I haven't really been participating much on this forum lately, so I thought I'd change all that. Today is my birthday, and being absolutely lovely,
Helen bought me a present. A 25mm, f/1.4 C-mount lens, complete with adapter. It was bought from eBay (
here's the auction itself, for as long as that link's worth anything). If you're reading this from the future, and the auction has gone, it cost £25, which in retail terms is usually about the same as $25 US.
So, here are a couple of pics of the lens itself, taken using Helen's GF3. All the images in this post can be clicked to see the image on Picasa Web, from where the full-sized original can be downloaded. All images are JPEG straight from the camera, with absolutely no editing, save for EXIF info about focal length and lossless rotation for portrait images.
Here it is off the camera. The lens came with two spacer rings allowing extreme close-up photography. They work, but extreme is the correct description. With one spacer, the maximum focus is down to about twenty centimetres. With two, it's getting quite silly.
Of course, being a cat owner, the place to start is with the cat.
Out of the window, the lens here was stopped down a little. There are no actual stops on the aperture ring. It has f-stops printed on the barrel, but there's no index mark (I'm tempted to add one). It smoothly closes down until the diaphragm closes completely, blocking all light. I exposed for the clouds (the sky was quite bright) so I'm guessing the aperture was around f/4 or f/5.
Leaving the house, I got the opportunity to see how the lens was with all sorts of light levels and at all sorts of scale. Here are the steps on the bridge at Jarrow Metro station. You can see that the steps sort-of remain in focus from top to bottom. The focal locus isn't a plane, and I spent the day getting to know the focal characteristics of this lens.
On top of the bridge, I didn't have time to focus on the train we were running to catch, so I stopped down a lot and just snapped. The depth is quite good here, although the vignetting is very noticeable. We made that train there on the left with about a second to spare.
Newcastle upon Tyne. This is Grey's Monument, and it's here that I managed to get a feel for the focal locus's shape. You can see that Earl Grey himself is in focus, as is the column about two thirds of the way down.
Here on the entrance to nearby Central Arcade, you can see that the focal locus is in fact a focal paraboloid, and quite a long one. The bottom of the arch is in focus, as is the entrance to the wine shop within.
Helen took this portrait of me in one of the shops. She didn't bother to focus, because she got lucky - my chin, my eyes and the brim of my hat are all spot on!
Here's Helen, when we took a break for lunch in a coffee house. Stopped down just a touch, the lens brought the background out of focus very smoothly, without any of the swirliness you'll see on other shots.
In the coffee shop, this shot really shows the parabolic shape of the focal locus. Clockwise, you can see that the purplish chair, the espresso cup on the tray, the cupboard on casters, the pictures on the wall at the back, the backs of the chairs on the right and the wood on the corner of the wall are all in focus, as is most of the floor.
I love this candid shot. Black and white suits this lens, I think. I love the area isolation that the crazy focus can give.
A quick snap of a jeweller in the street. Not technically amazing, but I like it.
This is
Ojay, a very well known and popular busker in Newcastle. I think he'd be pleased that I got most of his bass in focus, if nothing else.
This band on Northumberland Street wasn't so easy to photograph. The shot feels all over the place, if I'm honest... but so was the music. There's a dizzy feel to the image.
A couple of fairly random street portraits. This lens is small and unobtrusive, and it's clear that people aren't intimidated by it!
Helen's cool boots, waiting for the Metro home.
Now a couple of technical photos, just to show some down-sides to the lens. First, the Theatre Royal. This lens really doesn't do buildings very well. The focal locus is concave, whereas buildings are (on the whole) convex. It can be good at picking out a single detail, but not really capturing the whole structure.
The train shed roof at Newcastle Station. As you can see, there's quite severe chromatic aberration, purple fringing in particular, wherever there's high contrast in focus.
Subject isolation is quite nice in close up. The second of these two pictures of wild roses is showing three different branches in focus at different distances; the middle stem is about twice as distant.
This is a shot from my back window, stopped right down. As I mentioned before, the aperture can be closed completely. This was
very nearly closed. The wheelie bin in the garden was in bright daylight, and the exposure was two and a half seconds; I estimate the aperture to be something silly like f/100. The aperture closes to a slit; two opposing leaves come together. You can see this in the smeared diffraction blur. You can also see all the crud on my sensor's filter, and the vignette is hard and circular.
Finally, I laid some objects out in front of my keyboard (on which I am typing these very words). With the lens wide open, the remote control, the fountain pen converters in the drive mounting rail, the end of the fountain pen, the space bar, the mouse and the Bluetooth GPS unit are all basically in focus, following the paraboloid's intersection with the desk. The lens cap sat between them, however, is not in focus at all. Mind-boggling.
I love this lens. For the price, it's phenomenal. It's truly different to my other primes, and has a character all its own. I'd go so far as to say that it's not worth being without one. It's physically small, very light, and the adapter is nearly a flat disc. Inexpensive, small, light and half decent.
Finally, a couple of videos on Youtube.
Pan around the coffee shop
Aperture demonstration
10Thanks
My birthday present: 25mm F/1.4 C-mount lens. Lots of pictures!
