Image noise, optical characteristics
First of all let’s take a look at image noise, as one of the most important aspects that influence image quality. For obvious reasons we didn’t take a picture with all the phones at all ISO settings, as that would have resulted in at least 40 pictures – instead of this we have taken a look at pictures taken in bright sunlight in auto mode. The best is LG KF750, it makes beautiful images, but Samsung G600 and U900 are also amongst the leaders. Traces of noise reduction are the most powerful in the case of Nokia N82 and Sony Ericsson C902, while i900 and F480 take pictures that are quite poor in details and blurred. Pictures of G810 have a medium noise level, filtering, however, is weak, so the resulting images are quite rich in details.
Noiseless, noisy, noise reduced images
We can learn a lot about the lens used in the phones upon analyzing the sides of the images. That’s why we have taken a more detailed look at the corners of the images, and the results might be surprising for many of you: the most disappointing results were from Nokia N82, the one with the Made by Nokia. No matter the Carl-Zeiss lens, the left sides of the images are very blurred, which means that the lens are smaller than appropriate for the image sensor – fortunately there were no such problems with the Made in Finland edition. This has been visible at the N95s too, although it was less powerful – the reason for this is that the lens size is not appropriate for the image sensor. It’s especially funny at the weaker N82 that the left side of the images is much more blurred than the right side, which means that the center of the lens is not above the sensor’s center, thus it is poorly assembled. Rim obscuration is the most powerful at G810, and that’s no wonder since the lenses that have optical zoom – by the way this effect is present only at wide-angle view.
Blurred corners (on the left) and sharp center (on the right) on Nokia N82’s images
Besides the symptoms we have just described another thing that tells a lot about lens quality is chromatic aberration that is the degree of difference in colors. Convex lens work like prisms, they decompose light to different colors to some extent. When using cheap, low-quality lens it might happen that rays of light “coming” from a spot of the pictured theme might get distorted by colors on picture side (on the sensor). The flaw is visible at the contours (where light and dark parts meet) and usually only at the edges of the picture – for example in case of night pictures, or when there is a dark part, that is lit from the back, in front of a light sky. From these eight phones tested only Sony Ericsson C902 managed to produce this error, but at that one it is quite powerful.
Powerful chromatic aberration on Sony Ericsson C902’s images
It’s worth talking about the so-called hotpixels. These are such spots on the image sensor that, due to a manufacturing flaw, are much more sensitive than others, which means they get saturated much faster. The effect is present in case of night pictures, at higher shutter speeds (above 1/10 seconds). This has been characteristic for two handsets, C902 and N82, but it wasn’t very strong at any of them.
Hotpixels on Sony Ericsson C902’s night image
A cikk még nem ért véget, kérlek, lapozz!
