These two prime lenses have similar focal-lengths, similar maximum apertures, and similar price-points. It's no wonder that I see them discussed and compared with each other on forums fairly often. Given $700-900 to spend on a fast, relatively-wide, prime lens, which do you get? First, let's take a look at a high-level specifications summary to get a feel for what they offer (clear winners highlighted in green):
To summarize: the Nikon is a bit wider, smaller, and lighter than the Sigma. It's also a bit slower (2/3rds of a stop), but it's a good deal less expensive as well.
Construction and Handling
The Sigma really outshines the Nikon in both construction and handling. When I first got my Nikon 28/1.8G, I was disappointed with the light, plastic feel of the lens. The focus ring feel light and cheap. It most certainly doesn't feel like a $700 prime lens should. Unlike the Nikon, Sigma uses a metal lens barrel with a very smooth, well-damped focus ring. It's also larger and heavier than the Nikon, which really give the Sigma a nice, high-quality feel. The flip-side of that is that the light weight and smaller size of the Nikon can certainly work to its advantage. I prefer to travel light, especially when hiking, where every single ounce really adds up. In that sort of situation, the Nikon would be my go-to lens.
Focal lengths are tricky. What works perfectly for one photographer may feel completely wrong for another. To that effect, I've created two GIFs, below, which help to illustrate the difference in focal lengths. Please note that these comparisons are for the field-of-view on full-frame / FX cameras.
As you can see, the fields of view these lenses provide are actually quite similar. The Nikon may be slightly better suited towards landscape photos, and the Sigma might be a bit better suited for things like portraits and street photogoraphy. However, I like to challenge these sorts of assumptions, and I really think that either lens could be excellent for landscape, street, travel, and most other general types of photography - when placed in the right hands, of course. To give you an example, below is a landscape photo taken with the Sigma 35/1.4, and an environmental portrait taken with the Nikon 28/1.8.
I don't have the right resources or knowledge to do a full optical assessment of both lenses. The general consensus across the web is that the Sigma is the new resolution benchmark to beat. From what I've seen, I have to agree. It's pretty astonishing in terms of center resolution and sharpness.
That said, the Nikon is nearly as good as the Sigma, and I have absolutely no complaints about its resolution or performance. If you're eager to look at some charts and numbers, the brilliant folks at Photozone.de have reviewed both lenes:
As you can see, the resolution numbers are quite similar. In terms of flare-resistance, both lenses performed very, very well during testing. I didn't have any issues with flare, even with the sun in the frame. It appears that Sigma's multi-coatings are beginning to rival Nikon's expensive "Nano-Crystal" coatings.
In short: both lenses are optically excellent.
I enjoy bokeh (out-of-focus blur) as much as the next guy, but I tend not to obsess over it. In this case, the Sigma wins out over the Nikon 28mm f/1.8G. This is simply due to the slightly longer focal-length and faster aperture, which just makes it more "bokeh-rific" than the Nikon (given the same subject at the same distance). Nevertheless, the Nikon's bokeh is pleasing and soft in certain situations, and about as strong as one might expect from any 28/1.8.
Both lenses feature fast, quiet, ultrasonic motors. I've encountered reports of the Nikon 28/1.8 having some focus-shift issues at different apertures (in-focus at f/1.8 may be out-of-focus at f/5.6). I've thoroughly tested my copy, and have had no such problems. There is some noticeable field curvature that one must be aware of, but that's expected of a moderately wide, fast lens. I didn't notice any field curvature with the Sigma.
As far as accuracy is concerned, both lenses are very accurate. Over the course of my week shooting with the Sigma, I only experienced one hiccup and missed-shot due to an AF problem. This was while using the extreme, center-bottom focus point. Some users have reported problems with the Sigma on the D800 when using the extreme outer focus points, but other than my one missed shot, I didn't have any issues. In fact, I also missed a shot in a similar situation with the Nikon during the same time period. Overall, I'd say that these lenses are about equal when it comes to AF performance and accuracy. Neither one is absolutely perfect, but they're not terrible either. In fact, they're both quite good.
I've been taking photos with the Nikon 28/1.8G for nearly a year now, so I've had time to amass a number of sample images that I'm very happy with. Unfortunately I only had the Sigma 35/1.4 for less than a week, since I rented it from the wonderful people over at LensRentals.com. Nevertheless, I managed to get a handful of images that I'm content to display.
Summary & Conclusion
You really can't go wrong with either of these lenses. If cost, weight, and build quality are of negligible concern, then the decision could boil down to just one very subjective factor: focal-length. It really all comes down to the photographer's preference. Gary Winogrand famously used a 28mm lens for most of his street photography, but Henri Cartier-Bresson shot primarily with a 35mm.
For landscapes, I usually reach for a zoom (typically the 17-35/2.8 or 24-120/4) so that I can compose more precisely. For me, primes are more useful for travel, street, and portrait photography. Because of this, I find the slightly tighter focal length of the Sigma more appealing for general use. I also prefer the heavier and more solid construction of the Sigma over the Nikon. Conversely, I can see myself reaching for the Nikon when traveling light, like when hiking, where every ounce really counts. Other photographers might prefer working with primes for landscape photography, where the 28mm might be more appropriate than the 35mm.
If you're having a hard time deciding, I suggest renting these lenses from LensRentals.com before you choose. Or, you might try scotch-taping your zoom lens at each focal-length for a few days. It'll quickly become apparent which one you prefer.
Sigma 35/1.4 Pros
- outstanding optical quality
- 2/3rds of a stop faster than the Nikon
- robust construction
- nice, normal-wide field-of-view on FX
- on DX it yields a "normal" 50mm equivalent field-of-view
Sigma 35/1.4 Cons
- more expensive than the Nikon
- no rear dust gasket/seal on mount
Nikon 28/1.8 Pros
- outstanding optical quality
- light and relatively compact design
- nice, moderate-wide field-of-view on FX
- less expensive than the Sigma
- has rear dust gasket/seal on mout
Nikon 28/1.8 Cons
- 2/3rds of a stop slower than the Sigma
- cheap-feeling construction
- on DX it yields a slightly strange 42mm field-of-view