It surprises me how many people do not really understand what the “crop factor” is, and technical explanations seem to make it worse for newcomers. What sounds better: 1/2.7″ or ‘less than 10% the size of a full frame sensor’? Calculating the Crop Factor from the Sensor Diagonal Makes perfect sense to a marketing person who wants to make their sensor seem larger than it is. So they calculate the sensor size as if the glass tube was still included. Why? Because, of course, a thick glass tube used to surround the sensors. But if you look at the chart above you’ll see that a 1/2.7″ sensor actually has a diagonal of 6.7 mm. If you do the math 1/2.7 equals 0.37 inches, which equals 9.39 mm. Why do manufacturers keep using such an archaic measurement? Because it helps them lie to you, of course. That measurement system originated in ancient times (the 1950s to 1980s) when vacuum tubes were used instead of CCD or CMOS sensors in video and television cameras. The image sensor was, in those days, referred to in terms of the outside diameter of the vacuum tube that contained it.Ī video camera tube (courtesy Wikepedia Commons) But it’s easy to find how big a 4/3 sensor is in mm.īut then we get into all of these fractional-inch-type-measurements for the smaller sensors. The 4/3 marketing people probably thought “half as big as full frame” wasn’t a good way to present things, so 4/3 it was. Larger sensors are measured in millimeters: full-frame, Super 35mm, APS-C, etc. (Get it, “sense”, “sensor” – I have to have at least one pun per article. FormatĬommonly used sensor abbreviations make absolutely no sense. For example, the 35mm Cinema, Super 35mm, and APS-C crop sensor formats are nearly the same size (look at the sensor area) but of slightly different rectangular proportions. The aspect ratio of the sensor (4:3, 3:2, 16:9) will cause some variation, too. For example, Canon’s APS-C sensor is slightly smaller than Nikon’s, but slightly larger than Sigma’s. Please note that the dimensions may vary slightly from camera to camera. The table below shows the dimensions, in millimeters, of the various sensor (or film) sizes. People want to know things like “is Super 35mm format equivalent to a crop sensor or full-frame?” Other people, trying to sell their 16mm film lenses with adapters for 4/3 cameras fail to mention how much smaller 16mm film was than 4/3 sensors. Not to mention the marketers, always ready to make things as confusing as possible, are doing things like calling a 1/1.7” sensor “large” (it is compared to a cell phone camera chip, I guess).Īnyway, since I haven’t been able to find a single source to answer all these sensor format questions, I thought I’d put it all together here. The problem is even more complicated now that SLR lenses are being used on video cameras and video lenses on SLRs cameras. Is the Canon GX-1 sensor as big as those or more like a point and shoot?

Hardly a day goes by that someone doesn’t ask if the Fuji X-10 sensor is bigger than the Nikon J1 sensor. Plus Canon and Nikon have thrown new sensor sizes into the mix in the last year and a lot of people aren’t sure exactly where those sensors fit in among the better known ones.

Not many, though, know how much smaller a 2/3” sensor is than a 4/3 sensor, and fewer still the difference between those and a 1/1.8” sensor. Most people know the difference between a standard (APS-C) crop sensor and a full-frame sensor. We get a lot of questions about sensor sizes and crop factors.

Medium format 645 crop sensor vs frame