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Pixel Density: when Moore is less

By dpreview staff on Jul 3, 2008 at 13:59 GMT

We've added some new information to our product database to make it easier to understand the characteristics of camera sensors. The idea of megapixels is generally well understood but, mainly because of the way they've historically been presented, sensor sizes aren't.

We feel that relating these two pieces of information gives a clearer understanding of how they interact. To achieve this, we've added the new field: "Pixel Density" to our database, to help when comparing cameras. We think you'll find it useful.

Up until now, the sensor sizes have been provided as slightly obscure imperial fractions that hark back to a set of standard sizes given to TV camera tubes in the 50's. This is industry standard practice but by no means intuitive. To get around this, we've researched the common sensor sizes and used them to calculate a value we're calling 'Pixel Density.'

Pixel Density is a calculation of the number of pixels on a sensor, divided by the imaging area of that sensor. It can be used to understand how closely packed a sensor is and helps when comparing two cameras with different sensor sizes or numbers of photosites (pixels). Because the light collecting area and efficiency of each photosite will vary between technologies and manufacturers, Pixel Density should not be used as an absolute metric for camera quality but instead to get an impression for how tightly packed the imaging chip is.

Pixel Density now appears in our database and will appear when you look up a specific camera or when you conduct a 'Side-by-side' comparison in our Buying Guide. We'll also add it as a search criterion in the Buying Guide's 'Features Search.'

In recent months we've made small changes to the database (such as adding viewfinder specifications for DSLRs and tweaking the value ranges that can be used for searching it). We have even bigger plans for the future so, if you have any ideas you'd like to see implemented or think you have more sensible search ranges that should be applied, please get in touch. Use the 'Feedback' link on the left of the page and select 'Camera database error' as the Subject.

Click here to see a comparison of seven cameras with a wide range of different pixel densities

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