Recently I exchanged the Sony 20mm f/2.8 that I bought when I purchased my a6000 not that long ago for the Rokinon 35mm f/2.8. My thinking was that the two lenses were redundant since 35mm (50-ish in full frame terms) was my preferred focal length and the Rokinon seemed barely larger than the 20mm (2.43 x 1.30″ (61.8 x 33 mm) vs 2.46 x 0.80″ vs (62.6 x 20.4 mm)) while gaining another full frame lens in my quiver. No brainer, right? Nope. I really like the Rokinon, but it was not a suitable replacement for the 20mm. Why? Glad you asked:
- Despite its tiny profile the Rokinon better marries with the full frame Sonys in operation. Where focus speed seems adequate on the A7Rii it is less so on the a6000. No idea why. While not awful on the a6000 it is nowhere near as fast as the 20mm on the a6000. Had no idea how good that lens was until I no longer had it… The framework for an R&B or Country song right there.
- 0.5″ (12.6mm) does not seem like a huge difference in theory, but in application that turns a very pocketable camera into a somewhat pocketable camera. Also the slightly rounded front edge and metal build of the 20mm meant it went in and out of pocket far easier than the square cornered and plastic Rokinon.
Simple fix. Buy the 20mm again. One problem. Southeastern Camera had two tempting full-blown second-hand cameras (ones I always thought about buying) that barely cost more than the 20mm lens new that would be even smaller than the already petite a6000. The thinking was that for a little more spend than a lens ($350-ish) I could potentially have a whole camera ($500-ish).