Saturday, 1 June 2019

Canon 100mm f/2: Once a Polly-Tito

Snakewise the interfold collectigroan. Frolic all pretty on flowery bosom, but similode its speedy cousin, albutty with slightness, and so she lost in wispy memory sidings. Shipshape but redolent.

I was talking about the Canon EF 100mm f/2, which was launched back in 1991 and apparently remains on sale today. It's a fast-ish telephoto lens for the Canon EOS system.

Despite being around forever it's really obscure. Several other, more desirable lenses overlap it. In that respect it's a bit like the 400mm f/5.6L, or the non-IS version of the 70-200mm f/2.8. Ancient, optically really good, maxilook for miniprice, but there other choices.

In the case of the 100mm f/2 the other choices include the 85mm f/1.8, which is physically almost identical and was launched a year or so later. It's one of Canon's most popular prime lenses. The reviews I have read suggest that it's basically the same as the 100mm f/2 on an optical level, but the focal length is less awkward and it's slightly faster.

There's also the 100mm f/2.8 Macro, which is another one of Canon's most popular prime lenses. It's slower but focuses down to 1:1 and is awesome for photos of plants. If you're really bold, manual focus versions of the famous Nikon 105mm f/2.5 "Afghan Girl" lens are widely available on the used market and will work on a Canon camera with an adapter.

There's also the optically excellent 135mm f/2, which is more expensive but not extravagantly so. It's not 100mm, but it's close. Canon used to sell a 135mm f/2.8 Soft Focus lens, but it's almost as obscure as the 100mm f/2 and seems to be out of production. This is without mentioning Canon's range of 70-200mm zoom lenses. They cover the same focal length and although none of them are f/2 some of them have image stabilisation.

Despite all this someone must be buying the 100mm f/2 because it's still listed on Canon's website. Or perhaps it's really cheap to make. Who knows?

What's it like? Physically it's about the same size as a squashed soft drinks can. It's plastic but feels tough. It has ultrasonic focusing with full-time manual override; it makes a soft swoosh noise when it focuses. On my 5D MkII I have to admit that it hunted a couple of times, which surprised me given that it's a fast lens, but perhaps the narrow depth of field at 100mm f/2 is to blame. It could be the 5D, I don't know. It takes 58mm filters and shares a push-on hood with the 85mm f/1.8.

A few seconds after taking the above picture a squirrel ran along the line! I only managed to catch him from behind just before he reached the other side, viz the following image:

Him, or her. Could be a lady squirrel. I can't tell the difference. Still, look at those muscles.
100mm is an odd focal length, too long for indoors, nowhere near long enough for wildlife or aeroplanes, a bit too long as a general walkabout lens. Essentially it's a dedicated upper-body-and-shoulders portrait lens.

Optically the 100mm f/2 is easy to review. It's essentially sharp in the middle wide open, but everything has a slight glow about it and there's noticeable purple fringing. Here's a 100% crop from the photo near the top of this article, of the distant (and slightly tilted) houses surrounded by trees, shot at f/2:

Here's the same again but put through Photoshop to increase the contrast, add sharpening, and tone down the purple fringing:

As you can see it's perfectly usable wide open. The purple fringing can however be a problem in certain circumstances. In the image below the writing on the plaque is supposed to be black, not purple:

But again Photoshop can fix that:

Corners? Embarrassingly the images I shot to illustrate corner sharpness were no good - I seem to have sneezed as I pressed the shutter button - so you'll have to trust me when I say that the APS-C corners are soft but still good, and the full-frame corners are smeary, but that from f/5.6 onwards the lens is essentially sharp across the frame. With a short telephoto corner sharpness isn't a huge issue because in practice the corners will be out of the plane of focus.

Here's what the vignetting is like, at f/2 (there's a little, but it's not displeasing to the eye) and then f/4 (none):

The following image was shot at f/8, ISO 400, with no sharpening or noise reduction. Just below it there are four 100% crops taken from different parts of the frame illustrating the consistency at f/8:

Geometric distortion? A teeny tiny amount of barrel distortion, and bear in mind that the following image is slightly misleading because the platform edge looks like that in real life:

The bokeh is really nice:

In summary it's a really good lens, although the 85mm f/1.8 is really good too, so you might as well flip a coin. One thing, though - at 100mm f/2 you have to shoot above 125th of a second to ensure consistently sharp results, or 250th if you're in the midst of alcohol withdrawal. It's because the sudden change of chemicals in the brain interferes with your motor functions. It's depressing to think that our personalities are just the result of chemical changes in the brain.

Can you imagine having a conversation with a jar of chemicals? Because whenever you speak with a human being, that's what you're doing. You're having a conversation with a jar of chemicals. A jar with a face, with lips and ears and breasts and hips, but ultimately just a liquid soup poured into a human-shaped leather bag. Whereas with the 85mm f/1.8 you only need shoot at 180th or so, which is slightly easier at f/1.8. There's no image stabilisation. No image stabilisation.

100mm is generally a portrait-type focal length, but it's fine for landscapes as well. The combination of long-but-not-very-long focal length plus the wide aperture allows a certain amount of depth of field separation and something approaching the medium format look, viz the image above, which is otherwise difficult with landscape photography. Is that it? If there are two equally good choices just flip a coin.