OK, here's my lame go at the same thing. GX-10 top, GX-20 bottom, both with 18-55mm kit lens at 24mm, Av, f10, ISO 100, auto white balance. Exactly as Steve's: "The images were imported into CS6 by ACR, no adjustments were made. Colour balance left as shot.Images were resized to 900 pixels wide in CS6 (resampled, bicubic sharper) and saved at highest quality JPGs."

I'll leave it to others to determine any differences. I can tell, though, that the GX-20 has a tendency to introduce kittens into the picture...

First the GX-10:

[IMG]http://i1278.photobucket.com/albums/y507/crispinian/GX-10%20vs%20GX-20/GX10-web_zps2553c148.jpg[/IMG]

Now the GX-20:

[IMG]http://i1278.photobucket.com/albums/y507/crispinian/GX-10%20vs%20GX-20/GX20-web_zps6e548bf3-1.jpg[/IMG]

Maybe I need to link to larger images? I've never used Photobucket before, so maybe someone could briefly tell me what to do.

I've just got a GX-20 to replace my GX-10, but I haven't sold the GX-10 yet. I have the kit lenses for both. I'm thinking I should try and get some identical shots at 100 ISO from both cameras to compare side by side. I REALLY hope I don't end up preferring the GX-10 ones...

As the original poster, I hope no-one minds if I interject with what is now no more than an aside on a thread which has strayed a long way from its original intention...

I have ended up buying a GX-20 off eBay at what seems to be to have been a very good price. I daresay that was not affected by the pending release of the new model in any way.

You are quite right, this is what I was enquiring about. I just wondered why anybody would actually set the mode dial to Av or Tv, given that both are available off the P setting depending on which wheel you turn. But 'as a statement of intent' seems the best answer, really, if there are no actual technical differences.

As a brief follow-up, I've been taking some photos with my 28mm A f2.8 lens, and the exposure seems pretty spot-on to me. (Having said that, a bunch of the photos are incorrectly exposed in some way, but that's no fault of the lens. Every tried photographing a black kitten? Very difficult, especially when she's alongside her ginger brother).

Interesting idea! So more of a question of commitment, then, rather than any actual technical reason.

There is another mode, the Green completely automatic one, which I have never once used. I don't even really know what it does, but I assume that it makes decisions I would prefer to make myself. Might as well let the camera decide what to photograph.

I think we're talking slightly at cross-purposes here. I'm not questioning why there are straightforward aperture priority and shutter priority modes on the camera - they certainly need to be visible there for anyone coming afresh to the camera, for familiarity's sake. My question is rather why would you, or another skilled and experienced user of these cameras, switch to Av instead of P? Does Av provide anything which P plus rear dial does not?

LATER: The above was in response to John Riley's comment.

Sure, that's the reason I use(d) Av mode as well. My point is that P mode, as far as I understand it, gives you both Av mode and Tv mode, depending on which dial you adjust. So is there any reason why you would set your camera on Av mode, instead of leaving it on P and adjusting the rear dial?

Given that I'm pondering buying a K30 or K5, I'm wondering whether I should hold off until the new model is announced, assuming it will be at some point in October (as people seem to think). This is on the basis that retailers would discount some of their older stock, and that some serious users might want to upgrade and off-load their older camera. Is this what actually tends to happen, though?

Probably a stupid question, but here goes...

I've been getting to know my GX-10 a lot better of late. Having been used to aperture priority on film cameras, that's what I was using on the GX-10 until recently, when I started exploring the functionality rather more. I now tend to leave it in P mode most of the time, as it seems to me that it does exactly the same as Av mode if you want (one of the dials sets the aperture), plus you have the option to prioritize shutter speed instead with the other dial. Given this, why would I want to use Av mode? Or even Tv mode, come to think of it?