Canon EF 50/1.8 Review (versions I and II)

There have been two versions of the Canon EF 50/1.8 lens. According to Canon they are optically identical, but they differ in mechanical construction and features. The early lens (Canon EF 50/1.8), was introduced in March 1987, had a metal lens mount, distance scale, separate manual focus ring and IR focusing indicator. The latter (and current) Canon EF 50/1.8 II lens, was introduced in December 1990, has a plastic lens mount, no distance scale or IR focus indicator and no separate manual focusing ring (you rotate a knurled ring on the front of the lens).

One of the best things about the EF 50/1.8 is that it's cheap. Under $100 new for the "II" version. The original metal mount version seems to sell used for a premium, often over $150. In fact there's one on eBay right now (Dec 09) - "with slight fungus" - listed for $269. That's really a silly price, especially for a lens "with slight fungus"!. The original lens is slightly more desirable due to better construction, but I wouldn't pay a huge price premium for one, nor would I buy a lens with fungus in it! The true "going rate" for the Mk I lens (as of Dec '09) is in the $150-$170 range. Remember also that any "Mark I" original lens was made before 1990.

At $100 for a new Mk II lens or ~$160 for a used original version you get a lens that's at least 2 stops faster than a consumer zoom (3 and 1/3 stops faster than an 18-55/3.5-5.6 kit lens) and even a stop and a third faster than any expensive f2.8 "L" series pro zoom. For candid and low light work or when you need a fast shutter speed to freeze action this is obviously an advantage.

Specifications

Given a choice. I'd take the original version of the EF 50/1.8. The "II" is lighter and it may focus a little faster, but given a choice I'd rather have the metal mount and distance scales myself. If you want the original lens you'll have to look around for a used one though and they aren't all that easy to find. If you can't find a mk I lens, get the mk II and don't worry about it. You'll probably save $60-$70 anyway, and you'll have a brand new lens with a 12 month warranty, rather than a 19 year old lens with no warranty!

You might ask "just how well can a $100 lens perform?" and the answer is quite well! A 50mm lens is one of the easiest to design and make. It doesn't need complex optics like retrofocus wideangle lenses or telephoto long lenses. You generally don't need aspheric elements or exotic type of glass either. The size of the optical elements is also quite small (and therefore inexpensive) compared to faster lenses and you can make an excellent, well corrected lens with only 6 elements. No doubt Canon make a lot of them and they designed the lens down to the lowest price by using a plastic lens mount and a very simple focusing system with no expensive USM motor. You aren't paying for any frills with the 50/1.8 II and you aren't paying for many with the original version either.

Performance

How does the EF 50/1.8 perform in practice? Well, like all fast lenses it's a little softer wide open than stopped down. However even wide open it's still not bad and in fact a little softness can sometimes be useful when the lens is used for portraits! On a crop sensor body (such as a Digital Rebel, EOS 40D, 50D or 7D) a 50mm lens has the same field of view as an 80mm lens would on a full frame camera, so an EF 50/1.8 is a very good portrait lens for use with such APS-C sized sensor DSLRs. Being an EF series lens (not EF-S) the 50/1.8 is equally useful on a full frame DSLR (EOS 5D or 1D(s) series body) where it's a "normal" lens suitable for a wide variety of uses from travel to portraits. It's a maybe a bit short for "headshots" but fine for 3/4 or full length people shots.

Despite some internet claims to the contrary, I found the EF 50/1.8 is quite sharp even wide open. I suspect that some reports that it can be soft may be due more to focusing errors than any intrinsic defect in the lens. At f1.8 DOF is very small, especially when close focused. It does sharpen up a little (and gain contrast) when stopped down and this is typical for a fast 50mm lens. Both "Mk I" and "Mk II" versions are supposed to be the same optically but there are always lens to lens variations. I've seen magazine tests which rate the "II" version slightly better than the "I" version. In my tests, wide open, my "I" version had very slightly better edge resolution than my "II", and they were virtually the same in the center of the frame.

Center sharpness peaks at around f4 and at apertures between f4 and f22 there's very little difference between the 50/1.8 and the more expensive Canon 50mm lenses, the 50/1.4 and even the 50/1.2. The faster lenses may be a touch sharper and have slighly higher contrast between f1.8 and f3.5, but the difference isn't huge. It's also possible that the USM focusing on the f1.2 and f1.4 versions is slighly more accurate than that of the f1.8.

Distortion, astigmatism and chromatic aberration are all well controlled and none of these aberrations is likely to show up, even in large prints. There is noticeable vignetting (corner darkening) wide open at f1.8, especially when the lens is used on a full frame camera, but that's more of a characteristic of fast lenses on full frame cameras then a problem with this particular lens design. Some vignetting is present in all lenses. If it bothers you, it's easily corrected in Canon's DPP software if you shoot RAW and most current Canon DSLRs have a "Peripheral Illumination Correction" option, which when selected will automatically correct for vignetting in-camera when the images are saved as JPEGs.

For portrait work, where absolute razor sharpness isn't always an asset (people tend not to want to see their every blemish in high resolution detail!), I have no hesitation in shooting the 50/1.8 wide open.

The above is a 100% crop from an image shot with a 50/1.8 with the lens wide open at f1.8 using an EOS 5D camera (ISO 100). I think you'll probably agree that the resolution is pretty good with every eyelash clearly resolved - and in fact it perhaps shows too much skin texture! One warning though is that DOF is pretty shallow at f1.8. For a portrait taken from a distance of 6ft, the total DOF is only 5.5" (+/- 2.75") when using a full frame DSLR. That means if the tip of the nose is in focus, the ears might not be! It also means you have to be pretty careful exactly what you focus on. An example is shown below:

Again a 100% crop, shot with the EF 50/1.8 wide open at f1.8, this time using a crop sensor DSLR (EOS 20D). As you can see the left eye is sharper than the right due to the very shallow depth of field.

As an added bonus, the EF 50/1.8 II performs quite well when used with a Tamron 1.4x TC ( the Canon EF 1.4x will not fit of course), giving you a very usable 70/2.5 (or an equivalent 112/2.5 on an APS-C format DSLR like a Digital Rebel or EOS 40/50/7D).

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