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Sensor sizes explained
Posted on: 1/28/2013 7:57:00 PM under General
It's easy to assume that sensor sizes are relative to the size of a camera. Once upon a time, that tended to be the case but now things have changed somewhat. Why is it important? Very simply, the bigger the sensor, the bigger the area for those pixels which should guarantee both better low light performance and resolution.
The standard size by which all is compared to is good old 35mm, quite often now referred to as full frame. In the diagram below, you can see all of the popular sizes of digital sensors.
Next to each description are the dimensions of the sensor and the crop factor. That effectively tells you how much the picture will be cropped when using a comparable focal length for the lens. So a 50mm lens on an APS-C sensored camera would actually be 75mm (50 x 1.5). So not only are the larger sensor cameras going to give you better quality but they will also allow you to shoot wider for any given focal length. This is especially useful if you shoot indoors or landscapes.
So going up in size, we start with 1/2.3. This is predominantly the domain of compact cameras - ideal for their size but clearly with the smallest sensor, they are the most challenged and rely on technology to help as much as possible.
Next up is the 1/1.7. This is actually used by Canon's S95/100/110 compacts which are considered to be about the best portable cameras out there (and having owned one for a while, I can happily vouch for that). Fujifilm use the 2/3rds size sensor - that's what you will find in your X10 or indeed the new X20.
The next jump is to 1" sensors. These are the domain of Nikon's 1 range which are CSC's (compact system cameras with interchangeable lenses). You can still get a compact with this sized sensor and that is the incredible Sony RX100 which delivers frankly astonishing quality for its size and is a marvel of packaging - for the size (i.e pocketable) there is nothing to touch it.
And so we move on to 4/3rds. When Olympus and Panasonic launched the Micro 4/3rds mount, this sensor size's popularity rocketed and today, a very large number of CSC's are Micro 4/3rds using the 4/3rds sensor.
Canon built a brand new sensor for the G1X - it's a curious size and you have to question why they build a new sensor just for one camera (the EOS-M CSC camera has an APS-C sensor) remains an absolute mystery!
You might have thought that APS-C sensors were all the same size but you'd be wrong - Canon have a slightly smaller sensor than the competition. APS-C is a very common size these days. If you're an SLR owner, unless you have full frame or APS-H (Canon 1D), you've got an APS-C sensor. This size also appears in some CSC's such as Fuji's X-Pro 1 and E1 and of course the whole of the Sony NEX range (NEX-5r, NEX-6, NEX-7). We mustn't also forget the lovely Fuji X100 and its successor the X100s.
Next we move up to a no-longer used size - APS-H. This was used for the Canon 1D series - cameras that were very fast and predominantly used for sports photography. With the arrival of the Canon 1DX, that has now changed as it has gone full frame.
And that's where we end up - Full Frame. Canon now have an expanding range of full frame cameras (6D, 5D Mk II, 5D Mk III, 1DX) and Nikon are not far behind (D600, D800, D4). Sony have recently entered the full frame world with the A99.
You might think that full frame is the preserve of just SLR cameras but you would be wrong. Leica have been building full frame Rangefinder cameras for a while now and have had the market all to themselves with models like the M9-P. That has all changed with the arrival of the incredible Sony RX-1.
The Sony has redefined what is possible, fitting such an enormous sensor is such a compact body and to make things even better, they have combined with a purpose made fixed Zeiss prime lens. Cynics have shut up - very simply it is one of the best cameras out there.
So what does this mean going forwards? Well, full frame CSC's are not far away - this time next year you may well be able to buy one. Compacts will continue to push the boundaries in terms of packaging. When you couple this together with sensor technology like Fuji's X-Trans technology (this deserves a whole blog post of its own!), cameras can only continue to get better and better, pushing the boundaries of low light performance and dynamic range.
Good news for us consumers!