[Xperia Arc Q&A, Help & Troubleshooting] hygge:
I have now made some quick comparisons of my three cameraes under low light conditions.

Might upload test pictures later when I have the time, for now you will have to trust me :)

Camera 1. Xperia Arc 8MegaPixel

Camera 2. Olympus u Tough 12MegaPixel

Camera 3. Konica Minolta 5D dslr 6MegaPixel

Test 1 without flash

Xperia 1. Kamera advance app with lowest compression, no flash

ISO: 1000

Exposure: 1/8

Olympus 2. Default settings with disable flash

ISO: 400

Exposure: 1/4

KM 5D 3. Full auto, no flash

Could not focus, too little light, camera suggested 3-4 sec shutter speed

(was using OEM lense with bad aperture which gave it problems focussing, could have used a better lense but decided to use OEM lense to keep the comparisons fairly)

Results:

Olympus had only a tiny bit more details and allot more noise, picture was looking very bad up close.

Xperia Arc, even at iso 1000 the noise was lower than my Olympus and the picture looked more clean with nicer colors. I definitely prefered the Xperia result.

The olympus will not go lower than 1/4 shutter speed and iso 400. I selected night scenery on the Arc and got a picture with iso 160 and shutterspeed 1/2. This picture had even less noise but was slightly blurred at 1/2, need a more steady hand but still a very useable result.

My DSLR would not take a picture without focus.

Winner:

Xperia Arc, higher shutter speeds and a cleaner picture with less noise. I was surprised to see the loss of details on my 12MP Olympus at ISO 400 compared to the Xperia Arc.

Test 2

With Flash:

Xperia 1. ISO 400, shutter 1/24

Olympus 2. ISO 100, shutter 1/30

KM 5D 3. ISO 100, shutter 1/60

Result:

The Olympus with flash and ISO 100 gave a sharp, low noise picture and the 12MP provided better details than the xperia could show. The flash on the xperia is not very strong and it was not possible for me to configure it to use lower ISO than 400. The xperia arc picture did give a nice result with low noise.

The 6MP DSLR with flash give the same amount of details as the 12MP Olympus, my old DSLR is still going strong and a better lense will give an even sharper picture :)

Winner:

KonicaMinolta 5D wins, followed by Olympus. Xperia Arc still gave a nice result but with less details and more noise than the other two devices.

One last test at a really dark area without flash also proved xperia arc to be the winner. My Olympus would not go lower than 1/4 iso400 while xperia used 1/8 iso2000. The motive was only visible on xperia arc and even a fairly noisy picture at iso2000 is better than no picture at all :D

My own conclusion is that the xperia arc/neo is really good at low light performance and even outperforms many compact cameras, but the the weak flash give some serious limitations. The low shutter speeds will probably also be an issue taking pictures of moving motives in low light.

(did shoot a couple of shoots with sony camera app and did not notice any difference from Camera Advance, I used the 3PP camera to use as little jpg compression as possible but I doubt the pictures visually differ much)

It would be interesting to do some tests during daylight as well, it will not benefit from the improved low light performance compared to other camera sensors. I am curious to see how the dynamic range of this sensor is, can it compare to my Olympus compact camera then it would be a serious contender as my primary point and shoot camera as long as flash is not needed.