Back to Basics: Camera technology explained

July 11, 2013
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Welcome friends, to the “Back to Basics” series where we’ll run a fine toothed comb over each and every aspect of Android so that you can make an educated decision on which Android device is for you.

Android Authority Back to Basics

This week’s edition is going to focus on the little piece of technology that helps capture the best moments in your life. It’s time to talk camera technology.

There are a lot of misconceptions about cameras on mobile devices. A lot of people have been duped into believing that a higher megapixel count is the be-all and end-all of smartphone cameras, when there are actually a lot of factors which contribute to a great shot.

Megapixels are not the be-all and end-all of mobile device cameras

Somewhere along the way, somebody duped us all into believing that a higher megapixel count resulted in a better picture. However, the truth is that a higher megapixel count doesn’t always result in a better picture, and, in fact, it can sometimes be detrimental to picture quality.

So what does a higher megapixel count result in? In a word: detail.

So what does a higher megapixel count result in? Well, in a word, detail. A higher megapixel count will often result in more detail in the picture, which is perfect for heavy cropping and zooming. It’s also perfect for people who blow up their snapshots into big portrait pictures.

Some high-end smartphones feature a 13MP camera, but whether you need all those megapixels if you are just posting pictures up to your favorite social network is highly debatable.

Sensor size and aperture

An after effect of all of the slimming down of smartphones is the huge reduction in sensor size. If you take a look at a DSLR you’ll notice that the sensor is massive, but, in a smartphone that is less than 10 mm thick, it’s impossible to fit a sensor that big. So the manufacturers will use much smaller sensors.

The larger the sensor, the more light that can pass through, and the better your low light pictures will be. Sensor size is usually one of the first things to get cut down on a smartphone when the manufacturer wants to make a slim device. However, HTC has recently combated this with the UltraPixels sensor on the HTC One (more on that later).

1000px-Aperture_diagram.svg

Smaller numbers mean bigger apertures

Another factor for low light performance is aperture. The aperture is the hole that light needs to travel through to reach the sensor. They are very similar to our pupils, which dilate and contract depending on light conditions. If you’ve got your smartphone set on automatic, then it will choose the best (in the software’s opinion) aperture. This is illustrated using the letter “F” and a number after it. For example: the Galaxy S4 uses an aperture of f/2.2. Remember that the lower the number, the bigger the aperture gets. So lower numbers are better.

One of the biggest advantages of a large aperture is the ability to isolate your subject and blur out the background. That’s how photographers create that depth of field effect, by messing with the aperture.

Optical Image Stabilization (OIS) vs Digital Image Stabilization

If you’ve ever taken a video with your smartphone in your hands, it will often come out a little shaky, no matter how hard you try not to move them. That’s often because your smartphone uses Digital Image Stabilization, instead of an Optical Image Stabilization (OIS) system.

Using tiny gyroscopes, OIS systems physically move the camera lenses in the opposite direction of a sudden movement, keeping the image projected onto the sensor stationary. Digital Image Stabilization uses software to counteract the movements, by shifting the electronic image from frame to frame.

htc one coming to verizon

The HTC One uses Optical Image Stabilization

Which is more effective? Well, it’s hard to say, since manufacturers use different methods for OIS, and not all of the software in Digital Image Stabilization is the same. From personal experience I’ll state that OIS has given me better results, however, few smartphones and tablets use OIS technology.

The Lumia 920, the Lumia 925, and the HTC One are a few smartphones which utilize OIS technology, while most others resort to using Digital Image Stabilization.

UltraPixels

The HTC One uses an UltraPixel camera with a pixel count of 4MP. That’s much lower than the competition, but there’s a reason for that. What most manufacturers do is increase the pixel count without increasing the size of the sensor, meaning that each pixel is getting less light as the light is being divided among the pixels.

Image credit: HTC

Image credit: HTC

UltraPixels are larger than regular pixels and should theoretically perform better in lower light. While this has turned out to be mostly true, many reviewers have complained about the HTC One’s performance in well lit conditions, where the UltraPixels have less of an effect. Due to the larger pixels the pixel count on the One is lower than on other high-end smartphones, which means a lack of detail (when compared to other smartphones) in well lit conditions.

Software makes a difference

While the almost all of the above factors are hardware related, the software makes a huge difference as well. Besides Digital Image Stabilization, the software for a camera on a smartphone is constantly analyzing your field of view and tweaking the settings. A picture taken in automatic mode could look very different from one taken in a mode which is specific to the situation you are in. For example, below is a picture taken indoors and in low-light, in automatic mode, and in “Low light” mode.

Low light mde vs Automatic-aa

Picture taken by a Galaxy S3 in low-light mode (left), and automatic mode (right). Click to expand image.

HDR (High dynamic range) Mode

HDR mode is found on many Android devices (but not all), and is a process which enhances details in the subjects foreground and background. This can sometimes produce better results in low-light situations or where the background is too bright. We’ve explained everything there is to know about HDR in this article here.

Putting the pieces together

We’ve explained all the major factors that add up to taking a picture, but it’s time to put our money where our mouths are. We’ve set up a little test with three smartphones: the Galaxy S3, the Galaxy S2 and the Nexus 4. Here are all of the important camera related specifications for each smartphone:

 
Samsung Galaxy S3
Samsung Galaxy S2
LG Nexus 4
Megapixel count:8MP8MP8MP
Sensor size:1/3.2"1/3.2"1/4"
Aperture:f/2.6f/2.7f/2.4
Image stabilization:DigitalDigital Digital
Software:TouchWiz Nature UX 1.0 camera appTouchWiz 4.0 camera appStock Android 4.2.2 Jelly Bean camera app
Flash:LEDLEDLED

All of these smartphones have Digital Image Stabilization, the same Megapixel count, and all of them use an LED flash. However, they all have different apertures, and are using different pieces of software. The LG Nexus 4 also has a slightly smaller sensor. So what difference does it make?

Outdoor shot – Flower Power

galaxy-s3-galaxy-s2-nexus 4-flower-aa

These pictures were taken in the daylight, in overcast conditions, with the settings all on automatic. (click to expand images)

The Galaxy S3 produced a rich and vibrant image, with accurate colors (if slightly oversaturated) and had sharp detail overall. The Galaxy S2 provided an image which was vibrant and had sharp detail, however, the green leaves and the pink petals were over saturated. The Nexus 4 provided an odd result – it provided reasonably accurate colors, but lacked vibrancy and detail. Note how the background blurs slightly in the Galaxy S3, and even more so on the Nexus 4. This is due to their larger aperture (lower numbers remember), which provides provides a nice depth effect.

Indoor shot – chandelier

galaxy-S3-nexus-4-galaxy-s2-chandelier-aa

The images were taken indoors under LED lighting, with the flash off, and settings all on automatic.

These pictures turned out interesting as the hanging chandelier had LED lights reflecting off it, testing the smartphone’s software analysis. The Galaxy S3’s image processing software simply gave up here. I tried this shot multiple times and every time the image turned out blurry, lacked a lot of detail, and had a slight green tint. The Galaxy S2 surprisingly took a much better photo here, and kept the wires and crystals all in focus, but it appeared slightly soft on the edges of the chandeliers. The Nexus 4 also took a very good image. It was sharp and detailed, and probably the best of the bunch.

Indoor shot – Low light- Boxes

galaxy-s3-nexus-4-galaxy-s2-indoor-no-flash-aa

These photos were taken indoors, in low-light, with the flash off and settings all on automatic.

All of the images were very noisy and lacked detail, but the Nexus 4, with its larger aperture was the best picture and was reasonably lit, yet still very noisy. The Galaxy S3 was the next best, and the Galaxy S2 provided a very noisy picture and was poorly lit. Hint: the S2 also happens to have the smallest aperture (highest number).

Indoor shot – flash on – low light

Galaxy-s3-nexus-4-galaxy-s2-indoors-flash-on (1)

These images were taken indoors, in low-light, with the flash on and settings all on automatic.

The Nexus 4 overexposed the image, washing out the case of the Galaxy S3, but its camera also lit the area of the subjects the best. The Galaxy S2 lit up the subjects well, and exposed the images appropriately, with colors proving to be accurate. The Galaxy S3’s picture was well lit and evenly exposed, its colors were also accurate.

Indoor shot – clockwork

galaxy s3-nexus 4-galaxy s2-indoor shot-aa

Images taken indoors, with the flash off and settings all on automatic.

A little bit of noise was apparent on all shots. The Galaxy S3 portrayed the colors the most accurately, with the silver-gold mixture on the large standing clock preserved. However, it then proceeded to add a little yellow tint over the background and it also had the most noise. The Galaxy S2 and the Nexus 4 provided very similar results, both of them made the large standing clock appear to be silver.

Breaking the results down

Megapixels

All three smartphones feature 8MP shooters, however the results were not equal.

Aperture and sensor size

The Nexus 4 had the smallest sensor, however, it also featured the largest aperture, which mitigated the issue. It had the best depth of field in the flower picture, and it also performed the best in the low-light shot with the flash off. The Galaxy S3 and the Galaxy S2 have the same size sensor, however, the Galaxy S3 has a slightly better aperture and therefore had a better depth of field, and performed slightly better in the low-light shot.

Google LG Nexus 4 Logo aa 2 1600

The Nexus 4 has the smallest sensor, but the largest aperture.

Software

While they all featured the same flash and all used a Digital Image Stabilizer, they all featured different software. The Galaxy S3 was using the camera application in TouchWiz Nature UX 1.0, the Galaxy S2 was using the camera application in TouchWiz 4.0, and the Nexus 4 was using the stock Android 4.2.2. Jelly Bean camera application.

Each of them had their advantages and disadvantages. For example the Galaxy S3 quite literally gave up in the chandelier image, and the Nexus 4 washed out its image on the low-light with flash image. The Galaxy S3’s software offered the most customization to tweak things to be just right, and its HDR mode is much better than the Nexus 4 or the Galaxy S2. The Nexus 4’s camera on the other hand, offers a bare bones experience with little tweaking allowed.

Wrap up

Like I said before, the performance of the camera on your smartphone is dependant on a lot of factors. These were just some of the biggest factors, and while we don’t have enough time to get into all the little details in this article, here are a few articles for further reading:

So while smartphone and tablet cameras won’t be catching up to DSLRs anytime soon, there are Android running devices which offer supreme picture quality. The Samsung Galaxy S4 Zoom is an Android smartphone with a 10x Optical Zoom, and a 16MP camera. There is also the Samsung Galaxy NX, a mirrorless camera which runs Android for easy sharing to social networks or the cloud.

We’ll be back next week with another edition of the Back to Basics series, but if you have a question about anything Android related, head over to our AA Q&A page, where our team will answer your questions every Wednesday or just drop your questions in the comments below and I’ll be happy to respond.

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