If a 50mm f1.7 made by Pentax isn't sharp, even wide open, then something is very wrong with the lens or the technique.

If you set a MF lens to MF on the body then the shutter will fire at any time. Use a MF lens with AF set and it will only fire when in focus. This can be used for "trap focus" technique where you depress the shutter release and slowly turn the focusing ring until the shutter fires at the focus point.

The 2CR5 battery is absolutely up to the job. Don't forget that, unlike a DSLR, there is no screen to power, so the requirements are far less.

Interesting question. Maybe some would buy one for the perceived kudos of owning one.

Photographic reasons would include the very high level of control of coma, so point light sources are reproduced without smearing or distortion. In this reapect the Pentax lens is one of the best ultra fast 50mm lenses of any make.

It would also make manual focusing much easier in very low light.

In terms of quality it is as good as any of the 50mm lenses when stopped down to f8 and beyond, so it can also be used for general purposes. It is not suitable for use on bellows and other close up accessories because of increased curvature of field. That's the price we pay for the speed.

Time to calm down this discussion, there's no need for any of us to get annoyed.

Keep it civil please.

3200 ISO is no longer considered as unusual though. When I referred to "high ISO" I was really referring to the ridiculous 128,000 ISO sort of figures, which I do think are not necessary. You would lose the ability to control aperture by having to stop down too far, just as you would in daylight with ISO 1250 film. There's no scope for anyhting other than 1/2000 sec at f22 in bright light.

In practical use, I've never had a problem with 1600 ISO on digital - I use it as necessary. Sharp and grainy is always better than shaky and smooth.

I think this is starting to stray from the point, so to get back to what is a computer.

Surely if your computer is stolen and you say to a friend "my computer has been stolen" then they are not going to think you mean your camera. They know full well what your computer is.

They might ask "desktop or laptop?" but they will know what we all mean by a computer.

"Affirmative, Will Robinson....."

People compute but are not generally thought of as computers...

I suspect we all know really what a computer is, even though it is true that many items have computing ability.

An abacus is a primitive form of computer and there are totally mechanical computers that have been built that are not electronic. I think the OED definition, as given anyway, is somewhat lacking.

It just shows again how difficult it is to truly definitively define something.

Ah, but a camera is not a computer. You can't send e-mails and surf the Web on a camera. And you can't take photographs with a computer.

It's the same argument as "All elephants are pink. Nellie is an elephant, therefore Nellie is pink." Unfortunately for the argument, elephants aren't pink....