Nikon has restyled its current 50mm f1.8 AFS-Nikkor prime to look like a period lens, but being a G-type lens it doesn’t have a manual aperture collar so it doesn’t quite look the part. Never mind, if you do have genuine vintage Nikkors, the good news is that the Df can accept the older non-Ai types via a clever arrangement whereby the Ai coupling lever can be folded up so it can’t be damaged.
While Nikon still uses the same F-mount bayonet fitting it introduced in 1959 with the original F, there have been quite a few changes over the decades to the way camera and lens communicate. The most significant came in 1977 when Nikon introduced the Ai (short for Automatic [Maximum Aperture] Indexing) mount which eliminated the need to manually ‘index’ the metering to the attached lens’s maximum aperture… a procedure Nikon SLR users had had to perform every time they put a lens on a camera body. The last of classically mechanical Nikkormats, the FT3, was the first Nikon 35mm SLR with the Ai mount, but essentially the change was made to herald in a new generation of cameras starting, appropriately, with the FM. With the introduction of autofocusing, Nikon used CPUs in its lens to communicate electronically with the camera body, although the Ai (and subsequent Ai-S spec) meter coupling ‘ridge’ is still on any current Nikkor lens which retains a manual aperture collar (i.e. any model with a ‘D’ suffix after the maximum aperture designation). However, as a general rule, non-Ai lenses can’t be fitted to later bodies – including all the digital models – unless the mount is converted which is exactly what’s ‘built into’ the Df. Incidentally, while this is a first on a Nikon D-SLR, it was also available on the FM, FE, F3 and F4 plus the last of the Nikkormats. Back then, of course, a lot more photographers still had camera bags full
of non-Ai lenses.
With the meter coupling lever folded up, a non-Ai lens can be fitted and then, in the Set Up Menu, the focal length and maximum aperture is entered into the ‘Non CPU Lens Data’ listing. Additionally, within the same sub-menu, the exposure metering coupling needs to be set to Non-Ai Lens. However, because there is no actual physical coupling, it’s necessary to manually transfer the aperture setting from the lens to the Df (dialled in via the rear input wheel), but this really isn’t such a big deal considering you’re using a lens that could be up to 55 years old and still getting TTL multi-zone metering with the choice of aperture-priority auto or manual exposure control plus an electronic rangefinder. However, if you do find this arrangement a bit clumsy, there’s always stop-down metering which is made very easy to execute thanks to the Df having live view with an exposure preview function (manual mode only though). Just for the record too, the Df retains a body-integrated autofocusing motor so it will work with any AF Nikkor lens since Nikon launched the F-501 back in late 1986. Given the lengths that lens makers – Nikon included – go to these days to optimise the performance of optics on digital sensors, will you really want to put ancient glass on the Df? Maybe not, but it’s enough that you can… and there are some pretty good classic Nikkors. With the older CPU-equipped lenses, there’s a custom setting which enables straight aperture adjustment in live view via the aperture collar.
Of course, under the skin, the Df is still a D-SLR and, as noted earlier, based around the same sensor and processor as the D4, supported by the feature set and control systems mostly from the D610. The thinking here is not so much that this 16.6 megapixels full-35mm CMOS is from Nikon’s D-SLR flagship – as opposed to the 36.8 MP device in the D800 – with the associated kudos, but that ‘less is more’ in terms of the performance benefits of bigger pixels… for the record, 7.3 microns in size.
Consequently, the Df has the same massive sensitivity range which spans ISO 100 to 12,800, but then has four stops of extension (marked as ‘H1’ to ‘H4’ on the selector dial) which corresponds to ISO 204,800. There’s also a one-stop ‘pull’ to ISO 50 (‘L1’ on the dial). The bigger pixels also give an expanded dynamic range and have an inherently higher signal-to-noise ratio which obviously works hand-in-hand with the increased sensitivity.
The effective resolution of 16.2 megapixels delivers a maximum image size of 4928x3280 pixels and the Df then offers a wide choice of capture formats and file sizes. For instance, RAW files (in the NEF format) can be in 12-bit or 14-bit RGB colour and uncompressed, lossless compressed or compressed. JPEGs can be recorded at one of three compression levels or it’s possible to select ‘optimal quality compression’. In the ‘FX’ format – Nikon’s designation for its 36.0x23.9 mm (i.e. 35mm-sized) sensor, there’s the option of two smaller image sizes, but there is also the option of using the smaller ‘DX’ image size of 24x16 mm.
The Df can be set to automatically switch between FX and DX if one of the smaller format Nikkor lenses is fitted. As with the D4, images can also be saved as RGB TIFF files. The Df has a single card slot for the SD format – presumably as it can’t record video, Nikon thinks this is sufficient – with support for the HC and XC UHS-I high-speed devices. The real curiosity here is that the card slot shares the same compartment as the battery pack so it’s in the camera’s baseplate rather than on the side like any other Nikon D-SLR.
The maximum continuous shooting speed is 5.5 fps with the option of a low speed mode that can be set to anything between 1.0 and 5.0 fps. If you’re mentally ticking off the comparisons with the D610 – which has dual memory card slots – its top speed is 6.0 fps which is slight boost over the D600’s 5.5 fps. It’s hard to see the Df being used as a sports camera, so in reality, 5.5 fps is going to be more than sufficient.
The Information Display (left) includes the ‘Shooting Menu’ and ‘Custom Settings’ banks along the lower edge (four of each can be pre-configured). These then allow direct access to functions that may be regularly used (right). The image review screens include the choice of a brightness histogram alone (left) or a full set of level graphs (right).