November 23, 2014

Sony SEL50F18 Review: A Brilliant 50 mm F/1.8 Prime Lens for NEX Cameras

The new Sony 50 mm prime is almost identical to the kit zoom lens

Shortly before I received the brand new Sony NEX-7 camera (on my birthday, natch!), B&H Photo dropped another eagerly-anticipated item at my door: The new Sony SEL50F18 prime lens for E-mount cameras like the NEX-5 and -7. It’s brilliant technically, easily the best affordable E-mount lens. But it wouldn’t be my first purchase for a NEX owner.

Different Lenses for Different Purposes

People use cameras to capture images and video. Usually they are documenting life and capturing memories; sometimes they are producing art. Regardless, a camera and lens has no purpose in a vacuum, so they must be useful, not just technically excellent. “Pixel peepers” seem to forget this, as do gearhead techies (like me).

Humans perceive the world through the eye with broad perspective, and most see sharp contrast and rich color in the center. In 35 mm camera terms, this corresponds to roughly a 35 to 50 mm frame and an aperture of 1.4 to 2.0. Walking around with this hypothetical camera, a person could capture pretty much what their eyes are seeing.

But the APS-C sensor used in the NEX cameras crops images by a factor of 1.5, so an ideal walk-around NEX lens would be 23 to 33 mm. As for aperture, most NEX lenses are far “slower” than F/2.0, optically. The 16 mm “pancake” is just F/2.8, while the 18-55 mm kit zoom ranges from F/3.5 to F/5.6. Although serviceable, these lenses are not all that great technically.

This is one reason that the SLR Magic 35 mm lens is so nice on the NEX camera: It’s a 52.5 mm equivalent, just a little on the close side, and reasonably fast at F/1.7. Walking around with the SLR Magic on the NEX just feels good, and the compact size is a great match for the slim, mirrorless body. But it’s not perfect: There’s no image stabilization and manual aperture and focus impacts “right now” candid capability.

Introducing the Sony SEL50F18

What the NEX system needed was a fast, simple, affordable prime lens, and that’s just what Sony delivers with the new SEL50F18. As the name implies, it’s a fixed 50 mm lens with a speedy maximum aperture of F/1.8. It’s designed for the NEX system, so it includes a silent auto-focus motor with direct manual focus (DMF), integrated aperture control, and Optical Steady Shot (OSS) image stabilization. In short, it’s the “do-everything” fast prime lens we’ve all been waiting for.

The SEL50F18 is wonderfully solid, built of magnesium alloy, and the wide rubber-ribbed focus ring is a joy to use. Manual focus is “by wire” – turning the ring tells the camera to run the focus motor rather than directly moving the lens elements. But the system is reasonably direct and doesn’t interfere. Auto-focus is fairly quick, certainly better than the long SEL55210 tele-zoom but nowhere near the speed of the phase-detection system on an SLR camera.

A 50 mm lens results in a longish 75 mm field of view on NEX cameras. This is not ideal, as we will discuss below, and camera shake can be a real issue. Thankfully, the image stabilization built into the SEL50F18 works wonderfully. This is said to be the (optically) fastest stabilized camera system lens ever built; it’s technically very challenging to stabilize this much glass. And it works great!

The SEL50F18 retails for US $299. Although this is somewhat expensive for a mass-market prime lens, it’s a bargain for one of this quality and performance. It seems costly compared to the 16 mm prime and 30 mm macro ($150 and $250, respectively), but those lenses are completely over-matched by the NEX-7’s 24 megapixel sensor. They’re nowhere near as sharp and almost uselessly slow (optically speaking).

Real-World Photography with the SEL50F18

Attach the SEL50F18 to a NEX camera and prepare to be impressed. Open the aperture to F/1.8 (which is so much easier with the NEX-7 Tri-Navi wheels) and you’ll be shocked at the short depth of field and gorgeous bokeh. It’s crazy-sharp on center, too, and the whole image is brilliant when stopped down a bit.

Snapshots become "images" with a fast lens like this

Walk around a bit with this lens on a NEX-7 and you’ll immediately feel like a camera super hero: It’s sharp, quick, and so easy to grab a shot even in low light that you’ll forget about the built-in flash. It’s so fast and bright you’ll (finally!) be able to experiment with narrower apertures, even when shooting moving subjects indoors. The NEX-7 and SEL50F18 is a dynamic duo, to be sure!

I previously purchased a classic Minolta Rokkor-X 50 mm prime for my NEX-5. It’s a wonderful lens, priced under $100 and sporting a huge glass eye that opens up to F/1.4! But it was difficult to use this lens in the real world, with serious chromatic aberrations wide open and no image stabilization or auto-focus for quick shots. The SEL50F18 is as good as the Rokkor was supposed to be. It’s so good, there’s no point in owning both.

Low light? No problem! And bokeh to boot!

But the SEL50F18, like the Rokkor has a dose of kryptonite built in: At 50 mm, it’s just too “long” for candid use indoors. A 75 mm (equivalent) field of view is really quite narrow, requiring more than a few steps back from your subject. I found myself constantly backing up while using this lens, sometimes even bumbling into tables or running out of room with my back up against a wall! It’s fine for street photography and posed portraits, but very, very difficult for a night out with friends.

Before considering buying the SEL50F18, I suggest setting the 18-55 mm kit zoom lens (which nearly every NEX owner has) to 50 mm and leaving it there for an average shooting session. Take some candid shots of friends and family, a few landscapes, and a portrait or two. Get the feel of shooting at 50 mm, then decide if you can live with a prime lens fixed at that length.

Note that there is a near-perfect E-mount prime lens: The Zeiss Sonnar T* E 24mm F1.8 ZA (SEL24F18Z) is wonderfully useful at 36 mm (equivalent). It’s fast and sharp, but excessively expensive. As is the case when comparing the SEL55210 and SEL18200 zoom lenses, cost tips the balance even for NEX-7 buyers!

Stephen’s Stance

The SEL50F18 is a brilliant lens, and well worth the $299 purchase price. It’s currently in short supply, and selling for $50 for list on Amazon. NEX-7 owners especially should definitely consider adding this to their arsenal, since it’s the only affordable option to match the capabilities of that camera. But it’s not the first lens any NEX owner should buy, since 50 mm just isn’t useful enough for everyday shooting.

Although it’s outclassed by the NEX-7, the SEL1855 remains my first choice thanks to its wonderfully useful zoom range. After that, the long zooming yet affordable SEL55210 or simple SLR Magic 35 F/1.7 would be my next purchase, depending on your needs. The SEL50F18 is definitely a great buy if you can tolerate shooting at 75 mm (equivalent), and is far more useful than the 16 mm or 30 mm primes.

If you’re wealthy enough, a combination of the SEL18200 and Zeiss SEL24F18Z beats all, but this pair adds up to almost $2,000!

  • http://twitter.com/salamihawk Locust776

    Question: Isn’t crop factor used to figure out the effective image size difference for lenses built for 35mm film cameras and used on DSLRS?

    Therefore, if you have a 50mm lens built for the Sony NEX series of cameras (which use APS-C sized sensors, and NOT 35mm film), wouldn’t there be NO crop factor, since the lens is designed to put an image on an APS-C sized sensor and not a piece of 35mm film?

    In the case of the SEL50F18, 50mm = 50mm. Only if I were to use something like a Canon 50mm EF lens designed for a 35mm camera with an adaptor ring would I need to concern myself with the image sensor size differences, correct?

  • Torbju00f8rn

    50mm on the NEX equals 75mm on 35mm film