Canon EF 17-35mm f/2.8 USM L - Review / Lab Test Report - Analysis
Lens Reviews - Canon EOS (APS-C)
Article Index
Introduction
Analysis

Distortion

As usual this ultra-wide zoom lens shows some very strong barrel distortion at 17mm easing towards the long end (35mm) where the lens is basically free of distortion.

17mm:

20m:

24mm:

35mm:

You should probably expect more distortions towards closer focus distances.

Vignetting

The EF 17-35mm f/2.8 USM L showed a very unusual vignetting characteristic. On an APS-C DSLR it can take advantage of a sweet spot behavior but at 17mm the lens already showed an optimal behavior with no measurable improvement when stopping down (yes, I repeated the test row to make sure). Due to the decreasing natural vignetting there's a little less shading at 24mm. At 35mm the issue is marginally more pronounced at f/2.8 but negligible beyond.

MTF (resolution)

In the MTF lab the EF 17-35mm f/2.8 USM L showed a quite decent behavior but also a couple of glitches.

The worst spot is clearly the 17mm setting especially towards the extreme borders. Normally the "extreme border" performance is not provided for full frame lenses but the exception was necessary here to point out the weakness of this lens. The extreme borders @ 17mm are smeared at f/2.8 which very little detail left. Stopping down helps to lift the resolution figures but the extreme borders remain somewhat substandard. The center performance is in sharp contrast to the borders - the MTF figures are excellent here even at wide-open aperture.

At 20mm and 24mm the border quality is substantially better with good quality at f/2.8 increasing to excellent figures by f/5.6. There's a marginal decrease in quality at 35mm but the center remains excellent and the borders still reach very good figures at medium aperture settings.

An annoying characteristic of the lens is the focus shift when stopping down (residual spherical aberrations). At long focus distances the problem is hidden within the pronounced depth-of-field but with close-ups you may run into focus errors when relying on AF (the focus plane moves towards the camera). The lens also showed a quite pronounced field curvature (the focus plane bends towards the edges).

Below is a simplified summary of the formal findings. The chart shows line widths per picture height (LW/PH) which can be taken as a measure for sharpness. If you want to know more about the MTF50 figures you may check out the corresponding Imatest Explanations

Chromatic Aberrations (CAs)

Typical for most ultra-wide zoom lenses CAs (color shadows at harsh contrast transitions) are quite pronounced with this lens but they remain in line with what we've seen from similar lenses. As usual the issue is decreases towards the long end of the (ultra-wide) zoom range.

Verdict

During my days with this lens I was actually quite fond of the performance of the Canon EF 17-35mm f/2.8 USM L but I usually limited the usage to focal lengths beyond 20mm. A good idea also confirmed by the MTF tests which showed a quite poor border resolution at 17mm. However, in the 20-35mm range the performance is very good and comparable to what we've seen from modern Canon ultra-wide zooms. Same goes for the other image characteristics. The barrel distortions are very pronounced towards the wide end of the zoom range but pretty decent otherwise. Typical for most full frame lenses vignetting is no big issue on an APS-C DSLR. CAs are quite high but about average for a lens in this class. All-in-all the lens had its time but there're better alternatives available today.

Optical Quality:    
Mechanical Quality:
Price/Performance:discontinued
      
   What does this mean ?



© by photozone.de