In part 1, part 2, part 3, part 4, and part 5 of this series, Steve Litchfield looked at specifics of camera performance in the phone world. Now AAS guest writer Dirk Snoyt takes up the theme of camera phone flash research and gets all technical on the theme of colours. If you'd like to suggest a topic for us to cover next in the series, please comment!
Read on in the full article.
More than the flash, can we have some articles that provide more technical information (but understandable by ppl like us 😊) on how the CMOS is in current phones and should be for good photographs? I believe this is where the image is captured, isn't it?
Also how about articles on feasibility of including in optical zooms, better and natural image processing etc? I know part of the has already been covered, but am now looking for more details on this.
Not much we can do in terms of CMOS sensors, short of ripping the devices apart? Manufacturers wouldn't let us have really detailed information like that, I suspect.
Might be an article looking at optical zooms and zoom in general. Wait until my Samsung G810 gets back from the firmware-upgrader and then I'll see what I can do 8-)
Without the specifications of the separate phone components it is difficult to analyse and discuss them. The best photo camera analyses I have seen on the web are those of dpreview.com. They do a nice overall test with good comparisons. But they don't test any mobile photocameras (yet). A kind e-mail request offered by some interested parties and willing to submit phones for testing might change that.
Know that image quality depends heavily on a multitude of factors. A sensor's blacklevel noise, quantum yield, it's pixelquality (dead and otherwise abberant), blooming specs and A/D converter specs. Secondly lensquality is also extremely important. Think about it's light collecting qualities: it's aperture (creating the field of depth, usable shuttertimes), optical lens distortions and spectral abberations. Without the full device and hard- and software specifications or the right testing equipment, One is limited to what one can do. I'd love access to a spectrometer and some lightglobes and... and... including weeks of time to test etc... Another less obivous aspect is camera application and use, I.e. more than 3x optical zoom i.e. is pretty useless when shot handheld. Image stabilisation has only limited use. As such the practicality of optical zoom on a handheld mobile phone is has in reality very limited use. The mobile camera is far too light to be held stable in more that snapshots.
Worse not every shot is jpeg-processed identically. Small differences introduced by camera dynamics and the environment will lead to different jpeg compressions of the images. Each with a different pattern of blurry spots caused by zealous jpeg compression. Steve's conclusion the N95 takes better pictures than the N82 in his latest smartphone test is without doubt a result of such statistical variations. Without comparing large numbers of shots between the N82 and the N95 under identical and controlled situations it is very difficult to make a scientific reliable statement about it. I think the differences between the N82 and N95 are most likely very small and most likely tends in general cases to be in favour for newer versions (N82,N85, etc...), due to the fact producers tend to improve their production procedures for economical reasons (less rejects = more average quality).
Lenses and sensors are like Formula F1 drivers and their racing team. They interact together and when both are topnotch and properly matched they will win races.
Enfin, I could talk all day about this topic. I do think that the N95 and its bretheren do set a very fine standard for a smartphone. They have a nice mix of useful features without any particular weak points you often see in older/other mobile cameraphones, even those that do not try to be a smartphone. And for that they win in my view the best mobile phone product range with photographing capacity prize. NGNGNLDFSD, sorry had to detangle the tongue here. With both Samsung and Sony Ericsson putting topnotch pressure on Nokia to keep working at it ;^)
This was a great article. However, for me and in my opinion it really does not matter as these are camera phones. I have an N82 and must say that the shots are great, but they are no where when compared to my Nikon D300. If I happen to be out and about, I will maybe pop out my N82 for a shot but when it is time to get down and dirty, the Nikon is pressed into action. People that continue to harp about camera phones not being this or that seem to miss the point that they are just that, camera phones. They are limited by the size of the sensor, the processing power of the phone, not to mention the optics. If you want great photos, get a real camera, or be satisfied with the product your camera phone produces.
How about something about taking pictures in low light? This is where every camera phone falls down in comparison to a dedicated camera, in my experience.
Thanks all, suggestions taken on board!
Steve
Feel free to check some pictures of mine at http://share.ovi.com/snoyt. Several lowlight (nightmode, no nightmode and with and without flash) candlelight shots are available for both the N95 and N82 (Each has its own channel).
sapporobaby wrote:This was a great article.
Thanks.
sapporobaby wrote: However, for me and in my opinion it really does not matter as these are camera phones. ... If you want great photos, get a real camera, or be satisfied with the product your camera phone produces.
The artistique beauty of a picture lies not in it's technical achievement but by using it's limitations creatively to express something unquantifyable. To understand the camera nitty gritty will allow other people to do this better. You might show off the technical prowness and superiority of your DSLR, but that does not autmatically mean you can take great pictures. Flickr is rife with terrific creative photo's people have taken with their camera phones. A small sample can be found here, on James Burland's blog.
Another thing to consider is the pixel count compared to the size of the sensor.
As the physical size of each pixel get's smaller it will receive less light. To compensate the gain on the sensor has to rise. This also makes the sensor more sensitive to noise, both due to thermal effects and different responses between pixels.
The push to more megapixels aggravates this as the pixels have to become smaller. In a phone camera sensor where you want small sensor size and good adverse lighting performance you actually want a *lower* megapixel count sensor. This seems to go against experience but remember the older lower pixel count sensors were also lower quality.
Hopefully soon we will see camera phone sensors that can combine pixels to form larger virtual photosites as some mainstream pocket cameras can as well as exploiting recent CCD manufacturing advances like black silicon and reversed sensor construction.
--Charles
Dear steve,
Thanks a ton for shedding some Light on Illumination and Image quality of Today's camera phones.
I'd live to introduce myself as an LED freak,and so to say- RGB leds are very impracticable on Camera phones or any other devices for that matter. They had very poor CRI (color rendering index) as There were straight falls in Chromacity of wavelenghts between Red,blue and Green components.
ALL the White LEDs we have today (including N95's) are BLUE LEDs covered with yellow phosphor that emit White light. The Blue-UV spectrum of light excites the phosphor and causes it to "let-go" the extra energy in Form of white Light. In scientific terms, white light is a byproduct of the whole process.
I'll now tell how to identify Phosphor or RGB LEDs.
Simply look at them- yes, you can make out the Yellowish-creamy coating of phosphor on top of the LED base emmiter.
On the other hand, RGB LED has minute,3 SEPERATE emmiters, a Diffuser atop (to mix the light) then the Lens and A protective coat.
Not only is RGB LED expensive to make, but lets out a poorer quality light. they are now-plain extinct.