You could check that you have set the custom functions to centre spot autofocus, otherwise the camera will choose one of the autofocus points and this will change when you recompose. Very annoying and one of the first things to reset! With centre point autofocus you just point the camera at the target, half press the shutter release to lock the focus, keep it half pressed whilst you recompose and then fully press the release to take the shot.

When focusing in low light it will take all cameras longer - again a half press on the shutter release will start autofocusing and then when focused you can complete the action to take the picture. Again, make sure the custom settings are appropriate - I have the metering lock and autofocus lock set to the same point, for example.

Kim has summed things up pretty well there, but there is one factor that makes the MX a better bet - reliability. If I wanted a camera to take on a long trip I would rely on the MX more than the ME and derivative designs. I had lots of these over the years, and they all eventually suffer from various electronics problems. The MX is a very straightforward design and I have never had one fail.

Even the LX, superb as it is, does share some of the electronics traits of its less expensive siblings.

Changes could relate to the two new factories built by Pentax to respond to the high demand for the M series cameras. Or simply that they changed the sourcing of some bought-in components.

The ME cameras sold more, and probably a lot more if you count all the avriations. From memory, and subject to correction, the MX started at 15,000 per month and was increased to 25,000 per month. The ME went I think from around 25,000 a month to almost double that.

Of course that still doesn't give us an accurate total as it will have grown, peaked and fallen off. And the figures could be wrong....

If I can find the actual figures I have recorded somewhere, I'll let you know, but it'll still be as vague as above!

For Pentax info, depending on which era of Pentax you are interested in, there is this site, the Pentax User Club and magazine, and a wide variety of books that you could look at on Amazon or eBay. If you can be a bit more specific about your interests perhaps we could narrow it down to some specific suggestions.

There are plenty of Zeiss lenses for 42mm screw mount, but these are of East German origin and will not be up to the superlative standards of the West German lenses. Your Program Plus is a KA-mount Pentax and you will be well served with almost all bayonet Pentax lenses, but especially K, M and A series. Of these manual focusing lenses, the A series will allow all program modes to be used and will also be fully functional on your digital body.

You can also use all the Pentax autofocus lenses, but the latest versions with no aperture ring will only give full function on your *istDS. Also the DA lenses do not cover the full 35mm frame, so will cause vignetting (corner darkening) on your film SLR.

I presume that it's the same as the Epson, in which case I wonder why anyone would want to pay £2000 for a digital RF that has the same 6.1MP chip (probably) as the *istDS and which on tests performed quite badly.

Might as well spend a quarter of the price and get better results....

DOF relies on us being able to tolerate an image being slightly out of focus and not being able to tell the differnce. This is, of course, the "circle of confusion", the disc that the human eye cannot distinguish from a point.

In fact, a lens is only properly in focus at the distance it is focused on.

But as George says with ultra-wide designs, there's a considerable amount of DOF.

I used to have the Pentax 15mm and it was pretty difficult to take an out of focus shot....

It was a nice idea! The Voigtlander lenses that would be useable are quite interesting, but unfortunately the aperture rings work in reverse. That ruins the ergonomics - it's confusing to have lenses that are operating differently.

Another reason to stick with Pentax lenses!

I think that some or all of the Voigtlander lenses may be available in K mount versions - check with the importer to be certain.

Hi Kim

Thanks for that info - it's well out of my league as well....