Sunday, November 21, 2010

Buying A Camcorder Specs – More About Image Sensors

Digital image sensors are used to record digital images and video. Like glass and film there is a wide range of sizes and quality. That quality is dependent on who makes the sensor, the size and other features of the camcorder.


Digital Image Sensor from Wikipedia

That is all well and good but as a consumer what should folks look for on the package or on the product specific detail?

Hold on for a half second – I need to dip into the past to make the present clear.

Kodak 110 film

This is an example of a Kodak 110 film negative. There are images on the 13mm x 17mm negative. Depending on the quality of the camera used the print could be very grainy or a small quality print.

Even if a quality 110 camera was used to take the photo there is only so much data or information that can be stored on the negative. There is also a built-in limitation on how large you could make the print.

A 135mm film negative (I just remembered that is the correct name) aka a 35mm negative is larger.


The negative is able to capture more of the image data, greater details and tonality. There is more surface area covered with emulsion to capture the details.

Like the man said, everything old is new again.

Small Censors Here is where the dollars and sense comes in to play. If you have a lick of sense before you purchase a camcorder look at the sensor size. If the sensor size is not on the package or web site spec sheet move on down the line to those vendors that do mention the image sensor size.

The digital sensor size really should be measured in millimeters but because video is involved there is a historical carryover from analog video tube technology. It is also a good way to hide how small the sensor is in reality.

Digital image sensors between 1/8 and 1/1.6 inches are used in cell phones, web cameras and most consumer camcorders.

If the sensor size is within this range, with other factors taken into account, then the video recording expectations are that:

  • Outdoor recording will be adequate.
  • A fast lens meaning an f/stop of around f 2.8 or wider to allow for more light is present.
  • Indoor recording will be crappy unless you have a lot of light, excellent lens or the ability to adjust the amount of light coming into the device.

Examples:
Canon Vixia HF R10 CMOS Sensor Size 1/5.5"
DXG-567V CMOS Sensor Size 1/2.5"
Flip UltraHD Pocket Digital Camcorder CMOS 1/4.5"
JVC Picsio CMOS Sensor Size 1/3.2"
JVC Everio GZ-HM1SUS CMOS 1/2.33”
Kodak Zi8 CMOS Sensor Size 1/2.5"
Panasonic SDR-H85 CCD Sensor Size 1/8”
Samsung HMX-H100 CMOS Sensor Size 1/4.5"
Samsung S16 HD CMOS Sensor Size 1/2.33”
Sanyo Xacti VPC-E1 CCD Sensor Size 1/2.5”
Sony Handycam HDR-XR550V CMOS Sensor Size 1/2.88"
The constant is the size of the digital image sensor. The larger the sensor the better the quality of the image or recording.

Or looking at it another way, the smaller the sensor the less expensive the camcorder can be and the potential of a reduction of image quality.

Bottom Line

  • When looking to buy a camcorder look for keywords such as Image Sensor, Optical Sensor Size or Sensor.
  • There should be a number expressed in inches or millimeters to describe the size of the sensor. If the sensor is described X.X megapixels be on the alert for further non-disclosures.
  • In general, the smaller the sensor the less expensive the camcorder. Keep in mind there are other parts of the camcorder to consider in order to ensure a quality purchase.

This is series of posts that attempts to explain in plain language the technical specification sheet that many camcorders have on the package or at the web site.

Part One – What’s In A Name?
Part Two – Make and Model
Part Three – What Is An Image Sensor?

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