Canon EF 180mm f/3.5 L USM macro - Review / Test Report - Analysis
Lens Reviews - Canon EOS (APS-C)
Article Index
Introduction
Analysis

Distortion

As to be expected from a true macro lens the level of distortion is absolutely negligible.

180mm:

The chart above has a real-world size of about 120x80cm.

Vignetting

When using the lens on an APS-C DSLR there's only a slight degree of vignetting at f/3.5 which shouldn't be problem in most scenes and it's a non-issue at other aperture settings.

MTF (resolution)

In the lab the EF 180mm f/3.5 USM L macro showed a very good performance from f/3.5 till f/16. Beyond diffraction effects are the limiting factor - the f/32 figures are not shown below because there's only an image soup left at this setting. The lens showed a very even performance across the frame without any obvious centering issues. Nonetheless the MTF figures are a little disappointing for a Canon L grade tele lens - more so regarding its price tag.

Two lenses have been tested and the results were near-identical. Possibly the performance may be better at close-focus distances but for mainstream photography this is about what you can expect from a valid sample of this lens.

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)

Similar to most other fix-focal lenses chromatic aberrations (color shadows at harsh contrast transitions) are extremely low and nothing to worry about.

Bokeh (out-of-focus blur)

The quality of the bokeh is an important criteria for a tele lens and more so for a macro variant. This aspect of the EF 180mm f/3.5 USM L has been frequently discussed in many web forums. At f/3.5 the lens is capable to produce nicely circular and uniform out-of-focus highlights. However, the situation changes when stopping down to f/5.6 where octagonal shapes start to appear. This is certainly "too early" for a macro lens which is usually used at medium aperture settings at macro distances. At f/3.5 the bokeh shows also some one-sides "smearing" towards the image borders (see the card portion) which doesn't look overly pleasing. This smearing occurs only in close proximity to the focus point though (see the quadrant).

Here're two full size samples at f/3.5 and f/5.6.

Verdict

The Canon EF 180mm f/3.5 USM L macro is an interesting lens with a very good optical performance and exceptional mechanical qualities. Nonetheless the lens wasn't really able to fulfill the high expectations associated with a Canon L grade lens - there're even some zoom lenses performing better in terms of resolution. Beyond the resolution aspect the lens showed pretty perfect performance figures - minimal vignetting, next to non-existent distortions and marginal chromatic aberration. The bokeh, the quality of the out-of-focus blur is relatively decent although not stellar. The AF performance of the lens is a bit of a mixed bag. If the in-focus point is in a relatively close proximity to the current setting the AF is fast. However, if the camera has no guidance where to go the AF is extremely slow. That said AF speed isn't really relevant for pure macro photography where you tend to use manual focusing anyway. Macro photographers will certainly appreciate the "true" IF design (constant physical length) as well as the increased working distance compared to the EF 100mm f/2.8 USM macro. If macro capabilities aren't on your wish list you may prefer to look elsewhere though.

Optical Quality:    
Mechanical Quality:
Price/Performance:
      
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Last Updated on Monday, 29 July 2013 12:10

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