Review The Canon 50L (EF 50mm f/1.2L USM): my thoughts

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Thought I'd post this on here as well as my blog, because I feel that the 50L gets a lot of flack but it's my favourite lens :) All images are my own work. Hope this helps out someone who is trying to decide whether to pick up this much-debated lens!

The 50L is undoubtedly a 'Marmite lens' and by far the most controversial lens in their current L lineup, dividing opinion and inspiring strong emotions in both its champions and detractors. Some high profile photographers sing its praises, particularly wedding photographers such as Jasmine Star and portrait shooters like Sue Bryce and Lara Jade. It is championed for its beautiful, soft bokeh that has a unique dreamy quality.

On the other hand, a quick search on Google will show you that many photographers seem to purchase then quickly return this lens, complaining of softness and focus problems. The internet is awash with a whole range of posts on blogs and forums detailing the various joys and frustrations of using this lens, often leaving photographers who are seeking to choose between the 50L and its two cheaper stablemates - the Canon EF 50mm f/1.4 USM and the 'nifty fifty' Canon EF 50 mm f/1.8 II - with more questions than answers. Is this lens really worth four times the cost of the f/1.4, or more than ten times the cost of the nifty? Is the lens design 'faulty', causing backfocusing and focus shift issues? Having used this lens in a professional capacity for quite some time now and having done a lot of research into the facts behind the issues, I hope to be able to shed some light on this mythical and much-maligned beast.

Wedding portrait with the Canon 50L shot wide open at f/1.2

50L focus/softness issues: the facts
1) AF points and standard focal screens on modern DSLRs are only accurate to around f/2.8!
An important factor to consider that isn't widely documented and came as a shock to me when I discovered it is that even on my Canon 5D Mk III and all other current top of the line DSLR bodies from both Canon and Nikon, the most precise cross-type AF points are only accurate to around f/2.8. What's more, the standard Canon focusing screen in 5D bodies only shows depth of field to f/2.8. To further compound this issue, whilst previous versions of the 5D allowed you to switch out your focusing screen, the 5D Mk III features a fixed focusing screen which cannot be changed by the user without warranty-invalidating tinkering to install 3rd party screens.

The upshot of this is that whether you prefer to focus manually or use the camera's AF, it is impossible to focus with total and consistent accuracy on a lens opened up to lower than f/2.8 - and given that the sweet spot for the 50L is in the range of f/1.2-f/2, this is a huge disadvantage. Of course, this will be true of any lens used at wider apertures than f/2.8; nevertheless, I think it is important to be aware of these limitations when considering reports of focus inconsistency in a lens like the 50L, particularly from those who haven't used f/1.2 lenses before.

2) Understanding depth of field
Understanding DOF (depth of field) is crucial when using a lens like the 50L, because shooting at f/1.2 is a massive challenge with a steep learning curve. When I first started shooting with this lens wide open, I lost count of the number of people shots I had to reject due to the end of their nose being perfectly sharp but their eyes being out of focus! In fact, the DOF is so thin that often if your subject's eyelashes are in focus, their eye itself won't be! That was massively frustrating, but I will hold my hands up and admit that this was user error and not an inherent flaw in this lens. When shooting a portrait at a distance of, say, 1 metre (3 feet) with an aperture of f/1.2, you can expect the DOF to be under 27mm (see a useful online DOF calculator HERE). With such razor-thin DOF, any tiny movement back or forth by you or your subject can cause an eye to go blurry, especially if your subject's face isn't facing directly on to camera. One trick I picked up for nailing critical shots is to lock focus and fire a burst of three or four shots in quick succession, leaning backwards very slightly as you do so. This at least means you have some variation in the focal point, and hopefully one of the shots will nail the focus. It sounds crazy to have to do this, but short of risking damage to install an aftermarket focusing screen, only shooting in live view or looking at every shot you've taken on your LCD at 10x magnification between shots to confirm focus, I see no other practical way of making sure you've nailed focus. If you have a body with a good AF servo mode like my 5D Mk III, I'd definitely suggest using that if you're attempting to track moving targets and nail focus at shallow apertures, but that's more of a general tip than one specific to this lens. I redefine the DOF preview button - which is on the front of my 5D Mk III's body, near my right fingers - to switch to AI servo mode when held down, allowing me to quickly change from my usual one shot mode and back again without too much fiddling.

3) The 50L design's inherent issues
Due to its optical design, the 50L has a slightly curved plane of focus. This means that if you focus and recompose, you are almost guaranteed to get an out of focus shot. I learned this the hard way and it's still something that bothers me, because in fast-paced shooting environments with busy backgrounds I often used to use the closest AF point I could to my subject's face, then shift slightly to get the subject framed properly. I believe that a large number of people who complain about this lens are probably also used to using a focus-recompose technique. In general, it's recommended not to focus-recompose anyway if at all possible, so personally I saw using this lens as a good reason to stop doing so!

The 50L is also known to exhibit focus shift for shots taken at near distance (1-2 metres) at apertures between f/2 and f/4. Focus shift does not affect pictures taken at longer distances from the subject or shots wide open at f/1.2, but then you are dealing with the razor thin DOF issues I mentioned above, which become more pronounced at near distances. Finally, shooting narrower than f/5.6 gives you more DOF to play with and makes the effects of focus shift negligible... but then, you probably didn't buy and f/1.2 lens to shoot at f/5.6!

The 50L definitely exhibits quite strong chromatic aberrations in contrasty scenes. The CA of this lens is uncorrected as a deliberate design choice, as this trade off allows for its beautiful signature bokeh. This is generally fixable in Lightroom, but even so there have been some images I've captured in environments such as in a park during the day where the green aberrations around the edge of people has been starkly obvious and hard to fix due to its size. In these cases the image can still be fixed by post processing in Photoshop and cloning colour over the areas, but this is fiddly and time consuming. Chromatic aberration is a problem you'll find with many wide aperture primes, however, including the much-loved 85 f/1.2L II, so it's something worth learning to live with and/or fix.

In summary, most of the above factors are simply the harsh reality of using an f/1.2 lens on a modern AF-eqipped body that is geared up for lenses at f/2.8 and above... yet countless professionals continue to use this and other wide aperture primes, because we value the amazing images you can capture with them once you've learned to live with the issues and frustrations.

Portrait with the Canon 50L shot wide open at f/1.2

50L practical usage
If I had to pick just one prime lens to use at weddings I'd pick a 50mm, so as a Canon user the top of the line 50L was a no-brainer for me personally. 50mm is a very natural-feeling focal length on a full frame body, giving a field of view that is very similar to what our eyes see. It's flattering for portraiture and generally produces very honest, true to life images. 50mm is versatile enough for headshots, 3/4 and full body portraits; it gives me a working distance I am comfortable with and feels right for my documentary/reportage style of shooting. Other than group shots and some situations in weddings such as a chapel with restricted space, it's the lens I leave on my body 80%+ of the time at weddings.

One of the massive bonuses of the 50L is that you get a very bright image in your viewfinder and superb autofocus in low light conditions. The AF isn't lightning-quick, but it's solid and accurate. I much prefer to use natural light whenever possible and this lens will almost literally see in the dark; when combined with a camera with good high ISO handling capabilities such as the 5D Mk III, there are very few situations where you won't be able to get a usable image.

When you do manage to hit focus at f/1.2, something really special happens with the bokeh (out of focus areas). It's incredibly creamy, dreamy and creates great separation between your subject and the background. Even at narrower apertures it retains a very pleasing quality. It's a sharp, contrasty lens with great colours.

At over half a kilo, this lens feels just the right size and weight to carry all day long in my hand. It's fat but not too long and balances beautifully on the 5D Mk III.

Detail with the Canon 50L shot wide open at f/1.2

The 50L on paper
If you browse around various internet forums, you'll see this lens roundly trounced in technical comparisons with lenses such as Sigma's 50mm 1.4 Art series lens. Many amateur photographers are obsessed with the concept of sharpness, particularly corner-to-corner. Whilst the 50L doesn't win out in such pixel-peeping comparisons, it brings something else to the table that can't be expressed in terms of pure numbers and from blown-up photos of test charts; it has unique qualities to its bokeh and draw that are hard to quantify. The 'look' a lens produces is a subjective thing and from what I've seen, no other 50mm lens creates the kind of look this lens is capable of. Whether it's the right choice for your kind of photography is for you to decide, but personally I think it's fantastic for flattering, stylised portraits and thus a great choice for wedding shooters. The Sigma has a different knid of look and is maybe more suitable for other kinds of photography; it's certainly sharper and with less CA than the 50L, but as I discussed earlier this is a trade off and the Sigma's bokeh looks a bit flat and boring to me personally.

50L price vs worth
When you first put the 50L on your camera, you can immediately feel the exceptional quality of the lens in your hand. It is built like a tank, with a silky smooth focusing ring, all-metal construction and weather sealing to prevent dust and moisture entering the lens. Are the images it produces 10 times better than those from a 50mm f/1.8? Absolutely not, and it's definitely possible to produce top quality images using its little sibling. The differences in image quality are subtle, so only you can decide if it's worth the extra for you and your shooting style. If like me you are a professional and want the very best image quality you can get, the way to look at this lens is as an investment; if you learn to use it correctly and love it for what it is, it will produce the best results possible and last you a lifetime of shooting, something very few could say about the 50mm f/1.8, which feels like a cheap toy in comparison.

After a few months, I stopped being frustrated with the 50L and learned to love it more than any other lens I own; if you decide to take the plunge, make sure you give this beauty a fair chance and be prepared for some humbling experiences when it comes to nailing focus!

If you'd like to see more of my 50L photos, please visit my website - most of the images on there are 50L shots, as it's the lens I use 80% of the time at weddings :)