Help! dslr numpty asking questions

I bought a Pentax-A Zoom 1:3.5~4.5 28~80mm for £39 and have put it on my K-7. As I am a numpty and new to dslr I want to know if it will auto focus and if so how?

No, it can't auto focus as it has no screw drive. Pentax-A is a manual focus series that existed before Pentax had any AF cameras. Switch the camera to MF.

However, you can use the camera's green hexagon focus indicator in the viewfinder. Also there is the Catch-in Focus feature. See the camera manual for that.

Thanks iceblinker i thought as much hence the low price. i had noticed that when i focus the green hex appears and i have it set to beep when its focused too, very helpful. but i will say that it has very good iq much better than the 18-55 kit lens i bought with the K-7.

This is a manual focus lens, I feel sure, Steve.

You can use it on your K7 (how I envy you owning such a camera!) but you'll have to focus it yourself (not difficult - everyone had to do it not that long ago and I do it all the time.) Because it's an 'A' lens you can, however, lock the aperture ring and use the camera in aperture priority or program. You'll get focus confirmation (probably - I do on my K100 D) and, of course, image stablisation. You'll need to delve deep into the camera's menu to find a page which will say something like "Allow use of lens with aperture ring" or something similar. You only need to do this once.

Beware, though, do not buy any more manual lenses: they become addictive! YOU HAVE BEEN WARNED - I rarely use my autofocus standard lens and can't afford the new Pentax, Tamron, etc. lenses (it is only a hobby for most of us, after all).

Best wishes,

Andrew C.

Invest in a lens hood. As that lens does not have SMC coatings it will flare a little more easily than coated lenses.

Welcome to the wonderful world of MF glass. As has been noted, it can be addictive...

I'm not sure how that lens could be better than the 18-55mm DA lens. Mine is one of the best lenses I own, only bettered by my collection of old primes (fixed focal length lenses, eg 50mm, 55mm, 135mm). I have a slightly broken example of the Pentax-A 28-80 like yours (it doesn't extend when you turn the zoom ring, I fished the loose screws out but have yet to dismantle it enough to reinstall them) and to be honest it isn't the best lens of that era.

What you will also find is that the camera wants to know the focal length of the lens for shake reduction, which gets annoying with a zoom as obviously this changes when you move the lens! Obviously this isn't a problem with primes as the length doesn't change. That said, some manual zooms are quite desirable - I have a Pentax-M 75-150mm f4 on the way which seems very well thought of.

If you want an AF 28-80mm lens take a look at this. I have one of these lenses in silver, not the finest but a perfectly acceptable piece of kit.

When buying MF lenses have a good look around ebay. I saw several 75-150mm zooms for £50-£60, but waiting saw me net one for £25. I've even managed to find things like a Pentax-M 50mm f2 for £5 (needed a bit of mould removing but is now excellent) and a 55mm f1.8 for £8.50 (pretty much perfect aside from a little dust).

Anything from before the A series lenses will require you to use some special techniques in order to make it work, as the camera body won't be able to read the aperture from the lens. There are plenty of threads on here about how to do this and it's really simple when you have the camera in your hands.