I've had the Sigma 50mm f/2 DG DN I Contemporary Lens for about a couple of months now, and I think I'm starting to get a good feel for how it fits into the way I work.

TLDR. It is terrific as a lens for stills. Small enough to be unobtrusive, and light enough to carry all day without noticing. Beautifully made with a helpful aperture ring. Very sharp and contrasty, even wide open. Generally undistracting bokeh, and appealing rendering. Autofocus for street photography is fast enough that you don't even notice it. Depending on your precise needs, it is arguably a better choice than some lenses at a multiple of the price. A few downsides (none that worry me). I recommend keeping lens corrections on when working on Raw files in Lightroom. "Only" 15 frames per second max on the A1. f/2, while giving reasonable subject separation from the background (depending on the relative distance from the camera to the subject and the subject to the background), may or may not be enough, in which case an f/1.4 or f/1.2 lens would be preferable. The closest focus is 45cm: if you want (semi-)macro performance this would not be for you. In the current state of the market, the price is fair, especially if a cashback (or similar discount can be found).

I mentioned in the previous blog that I have been looking for a smallish, lightish, high-quality 50mm lens to use with my Sony A1, primarily as a street/travel lens. After going far too deep into the rabbit hole, I realized I was looking for something that would fulfil a role equivalent to a Summicron lens on a Leica rangefinder.

Many lens manufacturers have separate product lines (or sub-brands if you prefer) for different types of lenses with differing price points, maximum aperture, optical performance and build quality. The granddaddy of all this is Leica. Their premium lenses are Summilux (f/1.4) and Noctilux (around f/0.95). The -lux means "light", i.e. they have a very good light grasp, although “-lux” has the implication of luxury as well. The middle of the range, so to speak, are the Summicrons with apertures at f/2, priced lower than the -lux lenses (although still expensive to mere mortals) which are optimized as everyday lenses, fast enough for most purposes, and with very attractive rendering. Leica also have ranges of slower lenses (e.g. Elmarit and Summarit) that are correspondingly slightly less expensive still.

Likewise, Sony has its premium range G-Master (GM), its middle range (G), and lower-price FE lenses.

Third-party manufacturers now follow this path. Sigma has its Art sub-brand of lenses, which are high quality optically and challenge what the big brands can produce (e.g. the Sigma 50mm f/1.4 DG DN I Art lens). More recently, Sigma has introduced another sub-brand of somewhat lower priced lenses, that have about 1 stop slower aperture but are very well constructed, lighter weight, and more compact and aim to produce very high-quality images. This is the Contemporary I range. (By contrast to Leica's slower Elmarit/Summarit ranges, Sigma's third range is their Sports line of telephotos aimed at sports/action photographers.)

The Leica Summicrons are lenses I've shot with over many years, and I have two. I'm very fond of the idea of small, lightweight, high-performing lenses, that, while they give up a stop or so of aperture relative to the premium lenses, make ideal everyday lenses. Given the amazing sensitivity of modern sensors (plus AI-enabled noise reduction), f/2 should be fast enough for most of my purposes, not least street photography.

I was intrigued by the initial reviews of the Sigma 50mm f/2 DG DN I Contemporary Lens (I’m going to call it the Sig50-2 for short): when a cashback offer came up over the summer I jumped at it.

There’s never a free lunch, so there are some downsides to choosing a third-party lens to use on the Sony A1. The main one is that you don’t get 30 frames per second. This is well documented, and I have verified it for myself: 15fps max. For fast-moving birds or other forms of fast action, this would be a dealbreaker. The Sony 200-600mm lens gives me 30fps for those moments I need it. But for use with a 50mm lens? Not needed so much for me. On the other hand, the Sony 50mm f/2.5 does allow 30fps, if that is essential for you. There are times when I’ve used 10fps on the Lumix GX9, and this can be very useful to catch a precise moment on the street. 15fps is more than enough for general purposes with a 50mm lens.

The Sig50-2 does not focus especially close at 45cm. But that is close enough to get a frame-filling picture of your lunch if you are so inclined :) If that is not close enough for you, then consider the Sony 50mm f/2.8 macro.

I’m going to post a bunch of recent pictures with it on the A1, and I’ll put most of the commentary with the images as I go along. The images are from London, from Faversham boat yard and from a local field.

Long story short: I'm hopeful that I’ve found my Summicron-alike. I very much like what I've seen so far, but there are things I've not yet had a chance to try. I've not done any portraits, for instance, or anything at night: quite a lot more to find out.

I'll keep this as an ongoing commentary over the next few months to try to update both samples and some conclusions.

Aperture series. The series of images above shows the look of different apertures (use the arrows to move between different apertures). This is a bit of a torture test: the front tree is one of a row, so receding away from the point of focus are small branches and lots of leaves. Given how busy this scene is, my view of the bokeh is that it is very well-behaved and quite soft at f/2. The tree where the focus point is is sharp and stands out well. The aperture ring on the lens is a real help for this kind of series. I’m finding that, after using a front command dial for 18 years to change the aperture, this is a welcome return to much older (and easier) ergonomics.