Perhaps, it was indeed too soon to declare that I would only buy one A-mount lens in 2010. Here’s the second (the first being the rare Minolta 24-50mm F4.)

This is the Sigma 12-24mm F4.5-5.6 EX DG, which sets the world record for widest, brightest rectilinear lens for 35mm full-frame format. 122 degrees diagonal coverage!

Of course, my Peleng 8mm F3.5 circular fisheye does 180 degrees from edge to edge, but de-fishing the image to make a rectilinear projection loses a lot of resolution!

You can fit pretty much all you can see, in the frame!

Perspective distortion makes closer objects much bigger.

A common misuse of ultra-wide angle lenses is when they are not pointing straight at the subject – you get parallel lines converging. In this case it is recommended to stand further away, aim forward, and crop the excess floor.

However, it is great when you are in a tight space! I could not stand any further back.

It also gives plenty of leeway for group shots.

Also, you may find you’d be cropping feet a lot less often in tight spaces!

I used DxO Optics Pro Elite to process these pictures from the A900 – it applies a fair bit of barrel distortion correction, causing the corners to look more stretched out. Arguably, the barrel distortion of the original picture looks a bit more natural. Also, I shot this at a slower shutter speed, so don’t be confused between motion blur and stretched edges!

I was standing just in front of them.

So what about that other rectilinear lens for 35mm full-frame format? The Voigtlander 12mm F5.6 in Leica M mount? Here it is, with a Sony NEX-5 and Kipon M-mount to E-mount adapter.

It is, however, only for rangefinders with a shorter flange distance, or Sony NEX/Micro-Four-Thirds/Samsung NX cameras with an adapter. Though it won’t be so appealing on Micro-Four-Thirds due to the 2x crop factor, and the Samsung NX’s weaker ISO performance, especially since the lens is F5.6. It also does not zoom!

However, its main plus point is its tiny size!

I also stumbled upon the Sigma 8-16mm F4.5-5.6 EX DC HSM for APS-C cameras, which is slimmer, but has the same front-heavy balance. The Sigma 8-16mm focuses to 24cm close and has a front cap adapter (not to be confused with the lens hood) which takes 72mm filters. The Sigma 12-24mm meanwhile focuses to 28cm close and has a front cap adapter which takes 82mm filters.

While the 8-16mm does offer practical benefits in terms of size, there isn’t an APS-C camera that does 24 megapixels yet.