Sigma 18-35mm f/1.8 DC HSM Lens

On Thursday, April 18th, Sigma has officially announced their all new Sigma 18-35mm f/1.8 DC HSM lens.  This is a revolutionary lens, because it is the first zoom lens released with a constant aperture of 1.8.  In fact, the largest constant aperture zoom lens currently offered from other major camera lens manufacturers (e.g. Canon, Nikon, etc) is 2.8.  This is more than a full stop improvement in “light gathering power.”  In other words, when shooting with this lens wide open, you will be able to have a full stop of extra shutter speed or lower ISO, as compared to f/2.8 lenses.

Sigma 18-35mm f/1.8 Lens Review

For now, consider this review a preview.  That said, I will be continuously updating this preview with information about the lens as it becomes available, and ultimately will provide a review as soon as I am able to obtain a copy of the lens.

Currently, Sigma has not released any information about pricing or availability of the lens.

Sigma 18-35mm f/1.8 Side View with Hood

The lens is made for APS-C sensor camera bodies and Sigma has classified it under their “Art” category.  Sigma describes the Art category as:

“Along with landscapes, portraits, still-life, close-up and casual snaps, they’re perfect for the kind of photography that unleashes the inner artist. Ideal for studio photography, they offer just as much expressive scope when capturing architecture, starry skies, underwater shots and many other scenes. The full realization of the Art concept, the Sigma 35mm F1.4 DG HSM is the perfect flagship. Hold it in your own hands and appreciate it with your own eyes.”

Sigma claims their zoom lens “offers the same high optical performance of a fixed focal length lens.”  We shall see if these lofty words prove to be true or not.  I get the feeling they are equating a wide constant aperture zoom lens’s quality with that of a wide aperture fixed focal length lens, which is rarely the same thing.  It will be interesting to see if they can back these claims with this lens.

Sigma 18-55mm f/1.8 MTF Chart

Sigma 18-35mm f/1.8 Vignetting Chart

The lens will work best on APS-C sensor camera bodies.  This isn’t immediately clear in Sigma’s information about the lens.  In fact, on the main features page on Sigma’s website, they say “Introducing a new large-aperture APS-C format standard zoom lens.”  Upon further inspection of their information, listed on another page, Sigma explains that “vingetting will occur if the lens is used with digital cameras with image sensor larger than APS-C size or 35mm SLR, and APS Film SLR cameras.”  They also mention that the angle of view will vary depending on which camera body the lens is mounted on.

Sigma 18-35mm f/1.8 Lens Construction

On the variety of APS-C bodies from different manufactuerers, the Sigma 18-35mm f/1.8 lens will have a different equivalent (to 35mm) focal length, as listed below:

  • Canon: 28.8mm-56mm
  • Nikon: 27mm-52.5mm
  • Sigma (SD 9, 10, 14 and 15): 30.6mm-59.5mm
  • Sigma (SD1): 27mm-52.5mm

As can be seen in the picture to the right, the lens is constructed of 12 elements in 7 groups.  The front element of the lens does not rotate due to the inner focus system design.  This will allow for use of rotating polarizing filters without issue.

Sigma 18-35mm f/1.8 Front View with Hood

A nine bladed apeture should offer exceptionally round and beautiful bokeh, at any aperture.

New features beyond the astonishing aperture include a newly designed lens cap and AF/MF switch, a new lens hood, a brass mount and rugged build quality.  Additionally, the 18-35mm lens offers a hypersonic motor providing fast and quiet autofocus as well as full time manual focus override.

Sigma 18-35mm f/1.8 Distortion Chart

Sigma describes a vareity of challenges they overcame in order to create this lens.  Specifically, due to the wide aperture, it was very difficult for them to minimize spherical abberation, axial chromatic aberration, astigmatism and field curvature.  The company cites it’s experience in making the 12-24mm f/4.5-5.6 II DG HSM and 8-16mm f/4.5-5.6 DC HSM lenses. Sigma also re-iterates it’s new quality control techniques using a 46-megapixel Foveon direct image sensor.  A graphic on the lens distortion from Sigma can be seen to the right (click the image for a larger view).  All things considered, it looks like they have done an excellent job correcting for lens distortion.

Sigma USB Lens Dock

And finally, as with all of Sigma’s new lens series, it will be compatible with the Sigma USB Dock (sold separately).  The lens dock will allow firmware updates to the lens as well as allowing focus adjustments.

Final Thoughts

I think it’s safe to assume that based on Sigma’s new “high class” commitment to their lenses, the build quality and usability of the lens should be superb.  The only missing piece of information about this lens from Sigma is sample photos.  How sharp will the lens be corner to corner shot wide open?  How sharp will it be in every day use?  How will the color rendition be?  How clean will the bokeh be?

I guess we will have to wait and see.  I will be sure to create a full review of this lens as soon as I am able to get my hands on it.

Intersted in getting this lens?  It can be ordered today for $799.00

Sigma 18-35mm f/1.8 Side View

Lens Specifications

Lens typePrime
Focal Length12
Image stabilizationNo
Ultrasonic MotorNo
Filter Size46mm
Lens construction11 Elements in 8 Groups
Closest Focusing Distancein / m
Maximum Magnification0.08x
Size56 x 43mm
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