Introduction

Canon EF 85mm f/1.8 USM is one of two 85mm lenses currently being manufactured by Canon (the other one being EF 85mm f/1.2L USM). Combination of (relatively) large maximum aperture and affordable price (about US$350 as of June 2007) make this lens an interesting choice for portrait photography among mainstream consumers.

The optical construction of the lens consists of 9 elements in 7 groups. The build quality is similar to that of Canon's other consumer grade lenses - outer barrel is made of hardened plastic with rubberized focus ring (the lens does not have aperture ring so all aperture settings have to be controlled electronically from the camera). Canon EF 85mm f/1.8 USM features a true inner focusing mechanism (rear focusing to be precise), meaning that the lens cams do not extend out during focusing. Hence, no wobbling whatsoever. The lens sports a silent and fast ring-type USM AF as well as full-time manual focusing mechanism. It is relatively light and compact (for an 85mm lens that is), weighing 425g (15oz) and measuring 75x71mm (3x2.8in). The minimum focusing distance is 85cm (2.8ft). The filter size is 58mm.

 

Image

 

The lens is designed to fit EF mount and on APS-C type cameras with 1.6x crop ratio, it would have a field of view resembling that of a 136mm lens on a full-frame body. The lens accepts optional ET-65III lens hood and is compatible with Canon's EF 12 II and EF 25 II Extension Tubes. The factory box includes Canon EF 85mm f/1.8 lens, front and rear lens caps, manual and warranty card.

 

Summary
Lens Composition 9 elements in 7 groups
Angular Field ~29 degrees
Minimum Focus 85cm/2.8ft
Focusing Action AF/MF, USM
f-stop Scale f/1.8, camera-controlled
Filter Size 58mm
Lens Hood ET-65III (optional)
Weight 425g/15oz
Dimensions 75x71.5mm/3x2.8"
Lens Case LP1014 (optional)

 

Field Tests

The lens performed quite well in general tests. Images taken with the lens were tack sharp from f/4 (both in the center and around borders), but the lens seemed to struggle a bit around corners at its widest aperture, even with an APS-C camera. Colors were somewhat on a warmer side (something easily correctable during post-processing step). The lens produced decent but otherwise uninspiring bokeh. AF was accurate and reasonably fast, even in low light settings.

 

Vignetting @ f/1.8 - full frame vs 1.6x crop
Vignetting @ f/1.8 - full frame vs 1.6x crop

 

As expected from a medium telephoto prime lens, Canon EF 85mm f/1.8 showed no visible barrel distortion. Vignetting on APS-C type camera was well under control throughout the tested apertures, but on a full-frame body the lens showed minor vignetting at f/1.8, which is reduced at f/2.8 and becomes pretty much non-existent starting at f/4. The lens showed minor levels of chromatic aberration when wide open with both APS-C and full-frame cameras and was somewhat prone to purple fringing at f/1.8.

 

ISO 100, 1/4000, f/1.8, 85mm (100% crop)
ISO 100, 1/4000, f/1.8, 85mm (100% crop)
Sample images coming soon

 

Lab Tests

(This is an update to the lab tests report using a different sample of the lens)

Please note that MTF50 results for APS-C and Full-Frame cameras are not cross-comparable despite the same normalized [0:1] range used to report results for both types of cameras.

 

Canon APS-C: The first sample of the lens I sourced for testing showed rather average results in the lab - performance in the center was quite decent, but quality of borders suffered, especially at f/1.8. The difference in performance between the first and second samples of Canon EF 85mm f/1.8 USM is quite drastic. Quality in the center, which as I mentioned was already pretty decent, improved by an average of 5% across entire aperture range. The most noticeable improvement however was around borders. Here the second sample of EF 85mm f/1.8 USM finally showed what a truly good copy of this lens could achieve! While still somewhat softer (compared to the center) at f/1.8, image sharpness around borders almost matches that of the center and remains consistently high throughout the rest of the aperture range. At its peak, the lens is capable of producing high quality 19in and very decent 24in prints. Conclusion? Results are quite impressive (even for a medium telephoto lens) and rightfully put the lens into the top quartile of all prime lenses available on the market.

 

MTF50 (Line Width/Inch on the Print) @ 85mm
MTF50 (Line Width/Inch on the Print) @ 85mm

 

Normalized raw MTF50 @ 85mm
Normalized raw MTF50 @ 85mm

 

Chromatic aberration (fringes of color caused by sharp transitions) is quite moderate with wide apertures both in the center and around borders (not exceeding 1px). Once stopped down to f/4 and beyond, CA is pretty much minimal in the center, but persists around borders albeit at lower levels (~0.5px).

 

Image borders @ 85mm (100% crop): f/1.8 vs f/8
Image borders @ 85mm (100% crop): f/1.8 vs f/8

 

Canon FF: Canon EF 85mm f/1.8 USM (the second sample I tested) continued its impressive streak even with a full-frame Canon 5D. The trend with a full-frame camera almost matches that of an APS-C body. Performance in the center remains consistently high throughout the tested aperture settings. Borders are again somewhat softer at f/1.8 but by f/2.8 improve nicely and remain consistent throughout the rest of the aperture range. Conclusion? Considering that there are no major fall-offs in sharpness around borders even with an FF body, I declare a double whammy (a winner in normal language)!

 

Normalized raw MTF50 @ 85mm
Normalized raw MTF50 @ 85mm

 

Chromatic aberration on a FF body was moderate as well (~1.5px around borders) and is reduced to ~1px once stopped down to f/2.8 and beyond.

 

Image borders @ 85mm (100% crop): f/1.8 vs f/8
Image borders @ 85mm (100% crop): f/1.8 vs f/8

 

Alternatives

There are over a dozen medium telephoto lenses available these days on the market, and your choice does not even have to be limited to Canon lenses only. If you require a faster lens (and are willing to pay significant premium for that), take a look at one of Canon's flagship lenses - EF 85mm f/1.2L USM. Outside of the Canon camp, you might want to consider Sigma Macro 70mm f/2.8 EX DG, which is slightly slower then EF 85mm f/1.8 USM, but also has 1:1 lifesize macro capabilities. If you're willing to migrate to a slightly longer telephoto, then Canon EF 100mm f/2.8 Macro is a worthy candidate, as is Tokina AT-X M100 AF PRO-D 100mm f/2.8.

 

Recommendation

Canon EF 85mm f/1.8 USM is one of the best medium telephoto prime lenses in Canon's arsenal. Combination of stellar performance with both APS-C and FF type cameras and affordable price, make this lens an interesting choice for general as well as portrait photography. There does seem to be some variation in quality among different samples of this lens - the difference between the two samples I tested was sufficient to turn the lens from an average to a stellar performer. Be mindful of that.