Rokinon 8mm vs. 10mm vs. Sigma 8-16mm vs. Pentax 10-17mm Ultra-wide Showdown

Sigma 8-16mm Rating

The second of the two zooms, this one-of-a-kind zoom came home with this report card:

Pros

+ Very well built and attractive, minimalist design
+ Compact despite extremely wide 2x zoom range
+ Excellent center sharpness from wide open
+ Quick, accurate, and silent autofocus
+ Autofocus override via focus clutch
+ Well-designed and well-placed autofocus toggle switch on lens body
+ Mitigates vast majority of chromatic aberration
+ Excellent color rendering and "punchy" contrast
+ Above average flare mitigation, even in harsh sunlight
+ Zoom range of 8-16mm provides high versatility and UWA coverage
+ Only rectilinear APS-C lens to reach below 10mm - a truly one-of-a-kind zoom with an exceptionally wide field of view

Cons

- Lacks weather sealing or front filter threads
- Strong, inconsistent distortion below 10mm
- Slow aperture regardless of focal length
- Very strong vignetting from wide open until F8.0
- Front heavy when attached to lighter cameras
- Soft corners
- Discontinued in K-mount; difficult to find
- Issues recording EXIF data between 8-9mm
- Causes camera meter to underexpose
- Embedded hood makes it difficult to clean bulbous and deeply-seated front element

Rating

Bottom Line

The Sigma 8-16mm lens remains one of the most unique lenses we've had the pleasure of becoming intimate with. Fitted with an in-lens motor, there's not much more to ask other than weather sealing and perhaps better vignetting control. But if you are willing to live with these demerits, it truly is wider than any other non-fisheye lens there is—both primes and zooms—offering something you can't find elsewhere. And it does so in a relatively compact package with colors so rich you'll forget about not being able to attach a circular polarizer - we would swear there's one built in!

At the end of the day the only real constraint is its availability. Our "Value" rating above garnered an 8/10 because while it is a bit on the pricier side, it's still an excellent value for what it offers and how unique it is. The issue is finding a copy since it has been discontinued (only in K-mount) for some time now and must be purchased second-hand.

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Feel inspired to acquire your own? eBay is a good place to look for it.  Also, keep an eye on our Marketplace as they show up from time to time. Have your own and still haven't left a user review in our database? Do it now! Or simply see what other Pentaxians had to say about this lens from its many user reviews.

Our last individual lens rating, the Rokinon 10mm prime lens stands between you and the overall review conclusion.