Just picking up Rod's comment about batteries.

In any event, I always change all my camera batteries annually, every July. I have never had to change them more often for any of the Pentax cameras, either the M series ( 2 G13 cells) the MZ series ( 2 CR2) or the 645n (6 AA). In the case of the 645n I have put quite a few films through and the Duracell Ultra batteries are still going strong at the end of the first year.

Just to say that I have been really delighted with the handling and the quality of results from the 645n. It really is a logical step up for the Pentax 35mm SLR user - everything operates in exactly the same way and is instantly familiar.
I use the 645 format for large black and white prints, where the difference in quality is very obvious. It is best to use a tripod to get the best out of this camera, but hand held use is also possible with care. Because you can see the extra quality, though, you start to look for it and expect it, and the limitations of hand holding can become more marked.
The next purchase will hopefully be a wide angle lens - the 35mm-55mm zoom looks very interesting, but I might have to settle for the 35mm or 45mm which will be more compact, less expensive and might still have the edge on quality.

I think the viewfinder on the 645n is probably the best I have ever used - sharp and contrasty and superbly easy to focus manually.

I'm hoping to extend my lens range soon, and the 120mm Macro will be the first, for exactly the reasons that Rod gives.

I use a 645n with, at the moment, only the 75mm AF lens. The quality of this is very high indeed. I have also had experience of the 80-160 manual zoom, but I feel this lens is too big and heavy.

I too am planning to expand my lens range. For a wide angle I am looking at the 35mm or 45mm. For the short tele lens I was lookin at the 150mm, but the way my studio portraits are evolving I need to get in very close, so I may well opt for the 120mm Macro lens instead.

I expect all these lenses to be of the highest calibre. A 20"x16" black and white or colour print should be no problem at all. Certainly the quality is significantly better than 35mm results - for example, the improved skin tones are very obvious.

You cannot use the A setting on the lens with the Pentax K1000, which is a fully manual camera.

You are correctly setting 1/60 which is the flash-synch speed. On the automatic flash gun there will be some colour coded settings for automatic operation. For example, one of my guns has a red and blue setting. Let us assume we are using a 100 ASA film. The red setting then indicates an f/stop of f/2.8 and this would be set on the camera, offering automatic flash exposure from 7.6 to 40 feet. The flash gun will cut off when enough reflected light has been received by its sensor. The blue setting indicates the use of f/4 and offers automatic flash exposure from 5 to 30 feet.

This is only an example and your flash gun may have different colour coding and may be more powerful than the one I have quoted, but the principle remains the same.

Hope this helps!

My wife Sue uses a Canon S30 and some of the Jessops CF cards are SanDisk. There is only a very slight delay writing to any of the cards, no longer than the brief time the last picture is displayed, and she has never perceived it as a problem. Only a subjective answer, I know, but I hope it helps a little.

If you use any lens of a given focal length on a different format it will deliver the same image in all cases. But if the format is bigger than the lens is designed for it will not cover all of the negative (or CCD). Also, an 18mm lens on a small format will not be as wide a wide angle as on 35mm. So an 18mm lens designed for a digital camera will behave like any other 18mm lens when used on a 35mm camera, but it will need to have been designed to cover a 35mm frame to use it fully and there may also be issues with the other optical parameters - chromatic aberration in particular.

Hope that starts to help, but optics is a complex subject.....

The new Canon actually introduces yet another incompatible Canon mount!

I will stick to my (broadly) compatible Pentax lenses and will certainly be looking to purchase the new *istD. Hopefully, the new Canon camera will at the very least cause a downwards pressure on pricing generally. We shall see.

It all depends what you want to do with the images, but before I get anywhere near ready to buy a digital SLR it will need a full size chip and a resolution of over 10 megapixels. I was once talking to a scientist and in a rough guess we estimated that the average Kodachrome slide probably had an equivalent resolution of 50 megapixels. Then I bought a Pentax 645n and the goal posts moved again...

Thanks for the help, Matt, much appreciated!