"...However around the centre there is a circle of diamond shapes which disapear when properly focused...."

This is the 'microprism ring' and it is actually more useful in some ways than the split image centre.

It's a pity that one of these independant makers don't make a screen with just the microprisms because the centre could be plain then and the spot metering would probably work normally regardless of the max aperture of the particular lens in use.

"........Is it as accurate as the auto-focus? ..."

No!.....it's about a hundred times better!!

The fact is that manual focus using a split image rangefinder is THE most accurate method of focussing a SLR type camera. When you are practised at it it is also virtualy as fast as AF and frequently faster.

Then there is the amall matter of reliablility,....by the time you have grasped that the AF is not going to oblige this time that once in a lifetime shot is gone for ever.......

Why don't the makers use manual focussing lenses / split image r/f anymore?...

Because it's MUCH cheaper using electronic modules than it is to machine good foccusing mounts and cut precision screens with split-image r/f's, even if the electronics is deeply confused much of the time.

The big bug with all DSLR's is that they are consumer durables made by people who KNOW that you prefer gimmicks to accurate functionality and good design. That's one of the reasons why they ALL look like they have come from the 'Ford Mondeo School of Art and Design'.

What's it for?

George,

Pentax used to make FF lenses until relatively recently so it would not be difficult to dissinterr the designs,....indeed thay may have been keeping this very eventuality in mind.

A larger sensor (than APS) would allow less noise at higher iso as this seems to have limited the 10 meg cameras including K10 due to the physical size of the photosites.

Several places on the web are running 'official rumours' that Nikon will be using a 1.1 size sensor in it's new Dx3(?) pro camera to appear with or at the PMA show in orlando in about 10 days time.

This makes it more or less a certainty that Pentax will make a larger sensor model, since in order to climb the ladder they must chase Nikon in the manner of K10 chasing D200.....perhaps the legendary K1D.......

It all depends on whether Nikon enters the 'full frame' sensor arena,....if they do then pentax and others will be obliged to follow.

Just a few points;......

You could always use a 'cable release' which wil cost very little or even nothing and will work better in some circumstances that an electronic device,...you will have to rig up your own bracket for mounting as DSLR makers,..in their infinite electronic wisdom, or is it arrogance, have seen fit to deny serious photographers the facility of a threaded cable release socket.

Alternatively, how about a 'mini TV remote'?....these are tiny and very inexpensive. I was looking at some in a 'pound only' shop at the weekend,...for, surprisingly, £1

As regards the GX-10 / K10......the facts are that nobody really knows what the real differences are between the two as they are NOT identical........this will only be sorted out when someone tests them side by side using the SAME lens to make RAW files. Two or three so called side by side reviews have been done but until the above conditions are met they remain largely pointless.

".......I thought that the debate about prime v. zoom lenses had largely died a death....."

It has,...for people using zoom lenses.....

Then again quite a lot of those people think that a 5"x7" print is quite a large size. And, many of them don't really know what a really 'sharp' large print looks like because they have never actually SEEN one.

Quite a number of these people are the same ones who can't understand why one would cart a heavy tripod about......

Well you're the man to recognise it when you see it George.........

So as usual we are going to have to pay over a hundred quid over the odds for the privelege of buying this lens here in the UK......

Do aany of the independant makers do a 2.8 zoom at a sensible price?

Whats so great about this staggeringly expensive Pentax glass anyway?....when all is said and done, it's a ZOOM LENS!!!!....it's not like it was a high quality prime....nobody will be getting any really big prints using it, it's only a convenience and 'walkaround' lens.