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

Introduction

Have you ever wanted to get more of the scene in front of you in the frame than your current lens allows, especially if you don't have room to take a few steps back? Arguably the easiest way to do that—especially if you take into account stitching images together—is the acquisition of a wide angle lens. The most extreme wide angle lenses are known as ultra-wide: these can deliver diagonal fields of view well over 100 degrees, up to 180 degrees in the case of fisheye lenses.

We compare four of the widest lenses currently available for Pentax



In this day and age, there are many options afforded us as photographers to expand our fields of view. This comparative review, however, will be focusing on the four very widest lenses currently available for the Pentax K-mount (and the APS-C sized sensor)*:

We thus have a prime and a zoom from the rectilinear (non-fisheye) side of the house, and a similar pairing of fisheye lenses. If you are unsure, don't worry about what "rectilinear vs fisheye" means: in the pages to follow we've laid out what the differences are.

All four of these lenses are available new as of 2016, though the Sigma 8-16mm can be hard to find.

So whether you are in an open stadium, a tight bathroom, or on top of a mountain, which of the four do you believe will widen its lead on the path to being crowned the premier ultra wide angle for Pentax APS-C DSLRs? Read on to find out!

*EDITORIAL NOTE: Yes, there is the Sigma 4.5mm Fisheye that is technically wider, however it is so incredibly niche as a circular fisheye (the other two are diagonal, filling the entire frame) that it didn't warrant inclusion in this comparative review.