Wednesday, March 9, 2011

Nikon 50mm f/1.4 AF-D Review

In the earlier days of digital, the 50mm AF-D f/1.4 was something of a luxury lens in the Nikon world. Just as an example, see how many of DPReview's in-house shot's futured this lens mounted on a Nikon body. Many found the cheaper f/1.8 lens a revelation for sharpness at a very thrifty price, but in the days before nano-coating and all the exotic lenses that came after, the f/1.4 commanded a very steep price increase for an extra 2/3EV of exposure.

Nikon 50mm f/1.4 lens, wide open.

We now have other choices in terms of the newer G-version and an offering from Sigma. So is there still a place for the once top of the heap lens? Read on.

Compared to the D-type, neither of the newer f/1.4's come cheap, and make the f/1.8 look even more thrifty than before. By the time you get to f/5.6, there is virtually no difference between the three Nikons, but the Sigma falls behind.

The G-type retails in the $500 range but has better across the frame sharpness at open apertures. However, the raison d'ĂȘtre of the G lens has always been a mystery to me. 50mm on a DX camera replicates the classic portrait focal length, but all of the Nikon 50mm's merely have so-so bokeh. For better out of focus rendition, you're much better of with one of the 85mm lenses instead. As a walk around lens, 50mm is too long for DX, which nullifies the use of wide open apertures. As a "body cap" on a full frame camera like a D700, a 50mm is perfect... but if you don't shoot wider than f2.8, then there wouldn't be that much difference to the cheaper AF-D version.

Likewise, the Sigma has its fans, but to me it's a bit too much of a one-trick pony.... good at portraits but only so-so all around. It's also amazingly huge for a 50mm lens.

Which brings us back to the AF-D f/1.4. For a lens that you will want as a keeper, it won't see a lot of action if you're shooting a DX camera like a D90 or D7000. 50mm becomes the equivalent of 75mm on film, and this is just a tad too long to comfortable walk around with. Yet, a lot of DX shooters do this, because up until now, there haven't been a lot of good alternatives for primes. To put this into perspective, when was the last time you saw a D700 walking around with an 85mm strapped on? Didn't think so.

The key to taking advantage of the 50mm is to use it in a place where you will be walking about to your subject, and not backing away from it. Hold up your hands with your elbows tucked into yoursides. Make a rectangle with both hands using your outstretched thumbs and index fingers held at 90 degrees.... this rectangle is about the size of the field of view that you would get with the 50mm on a crop frame camera. It's too restrictive for general photography, but it's good if you are thinking about how you would like to isolate your subject, like in a portrait or headshot. One metaphor that I like to use is to think of using the lens as a laser-tag toy. The trick is to mentally "tag" your subject with an imaginary beam of light between it and your camera before framing... otherwise, if you just point the camera before planning the shot, it will feel like you are shooting with your head stuck in a jar.

Night Market, Richmond, B.C., Canada

Of course,there's the whole low light thing, but there's more to the light gathering ability of this lens than just the aperture. Typically a prime lens will be about 1/3 of a stop more efficient than a "fast zoom" at the same aperture. That is to say, if you compare the 50mm at f/2.8 to the 24-70mm at the same aperture, the 50mm would require a shutter speed of 75% of that required by the the zoom. The difference between the two lenses is like the difference between being held in a stuffy room verses being outside in the fresh air; your camera just feels like it's breathing better. You just have to zoom with your feet.

And of course, it's not all roses. Fast f/1.4 lenses are notorious for being soft wide open. To be honest, f/1.4 is really only for emergencies and portraits, as the loss of detail and razor thin plane of focus are quite marked. To top it all off, opening up the lens really exposes its optical flaws, especially spherical aberration, which makes for a somewhat nervous and unsettled looking bokeh. Fortunately, the situation improves with a little stopping down, and to revisit the old f/1.8 or f/1.4 question, the more expensive lens is sharper from f/1,8 up to f/2.8. So if you are shooting open all of the time, yes, there is a benefit to paying for the more expensive lens. How much that benefit is worth is up to you.

Just to give you a practical example, I'd typically bring a Tamron 28-75 and my 50mm to weddings. I much prefer using the zoom for it's versatility, but find that in most indoor settings, even at f/2.8, the ISO has to climb past 800: I'm loath to let it go past 1000 on my D80. Switching to the 50mm, that drops to ISO 400 at f/2. Of course, the plane of focus is reduced by using a wider aperture, but in weddings, you are typically shooting at longer distances anyway, which mitigates this somewhat. You might be wondering about using a stabilized lens instead... If you take the 16-85mm, at 50mm, the widest that it can open up to is f/5 If we assume that the VR system conservatively gives you about two stops of hand-holding power, that brings you to the equivalent of f/2.6ish. If you assume three stops advantage with VR, that brings the two lenses about equal, except that te 50mm will be shooting with faster shutter speeds and far more capable of freeing moving subjects. The only thing I would say is to be wary of trying to shoot groups of people with the 50mm at wide apertures... the narrow plane of focus just isn't going to work.

Fraser River, Richmond, B.C., Canada
The 50mm AF-D was and still is a popular lens, and is easy to find on the used market.  Prices will vary, but at the time of writing, cheaper copies typically ask for between $260 and $300 depending on condition. My advice is that you should pay no more than $280 after negotiations for  a good copy. If you find one with the HR-2 screw on hood that's great, but I find that I hardly ever use it, as the lens is fairly resistant to flare.

Be aware that as an older screw-drive lens, it won't auto-focus on the D40 through to D5000 cameras. I bought mine used from a chap who used it for portraits on his D60. When I test drove it on my D80, he said that it was the first time that he saw the lens auto-focus in action!

1 comment:

  1. Great article, mate! Just bought one to photo theater plays with a D7000, can't wait! Greetings from Curitiba-Brazil.