I recently accquired a cheap brandless CCTV C-mount lens from E[vill]-bay for the grand total of SGD$41 plus shipping. I already have the C-mount adaptor from JLphoto so naturally since the flange range of the Nex is the shortest (18mm) which means I can mount literaally all known lenses ever produced in the market...
I picked 25mm as I already have other various 28mm, 35mm and 50mm in other mounts (mostly in M42 or Leica M-mount) And before the purchase, I already suspected that there will be very strong vignetting if I used this lens on the Nex.. This is because it already shows strong vignetting on the Oly/Panasonic m4/3 sensors which has a 2x crop factor.
Nevertheless, I already have a plan to reduce the vignetting by composing my shots in square formats :) So basically I took a shot and crop it later in lightroom.
The lens is pretty sharp.. at the centre of course as you can see in the pictures below. Colours are pretty vibrant too! Its bloody multi-coated some more! hehehe
I would say its the cheapest arsenal in my lenses (about same price as those Diana lenses but much much better built of course)
Its a very good buy to me and I actually quite like it as I did not need to spend time PS other then crop and adjust a bit of contrast or brightness. At first I could not get the lens to focus sharply because the mount seems to be too close to the sensor.. Might be the adaptor fault but after I put a rubber band on the mount and slightly increased the flange distance. It works marvellous. It also comes with an extension tube too, allowing me to go macro :P
And the good part is that with the tube extended.. the Vignetting actually was actually lesser. So I could get a full square photos with little falloff. Another funny thing about this lens is the aperture. It is round all the way till f/2 but starts to become rectangular after f/2.8 ... hehe.. So you might experience wierd bokeh if you stopped it down . I shot mostly wide open in these photo so maybe I will post some examples later.
Highly recommended for those who like special effects in their shots without the hassle of photoshop. And yes, of course you can use your thousand dollar lens to shoot and edit the effect in PS. But I rather spend $40 to have a less of a hassle.
The point is. Know your equipment and shoot accordingly to the strengths of the equipment. As the post title says. Cheap lens does not mean lousy photos :)
You may enjoy the rest of the series here in my facebook album.