Not ready for prime time.

Part I is here.

I’m a street snapper. That means I have no use for focusing systems like LiveView which turn your DSLR into a capable, tripod-mounted field camera. You set it up, magnify the focus area and determine critical focus using MF on the LCD screen. This side-steps a host of variables relating to focus screen positioning, AF motor stepping and so on. I suspect it’s what most testers use when concluding that the Sigma is a stellar performer. But for street work, LiveView is anathema. You need something fast and unobtrusive, meaning viewfinder focus.

With this Sigma lens I have rarely seen such incredible resolution, regardless of aperture. And very few lenses, of the many I have used, compare when it comes to color rendering. In regard to these attributes, the comparable lenses are the 24-105mm Canon L (for color, resolution is just OK) on the 5D, the 35mm Asph Summicron-M used with Kodachrome film on a Leica M2 and the 16-35mm Nikkor AF-S I use currently. In the Lightroom Library view, images from these lenses, newly imported, simply pop with three-dimensional rendering and vibrant color.

But the 35mm Sigma I borrowed has one disqualifying fault. It simply cannot consistently focus the image correctly. It’s not a one-way deal where everything is back- or front-focused. That would be fine. Fine Tune would correct that. No, it is far worse and it’s not correctable. The AF focus errors this lens makes on my Nikon D3x are random.

The focus (!) here is on resolution of fine detail for the simple reason that you can more or less fix other errors in processing but you cannot put back lost resolution.

Here are two examples of how poorly the Sigma lens focuses, destroying resolution in the process.

In the first I focused on the head of the man on the left. I was seated, elbows on the table, no rush or stress. No question what I focused on. This was about as methodical as it gets. I used spot focus and recompose, as the subject was far enough away that recomposition would change the subject-to-camera distance by a negligible amount.

Now here is where the lens focused:

Nice, sharp wall.

The focus is a good two feet further away than required.

Another example. This snap of the two charming pups was focused on the right eye of the right pup:

This time the lens decided to focus on the nose of the pup instead of the eyes, 9″ closer than required.

Nice nose. Where it is sharp, the resolution is stunning.

Think those are bad? No, these were not at f/1.4. The first was at f/2, the second at f/4. f/4, and the lens missed focus by a country mile! Goodness, I can scale focus manually better than that.

I have many examples like this and the directional error is random. So I did the obvious thing and extended a ruler on the rug, the camera on a tripod and banged away at the target with the camera at 45 degrees, at a point 5 feet away. A typical street snapper’s working distance for a 35mm lens on FF. Yup, sure enough. The Sigma randomly front focused, back focused and occasionally nailed the focus. Sorry, for street work ‘occasionally’ does not cut it. There are enough variables driving failure without having to worry about your gear functioning properly.

In my street tests I used a variety of focus methods, Single Servo spot and recompose, Continuous 9, 21, 51 and 51 3-D matrix focus, and so on. And the most damning test of all is that my 85mm, f/1.8 AF-D Nikkor, yes the one with the ghastly plastic barrel and resolution to die for, discloses no autofocus variability errors at f/1.8. And that’s more demanding than 35mm at f/1.4. I did not use manual focus as it’s pointless to buy an AF lens to manually focus it in my kind of work.

Maybe all those testers singing the Sigma’s praises use LiveView on a tripod thus sidestepping the issues with the AF mechanism. Maybe mine was a stinker. A sample of one is not meaningful statistically. But the bottom line is the lens does not deliver. Well, it was a cheap $60 experiment. Thank goodness I did not buy this clunker.

Cross-check:

I also tried the lens on my D2x body with its APS-C sensor. The older CAM2000 focus module in the D2x (the D3 shares the CAM3500 with the D700 and D300) is of known accuracy, delivering perfectly focused results with the 85mm f/1.8 AFD at full aperture. The results with the Sigma lens were identical to those on the D2x body. Accurate focus is a matter of chance, with the lens getting it wrong some 50% of the time. Time and time again.

As further confirmation, I switched to the Nikkor 35mm f/1.4 AF-S G lens (of which more, later), and the Nikkor nails AF at f/1.4 at all distances every time using the same camera bodies. So there’s some grounds for concluding it’s not me at fault but Sigma’s AF mechanism.

LiveView + MF:

I tested focus accuracy using the D3x and LiveView, focusing on the LCD screen using a tripod, with the image magnified to the maximum. At f/1.4 DOF is very shallow making manual focusing pretty easy. Every image thus exposed was critically sharp at the point of focus, confirming that something is wrong in the AF mechanism in my sample of this lens. Too bad LiveView is useless for my purposes.

If you only ever use LiveView and manual focusing this is a great lens but you can buy the Samyang 35mm f/1.4 for a mere $500 or so, even less in alternatively branded guises. It’s reputed to have equal or better performance but deletes the Sigma’s AF.

Bokeh:

The out of focus bits which are meant to be out of focus? Suffice it to say that I prefer to look at the sharp bits, but here’s a snap with a detail section:

This was taken at f/2.

Here are some more:

Lots of bread. At f/2.

Fancy cheese shop. Note the low halo effect around the light in the frame. At f/1.7.

Reader. At f/1.4. My lens profile has removed vignetting.

Comparisons with the 35mm f/2 pre-Ai Nikkor-O 35mm f/2:

If you can get it to focus correctly, the Sigma has better resolution than the old Nikkor at f/2. ‘Better’ meaning that the difference starts to show in prints over 20″ in size. The Sigma at 665 grams is a monster compared to the 280 grams of the Nikkor. The Sigma renders colors better. In fact, it renders colors superbly, as well as any lens I have used. The Nikkor handles well and is a joy to use, despite the need to have to focus manually. Both lenses suffer from modest barrel distortion and significant vignetting wide open, these easily corrected with good lens profiles.

The one thing I really missed in the Sigma (apart from correct focus, that is) is the aperture ring. Like current Nikkor G lenses, you can only change the aperture using the control dial on the camera’s body. I unconsciously set the aperture on the Nikkor by feel, counting the clicks, without even looking at the lens. With the Sigma, I have to activate the camera with a first pressure on the shutter button then look at the LCD screen or through the finder – less suited to street work.

Is my lens an outlier?

Check the comments on Roger Cicala’s blog. There are several along the same lines, identifying inconsistent autofocus. By the way, my rental was brand new, so it’s not as if the lens had been beaten up before I borrowed it.

Purchase risk:

This is a sample of one and no basis for extrapolating conclusions to the population as a whole. However, given Sigma’s poor record of quality control I would guess that the buyer is taking a significant risk on this optic. You might just get a superb one. But be prepared for disappointment and possibly multiple exchanges. Sure, the 35/1.4 Nikkor AF-S is twice as much so it comes down to two things. What is your time worth and how much do you care if you miss a great snap? I own many Nikkors, MF and AF, often bought very well used, and have yet to have any optical issues with these fine lenses, whether from the classic metal era or the modern plastic wonders. In fact the only issues I have had is creeping zoom collars on trombone zooms, easily remedied with a piece of electrician’s tape on the barrel.

My best guess as to what is wrong:

Sigma may have used a stepping motor with too few steps but I doubt that. The economic savings compared with the reputational risk, given Sigma’s new commitment to quality control, make no sense.

Sigma may have messed up the math which has the contrast detect function in the camera position the focusing mechanism just so. I doubt that, too. Many users are reporting stellar results with no AF issues and this would not explain the random focusing errors either side of correct focus.

So my best guess is that the AF mechanism is binding owing to poor assembly and that the lens is not making it to the peak contrast/best focus setting. If I am right, proper assembly and maybe tightened tolerances in a couple of key parts should do the trick. Sigma can sell these all day long for $100 more if that’s what it takes to tighten up (loosen?) assembly procedures.

A failure:

In conclusion, my borrowed sample of the lens was a tantalizing disappointment. The resolution, when properly focused, and the color rendering are both to die for. But if you can’t get a lens to focus properly it might as well be the bottom of a Coke bottle. And the Sigma simply cannot be trusted to nail focus consistently. It missed focus 50% of the time I used it, some 300 exposures. Thus my opinion of Sigma’s lenses – see Part I – remains sadly unchanged. If Sigma can fix what ails this lens’s electro-mechanics I’m a buyer for the truly outstanding optics.

Follow-up:

Recent comments on Roger Cicala’s blog:

As the lens shows such promise, despite it’s faulty AF mechanism, I wrote Sigma and received the reply below:

Now bear in mind I am not a professional, so my findings are likely irrelevant, as Marc Farb’s reply suggests.

I have written to Sigma referencing this post and have told them I am a buyer if they can fix the AF/QC issues. I also alerted their Marketing Manager of the abject rudeness of their purported technical support person, Marc Farb, who subsequently wrote me an even more ill informed note – if that is possible – explaining that “…. 98.6% of errors are the fault of amateur users”. Clearly an authority on the matter.

In fairness to Sigma, they replied in two days and offered me a new loaner by the end of January 2013 when new shipments arrive in the US. I also understand that Farb was reprimanded. Not a moment too soon. I have taken them up on their offer as I do believe my sample was a dud as regards AF, and the lens is so clearly better than the Nikkor 35/1.4, which I also tested, that I very much want to get a good one. I’ll update here once I have a good one.

Use of Nikon Capture NX2 software to determine focus point:

One chat board – I think it was DP Review, which has some of the lowest quality discussions on the web, replete with personal attacks – had the statement from one purported ‘expert’ that Nikon’s Capture NX2 app (free 60 day trial) could be used to determine the exact point the camera focused on. This is completely wrong. What Capture NX2 will show you is the focus sensor that was used to acquire AF. So if you use the central sensor for spot focus, all you will ever see is that sensor highlighted in the center of the displayed image if you toggle it On. Focus on the edge of the frame then recompose and you will not see what you focused on before recomposing. I know. I tested it. You will only see a central pair of square brackets telling you that the central focus sensor was used. Duh! Useless, in other words, to determine where the camera acquired focus. Useless for any purpose, really. In addition to this worthless ‘feature’, NX2 is some of the most ghastly processing software yet made. Stick to Lightroom and Photoshop. And avoid the DP Review chat fora like the plague.

Update: An update addressing quality control issues, and with results from the third copy of this lens which I tried, appears here.

My Sigma 35mm f/1.4 review.

I have generally stuck with lenses from the maker of the camera body – Leica, Canon, Panasonic/Olympus and Nikon – for the simple reason that I have the most awful memories of the aftermarket alternatives. When I worked in cameras stores during vacations as a kid, the most returned items were lenses from the likes of Tamron, Soligor and especially Sigma which, when not just downright awful optically would often fall apart mechanically. For the generally modest savings compared to the real thing and the massive attendant depreciation, the economics simply did not solve. My Sigma 35mm f/1.4 review follows.

But more recently old line designers, like Zeiss and Schneider, started making inroads into the super premium FF, APS-C and MFT lens markets, generally at prices substantially higher than the camera makers’ own lines. Cosina manufactures the Zeiss designs. I’m not sure who makes the Schneider ones. Maybe it’s Samsung, given how many of their cameras feature Schneider lenses. One thing is fairly sure and which is that neither is made in Germany.

Sigma, that maker of many of the worst clunkers in optical history, made some early progress under contract to Leica for Leicaflex lenses, the 28-70mm f/3.5-4.5 Vario Elmar being one example where Leica’s eagle-eyed inspectors claimed to have bestowed some QC discipline on a manufacturer alien to the concept. That was ages ago. More recently, Sigma came out with two well reviewed primes in the 50mm and 85mm optics, both AF and both f/1.4, though reports of autofocus issues with both abound. That’s pretty tough competition with the Canon and Nikon versions, especially at 85mm, but Sigma garnered a following for its lenses, suggesting that they were turning a new leaf.

It is very much in all photographers’ interests that independent lens makers succeed. Nikon and Canon have greatly increased the prices of their best primes, with their 35mm f/1.4 offerings selling for $1,500 and $1,600 respectively, with stellar reputations to match. That is a lot of money. Yet, had you told me that I would be trying a Sigma lens on my Nikon I would have laughed all the way to the boozer. But I am doing exactly that (trying the lens, that is, not laughing en route to the boozer), awed by the incredible critical reception for this optic. Either Sigma has very deep pockets to fill the shallow ones of the paid review set, or there’s something exciting going on here.

The Sigma 35mm f/1.4 DG HSM A1 is a non-VR AF full frame lens from Sigma which comes in a variety of mounts. Nikon versions remain back-ordered but I was able to rent one for the weekend and can report on it here. It will cost $900 with hood and case.

My rental, s/n 50004444, came from Borrowlenses.com for the simple reasons that they are down the road from my home and because they had just got the first ones in stock. I paid $60 for a weekend rental. After the foul stench left by my prior Sigma experiences I was not about to plonk down cash without a dry run first. The big appeal here, of course, is the auto focusing design and f/1.4 does not hurt either. That should mean optimal resolution by f/2.8 for really large prints, and 35mm is very much in my sweet spot for street snapping. I do not really need a zoom or anything much longer for that.

The cool dudes at BorrowLenses.com. D3x, 35mm Sigma at f/4.

Some of the best lens test data recently is coming from Roger Cicala at a competing lens rental place named LensRentals.com. What distinguishes his analyses is that he tests dozens of lenses of any one type on his optical bench, thus reporting not just on quality but also on manufacturing consistency. And that’s a must have for Sigma optics whose history of poor QC and inconsistency is legendary. Cicala only has one sample of the Sigma in Canon mount at the time of writing, and you can see his review here. Doubtless he will soon report on sample variability.

The lens is distinguished by its largely metal (there’s a thin rubber coating on the focus collar) finish, a marked departure from the plastics used by Nikon and Canon in even their costliest offerings and, uniquely, a rumored add-on device which will attach to the lens and permit updates to firmware and focus collimation through a PC (please, Sigma, make it work with Macs) with a USB connection. No details yet on the pricing of this innovative device. It really should come free with the lens, given Sigma’s reputation. The lens is all black, with none of the garish gold markings (Nikon) or ‘look at me’ red rings (Canon) which add zero value to the user experience. The gold and red stuff always reminds me of insecure Americans who emblazon their rear view windows with ‘Harvard’, ‘Yale’ or ‘Balls Pond Road’, the last for the degree-mill set.

The depth-of-field scale on the lens – visible in the image above – is useless and should be dropped. The gearing of the focus movement means that there’s insufficient space for a proper DOF scale. Further, these scales can only be meaningful at a specific enlargement ratio and really are a thing of the past. For that matter, the focus distance scale should also be dropped.

The chromed blob visible in the above picture is marked ‘A’, and is purportedly a statement that the optic is a member of the manufacturer’s ‘Art’ line of lenses. This is marketing BS of quite exceptional purity.

I do not understand weatherproofing issues. The Sigma has no rubber O ring – found with certain allegedly weatherproof Nikon and Canon optics – on the bayonet flange. My 16-35 Nikon AF-S has this ring and it strikes me as an exercise in futility. Quite how water could penetrate the very tight seal between lens and body beats me, O ring or no O ring. What ‘weatherproofing’ means to me is that there is a good seal between the moving parts of the lens – the focus collar and A-M switch – and there is no data I have seen which compares the Sigma with the Canon and Nikon offerings in this regard. So I am pretty clueless here. Suffice it to say that ‘reviews’ state the Sigma is not weatherproofed. Beats me what that means or how they know. In heavy rain I would simply encase the barrel in a plastic bag and have at it, using AF, as no external parts move when the lens is focused using AF.

Early reviews suggest that the lens not only outperforms the Canon and Nikon alternatives optically, it also is more than a match for the $1,840 Zeiss 35mm f/1.4 optic, which is MF only. I cannot comment, not having used any of the alternatives. The Sigma is AF with AF override or MF optional. The feel of the focus collar does not change between the A and M settings and is quite the best I have experienced in a lens with internal motors, and superior in smoothness and damping to the AF-S 16-35 Nikkor. You do not feel or hear any gears using AF override or MF. The AF mechanism is audible to the user in quiet surroundings, inaudible to everyone else. A tactile and aural delight.

The lens is very solid in the hand and no lightweight. Balance on the Nikon D3/D2 is a bit front heavy as there’s a lot of glass in this optic, but the combination handles well. My 16-35mm Nikon f/4 AF-S VR weighs 1.5 lbs and is 4.9″ long, taking 77mm filters. The Sigma, a non-VR prime, comes in at almost the same weight but is only 3.7″ long. It takes 67mm filters. Fit, feel and finish all harken back to the golden era of all metal lenses with brass helicoids. The plastic petal-type hood, included, clicks on nicely but adds a lot of bulk and length. My rental came with front (pinch type) and rear caps, the hood and a protective filter. I did not use the hood – it is silly-large for a street snapper, though it does clip on and reverse nicely, still permitting the use of the front cap. The rental lens appears new.

Because of Sigma’s poor reputation, the first thing I did was point the lens at a bookcase – tripod, MLU, remote release – to determine whether any fine focus adjustment was required. My Nikon D3x correctly reported the lens as a 35mm f/1.4 in the fine tuning menu and required absolutely no adjustment for optimum auto focusing. I wasn’t about to hit the street only to find that everything was out of focus. Further, infinity focus was just as accurate. Indeed, I simply could not reliably get sharp focus at any distance at f/1.4 and f/2.0 with manual focusing, using the LED focus confirmation light, whereas AF nailed it every time. Impressive, especially in light of all the grumbling on the web. Impossible to know if this is sample variation or user error.

The obvious comparison here is to my 1971 pre-Ai 35mm MF Nikkor f/2, a stellar performer from f/2.8 down, and clearly delivering better resolution than the current 16-35mm f/4 AF-S optic I also use. More on that in Part II.

Sigma on the D3x compared to the much smaller 35mm f/2 MF pre-Ai Nikkor. Sigma’s hood removed.

The one anomaly compared to Nikkors is that the focus collar rotation is opposite to that of the Nikon optics. Still, with AF it’s not a big deal but may take some getting used to if you use AF override, done by simply manually rotating the focus collar in AF mode, like on current Nikkors.

The next task was to make a lens correction profile as the Sigma is known to exhibit fairly serious vignetting at f/1.4, and my profile corrects it. If you must have vignetting, that should be a user choice at the processing stage, not a lens default. Doubtless Adobe will publish one eventually. Mine is made at f/1.4, f/2, f/2.8 and f/4. Vignetting is gone by f/4 and Lightroom and Photoshop will automatically select the correct version defaulting to the last at any aperture smaller than f/4. This profile also removes the small amounts of lateral chromatic aberration the lens displays and also removes a small amount of barrel distortion. You can download the profile here. This profile works with RAW images only. That page includes OS X and Windows installation instructions.

If your import preset in Lightroom is checked to invoke the lens correction profile or if you check the box below, you will see this on import in the Develop module:

Lens correction profile in Lightroom 3 and 4.

While I have named the profile “Nikon D3X ….” it will be correctly invoked with any Nikon camera. The ‘Model’ field description is what LR uses to look up the matching lens profile; the name of the camera body is irrelevant. I have no other non-Nikon bodies or lenses with which to test this profile, but it should also work fine with Canon, Sony and Sigma bodies, though you may have to select it manually. The profile is fine with FF and APS-C, though less needed on the latter which cuts out much of the corner vignetting.

DPReview drooled all over their sample and you can read their findings here while I make off to take some snaps with it. Just don’t get too thrilled about their field snaps as one of the qualifications for being a DPReview tester, an otherwise worthy bunch, is a total inability to take a good photograph, a qualification shared by optical lab rats worldwide. No problem. They are not paid to take great pictures.

I’ll update this Sigma 35mm f/1.4 review in Part II.

A lightweight 28mm.

This one seems to have slipped through the review mill, so here are the details.

Mine is the pre-Ai version of 1971 with the metal scalloped focus collar . It’s considerably smaller and lighter than its f/2 sibling and can often be found for around $40. My mint copy ran $63 delivered. Construction and engraving quality represent the very best Nikon ever accomplished. The lens is a fine match for lighter bodies; it tends to be a bit too small for best handling on the larger bodies with battery grips.

I removed the five slotted screws retaining the bayonet flange, removed the aperture ring and filed down the necessary relief to clear the aperture feeler on modern Nikons, making this into an Ai lens. You can see the relieved arc in the picture below.

CPU installation on this one is tricky as the rear baffle is sloped, for some reason. It has to be removed and cut back to create the plane perpendicular surface to which the CPU is glued.

CPU installed after the baffle was cut back.

As usual I have created a lens correction profile which you can download here.

This file includes three profiles, at f/3.5, f/5.6 and at f/8. LR and PS will use the closest match. The 28mm f/3.5 shows vignetting at f/3.5, disappearing by f/5.6 with very minor barrel distortion being corrected.

This profile is for the pre-Ai and Ai versions, which had 9 elements in 8 groups. I have not tested this profile with the later Ai-S lens, though it appears to have a similar optical design.

If you use a filter, make sure it’s a slim one. The correct hood is model HN-2. I use one with a standard slim Nikon 52mm UV filter.

As is common with pre-AiS lenses, the aperture stop down lever exhibits substantial non-linearity, as illustrated here so you really want to pass aperture control from the camera to the lens’s aperture collar to assure proper metering.

The lens is sharpest between f/5.6 and f/11 where it cedes nothing in definition to its far costlier sibling.