies (in terms of image quality) as those small sensor bodies don't look into the corners of the lens (where its weaknesses are most apparent). But such users may be better off looking at the expanding range of EF-S lenses that specifically match the APS sensor body. The down side is that if you do upgrade later to a full frame body, you'll have to sell all your redundant EF-S lenses, as they don't work on the 5D (but see below for the flip-side).

For a 30D or 40D user, I'd be tempted to say, go the extra mile and shell out for L Series glass.

For a 5D user, I'd not recommend this lens as you'll be disappointed by the poor image quality in the corners of the image and be wasting the potential of this body. I'd strongly recommend use of only L Series lenses for this body.