Choosing a nifty fifty

As a Sony digital imaging ambassador, I’ve had the privilege of using both the Sony 55mm f/1.8 and 50mm f/1.4 lenses side by side for the last few weeks. This feature shares my quandary: which is best for me?

One of the more delightful First World problems that photographers have to tackle, especially Sony E-mount photographers, is which standard focal length lens they should have. The choice of auto-focus lenses in native mounts is itself pretty confusing: currently seven models. If you really want to make life difficult, you could bewilder yourself further by admitting all 50mm lenses that can be fitted by adapter. Then the list runs (probably) to over 40 lenses from the extravagant 50mm f/0.95 models to very cheap 50mm f/2.8 models. A search in eBay will turn up over 2000 items for sale, almost all of them will fit Sony E-mount given the right adaptor.

For Sony faithful, the choice could be said to boil down to choosing between the Sony 55mm f/1.8 and the Sony 50mm f/1.4. Well, at least that’s the choice that I faced once I whittled all other contenders down.

I wanted stellar optical performance to match the capabilities of the A7R2 sensor. That removed the Sony 50mm f/1.8 and 50mm f/1.8 OSS lenses as these aren’t entirely up to the job, and were never designed to be. I removed the Zeiss Loxia as I wanted auto-focus. The Zeiss Touit looks like a 50mm lens but it’s for APS-C sized sensor, so really it’s a 75mm optic. That leaves the Sony FE 55mm f/1.8 ZA Sonnar and the Sony FE 50mm f/1.4 ZA Planar. And choosing between them proved more difficult than choosing between chalk and cheese.

What’s going for the 55mm f/1.8

This is a delightful package: fairly compact, and even cute. Although it’s clad in metal, it feels sturdy yet quite light. Its minimal, Bauhaus-lean, design makes it appear even more lean.  In fact, it’s so compact it takes a wee 49mm filter. This takes me back to the time 49mm was the standard size for a very wide range of lenses, with 52mm being for ‘big’ lenses. Nowadays, all my filters are 72mm in size, or even larger.

Its optical performance is almost the stuff of legends. It’s extremely sharp from the get-go at full aperture, improves steadily in the centre with the edges catching up quickly with smaller apertures. It focuses quickly and silently on A7/A9 series cameras and is generally very well behaved.

Although it’s not a cheap lens at around US$900, there’s no question that it can satisfy highly choosy users and is suitable for professional tasks. With a relatively compact lens that weighs less than 300g, the package is perfect for street and travel photography. I want!!

Oh, wait.

What’s going for the 50mm f/1.4

The antithesis of the 55mm, the 50mm f/1.4 lens is big, fat, heavy and far from cute. It’s imposing. It’s clad in what feels like armour-plate and is extremely sturdy weighing nearly 800 g and sticks out over 100mm. In fact, I believe it’s the largest standard lens for 35mm photography there is apart from the monster Zeiss Otus and larger than even 50mm f/0.95 lenses. Although it’s perfectly possible for a 50mm f/1.4 lens to front with a 49mm diameter filter thread, this lens demands a whopping 72mm filter. It also costs hundreds of dollars more than the cute yet very capable 55mm optic. In short, ‘nifty fifty’ it ain’t. More like ‘fatty fifty’.

Large and little: optically but 5mm in focal length and a third of a stop difference. But quality has always been subject to law of rapidly diminishing returns.

Nah; forget it.

Not so fast! You know, there are some optics that do a lot of the work for you. I don’t know how, but they are the lenses that become the classics because they tickle the light somehow to add a touch of lip gloss, a bit of sparkle to an image. Somehow you don’t have to work so hard to get something that works.

The Leica 50mm Summicron of the late 70’s is one those, and so is the Zeiss 80mm Planar for medium format. Others I might mention are the Nikkor 105mm f/2.5, the Canon 85mm f.1.2. These optics just leave some kind of signature on the image, whisk up some star shine of magic. For me, the Zeiss 135mm f/1.8 also adds a dose  of magic into its images (if only  homeopathic in strength.)

And so it is with this 50mm lens. Within moments of first using it, I knew it was doing something quite special to the image, particularly at full aperture. Photographers talk a lot about bokeh and the quality of blur. Actually, that’s not too interesting to me. What’s important is whether what’s meant to be sharp is really sharp. If so, we then easily take everything else as pretty blurred.

We can argue about how clean the blur is, whether it’s a bit onion-ringed or not. Whatever. I want sharp to be sharp. That’s really what you’re paying for. And this baby is sharp at full aperture. It is more than usefully or in practical terms sharp, it is truly sharp. Visually edges are high acutance: there’s a steep shoulder on each in-focus border between different areas. None of that chintz-curtain glow of older lenses. Also its ability to resolve even low-contrast details is very impressive.

Stopped down, the lens produces simply stellar images with a beautifully rich colour palette as chromatic aberrations of various sorts appear to be held in very tightly. By the standards of a few years ago, this may even count as an apochromat – three colours are brought to common focus. (But don’t tell the engineers at Zeiss I said that; they’d rap my knuckles for even thinking it). The upshot is that even rather prosaic images can look stunning: you just wallow in the life-like presentation of details and transitions.

So the up-shot is?

To the extent that some photographers are so demanding of quality that they will haul large-format cameras up a mountain, it’s worth putting up with a monster lens if it gives you what you want.

I muse that in a perfect world, I might wish to own both the 55mm and the 50mm lenses. I’d take the 55mm when I need to go light weight. But you can guess what will happen. If I have the 55mm I’ll wish I had the 50mm for that portrait I come across, or for that still-life that needs razor-thin depth of field.

Besides, there are some extra nice things about the 50mm. I like the petal lens hood. I like having the aperture ring on the lens. And best of all, I love having an aperture ring without clicks, so it’s easy to whip it from full aperture to a smaller one with almost no effort. Clicks were invented because photographers needed accurately repeatable settings when manually transferring hand-held exposure readings to the camera. These days, it hardly matters which aperture exactly you set – the camera systems are constantly fine-tuning anyway.

Shot at f/8, hand held. Look at the spikey flower to the right of the white in the centre. We’re going to zoom in 400% in the next shot.

At 400%, we see details not only for the main spike, then the secondary hairs and even the tertiary hairs! And notice that this is happening at relatively low contrast and bright – usually where lens resolution is weakest.

The matter of stopping down brings me to something I don’t care for: Sony’s habit of auto focusing with the aperture stopped down to the working setting. This causes a slight flicker in the image if you have set a small aperture. And when you focus on an object, lift your finger off and press again, the camera re-calculates the focus, even though it’s already in focus.  There are good technical reasons I can think of for this behaviour, but in practice it belongs to the ‘Meh’ group of responses to any camera handling.

300+ words on the design

(Skip to the conclusion if technicalities make your eyes water, or simply bore you.) The cross section of this lens shows that, despite carrying the illustrious ‘Planar’ moniker, it’s a long way from the classic Planar design (the right-hand one in sectional illustration below). The classic design is kind-of symmetrical, which gave it excellent corrections all round (symmetrical designs do that). This Planar doesn’t look at all symmetrical in layout, even if you squint. My guess is that the engineers wanted to move the entrance pupil as far from the focal plane as possible.

The easiest way to tell where the entrance pupil lies is to find the lens’ point of perspective. This is the axis of rotation about which there is no parallax: it’s what panorama photographers work with all the time. With a little imprecise fiddling about on a tripod, I think the entrance pupil lies less than 5mm behind the front vertex (surface of the first element). But don’t quote these figures! I was checking by eye and not by instrument.

If I’m right, we have a quaintly named quasi-image-space telecentric optic in our hands. This mouthful means that the entrance pupil is a long way forward compared to normal. This makes light rays reach the sensor surface more nearly at right-angles than normal. We’re rewarded with more even illumination of the sensor (the path length of light at the periphery is not too much longer than through the centre). The design also reduces colour errors caused by rays hitting the sensor at an oblique angle.  But all this calls for a very complicated design that comes with a high price in several departments.

Making this optic is extremely demanding. Lots of elements with fancy glass and aspherical profiles not only push up production costs. There are many air-to-glass surfaces – I count seventeen – that could cause loss of contrast from internal reflections. This means the engineers had to work very, very hard to keep image contrast high. Quite amazing, really, how well they’ve done.

Conclusion: a deluxe saloon

This optic is obviously not the Volkswagen of lenses. It’s too bulky, heavy and expensive for that. Yes; it’s more like some fancy class of Mercedes. High barrier to entry, but fast, smooth and it gives you immaculate, top-notch performance. If you want the best, it’s not only the best, it’s hard to see how it could be much better.

The best way is to end with a snap shot at f/1.4. Enjoy!

Handheld at f/1.4, auto-focus, and straight out of camera. No messing.

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3 Responses to “Choosing a nifty fifty”

  1. Margaret Foo 14/07/2017 at 4:37 PM #

    Both looks great 🙂

    • Tom Ang 15/07/2017 at 3:23 PM #

      Yup. In their way they are. That’s why it’s difficult to choose between them. Hope you enjoyed the article!

  2. Anon 31/07/2017 at 10:18 PM #

    How about comparing the two vs the Samyang AF 50/1.4 ?