At present, small sensors are named after the dimensions of a hypothetical glass tube that would surround the sensor, as if they were a 1950’s Vidicon tube. We will instead focus on actual sensor dimensions.
The way the industry describes small image sensor sizes (eg: 1/2.3″-type) is not just unclear but actively misleading. So, we’re going to change the way we describe sensors to make sure readers aren’t so easily confused.
Small sensors are currently named after the diameter of the VIdicon Tube they could be substituted for.Photo: Sphl, CC BY-SA 3.0, via Wikimedia Commons
Every few years a website or YouTube channel discovers or explains that no aspect of a ‘1″-type’ sensor is actually one inch long. Our own article explaining the topic was published nearly twenty years ago, and yet the issue is still causing confusion. This confusion is only made worse when the word ‘type’ is left out of articles and videos, making the name look like a measurement, rather than a designation of sensor class.
From today, we plan to use drop the reference to inches, and refer to 1″-type sensors as Type 1 sensors.
This doesn’t make the names any more descriptive, but at least removes the confusion and potential to mislead that exists in the current naming scheme, with its implication that it represents an actual measurement.
As well as changing our own style guide, we’ve approached a series of major publications and YouTube channels. Imaging Resource, PetaPixel, Cameralabs, Gerald Undone and The Art of Photography have all said they’ll follow the same approach, and we hope others will follow.
Sony Semiconductor, one of the world’s largest sensor makers, has also adopted this naming system.
In addition, in response to our recent poll, we will also specify the approximate sensor dimensions in mm, wherever possible, to make it easier to visualize the size being discussed.
Old naming system
New name
1″-type sensor
Type 1 (12.7 x 9.5mm) sensor
We will quote sensor area in comparison tables, as it’s the difference in imaging area that has the biggest impact on image quality for single-shot photography, and we believe area is the more intuitive way of conveying the magnitude of sensor size difference.
Examples
Designation
Dimensions(Typical)
Sensor area(Typical)
Diagonal(Typical)
Crop factor(vs 35mm)
Type 1/3.4
4.0 x 3.0mm
12mm²
5.0mm
8.6
Type 1/2.3
6.3 x 4.7mm
29mm²
7.8mm
5.5
Type 1/1.28
10 x 7.5mm
75mm²
12.5mm
3.46
Type 1(4:3)
13.1 x 9.8mm
128 mm²
15.9mm
2.65
Type 1(3:2)
13.2 x 8.8mm
116mm²
15.86mm
2.72
This same system could, in principle, be applied to larger sensors, but we feel these are alreadry sufficiently well understood that we won’t need to change the way we deal with these.
Designation
Dimensions(Typical)
Sensor area(Typical)
Diagonal(Typical)
Crop factor(vs 35mm)
Four Thirds
17.4 x 13.1mm
227mm²
21.77mm
2
APS-C
23.6 x 15.7mm
372mm²
28.4mm
1.52
Full Frame
36 x 24mm
864mm²
43.3mm
1
Medium formatType 3.4
44 x 33mm
1452mm²
55mm
0.79
We’ll apply these changes immediately and update our database soon. This change is likely to have most impact on our drone and smartphone coverage, but we’ll aim to be consistent throughout.