GEAR REVIEW - NIKKOR 50mm f/1.8G
The Nikon 50mm f/1.8G AF-s is the latest incantation of what many Nikonians refer to as "The Nifty Fifty". Launched in 2011, it sports an all new optical design, instant manual focus override, rounded aperture blades for improved bokeh and of course an inbuilt silent-wave motor. Nikon also plumped for a lens hood too. Something the older f/1.8 AF-D doesn't have.
It's a long overdue addition and was eagerly awaited by many entry-level camera using enthusiasts. Considering the D40 was launched in 2006, Nikon dragged their heels for 5 years before releasing the f/1.8G. As virtually all of the entry-level bodies like the D40 lack a focus motor, they are unable to auto-focus with AF-D lenses. Anyone wishing to use an AF 50mm lens on anything from a D40 to a D5300 was forced to buy either the Nikon or Sigma 50mm f/1.4 lens, which retail for £270 and £330 respectively. Given that that older and still excellent 50mm f/1.8D retails for £100, the additional outlay for a f/1.4 peeved many people, who instead opted for the 35mm f/1.8G instead. Thankfully Nikon filled the gap in their line-up with the f/1.8G retailing at a respectable £150.
So what do you get for your money? Well, as already mentioned the lens has undergone an optical overhaul which now includes an aspherical element, resulting in a lens that has considerably better center sharpness wide open, than its predecessor. It does come at a trade-off with edge sharpness though, which even stopped down never really competes with the older AF-D version, surprisingly. The diagram below from DXOMark.com shows the optical benefits and shortcomings.
At 30g heavier, it feels a bit meatier in the hand than it's older brother. The body is noticeably wider and the filter thread is 58mm compared to the 52mm of the AF-D. The inclusion of the hood helps to deal with unwanted lens flare although to be fair the inset front element is already shielded somewhat. I always keep a hood mounted, just to protect the filter thread.
One nice new feature is the weather sealing on the rear of the lens, which helps to keep rain, dust and other undesirables out of your camera body. This is something borrowed from their newer professional lenses and is a welcomed sight. As with all AF-S lenses, it is gelded (hence the G denomination). This means you have no aperture dial, as on the AF-D. It's a shame that Nikon decided to go this route because you cannot use the lens on focus bellows like the PB-6, nor can you reverse mount the lens for macro work and stop it down.
Focus speed is fast and accurate. Possibly a fraction faster than the AF-D on the D800, which has a powerful AF-motor in body, but nothing that you would be immediately apparent. The focus barrel is well dampened, precise and feels better geared than the AF-D. If you do like manual focusing then you would have to disengage the focus motor on the camera to use the older version. Not something that ever affected me personally but I dare say an annoyance to some people. One thing I do like is the silent wave motor. If you're trying to get a candid shot, the new 50mm is very stealthy, hardly making a sound. The AF-D is more like a rusty chainsaw in comparison and will alert your subject to your presence. With kids, this can be a problem at first, until they switch off to the noise.
Out of camera @f/1.8, the AF-D has some softening to edge detail.
The AF-S has better resolution wide open
The rounded aperture blades of the AF-S definitely give a softer bokeh, with circular balls of light, compared to the polygonal shapes created by older versions. Bokeh is something that has become more relevant to photographers in recent times and in some instances is a reason why people will purchase a particular lens. The Lomography Petzval 85mm f2.2 for example.
Is it worth upgrading from an AF-D to the AF-S? Mmm. That's a tough call to be frank. If you shoot wide open all the time, then yes the step up in optical quality is quite noticeable in the center of the frame (if you position your subject on one of the 1/3rds of the frame, then no) - just bear in mind that by f/2.8 things are pretty close resolving wise at a very shallow aperture. If you tend to be stopped down to f/4 or beyond with the lens and edge-to-edge sharpness is more important to you, then the older AF-D version wins hands down.
In summation, the new 50mm f/1.8G AF-S is a great lens and is still good bang-for-buck at £150. For DX bodies with no AF motor it's certainly a lot more pocket friendly than the f/1.4G. The focal length is good for portraits, although I'm not a fan on an FX sensor, purely due to the way it renders the face for portraiture - at least for adults. For environmental portraiture, no issues. Its focus speed is ideal for kids on the move and the ability to isolate eyes is great - provided your subject is stationary.