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Camera Phone Technology 101

Introduction

If you’re going to rely on your smartphone’s camera to record life’s most meaningful moments, you need to understand how it works and what specifications and features are important for maximizing still image and video quality.

How can you tell if a digital camera will take good pictures? Is the camera in a $700 flagship phone really any better than one in a $200 phone? How does pixel size and focal length affect image quality, and what the heck is an f-stop? Photography has a language all its own, filled with technical jargon. Marketing hype and bold claims of DSLR-quality images only add to the confusion. Fortunately, you do not need an advanced degree in optics or be a professional photographer to select a good camera; you just need a little help from Tom’s Hardware.

This introduction to digital camera technology will define key terms and explain how camera features work. It will also help explain the image capture process, from the lens array to the sensor to software post-processing. Using this knowledge, you can choose a camera that meets your needs, take better pictures, and bore people at parties.

What To Look For

For those of you afraid of information overload or who just want a quick summary to refer back to, the table below lists the important specifications and features you should look for to improve your camera experience.

Specs & Features Function Recommendation
resolutiondetermines an image’s level of detailHigher resolution is better as long as it does not compromise pixel size.
pixel sizedetermines the dynamic range and signal-to-noise ratio of the camera sensorSensors with larger pixels generally produce better quality images.
BSI or FSIaffects the light gathering capability of the sensorBSI sensors gather more light and produce better quality images.
autofocusgoal is to produce sharp images with minimal focus lag in all lighting conditionsPDAF and laser AF are both superior to contrast detect AF. Look for hybrid AF systems like PDAF + laser in the future.
HDRhandles scenes with both bright areas and shadowsHDR is good, automatic HDR is better, automatic HDR for both stills and video is best.
EIS and OISreduces image blur caused by shaky handsEIS is good, OIS is better.
lens element countmultiple lenses are required to overcome optical aberrationsMore lenses can be better, but lens count is not a definitive performance parameter.
aperturearea of the entrance pupil limits how much light can reach the sensorLower f-stop values are generally better, but it’s complicated (see below).
focal lengthFocal length is related to how much of a scene is captured in a frame. A shorter focal length provides  a wider angle of view.The full-frame 35mm focal length is a good reference, but there’s no optimal value. If you take pictures of things that are relatively close to the camera, a wider angle of view may be desirable.
ISPA specialized processor that runs various algorithms for constructing and improving still images and videos.A faster ISP improves image capture time (reducing “shutter lag”) and can run more sophisticated algorithms for improving image quality.

You’ll also need a good camera app to accompany the hardware. Several OEMs include good camera apps with their devices, but there are numerous third-party choices too. Look for an app with an easy to use interface that places the controls used most often (flash, HDR, timer, etc.) within easy reach. The preview displayed by the electronic viewfinder should match the image captured by the camera—it should not be cropped or have a different aspect ratio. Photography buffs or people who want to express their inner artists should find a camera app that offers a full manual mode and RAW image capture.


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  • blackmagnum
    Thanks for the informative article. You might have just cured my insomnia.
    Reply
  • AndrewJacksonZA
    A very informative and nicely presented article, thank you.
    Reply
  • wtfxxxgp
    Thanks for the informative article. You might have just cured my insomnia.

    Geez. That was a cruel comment! hahaha

    Seriously though, that article was very informative for those of us who like to know a bit about everything :)
    Reply
  • David_118
    Great article. Very Informative. It would be useful, knowing these concepts, if there was a studio that took mobile cameras and used them on some standard set of scenes, either photographing paper with test patterns, or constructed scenes in low light, or whatever, that could measure things like signal-to-noise, HDR performance, optical abberations, shutter speed, etc. Anyone know of such an outfit?
    Reply
  • MobileEditor
    Great article. Very Informative. It would be useful, knowing these concepts, if there was a studio that took mobile cameras and used them on some standard set of scenes, either photographing paper with test patterns, or constructed scenes in low light, or whatever, that could measure things like signal-to-noise, HDR performance, optical abberations, shutter speed, etc. Anyone know of such an outfit?

    There are several labs, such as DxOMark, Image Quality Labs, and Sofica, that perform these tests. We're considering adding some of these tests to our reviews, but they require expensive equipment and software to do it right. Hopefully, we'll be able to expand our camera testing in the future--budget and time permitting.

    - Matt Humrick, Mobile Editor, Tom's Hardware
    Reply
  • Albert Rampo
    Toronto Everywhere !!!
    Reply
  • sr1030nx
    Any idea what Autofocus method the lumia 950 uses?
    Reply
  • falchard
    I wish they introduced an updated version of the Lumia 1020. 41mp *drool*
    Reply
  • zodiacfml
    Good job. Finally, someone who really knows about what's being written. The tone and some information though might be too much for someone who has not even heard of shutter speeds or aperture. I also feel there's information overload as each topic/headline deserves its own article including investigation on megapixel/resolution spec.

    Reply
  • dbdarrough
    Excellent article! This is why I go to Tom's Hardware for articles like this.
    Reply