Canon EF-S 18-135mm f/3.5-5.6 IS USM Review

Canon EF-S 18-135mm f/3.5-5.6 IS USM Performance

Sharpness has been evened out across the focal length range pretty well overall. At 18mm, central sharpness is very good from f/3.5 to f/16 and only drops to a good level at f/22. The edges start off with good sharpness at f/3.5, becoming very good from f/5.6 to f/11, good at f/16 and just fair at f/22.

At 24mm, centrally we start off with very good sharpness at f/4, becoming excellent from f/5.6 to f/8. f/11 and f/16 are still very good, but f/22 and f/25 are only fair. The edges are only fair from f/4 to f/5.6, becoming good at f/8, very good at f/11, then falling to good at f/16, fair at f/22 and really quite soft at f/25.

50mm starts off good at f/5, rising to excellent at f/5.6 and f/8. It is very good at f/11 and f/16, good at f/22 but becoming soft at f/32. The edges are good from f/5 to f/8, very good at f/11, good at f/16, falling to fair at f/22 but again becoming soft at f/32.

135mm is the weakest performance, the centre being very good at f/5.6, excellent at f/8, very good at f/11 and f/16, but falling away to just fair at f/32 and soft at f/36. The edges are very good at f/5.6 and f/8, good at f/11, just fair at f/16 and f/22. The result at f/32 and f/36 is very soft.

Although the MTF50 results are nowhere near perfect, in common with other 18-135mm lenses bright and crisp images can be made at wide to mid apertures. This is likely to cover the most common use as a general purpose travel lens. It may be arguable that the smallest apertures could have been left out altogether, as results beyond f/22 may not be worth the potential extra depth of field.

How to read our charts

The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges.

The scale on the left side is an indication of actual image resolution as LW/PH and is described in detail above. The taller the column, the better the lens performance.

For this review, the lens was tested on a Canon EOS 80D using Imatest.

The picture with CA (Chromatic Aberration) is consistent across the zoom range. The centre of the field is highly corrected, at some points approaching zero. In any event, there is no visible fringing. At the edges, correction is generally held to below 1.5 pixels but is especially good around the 50mm mark. There may be some fringing visible at bright edges, but this should easily be corrected in software if desired.

How to read our charts

Chromatic aberration is the lens' inability to focus on the sensor or film all colours of visible light at the same point. Severe chromatic aberration gives a noticeable fringing or a halo effect around sharp edges within the picture. It can be cured in software.

Apochromatic lenses have special lens elements (aspheric, extra-low dispersion etc) to minimise the problem, hence they usually cost more.

For this review, the lens was tested on a Canon EOS 80D using Imatest.

Flare is more of a problem, and as suggested at the start, it would be a very good idea to provide the dedicated lens hood with the lens. Many marques do this and it could make a serious difference here. Where very bright light encroaches on the image area, without a hood flare overwhelms the picture. There are also artefacts created. There is no such problem with side light or lighting full on and it does not prevent most image making from being perfectly satisfactory, but backlight is a problem.

Distortion starts with -3.86% barrel at 18mm, which is very obvious in the pictures. This has reduced to -0.545% barrel at 24mm and evens out at around +1.55% pincushion at 50mm and +1.54% pincushion at 135mm. This is all the right way round as we are well used to barrel distortion in wide angle lenses and pincushion in telephotos. If it were the other way round it could look very strange to our eyes. This can, of course, be corrected in software.

The bokeh of the lens is actually quite pleasant, giving smooth transitions in the out of focus background areas. This is especially so at wider apertures and where the main subject is closer to the camera.

Value For Money

The Canon EF-S 18-135mm f/3.5-5.6 IS USM lens is priced at £449 and the Power Zoom Adapter PZ-E1 adds £129. The previous lens, the Canon EF-S 18-135mm f/3.5-5.6 IS STM, costs £319.

Looking at other marques, the only matching specification is the SMC Pentax-DA 18-135mm f/3.5-5.6 ED AL IF DC WR at £379.

This leaves the new Canon lens at being a bit pricey, and adding in the Power Zoom Adapter and possibly the TS-E Lens Tripod Adapter will add to that cost.

For more options have a look at the Top 15 Best Canon EOS lenses, or have a look at the Top 10 Superzoom Lenses.

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