When it comes to focal lengths, 35mm serves two purposes: as a "normal" perspective for APS-C cameras and as a mild wild-angle for full frame shooting. Theoretically, one good full-frame 35mm lens is all that a photographer needs; it could be mounted on a crop-frame camera as a normal and saved for the presumptive day when the jump to full frame is made. That's certainly what many people did (or tried to do) with the Nikkor AF 35mm f/2 D, but that strategy won't work quite so well in the age of the D800. To that end, Nikon has now made a FX and DX version of the same lens, and it would be tempting to think of the FX version of the 35mm f/1.8 as the "keeper lens", but in reality, these are two different lenses for two different purposes.
The reason why the AF 35mm f/2 D never quite reached acclaim as a "bridge" lens between DX and FX was because of the march of technology. It was a decent and cost-effective lens to bridge the gap between the D300 and the D700, but times have changed. It's flaws are more apparent on the D800 and more pertinently, photographers have been asking more and more from their lenses as general knowledge of optics as increased across the photographic community.
|Left: Nikon 35mm f/1.8 DX Right: 35mm f/1.8 FX|
Hence, the FX version of the 35mm f/1.8. This is an optic that is more suitable for modern full frame cameras, but in order to be as such, it's a relatively expensive part to be used on a DX camera. The 35mm DX is the very definition of cheap and cheerful, whereas the FX lens is built to a budget in what is an ostensibly expensive market space. It's a bargain compared to the f/1.4 lens, but it still needs to be built to a quality that's suitable for use on the FX Nikons; that's where the price difference comes in.
|Left: Nikon 35mm f/1.8 DX Right: 35mm f/1.8 FX|
It's also impossible talking about 35mm's without mentioning Sigma's f/1.4 ART lens. Many "budget" FX shoppers will be cross-comparing these two lenses. The safe choice is the Nikon; something more on the beaten path and cheaper by a few hundred dollars. The Sigma is in a different category. It's heavier, denser and better built, and has optical quality to rival the much more expensive Nikon 35mm f/1.4.It's also quite attractively designed.
|Left: Nikon 35mm f/1.8 FX Right:Sigma 35mm f/1.4 ART|
In terms of construction, the Nikon 35mm f/1.8 FX is similar to the 28mm f/1.8 G... not heavy at all, but a bit on the long side for what you would expect a lens of this focal length to be. The barrel is dominated by the focus ring that isn't as nice to use as the Sigma. The focus throw is quick, but the focus ring is not damped, which gives a "budget" feeling to the lens when it is manually focused. Quite frankly, for $600, you would expect better, but it's no worse than the 28mm f.1.8. Unlike some of the recent Nikon primes, the body of the lens doesn't just out past the front element as if it were a built in hood. Thankfully, in the age of cost-cutting, a bayonet-style petal hood is still included with the lens.
|Nikon 35mm f/1.8 FX on Nikon D7100|
You can use this focal length as a "normal" lens on the DX cameras. In terms of size and weight, it balances evenly on a D7100, but it's not particularly small for a prime lens. The impracticality of using this lens as such is that the DX version does nearly the same for less than half the cost, and is much smaller.
|Nikon 35mm f/1.8 FX on Nikon D610|
On the D610, the 35mm f/1.8 FX feels right at home. In fact, all of the f/1.8 primes or f/4 zooms more or less feel at home on the D610; they work with the weight of the camera and don't tip it towards the front heavy side in the way that the f/2.8 lenses do. When mounted on the D800, the lens feels as though its missing a bit of weight.
Image Quality: DX (Nikon D7100)
This is an example of what the bokeh and overall rendition looks like when focused on a subject at short distance (~4 feet, ISO 1600). As this is an out of cameras JPEG, the camera's internal image processing does electronically correct the image for distortion, vignetting and chromatic aberration, though not completely. The bokeh with the lens wide open isn't quite as harsh as what you would get from the DX version of the 35mm, but it's not quite buttery smooth. The blur isn't overly harsh, but it is busy. The quality of the background blur improves at f/2.8 despite the depth of field increasing. By f/4, the general sharpness and global contrast across the frame are close to the peak of what the lens can do; from f/4 to f/8 it's all fairly good with the sharpness of the lens.
Ignoring the differences in subject sharpness, which are confounded by variables such as different lighting and camera sharpening settings, the quality of the bokeh between the Sigma wide open compared to the Nikon is a bit smoother. Part of this reason is because of the extra amount of maximum aperture, but the differences also come down to optical design. A case could be made that these aren't comparable lenses because they aren't the same focal length nor are they the same maximum aperture, but when mounted on APS-C cameras, shooters will generally use these two lenses in the same manner. To that end, the full frame lens is not always the best choice, and there is an advantage to using an optic that was designed around the crop-frame format.
Image Quality: FX (Nikon D800)
This lens makes for a more interesting tool as a FX lens. Same conditions, but mounted on a D800. Using a wide-angle lens with the aperture wide open is a tricky affair, but it can give a three-dimensional feeling to a scene, mostly because background blurring at this focal length is somewhat unexpected. Unless of course, you are a Leica shooter. The results are crisp and generally free of an objectionable defects.
Just as in the APS-C example above, it seems fitting to compare the Nikon against the Sigma 35mm f/1.4 DG HSM "ART". Once again, shot on a different day and with different positioning and lighting, so only general impressions are applicable. (Mounted on a Canon EOS 5D Mark III)
As with it's smaller 30mm sibling, the Sigma 35mm produces a more (subjectively) pleasing background rendition than the Nikon when wide open, but maintains excellent clarity in the plane of focus.
With regards to resolution, distortion, chromatic aberration etc... a full blown objective test of the optical qualities of the Nikon 35mm FX lens is beyond the scope of this blog, but here's an example of what the center sharpness looks like at f/5.6 when shot with a D800. Ostensibly, the Nikon 35mm f/1.8 FX is capable of a fairly close minimum focus distances for a wide-angle lens. Click on the close up to see a 100% crop:
Even though you could use it for a DX camera, there are more cost effective choices. This lens is neither small nor is it inexpensive, which detracts from the benefit of the smaller system. That said, this is properly a "budget" FX lens, but at $600 USD, it's not cheap. Then again, none of the FX Nikon primes are truly inexpensive: they're merely less expensive than the f/1.4 lenses. As a replacement of the older screw-drive 35mm f/2 AF D lens, the cost increase is fully justified by increase in image quality. As an approximation, the improvement of the 35mm f/1.8 G version over the AF-D version is like the difference between the G version of the 50mm f/1.4 and the older D version. That is to say, the results aren't perfection, but there is a noticeable improvement... as well as a tangible increase in cost.
With thanks to Broadway Camera