Camera Quality

Branding - The K800/K790 is the first mobile handset from Sony Ericsson to carry the brand name of Cyber-Shot, does this really make a big difference? No not really, it’s just a marketing ploy, brands are used on a daily basis for a multitude of products, brand does not always equal quality. Or perhaps I could be wrong and the reason Sony Ericsson labeled the K800/K790 Cyber-Shot is to show a stamp of approval on the level of quality found in the camera component. Will the K800/K790 live up to the Cyber-Shot name or put it to shame? That’s what we are here to find out.

The Lens Dilemma - The K790 is essentially a compact digital camera, it possesses the same strengths and weaknesses. Obviously the benefit of compact cameras are their size, which translates into convenience for the end user. Everything comes at a price, this reduction in size isn’t free. You’ll pay for it in blur shots and noise filled photos. The Achilles heel of compact digital cameras is low light conditions. So why do compact cameras suffer from these issues more so than their larger counterparts? Lens, lens, lens… Hmmm did I mention lens? Yes, the lens is a major contributing factor to compact digital camera woes. The problem with compact camera lenses is their size. The smaller the lens the more time the camera(sensor) needs to absorb light. This increase in time to capture a shot is critical. Unless the user is able to maintain perfect stillness throughout the duration, a blur shot will result. It’s in our best interest to keep the shot duration, also known as shutter time, to a minimum.

Noise in photos is also linked to lens size and has a relationship with shutter time. Noise is the random white dots that appear in our photos, which the K790 is prone to, often the result of poor lighting conditions. The biggest source of noise, comes from ISO sensitivity, which describes how sensitive the camera’s sensor(captures light) is to light. ISO sensitivity can be increased or decreased, the higher the ISO the less time it takes to capture the image, the lower, the opposite holds true. One may think, well with the higher ISO we can reduce the shutter time to solve the blur shot problem. This is true, but as ISO sensitivity is increased, so does levels of noise.

It becomes a balancing act, have your ISO sensitivity just high enough to avoid blur shots, but not so high that you introduce large amounts of noise. So keep in mind, the lower the lighting conditions, the increase in noise and likeliness of blur shots. These are inherent weaknesses of small lens cameras, there’s little a user can do to solve this problem. On the bright side, we don’t have to manually control shutter times and ISO sensitivity as the K790 will automatically adjust the settings for us, but don’t expect stellar results, there’s only so much adjusting shutter time/ISOs can accomplish. So if this is all done automatically, why did you just fry my brain? It wasn’t just for the sake of mindless torture, this background information will help you make sense of the forthcoming test photos.

Mega Pixel Myth - There’s been a lot of talk about the Mega Pixel Myth on the internet as of lately. Many would argue that more pixels does not always translate into better quality, which is true to a point. So is Mega Pixel count as insignificant as they say? I can’t say that I agree. There are two main advantages I see in having higher Mega Pixels. One, you can have larger prints. Two, you have more room to crop the photos in order to remove unwanted photo distortions. There is some truth to the Mega Pixel myth. For most, there really isn’t much benefit in going beyond the Mega Pixel count that covers one’s specific needs. To help one decide how many Mega Pixel one needs, one must know the photo print size they desire. From this print size we can figure how many Mega Pixels will be sufficient for that print size. Once the Mega Pixel value is figured, ask yourself, do I want extra leeway to crop photos? If yes, then you may want to purchase a camera with a tad higher Mega Pixel count. Since we are reviewing the K790 today, we should focus on the question, does the K790 meet your personal photo print size needs? To answer this question we should look to the K790’s Mega Pixel count capability.

If the K790 is capable of 3.2MP how does that translate into print size? Now I could simply tell you the exact size you can print photos for lossless quality, but I believe it would help you more if I showed you how these numbers are figured, so in the future you will be able to decide on your own if the camera in question has enough Mega Pixels to suit your needs.

We’ll use K790’s 3.2MP camera as our example. For simplicity sake we’ll say the Mega Pixel count on the K790 is 3MP, the pixel count is calculated by multiplying the height x width of the photo, in this case it’s 2000×1500. We know the dimensions of the picture in pixels, but we still need to convert the the dimension from pixels to inches. In order to convert the pixels to inches we need to know what the eye is capable of seeing, there’s no point in having higher pixel/dots density in photos if the human eye cannot tell the difference. According to Wikipedia the human eye can see up to 300PPI(pixels per inch), beyond this value, the human eye cannot differentiate. This statement has been disputed, but we’ll use this number as a general rule of thumb. Divide the height and width by 300, you should end up with 6.67×5in, this is the maximum size you may print a 3MP photo without loss of quality. Another important note to keep in mind, the printer should be capable of printing 300DPI(dots per inch) or higher, otherwise optimal photo print quality will not be realized.

The K790’s 3.2MP camera does have another advantage over lower resolution cameras. Users who want to go the extra mile in terms of photo quality, can do so by cropping their photos. How does cropping help improve photo quality? Well when you take photos, they are never really perfect, there’s always a slight curvature near the edges of the photo, this is called barrel distortion. This problem can be avoided by placing the subject at the center of the photo where there is the least amount of barrel distortion. In post photo editing one can crop the center of the image, which removes the edges of the photo, thus removing the barrel distortion, while keeping the subject intact. Because the K790 has a decent amount of Mega Pixels, the user will have more pixel real estate to crop the photo, and still be left with decent sized photos. Try cropping with lower resolution cameras and you might just end up with a thumbnail…

Sensor - The K790 uses a CMOS (complementary metal oxide semiconductor) sensor, where as normal digital cameras use CCD (Charge Coupled Device). The sensor is what captures the light that travels through the lens, which it records as specific values of light, creating an image from this information. The problem with CMOS sensors is the transistor placement, as they are found on the sensor surface. Meaning less surface area for light to be absorbed, which results in increased shutter times and your chances of a blur shot. CCD sensors have the tendency to perform better than CMOS sensors in terms of photo quality and keeping noise levels low. The reason mobile manufacturers prefer CMOS sensor based cameras is their low-power requirements. CCD sensor power requirements can be vastly greater than CMOS sensor, requiring as much as 100 times more than CMOS. So using a CCD sensor based camera would be less than ideal for a mobile device in that sense. From what I’ve seen in my photo quality testing of the K790, it appears the CMOS sensor is of very high quality.

Table of Contents:

Page 1: IntroductionPage 2: Physical AspectsPage 3: Camera BasicsPage 4: Camera QualityPage 5: ConclusionPage 6: Camera Options

Filed under: Sony Ericsson