Sigma 18-35mm F1.8 DC HSM Review

September 2013 | By Andy Westlake and Richard Butler

Review based on a production Sigma 18-35mm F1.8 DC HSM

Sigma has a long history as a lens maker, having been founded over 50 years ago. In the film era it was best known for relatively inexpensive lenses that undercut the camera makers' own equivalents in terms of price. But this has changed over the part decade or so; while other companies have shifted manufacturing to cheaper locations such as China and Thailand, Sigma has stubbornly refused to move from its factory in Aizu, Japan. This means it can no longer compete in the same way on price alone, and it's therefore switched its focus towards higher-value offerings.

Over the past few years we've seen increasingly ambitious concepts appear from the company's design studios. The original (and recently-replaced) 30mm F1.4 EX DC HSM has long been one of our favourite lenses for APS-C SLRs, and the 50mm F1.4 EX DG HSM grabbed our attention back in 2008 due to its sharpness at large apertures. Most recently the 35mm F1.4 DG HSM impressed us with its exceptional optical quality at a very competitive price. This all bodes well for the company's latest offering - the record-breaking 18-35mm F1.8 DC HSM, which is the first constant F1.8 SLR zoom lens to hit the market.

Sigma's choice of F1.8 as maximum aperture isn't a coincidence; it means that the lens will offer the same control over depth of field as an F2.8 zoom does on full frame. What's more, it will also offer effectively the same light-gathering capability as an F2.8 lens on full frame. By this we mean that it will be able to project an image that's just over twice as bright onto a sensor that's slightly less than half the area, meaning the same total amount of light is used to capture the image. This is important as it's a major determinant of image quality. Essentially it means that APS-C shooters will be able to use lower ISOs when shooting wide open in low light and get similar levels of image noise, substantially negating one of the key advantages of switching to full frame.

As we'd expect at this level, the lens uses an ultrasonic autofocus motor for fast, silent focusing. It's compatible with Sigma's new USB dock which allows you to fine-tune autofocus behaviour in much more detail than the AF microadjust corrections found on SLRs, which should help get the best possible focus accuracy and make the most of the large aperture. It also incorporates several of the thoughtful design touches that we were impressed by on the 35mm F1.4, including an improved AF switch, and a large grip area on the base of the barrel for better handling.

The lens's 27-53mm equivalent focal length range is obviously a little limited, but should still be rather useful for such applications as wedding and events photography. So while it may not quite match the capabilities of a 24-70mm F2.8 on a full frame SLR, for existing APS-C users it should offer something very close. Crucially, at a street price of around $800 / £650 at the time of writing, for existing APS-C shooters it's an awful lot cheaper than buying a 24-70mm F2.8 and a full frame SLR to go with it.

Overall the 18-35mm F1.8 is a really intriguing product, and we applaud Sigma for pushing the boundaries of lens design ahead of the more conservative camera manufacturers. But can an F1.8 zoom really deliver good results? Let's find out.

Headline features

18-35mm focal length (approx 28-50mm equivalent)
Extremely fast F1.8 maximum aperture
Ring-type ultrasonic focus motor with full-time manual override
Initially available in Canon EF, Nikon F and Sigma SA mounts; Pentax K and Sony Alpha to follow

Angle of view

The pictures below illustrate the focal length range from wide to telephoto (on Canon APS-C, 1.6x). The 18-35mm covers a modest 2x zoom range.

18mm (29mm equivalent)	35mm (56mm equivalent)

Sigma 18-35mm F1.8 DC HSM specifications

Date introduced	April 2013
Street Price (August 2013)	• $800 (US) • £650 (UK) • €850 (EU)
Maximum format size	APS-C
Focal length	18-35mm
35mm equivalent focal length (APS-C)	• 27-53mm (1.5x) • 29-56mm (Canon 1.6x)
Diagonal angle of view	76.5° - 44.2°
Maximum aperture	F1.8
Minimum aperture	F16
Lens Construction	• 17 elements in 12 groups • 5 SLD glass elements • 4 glassmold aspherical elements
Number of diaphragm blades	9, rounded
Minimum focus	0.28m / 0.92ft
Maximum magnification	0.23x
AF motor type	• Ring-type Ultrasonic Motor • Full time manual focus
Focus method	Internal
Zoom method	Rotary, internal
Image stabilization	No
Filter thread	• 72mm • Does not rotate on focus
Supplied accessories*	• Front and rear caps • Lens hood LH780-03
Weight	810g (28.6 oz)
Dimensions	78mm diameter x 121mm length (3.1 x 4.8 in)
Lens Mount	Canon EF, Nikon F, Pentax K, Sigma SA, Sony A

* Supplied accessories may differ in each country or area

If you're new to digital photography you may wish to read the Digital Photography Glossary before diving into this article (it may help you understand some of the terms used).

Conclusion / Recommendation / Ratings are based on the opinion of the reviewer, you should read the ENTIRE review before coming to your own conclusions.

Images which can be viewed at a larger size have a small magnifying glass icon in the bottom right corner of the image, clicking on the image will display a larger (typically VGA) image in a new window.

To navigate the review simply use the next / previous page buttons, to jump to a particular section either pick the section from the drop down or select it from the navigation bar at the top.

DPReview calibrate their monitors using Color Vision OptiCal at the (fairly well accepted) PC normal gamma 2.2, this means that on our monitors we can make out the difference between all of the (computer generated) grayscale blocks below. We recommend to make the most of this review you should be able to see the difference (at least) between X,Y and Z and ideally A,B and C.

GearShop

Sigma 18-35mm F1.8 DC HSM Lens (Canon EF Mount)●	$799.00	Buy on GearShop
Sigma 18-35mm F1.8 DC HSM Lens (Nikon F Mount)●	$799.00	Buy on GearShop
Sigma 18-35mm F1.8 DC HSM Lens (Sony A Mount)●	$799.00	Buy on GearShop

Sigma 210101 18-35mm F1.8 DC HSM Lens for Canon APS-C DSLRs (Black)	$795.00
Sigma 210101 18-35mm F1.8 DC HSM Lens for Canon APS-C DSLRs (Black)	$795.00
Sigma 210306 18-35mm F1.8 DC HSM Lens for Nikon APS-C DSLRs (Black)	$799.00
Sigma 210109 18-35mm Lens for F1.8 DC HSM for APS-C sized sensors (Black)	$768.65
Sigma 30mm f/1.4 DC HSM Lens for Canon Digital SLR Cameras (Black)	$455.95
Sigma 210110 18-35mm Lens for F1.8 DC HSM for APS-C sized sensors (Black)	$774.49
Sigma 878101 USB Dock Lens Firmware for Canon Lenses (Black)	$59.00
Sigma AF 18-35MM F/1.8 DC HSM Lens Kit for Pentax	$799.00
Sigma 884306 17-70mm F2.8-4 DC Macro OS HSM Lens	$384.45
Sigma 30mm f/1.4 EX DC HSM Lens for Canon Digital SLR Cameras	$469.00
Sigma 30mm f/1.4 EX DC HSM Lens for Nikon Digital SLR Cameras	$309.95

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Comments

Total comments: 275

Impressive IQ but unfortunately only a toy rather than a tool. If I shot landscapes I would have much preferred a slower, lighter lens with image stabilization. For the travel, street, documentary and event work that I do the inconsistent AF renders the lens useless for me. I might as well use a slower, smaller, lighter and more inconspicous lens and shoot at higher ISO. After smoothing the noise in pp the result should be the same as a misfocussed image from this lens. In the end it seems the lens will not turn your Aps-c camera into something of a full frame equivalent.(Save for the dof )

Dont get me wrong, I admire the optical achievement. But without reliable Af, this optical splendour is just wasted for the majority of the practical applications this lens was designed for. My agency (alamy) rejects all misfocused images (however slight) and for large gallery prints misfocussed images are not usable anyway. What a shame.

1 upvote

Where exactly is the "shame" part with this lens, I guess I'm not getting that part?

1 upvote

That it doesnt AF properly.

1 upvote

Use the camera's microadjustment to fix it. We do that with other lenses, so I don't see why we can't do it with this one.

0 upvotes

Did you read the review?

0 upvotes

Why oly cant has?

2 upvotes

Indeed. Why can't has :(

1 upvote

my highest respect to the sigma engineers for this exceptional lens, but from my point of view it makes absolutely no sense. i stay with the APS-C sized sensor, because i want a good compromise between IQ, handling and compact size of the "package", my canon 60D with a tamron 17-50 (no VC, trusted, lasted over three bodies) comes close to this. if i accept to carry a lens this big, and to carry it with comfort you need the larger camera bodies, i would go FF. in that zoomrange there is no creative benefit from 1.8, i'm pretty sure. so a nice compact 2.8/17-55 or so with that excellent IQ would have exhilarated me much more.

1 upvote

In your point of view the 28, 30, 35 primes makes absolutely no sense, is that right?

3 upvotes

imho, absolutely. my photography now is about immediate reaction on the changing subject. changing lenses decelerate (and collects dust). don't judge me wrong. i experienced the creative challenge and the verve of a many nice primes (except there is no equiv. to a 1.4/35 FF for APS-C DSLRs, right). for several decades (beginning in the film era) i believed in primes, but i have overcome this religion.

Comment edited 38 seconds after posting

1 upvote

In the glory days of the film era, the zooms were loved by the amateurs and despised by the professionals. Today, it is just the opposite. Go figure…

2 upvotes

Well, that you don't need the lens, doesn't make the lens less useful for others.

6 upvotes

Awesome lens. Awaiting Full Frame equivalent.

10 upvotes

I don't think that a 35mm equivalent is a sure thing. If anything, this lens may have been made with a goal of keeping APS-C users from moving up to 35mm. This is a large lens, and the 35mm version would be even larger. For some users on the fence between APS-c and 35mm, this may be enough to keep them in the "cruiser-weight" division.

2 upvotes

You're awaiting what? The 24-70/2.8 FF lenses were available, well ... forever. They also have better range and better resolution on FF.

7 upvotes

You should start going to the gym, the FF version will weight 5 kilos !

Comment edited 57 seconds after posting

1 upvote

It is valid and possible. A FF equivalent of sensible size and cost would probably weigh and sized the same. The compromise would be 2x zoom, worse vignetting and CA, soft corners, less detail wide open, and not so constant aperture, like f2 or f2.2 at the longer end.

I'm actually baffled why it is an EF mount despite APSC coverage. I guess Sigma wants to force Canon to produce FF cameras with APSC crop modes similar to Nikon.

Comment edited 4 minutes after posting

1 upvote

Calorie burner and awesome optics in one package! Even better :P
I believe in evolution. Some people thought this lens to be impossible as well. One day we'll be holding our 24-500 1.0 compact lens and look back at the good old days :P

Comment edited 4 minutes after posting

3 upvotes

@zodiacfml All third party lenses for APS-C use EF mount as far as I know - I bet the manufacturers see no reason to support another mount format since their lenses have to work with Nikon and other cameras that don't have APS-C specific mounts, they can't engineer an APS-C lens that takes advantage of the EF-S extra inside camera length.

0 upvotes

Sigma has shown courage and great skill to produce this outstanding lens.
I really hope we will see more high-quality lenses like this one soon!
Please Sigma please make a more versatile mid-zoom-range with F1,8 next.
Thank you :-)

1 upvote

And so say all of us ! Except people who don't like 3rd party lenses or those who recall that Sigma have often had problems with AF in the past. No, I'm not blasting Sigma - this looks to me to be a sure fire winner !

0 upvotes

One thing I have to disagree with is two of the "cons"

"restricted zoom range". How can the zoom range be considered restrictive? Maybe if you compare it to a STANDARD zoom. But this is NOT a standard zoom. It's in a class of it's own. It's a super-fast zoom. You don't buy this lens for range. You buy it for low-light capability. If you look at it from that point of view it's not restricted. If you are going to lump it in the standard zoom category then ALL f/2.8 zooms must now have in the Cons column "restricted aperture setting"

"physically large for a standard zoom". Again, this lens is NOT a standard zoom. If you want speed you need big glass. To be perfectly honest. This lens a actually SMALL considering what it does.

37 upvotes

i totally agree with this comment ......

1 upvote

But this lens has been marketed by Sigma as being an alternative to a full frame camera with an f2.8 zoom, so it's perfectly fair to make the comparison and yes compared to an 24-70mm f2.8 zoom it does have a more restricted zoom range.

3 upvotes

Agreed 100%.

"Limited zoom range"being a con is a laugh. That's a "pro" of this lens. That's why people would buy this lens!!

It's not an 18-250 mm lens, but that was never the point. Do reviews of prime lenses all say "limited zoom range" as a con?

Comment edited 1 minute after posting

3 upvotes

@Andy Crowe: "But this lens has been marketed by Sigma as being an alternative to a full frame camera with an f2.8 zoom"

Please show me where SIGMA has specifically said that this lens is an alternative to a full-frame camera.

I'll save you some time. You can't show me that because SIGMA never made that statement. It's being marketed as the "first wide-angle to standard zoom lens to achieve a large aperture of 1.8. Designed specifically for APS-C sized sensors".

Sigma makes no claim that this lens is an alternative to FF. They say it's a FASTER zoom for APS-C.

0 upvotes

The lens weighs 1.8 pounds, and it is quite gigantic. With such size and weight the range does seem quite limited, I agree with the reviewer.

1 upvote

@photogeek:

The Nikon 17-35mm f/2.8 weighs 1.7 pounds, is the same width and is only a 1/2 inch shorter. I've never heard anyone complain that the Nikon 17-35 was a gigantic lens with limited range.

So in the same size package you get 1 1/3 of a stop more light. Seems pretty fair to me.

0 upvotes

@JDThomas

The Nikon 17-35mm f/2.8 is a full frame wide zoom, not a DX standard zoom.

I do not understand why everyone is stating that the limited zoom is not a 'con'. It is. It just may not be one that is a big deal to you personally, but it's still a con compared to a 17-55 2.8. It's up to you to decide if you want speed or range.

The issue here seems to be that people do not understand that 'standard' in standard zoom means focal length - nothing to do with speed. Just like primes - wide, standard and telephoto.

1 upvote

It is NOT a "con" it is COMPROMISE that you must make when making the decision to buy a ZOOM lens with an f/1.8 aperture.

By your reasoning the Nikon 24mm f/3.5 PC-E should be lumped into the same category as the 24mm f/1.4G. They are both expensive, large, and heavy. Is the small aperture and lack of AF on the PC-E lens a "con"? No. Because it a specialty lens. As is the Sigma 18-35mm f/1.8

The only people that see it as a CON are people that want ONE lens to do EVERYTHING. This is a fast zoom. There is no other alternative, hence this lens is an a class of it's own and cannot be compared to a standard zoom.

In any case the the lens isn't even a "standard" focal length if you want to break it down to the brass tacks of your focal length descriptions. A 42mm equivalent is at the bare minimum of a normal focal length. So for all practical purposes this is a WIDE-ANGLE zoom not a "standard" zoom.

Comment edited 54 seconds after posting

2 upvotes

JDThomas makes VERY good points. Since the Sigma is a lens in a class of it's own how can the range be a con? "Con" against what? Against a FF 24-70, 17-55, ....? Ok, so the flip side of those is the "con" of 2.8. All of these have compromises. It all boils down to which compromise works within your needs.

1 upvote

@JDThomas Oh yeah you're right, the bit I'm thinking of is actually the DPR editorial tacked on to the beginning of the original press release

0 upvotes

It really seems an excellent ''short wide zoom'' lens.Let's also forget about mediocre bokeh as the focal distance is not the one relating to such an ability.Let's also forget about speedy auto focusing in the widest aperture as due to the narrow dof can't be stellar anyway.
The real benefit for such a short zoom lens would actually be to behave on a 90% level equally to the relevant fixed prime at any of the focal lengths in regard.My idea is that it does.A perfect choice although not extremely useful.

0 upvotes

I would have thought the zoom range would be a pro for this type of lens not a con. If i bought this lens it would be because of the zoom range at 1.8..

Comment edited 2 minutes after posting

1 upvote

It's a bit of a specialist lens. With under 2x zoom and falling in the focal lengths known as "standard" zoom lenses, it hardly replaces a 18-55, it's too big and too heavy especially for APS-C standards. Better think well first before spending the dollars! It will replace a few primes in the same range but should not be very practical for day-to-day shooting, I believe...

2 upvotes

Inconsistent shot-to-shot AF rings a bell: same issue of the Sigma 35mm f1.4 (I owned 3 copies).

4 upvotes

Should use only Nikons for focus testing - much more precise, at least on one side ;)

Seriously, great performance Sigma from an enthusiastic 35/1.4 Art owner.

1 upvote

This is what would worry me - Sigma (sadly) have a history of such....my one and only Sigma lens packed up on me - something in in over 35 years of using an SLR had never happen too me..Today I stick with Pentax for Pentax, Nikon for Nikon and Canon for my Canon's.....

0 upvotes

I would have been keen to learn about AF consistency using the new 70D's dual pixel live view AF.

1 upvote

Unfortunately, we don't currently have a 70D to test that out. Sorry for that.

0 upvotes

Are you kidding?

People are buying them in the stores and using them. How can you not have one and have started a review?

Other sites will be lightyears ahead of you

1 upvote

We've already published an extensive preview of the EOS 70D based on a pre-production camera, including our usual set of test shots and a first look at the Dual Pixel AF system. We're due to get a full production camera soon. Sadly though we haven't had a 70D and an 18-35/1.8 in the same place at the same time.

Comment edited 30 seconds after posting

0 upvotes

My 70D arrives on Wed ... from Amazon

0 upvotes

I have been using the 70D and Sigma 18-35mm for about a week now and so far the live view AF is very consistent and accurate compared to the viewfinder AF. I haven't tried it out with fast moving subjects yet but so far it looks rather promising.

3 upvotes

@ Andy, preview? great but other have REVIEWS out.

You cant get a 70D? Are you for real? Maybe fire the person in charge of procuring products and get someone who can either get it straight from the manufacturer or can get his ass in a store and BUY it!

1 upvote

@ Matt, do you have to be obnoxious?
It's not because they don't have the one body you want that you have to try and give them such a scolding...
The preview they made was as good as any of your reviews since it was made with an actual 70D. Yet I believe they made it before the release date, with a body which wasn't for sale or given to them permanently by canon. That's why they don't have it anymore.

0 upvotes

@Adrien. I dont want a 70D But if the #1 camera review website can not get in the #1 new camera from the #1 camera manufacturer after it IS IN THE STORES, then someone is not doing their job right.

You can buy the 70D in the stores .... If they dont have one then its incompetence

3 upvotes

You seem to be under the misconception that reviews happen in the present and not in the past. Reviews are just like articles. They get done, then written up, then proofed, and then finally get published. Chances are when this was started they were not in the stores as yet and they only had a pre-production model somewhere in someones possession. And likely not the reviewers.
Commenters need to have a better grasp of reality.

Comment edited 24 seconds after posting

0 upvotes

You seem to be under the misconception they buy all the equipment they test.

0 upvotes

@sandy b

I seem to believe that if I ran a review site I would get the camera wherever I have to so that I can have a review first and collect the revenue through web traffic. If I dont get it delivered by Canon, I will go out and buy it as it pretty much wont cost me anything anyways.

But thats just me

1 upvote

Doesn't Amazon own DPR? Couldn't they just send a 70D over for testing and then DPR could send it back and Amazon could just sell it as "used-like new" and still make some money on it? It is completely ridiculous that DPR seems to be the only website that couldn't get a review copy of the 70D. Especially since their parent company has them for sale and in stock. Even DigitalRev's youtube review for the 70D is out already.

0 upvotes

Don't blame the dudes. The failure by the Canon PR department...they should realize that after Popular Photography, DPReview is the most important source of information for American photographers.

0 upvotes

I don't get why people use "normal" zooms — this is the range where it's incredibly easy to "zoom" by just getting closer or farther from the subject. I get UWA and tele zooms, but I haven't owned a "standard" fast zoom for well over a decade now. I just have 35 and 50mm primes instead, and 80% of the time I just leave the 35 on the body.

3 upvotes

I agree. I got a 35mm on mine body all the time. My main lens.

1 upvote

In my world there are fences, railings, rivers and streets.

29 upvotes

Zooming with your feet changes the perspective though, and there's not always enough space to move back far enough to get a wide view with a ~50mm equiv prime.

18 upvotes

Zooming with your feet it utter BS. If you take a lot of photos often time you have to shoot within a second to capture the moment and there is not time to plod around.

20 upvotes

@Comitant: And always using zoom can easily make you lazy. Some people prefer photos with well balanced thought-out perspective over hasty snapshots, even if that means missing the moment.
No photo is better than bad photo.

1 upvote

I often need WiDER and can't get further back in time if I'm shooting say a cloud formation. :-)

I fact I now often use my iPhone in Panorama mode to get really wide

0 upvotes

The thing is, the cool part of the lens is the 18/1.8 with damn fine quality part. The rest is all bonus - yes, i could crop the center of the image, but going in to 35mm is easier and higher quaility.

And some times, you just cannot go back. Try making images indoors, for example - which, conveniently, is also where you really enjoy having a fast lens.

1 upvote

18mm at 7 paces is a completely different perspective than 35mm at 14 paces.

It may be "about the same" to you, but that doesn't mean we arethe all so generic in our composition.

1 upvote

@Comitant: that's the thing. I don't take a lot of photos, and I delete about 80% of the few photos I take. I'm not interested in creating mountains of garbage that I will never have the time to dig through later on. If a picture is not excellent, or if it doesn't have documentary/sentimental value, it goes straight to the trash bin. Thankfully, this no longer costs anything.

0 upvotes

@Suntan: yes it is, but if I need wider perspective, I'll just put on a 24mm prime. Still lighter than hauling a monster zoom around, better image quality, cheaper, smaller. What's not to like? Or I could even put on a 14-24mm zoom, if I expect to be shooting wide for a while (I have a FF camera). That way I can get much wider and get exaggerated WA effects, which I kind of like.

0 upvotes

@imsabel: indoors I don't need a fast lens at all. I just bounce flash off the ceiling, and set my lens to whatever aperture it performs well at (about f4 for primes, f/2.8 if I have a longer lens on and need to blur the background).

0 upvotes

Well for one thing you won't be getting better image quality with primes, period. And you don't have to miss something by taking time to put a prime on or change one. I used primes for over 30 years. Now I generally use top zooms because there is little difference between them and primes, sorry. A bag full of primes will weigh as much as this lens of course.

1 upvote

Focal length is used to control the size and amount of the background behind your main subject. The wider the lens, the more background you'll see. The longer the lens, the less background you'll see. There are all kinds of reasons for this, but that's what it's for.

I know that from an optical science point of view that this isn't completely true, but for a working photographer it's a great rule of thumb.

0 upvotes

In my opinion, the conclusion that "… the lens is effectively diffraction limited… (because) there's no measurable increase on stopping down" cannot be drawn from the measurements.

A perfect (diffraction limited) f/1.8 lens produces an Airy disk with a diameter of 2.4 µm, and a ultimate resolution of little more than 6000 LW/PH for an APS-C sensor (22.2 x 14.8mm). The corresponding MTF-50 would be about 3000 LW/PH, which is considerably higher than 2000 LH/PH measured by DXO. It is clear, now, that the measured "low" value of 2000 LP/PH is not directly related to diffraction limits, at least for the 1.8 aperture.

In conclusion, it is impossible to say from the data that the measured value of 2000 LW/PH was given by sensor limitations (3648 pixels height), lens limitations (aberrations and/or diffraction), or a combination of these factors. Probably the (excellent) behavior of the Sigma lens at 1.8 is due to a combined effect of aberration and diffraction.

4 upvotes

Exactly my thought when I read that. I have several lenses that don't get any sharper when stopping down when used on my D800 and they certainly are not diffraction limited.

0 upvotes

I think we can talk about perfect f/4 for 35mm format
(or perfect f/2.5 for APS-C or perfect f/2.0 for 4/3 ...)
which will need 470MPix (stacked pixels, need more for color filters, say 1.5 times) to fully resolve.

the calc is: 24 * 36 * (1477 / 4)^2 * 4
we may have perfect f/2.8 primes but let's go 500MPix first.

Comment edited 2 minutes after posting

0 upvotes

It's almost perfect lens for now, I am not worrying about future bodies have higher pixel density. For me 16-20M is enough. 24M is bit too much. I never print 20X30 inches.

0 upvotes

I need more pixels because I never print (except for some seniors). people often think in detailed formats they have than what they need.

what we need is higher resolution that can equal or better our eyes which got well over 100 million pixels.

0 upvotes

If my Nikon 35mm f/1.8 is having trouble nailing focus at f/1.8, I can't say I'm surprised the Sigma is the same. It's a very thin DOF. It's still the lens of the year and an insane bargain. I mean, 4 spherical and 5 SLD elements in a 800$ lens!

7 upvotes

The 35/1.8's AF may be on the slower side but it pretty much always nails it for me.

0 upvotes

Yup. I noticed some issues with the focus too, at times.

Just out of spite I switched to f/2.8 and everything looked perfect. So its not worse than all the other lenses I own, its just that only the sigma has the shallow DOF to make it matter if the focus is set to the last meter.

0 upvotes

Looks like it could just about work on a 1.3x crop. Might be fun to try.

2 upvotes

Yes it works!

0 upvotes

I own the Sigma 18-35mm f/1.8, the Canon 17-55mm f/2.8 IS, the Sigma 50-150mm f/2.8 IS, and two more lenses.

I don't find the Sigma's autofocus to be any more reliable or unreliable than any other lenses'.

This brings be on to a bigger question: Is it even technically possible for the lens to affect consistency in this regard? It is the camera's autofocus sensor that reports "sharp" or "not sharp", so how can this be the lens' fault?

I have always found this to be a problem with phase-detect AF, regardless of which lens I'm using. Is there really a lens out there which always delivers perfect focus using PDAF?

I have a personal theory that states that the wider a lens is, the harder it is for the PDAF sensor to tell the difference between in-focus and out of focus. This seems to be very much true for the two UWA lenses I have owned, as well as the wide end of my standard zooms.

3 upvotes

The Sigma 35mm F1.4 DG HSM focuses more accurately on the same camera bodies that we used to test the 18-35mm.

6 upvotes

from AF sensor's point of view, a lens' aberration (esp. peripheral for PDAF) and out of focus bokeh (may surpass the length of an AF sensor) at open can make problems. this means medium to not too large aperture lenses may perform better (say f/2.8 to f/4).

from the control point of view, some lenses may have heavy AF groups, non-accurate motor, old set of control commands, and bad execution to make AF slow and instable.

then Sig 35/1.4 may have well controlled peripheral aberration judging from the AF performance.

Comment edited 3 times, last edit 3 minutes after posting

0 upvotes

@David

If I'm not mistaken, a camera with phase detect AF actually says "focus to 1.667 meters" when it's not in live-view mode.

0 upvotes

how does it know to focus on the eyes instead of say nose or side of the face wide open?

1 upvote

For PDAF, the AF sensors are in fixed locations in the viewfinder, and chosen by the photographer, so the target for AF is whatever the photographer puts under the AF sensor.

0 upvotes

Great lens but boring bokeh. Lacks character (or you guys are no good at making interesting bokeh shots).

0 upvotes

But isn't that what the masses want? If a lens has any character people tend to complain that the out of focus areas are "harsh" or "nervous" or "blobby".

10 upvotes

lens design, like everything else, is a compromise of conflicting requirements and you can get much better quality if can afford taking out one or two specs and put into minor list.

the Nikon 24-70/2.8, the king between 2007-2012 and still top class zoom, got not so good bokeh either and field curvature is not corrected well.

0 upvotes

@yabokkie: "Not so good bokeh"? For a standard zoom lens I think it's superb, and at 70mm it's beautiful. Of course, it's not f/1.8, as you know.

0 upvotes

> Of course, it's not f/1.8, as you know.

both of them are f/2.8 equiv.,
whatever the job an aperture can do they can do the same.

Comment edited 13 seconds after posting

0 upvotes

@yab, Ahh Nikon, http://www.lensrentals.com/blog/2012/11/canon-24-70-mk-ii-variation

0 upvotes

>both of them are f/2.8 equiv.,

not on an aps-c sensor :p

@JDT the masses must be boring as well.

Comment edited 3 minutes after posting

0 upvotes

@D1N0: "the masses must be boring as well."

Haha. No Comment.

0 upvotes

What you are saying in the conclusion is that the OVF of the Canon was not up to the task of confirming focus. If you had tested on a Sony with EVF, maybe the conclusions of mis focus would have been different (focus peaking and magnification views).

3 upvotes

Difficult to test this lens on a Sony at the moment, as it's not yet available in Alpha mount. Also bear in mind that the real problem is inconsistent focusing wide open, and it's not obvious a Sony body would do any better.

7 upvotes

it might be an interesting idea to make an accurate shift adapter for Sony E mount to test all full frame SLR lenses on a NEX body and you could sell it as "DPReview shift lens adapter #1."

Comment edited 49 seconds after posting

0 upvotes

@yabokkie what the shift adapter be for, in the review? Many FF cameras these days support CDAF so the lenses' CDAF potential can be tested on a FF camera no problem.

Also this lens is APS.

0 upvotes

EVFs disgust me. I used one on a mirrorless camera close to a year; I ended up dumping that EVIL camera and all the accompanying lenses. Heartily ran back into the comforting embrace of my OVF DSLRs.

Just say no to EVFs.

Comment edited 47 seconds after posting

3 upvotes

Forget EVF - how about using the display?

0 upvotes

@photo nuts I suspect you may have been spoilt by decent large pentaprism viewfinders, I found the EVF on even the original Panasonic G1 far better than my previous DSLR's small pentamirror viewfinder in low light and at least as good (helped by the better magnification) in good light.

0 upvotes

@photo nut

what didnt you like about using an evf? and what camera was it?

the evf on the nex7 and omd work really well. i find them to be excellent performers. sure in properly lit scenes i prfer an ovf but once you get into more challenging light situations, the evf outperforms its counterpart.

i have often found ovf to be difficult to use with heavy backlit scenes and under low light situations. with practice and experience you can guestimate the proper focus but it cant beat the live view the evf's offer. evf's are a lot more immediate. there's no guessing involved. you dial in your settings and see how it affects your shot. the ovf can only compete under ideal situations. all else, the evf is more useful.

0 upvotes

Well deserved GOLD award Sigma.

18 upvotes

Wow. First comment, but I have nothing to complain about...

5 upvotes

Total comments: 275

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