[Xperia Z1 Compact General] davew:
[engage photo nerd mode]

I've been doing a lot of testing, and the raw material we have to work with from the Z1C isn't ALL that bad. The focussing is a bit off, I agree - but experimentation with the different focus modes pays dividends. ISO noise is also bad - the Z1C produces more noise at even modest ISO levels so it is vitally important to keep to 200 or up. If you nail the shutter speed, ISO and focus the basic image quality its really not that bad - the dynamic range and sharpness is actually quite acceptable and better than say, an iPhone 4S and a Galaxy S2 (two other phones I compared against).

There's no macro-blocking visible in any of my shots even at 400% zoom so the JPEG compression seems fine. What I do see however are demosaic artifacts that have been aggressively sharpened by some poorly chosen post-processing. I wondered quite a long time why Sony chose their post-processing configuration so poorly and here's what I think. I think it all really comes down to that 20mpx sensor:-

1. The pixel size on the sensor is too small for the lens array's resolving power. 1.2 μm isn't enough for a f/2 lens at 4.9mm, it's really close to being diffraction limited. We see softness in the 20mpx images that goes away when you rescale to 8mpx.

2. The tiny pixel size also means that the sensor is less sensitive to light which gives more noise. The dynamic range plummets as ISO goes up giving fuzzy, grainy pictures even in not very challenging conditions like an overcast day. Really you'd want a faster lens on this thing than f/2.0 (which is about f/10 equivalent in a 35mm system I'd say). But imagine making something like that so small for about the $10 a camera module costs!!

3. Overall the camera subsystem has to process a heck of a lot of data in a short time, especially in burst mode. To keep shot-to-shot time down, Sony has to use simpler, less effective algorithms for demosiac, denoise, sharpening etc.

4. Because of the general softness and noisy nature of the raw images, the post-processing sharpens way too much and it looks terrible, especially at 100% zoom plus - but most people don't "pixel-peep" nor post process their images.

So will Lollipop and the Camera2 API fix this? possibly not. I've read on Anandtech that devices with a separate image processor (like the Z-series with their BIONZ chip) might be bandwidth limited on the buss between the sensor and the ISP and thus not be able to implement the full API. The IMX200 in the Z1C uses CSI-2 as the interface protocol which, according to Anandtech, might not be fast enough :(

So anyway here are my tips to get the very best image quality out of the Sony Z1C:

1. Shoot in manual mode, 20mpx

2. Keep the ISO as high up as you can, never let it go below 200.

3. This will reduce the shutter speed, make sure it never goes below 1/25 of a second unless you have *very* steady hands or a tripod.

4. If you're not a pixel-peeper, resize your pics to 8mpx and the quality will be fine.

If you're a pixel-peeper, get Corel Paintshop Pro X7 (its only like, 30 bucks) and then:-

1. Import the JPEG and run the Salt and Pepper filter at size 3 sensitivity 2 non-aggressive to filter out the worst of the oversharpening artifacts.

2. Use the JPEG artifact filter set to Low, with Restore Crispness at around 30 to get rid of the demosaic artifacts.

3. Increase the colour depth to 16bit, resize to 8mpx and export as a TIFF file

4. Import into Lightroom and it'll be fine for any processing you might need to do.

I haven't found equivalents in GIMP, Lightroom or Photoshop plugins that can clean up the Z1C images like Corel does. Everything else I tried just destroys the detail. Topaz Denoise comes close but you have to use it on quite a high setting.

I'll see if I can't put up some before and afters later.