I was drawn to the Sigma after having used Nikon's competing 35mm f/1.8 lens and hearing many comments to the effect that, in addition to its greater speed, the Sigma offered better bokeh and significantly better build quality. I also personally prefer the 30mm perspective for use as a "normal" lens on DX - so given the praise I'd seen for it, I bought a copy of the Sigma and have spent a fair amount of time using it, alongside the Nikkor, under a variety of shooting conditions.
The advantages noted for the Sigma do exist, and they do work in its favor. Nevertheless, I came away disappointed, and have gone back to using the Nikkor exclusively despite its minor drawbacks.
There are two primary reasons for my dissatisfaction, which combined to lead to a single effect: unacceptable image quality at large apertures. Let me first say that for my purposes, the only reason to use a fast prime lens is to use it at large apertures. In circumstances where I don't need a large aperture, I will keep one of several excellent modern zoom lenses on my camera, any of which offer sharpness and color rendition that matches or exceeds that provided by even good prime lenses. A good zoom gives versatility in terms of focal length, and I am not a purist in terms of equipment choice: I use what I feel to be the best tool for the circumstances I find myself in. The only time I find a prime lens preferable is when I need to use a large aperture, and consequently such a lens' performance at large apertures becomes by far its most important quality.
I was, unfortunately, very quickly disappointed with the Sigma's image quality. After subsequent fiddling, both in regular use and in semi-formal "testing," to determine the reasons for the poor sharpness, I realized there were two separate issues contributing to its mediocre performance: first, it focused inconsistently. This seems distinct from most focusing-related complaints here, as my copy didn't consistently front-focus or back-focus: those problems can apparently be fixed, at least on some samples. This lens simply wasn't consistent enough in its focus to hit its depth of field at wide apertures, a rather critical failure for a fast lens. Even among Nikkors, some lenses are better than others, and one big advantage of the newer AF-S Nikkors is that they tend to focus very consistently, if not always quickly: they will make the small adjustments necessary to keep the subject in sharp focus, even when depth of field is narrow, and they consequently provide a very large proportion of perfectly focused images. The Sigma, at least my copy, was not able to do that.
Second, exacerbating the focus issue, was a general lack of sharpness at large apertures even when focus was perfect. Whether the subject was a simple test chart or a real-life target, the lens' sharpness was just not very good as the aperture widened past about f/4. It was worst wide open, where I would characterize it as useable but fairly poor, and not, unfortunately, much better at f/1.8 or f/2. F/2.8 was better, but still markedly soft, f/4 was fairly sharp but still not on the level I expect from today's high-quality lenses. Along with the lack of sharpness at larger apertures came a lack of contrast - photos taken with this lens at f/1.8 were significantly less contrasty than those taken with the Nikkor 35/1.8, a typical side effect of poor sharpness as the colors run together within areas of fine detail, rather like a small-scale water color painting.
Were these performance issues significant enough to be noticeable on normal-size prints? At f/4, probably not. At f/2.8, maybe. However, there is no point, for me, in using a lens like this unless I can effectively use it at f/1.8 and below - and at those apertures, the lack of detail and contrast would keep me from using it except in shots where detail was simply not important - and yes, it would be noticeable even at ordinary print sizes, or displayed un-magnified on a computer monitor.
My conclusion, then, was that the lens did not meet my basic personal requirements for image quality. It does, however, have its good points, and in giving it a rating I consider it a three-star lens. It is genuinely fast, and its f/1.4 aperture can allow one to capture images that would simply not be possible with other lenses. It is reasonably sharp at ordinary apertures, and it is capable of producing colorful, contrasty images, the equal of even very good Nikkors - a probable testament to Sigma's use of high quality coatings. Its build indeed appears very stout; and if its focus feel is the typically high-friction, gritty feel of modern internal-motor lenses, then at least the focus ring is well placed, accessible, and easy to use.
A few miscellaneous comments that might be of importance to some users of this lens, and in particular some points of comparison to the 35/1.8 Nikkor:
- The Sigma uses a 62mm filter thread. This may be relatively Canon-friendly but is not a common size on modern Nikon gear. Consequently a new lot of filters and step-up-rings would need to be purchased if I were to keep the lens, adding cost and bag clutter. The Nikkor uses a very standard (for Nikon) 52mm filter.
- The Sigma rear cap is infuriating in that it only goes on the lens in one orientation. Every Nikon, Tokina, etc. lens I've used allows the cap to be put on in any of several orientations, and in comparison the Sigma cap is a pain in the neck to use. The best option here might be to use a spare Nikon cap for the lens, or buy one if you don't already have an extra.
- I would not describe the bokeh of the Sigma as excellent. It is much better than most newer Nikon and Nikon-mount lenses, but that is primarily because most such lenses, unfortunately, have poor bokeh. The Nikon 35/1.8 has poor bokeh. The Sigma has what might appropriately be called "neutral" bokeh, in that the discs created on the image by out-of-focus point highlights have approximately even intensity of illumination across their diameters. A lens that has bad bokeh will show bright rings at the edges of these discs, while a lens with excellent bokeh will show diminishing intensity from the center of these discs to the edge. The latter allows all out-of-focus points to blur together gently, while the former creates hard edges on out-of-focus objects. The Sigma is between these extremes.
- Bokeh is of lesser importance in a "normal" lens than in a lens of longer focal length. This is simply because the degree of blur attainable is less at smaller focal lengths. The Nikkor and the Sigma can create approximately the same degree of blur (the Nikkor is 35mm, remember), but it is in most cases a subtle out-of-focus effect, not dramatic as it can be with longer or telephoto lenses. Consequently the character of that blur - the bokeh - is less noticeable and therefore less important. It is simply harder to generate unpleasant blur at 30mm/35mm than it is at longer focal lengths. For this reason, I didn't find the Sigma's bokeh advantage to be particularly noticeable in my photography, even when using the lens at large apertures. The exception to this rule is when the lens is used for close-range photography, in which case the background will be thrown well out of focus.
- I prefer the Sigma's 30mm focal length to the Nikkor's 35mm. To my eye, 35mm is just a bit long for a "normal" lens on DX, and I usually want a bit more working space than I'd like at 35mm. In this respect I prefer the Sigma - although Nikon's 28mm f/2.8 is another, very inexpensive, alternative.
Final note: This is an honest review of a lens I've actually owned and used, in comparison with other lenses that I've actually owned and used. Unfortunately, there are always people who click "negative" reviews as unhelpful no matter how accurate the review, and that does a dis-service to other Amazon customers as those reviews wind up at the bottom where they are not seen. I wish more honestly critical reviews were available to help me make purchasing decisions, and I hope you think so as well.
Other Lenses:
I've had the opportunity to own and use many different Nikon lenses and have posted my impressions of some of them here on Amazon. For those interested, here are short summaries. I have used all these lenses on Nikon DX-sized DSLRs, most recently my current D90. Refer to the full reviews for further detail.
Nikon 28mm f/2.8 AF-D: *** Competent, sharp lens is a good fit as a bargain DX "normal" prime. Slow f/2.8 max aperture poor. Very inexpensive in used market.
Nikon 35mm f/1.8 AF-G: ****1/2 Terrific lens at a bargain price. Not without flaws, but excellent in all important respects. A pleasure to use.
Nikon 35mm f/2 AF-D: **** Sharp, especially at large apertures, moderate contrast. Classic "normal" lens for DX but consider new 35mm f/1.8 AF-S instead.
Nikon 50mm f/1.8 AF-D: *** My sample was unacceptably poor at large apertures. Perhaps a below-average sample. Focal length not ideally suited to DX.
Nikon 85mm f/1.8 AF-D ****1/2 Very good short-to-moderate telephoto on DX. Acceptable at large apertures, very sharp stopped-down, moderate contrast. Potentially excellent for portrait use.
Nikon 16-85mm VR ***** Very sharp at all settings, excellent contrast, very useful zoom range including true wide-angle at 16mm. Excellent VR. Best-kept secret for DX users.
Nikon 28-200mm AF-G *** Of two samples, one was excellent and one poor, so watch for sample variations. Very good contrast. Not ideal hand-held due to lack of VR. Not ideal for tripod use due to design.
Nikon 55-200mm VR **** Very good lens, very good sharpness and contrast, no fatal flaws. Cheap feel and feature-challenged, but has effective VR. A bargain.
Nikon 70-300mm VR *** My sample had very poor performance above 200mm, good to very good elsewhere. Good contrast, generally very good focus performance. Good sports/action lens. Not good where critical sharpness is desired. Possibly a below-average sample. |
Expedited Available
"Imperfect but capable fast prime"
"sheer beauty"
"Had to get rid of it !"