Canon EF 50mm f/1.4 USM > Reviews (1)

Overview
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The Canon EF 50mm f/1.4 sits in between the cheap-o f/1.8 mkII version and the ridiculously expensive f/1.2 L-series version. There was a crazy f/1.0L lens at one time but this seems to have been discontinued (presumably as nobody could afford it). It is a "standard" prime lens but only for full frame DSLRs like the 5D. On a APS-C body it equates to 80mm.

I bought it because I wanted a small and inconspicuous lens to use on my 5D and one that would plug a gap in my lens line-up that consists of f/4 L-Series zooms. Namely, a low light, shallow depth of field lens.

Construction
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The main things to note about the three variants is that the f/1.8 has a plastic mount and a micro-motor AF. The f/1.4 has a metal mount and a Micro-USM AF motor (quieter than the micro-motor but noisier and slower than a ring USM AF). The f/1.2 is a pukka L-Series lens with solid build quality and a ring USM AF motor.

Basic construction of the f/1.4 is a little disappointing considering its price tag of £230. Apart from the reassurance of the metal mount, it is a very plasticy thing. In some ways it's a good thing as it doesn't look like £230-worth of kit so is less of a risk in attracting muggers on the lookout for bling. On the other hand it just doesn't feel like £230-worth of kit. When you pick up an L-Series lens you instantly know from it's feel and heft that you are holding a quality bit of kit.

The front element is well recessed into a stepped slope tube (to minimise light reflections) and so I didn't bother with a protective filter as it's much harder to accidentally touch or scratch the lens than on most L-Series lenses that have very exposed front elements.

Operation
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The working of the lens is a bit archaic. The Micro-USM motor drives a geared AF that pushes the front element in and out (just as my Pentax K-type 50mm f/1.7 prime did - only it was built much better than this lens... ahh... those were the days...). It would have been nice to have internal focussing with a sealed front element (water and dust can ingress through the sliding barrel). This also adds to the slowness of the AF. Actually, it's not that slow but much slower than the internal focus systems on my L-Series lenses that snap to focus in the way that soldiers snap to attention. For filter users, the front element does not rotate, just extends in and out when focussing.

Perhaps the most irksome thing is the manual focus ring. Unusually for a Micro-USM lens, it does allow full time manual focus. On most, the gearing prevents you from adjusting it unless you flick the switch to manual. The problem is the feel. There's some kind of clutch in there and turning the focus ring is a disturbing sensation - like something inside is grinding. When I tried it in the shop, I worried, "Am I focusing it or breaking it"? It doesn't inspire confidence but it works. The fact that the focus is geared is good in that the manual focus ring has a lot of travel in it and you need it when using the big f/1.

4 aperture that results in startlingly shallow depth of field. Critical focussing is very important on this lens.

The lens has a useful distance guage on the front and a f/22 depth of field guage so that you can set the lens manually to a hyperfocal distance and then (albeit in strong sunlight) ignore focus altogether.

Performance
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Now I read a lot on photo blogs and so on about this lens. The main thing that worried me was a lot of posts claiming that the lens has problems with bad examples (sometimes batches) where the lens back or front focuses. This means that you focus on a spot and the picture comes out blurred because the lens actually set its focus point to somewhere closer or further away than intended.

This only becomes obvious at close range (like 50cm to 1m) and when using the lens wide open (f/1.4) because the depth of field is so shallow. If the lens were to be out of calibration by as much as 2-3 cm then the picture would be ruined as the wrong things would be in focus (the subject critical point was at 60cm but the lens back focussed to 63cm).

I tried this out in the shop with a rental lens and at home with my new one and didn't find this to be the case. I used a sheet of paper with fine text and took a few shots of a particular line of text with the paper at a low angle. This way it would be obvious if the lens was front or back focussing because it would show the wrong line of text being sharp (compared to the one I intended). Happily, neither showed this problem.

Taking a variety of photos indoors and outdoors I got a feel for what it was like. Some people have complained that the lens looks unsharp and "dreamy" at f/1.4. It isn't. It's just sharp over a very narrow distance. I use a 180mm f/3.5L Macro and that has a depth of field of the order of a few milimeters at f3.5 and its macro working distance - if you don't focus carefully and don't stop down, almost EVERYTHING in the frame will be out of focus!

A f/1.4 lens is very good at taking available light shots in low light but the trade off is depth of field. The f/1.2L has more extreme shallow depth of field and the f/1.0 must have been almost impossible to use wide open at close range!

In very dim light and where there was little contrast in the scene I found that the lens could not lock on to focus and I had to resort to manual focus or guessing by use of the focus scale. It's a little noisy when working but not annoyingly so.

The very shallow depth of field is a special effect and you can use it to pick small things out in a scene by selective focus. For more "normal" photos I tend to set it to f/2.8, which still gives good low light performance but more sensible depth of field.

When taking landscape shots with a figure in the bottom of the frame (a portrait of a tree with a person standing under it from a range of 20m) I did notice that on close inspection there was some chromatic aberration (colour fringing) on the person's face. But you had to blow the picture up to 100% to see it.

Not bad performance for a lens from the normal USM range.

I'm very impressed with the colour and contrast of the lens. It almost takes over-saturated pictures. In good light, images really pop and stopped down a bit to f/5.6 it gives cross frame sharpness at least as good as the f/4 L-Series zooms.

At f/1.4 there is a little vignetting in the corners (on a 5D body) but this disappears by f/2. Compare that with the 24-105mm f/4L that vignettes strongly at f/4 and still a bit at f/5.6.

Conclusion
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Unless you really need the extra light gathering power of the much more expensive f/1.2L lens (some £620 more) or really want that scalpel-like shallow depth of field for a special effect, the f/1.4 lens does a pretty damn good job for the money.

While not up to the build quality standards of the L-Series lenses, it's not bad and does look a lot less conspicuous when walking around town. If they made a f/1.4L for around £400 (instead of the £850 tag of the f/1.2) I'd probably jump at that to gain a true ring USM AF, more solid build quality, weather sealing, and better control of the edge CA distortions.

But until that particular dream comes true, this lens is a solid recommendation.