... with light, not with Photoshop.

Forgive the digression, but has there ever been an F1.0 (or less) lens?

Or indeed if you simply want to use less than 100% of the frame.

Suppose you crop the frame to half the linear dimensions (ie half the height and half the width).

It's not an extreme crop, especially for a distant subject. But your 6 MP is now only 1.5 MP - not even as good as a lot of mobile phones.

Not shooting at the maximum resolution possible is just a pointless limitation. What use is all that spare space on the memory card? In comparison with the £700 for the camera, the cost of a couple of spare cards is negligible.

Erm, what is?

Back in the old days the bloke would look at the image on a ground glass screen, and it would be big enough to actually look at from a sensible distance. Ok, he had to have a cloth over him because it wasn't all that bright, but never mind. Presumably the image was upside down, as well, but that's just another minor detail.

Then we had viewfinders.

Now, of course, we've come full circle - and we have these stonking great LCD screens taking up the entire back of the camera. They're bright, the focusing is done for you, and they let you see what the picture will look like from the same sort of distance that you'd look at a print.

In due course, I expect, SLRs will implement live view too.

But I think in times to come, viewfinders that you had to jam uncomfortably up against your face will be seen as a bit of an aberration.

This was simple. Also a bit unoriginal, I was just messing about with some long exposures really. But maybe something along those lines...

Edit.. this one's a bit better, maybe..

Cheers Pete - it just makes life a lot easier for the one looking at the photo.

The reason I prefer links once the thread discussion is under way is because you don't have to scroll for miles to get to the comments.

If a picture can be seen in its entirety when it's the first in the thread, I think that's fine. For subsequent ones I like to have the choice of clicking on a link - and of course if it's a link, you get the pic in a new tab (or window), and can toggle between resized for the window or full size, which is nice if you want to look at a particular part of the image.

Just my preference, though, nothing more.

I wish you'd post large photos as links like this all the time - it's the only time I ever get to see the whole thing when they're in portrait orientation, since the browser resizes them automatically, whereas it doesn't when they're inline. I'm sure I'm not alone in having a monitor with a resolution of 1280x1024, and in not having the patience to constantly copy it elsewhere so that I can see it all.

Totally accept this.

But can anyone answer this more specifically?

I'm likely to stick with the '10 for quite a long time. The Sigma seems brilliantly specified for the price... whence the huge price differential compared with the 540?

Is this any more true of Sigma than other makes?

Even Pentax - there are only two flash guns that work properly with the K10D AFAIK, so anyone that bought the K10D and already had a non 360/540 Pentax flashgun is pretty stuffed.

The point is, the Sigma EF 500 DG Super is less than half the price of the Pentax AF540 FGZ.

If it works well with the K10D, the £185 you save (at Bristol cameras, haven't checked any others) with the Sigma is hardly insignificant.

I'm just a simple soul, with little experience. I've bought three SLRs in my life, and none since about 1990 - I'm not likely to get another one anytime soon.

What would the real disadvantages be, buying the Sigma rather than the Pentax. Is the build quality poor? Are there some features missing (I got very bogged down in the spec sheets, so a simple comparison would be greatly appreciated)?