If the OP is still reading, this may be of interest:

http://cgi.ebay.co.uk/SMC-Pentax-A-Auto-50mm-Prime-Lens-f2-Excellent_W0QQitemZ11...

Only an f2, but with prices as they are that's not a bad buy.

I've seen that 35-70mm transparent before now. No reason for it not to work - it looks as though only the outer casing is transparent, the innards are all solid as per normal.

Most of the Pentax-F lenses are a good bet, check that the lettering next to the distance scale includes the letters "SMC" as not all had this coating, they did a couple of non-SMC zooms that were usually bundled with SF7s. I have one, and it's a pretty decent performer but struggles to bring much vibrancy to a scene. I may revise my opinion after trying it again come summer.

The other one that comes up cheaply (and is best avoided) is the F or FA 35-80mm. I bought one attached to an MZ50 for £10, which is about what they're worth! Not unusable but if you're after one good general use zoom then there are far better ones out there.

The birds eye might be fun to play with, but I can't see many people parting with as much money as it would most likely have cost. It would doubtless have been as expensive as any other prime, if not more so due to the lack of any economies of scale.

I do like the look of the 300mm f2 on the prototypes page though - even if it does rather resemble part of a CVT drive system!

There were also a handful of Pentax-branded zooms without SMC coatings - I think there were A and F versions of 28-80mm and 70-210mm without it. I have one of the Pentax-F 28-80mm lenses which is ok - solidly made, but it just doesn't seem to have the vibrancy of my other lenses where colour is concerned

Weirdly I wouldn't actually want to use my Pentax-A 50mm manually, as the aperture ring is plastic and doesn't feel anything like as precise as the M series version. On a DSLR that doesn't matter as you're setting the aperture via the camera body rather than directly on the lens. Just set it to A and treat it like a modern lens.

Here's a brief run-down on using manual K mount lenses on a DSLR (M or K series):

Go into your camera menu and set "allow aperture ring" (not sure of the exact wording)

Fit the lens, switch to manual focus and select Av or M mode.

When you switch on, the camera will prompt you to set the focal length of the lens so that the shake reduction can function properly. Just dial it in and press ok, this step also applies to A series lenses.

If you're in Av mode then the aperture setting on the lens doesn't matter. The camera will meter and shoot with the lens held at its widest aperture, regardless of what you set.

In M mode the aperture ring does make a difference, but you need to press the green button (or +/- button on some bodies) to have the camera stop the lens down and take a reading.

It does have uses, I've tested M series lenses on digital before using them with film to make sure that they don't have any problems and I do have a Pentax-M 135mm that I intend to use regularly with my K-m. But I try to stick to A series primes - now have 28mm, 50mm and 200mm lenses.

Manual zooms are a bit of a pain due to the need to set the focal length for the shake reduction, obviously when you zoom this will change but the camera won't know unless you switch off, on, and set the new length!

Buy the A version, it'll make life much easier!

Optically the lenses are identical. The M series lenses are earlier fully-manual lenses from the days when the aperture was set with the ring on the lens, the A are slightly later and feature the ability to have the camera body set the aperture (with aperture ring set to "A").

M series or earlier lenses on a DSLR require you to use Aperture priority or Manual modes, the former will meter and shoot with the lens set to its widest aperture while the latter can be a bit hit and miss in getting a good exposure. A series lenses will allow you to use all the modes apart from (obviously) Auto focus, as well as enabling the camera to report the aperture in the viewfinder and on the LCD.

Any K mount lens will fit and work, however the A series ones are more flexible.

I have one of these, they are truly tiny! Not too expensive to buy if you fancy getting hold of one as an interesting addition to a collection, I paid about £20 for a good example with 24mm lens and the smaller of the two matching flashes.


I had another one with the 18mm wide angle lens a few years ago, it's somewhere in the house (I hope) although I haven't seen it for ages.

Did anyone else have one of the really cheap 110 cameras where the whole thing was barely larger than the film (with a fold-up viewfinder on the top)?

Something that has occurred to me: Do we have a "Beginner's guide to manual lenses" here? If not, could we write one between us?

I'm thinking in terms of basic instructions for using them (enabling aperture ring, using green button in M mode, the fact that you don't need to do this with A lenses but that those need to be in A mode), and a few suggestions as to which lenses to look out for. There must be a few newbies out there who'd be interested in using an old prime lens or two but don't necessarily know how to make it work.

The main advantage that I can see is that you can try all sorts of effects. If you don't like them, just click "undo" and start again. In the darkroom you'd have to fully develop each image to find out whether it worked or not.

Depth of field relates to how much of an image is in focus, and it's a lot simpler to deal with on older manual lenses as they usually have a depth of field scale. Basically at f2.8 things slightly in front of or behind your subject will be out of focus. As you stop down the depth of field increases, so items around your subject become less blurry.

For example, if I'm photographing birds on a feeder with a telephoto lens I may want shallow depth of field to render the greenery behind a blur, making it less distracting and a pleasing background to the birds. The wider aperture will also allow me to use a faster shutter speed, handy when dealing with nervous wildlife. However, if I'm photographing a model truck in macro then I will want a deeper depth of field in order to have as much as possible of the subject in focus rather than a pin-sharp windscreen with a blurry bonnet.