The problem with cameras on mobile phones is that they’re all crap – do you want to know why?.
In the olden days (you know when people used film cameras) no matter what camera you had, whether it was a cheap piece of plastic crap or the best SLR in the world, it all had one thing in common: 35mm film*. And the one thing 35mm film did well, was take photos no matter what the lighting conditions. Even in dark situations, without flash, you’d still be able to get some kind of photo from it. * assuming you weren’t using a 110 or APS camera. An example on flickr, and another example above with flash (I assume the flickr link is using 35mm film which measures 24x36mm).
With a digital camera – nearly all of them have flash (I’d estimate 99%) – so in dark conditions you can use the flash and get a half decent photo (generally speaking). Some of the time you can switch the flash off, setup the self-timer, put it on a wall or a tripod and take a half-decent night shot. Which is fairly impressive considering how small the sensor is in relation to 35mm film. (The average compact digital camera sensor size is 7.2mm x 5.3mm (1/1.8 sensor), this is roughly 5x smaller than 35mm film, with an average Pixel area(µm2) of 2.6 – 3.8µm2) (Using a 12mp example: Canon Powershot G9 with a 1/1.7″ sensor, the pixel area is 3.8µm2). Example above taken with the Casio Exilim Z120.
On a side note: Do you remember when Digital Cameras were still new? Like in 2002 or 2003 when digital cameras were still so new that they had to write “Digital Camera” on the front of it somewhere so that you knew it was a digital camera? Simply being a digital camera in 2001 was so exciting and new that they simply used those two words together as a marketing tool / selling point for the camera. Now you’re lucky if you even have the model number written on it, and rarely do you find the manufacturer name on the back these days. (They used to always put the manufacturers name underneath the screen – like this). Now it’s more likely the be the huge number of megapixels or optical zoom or screen size that’s plastered all over the camera.
With a camera phone – most of them don’t have a real flash (maybe 1% has a real xenon flash (the Sony Satio is the only recent one) that is equivalent to the flash you find in a Digital Camera) – and the rest – if you’re lucky (or unlucky depending how you feel about it) – has an LED or a “twin” LED flash. The problem is that even with (or without) the LED flash, the camera’s just don’t cope with low-light situations. You can put the phone on night mode (if you’re lucky), put it somewhere steady^ and switch on the self-timer, and hope it takes a successful shot. The problem is that the sensors in camera phones are even smaller than compact digital cameras. They just can’t get enough light into the sensor, and that means in low light situations they produce crap noisy images that are over-processed so much that you’re lucky there’s any image left to view. Further problems are caused due to the small sensors lacking the ability to capture dynamic range, so dark areas are underexposed, and bright areas are overexposed, further reducing detail in images (the example above taken with the Nokia N86 – where’s the detail in the steps?). The latest 12 megapixel camera phone sensors made by Sony have a 1.4µm pixel size – which is again 2.7x smaller than compact digital camera sensors. (2.6mm x 1.96mm estimation). This is roughly 13.8x smaller than 35mm film.
In a nutshell – it’s all about the light – 35mm film cameras can absorb lots of light, and therefore take photos in dark conditions and get as much colour and detail as possible. Digital Cameras, more so compact cameras, have much smaller sensors and struggle in low light, but don’t do too bad a job of it thanks to having a flash, however, they are very much on the limit of acceptable image quality (that’s why Digital SLRs get better image quality – they have larger sensors). Camera phones on the other hand have had to miniaturize to the point where image quality is badly affected, and the only way to get good photos from them is to use them in ideal light, or have a real xenon flash for times when lighting is poor.
^ Options are limited as I don’t know of any camera phones with tripod mount, and you’re generally lucky if the phone will stand on it’s side without falling over. Even on the “Photo-centric” Nokia N86 8mp you can’t stand the camera on it’s side without it falling over!