Impressionist Painting Effect FZ1000 Subject 1.3 kilometers from the camera over ocean and beach, I-Zoom at E800mm. Strong atmospheric distortion. |
In the good old days of film there were not many sizes from which
to choose. Most people used 35mm film which was actually 35mm wide, and I suspect many would have been only vaguely aware that any other size existed.
However since the
beginning of digital photography there
has been a profusion and confusion of sensor sizes. Adding to the muddle,
camera makers got into the habit of naming their sensor sizes in the most
bizarre way. They used as reference the diameter of a notional cathode ray tube
which would have been required in the 1950's to incorporate the particular
sensor. To make matters worse they described this in inches then expressed the
dimension in a weird inverted fashion like [1/1.7 inches]. Nobody presented with this bit of nonsense
would have the faintest clue how large
the sensor might actually be.
Maybe the manufacturers were deliberately obfuscating the
size issue, perhaps to divert consumer's attention from the fact that most
digital cameras used a sensor very much smaller than the imaging area given by
35mm film.
There is a simple,
useful alternative namely to
designate a sensor by it's diagonal dimension. Lets' see how this works in the
table below:
Sensor
Type
|
Aspect
Ratio
|
Nominal Dimensions
(mm)
|
Diagonal
(mm)
|
Area (squ.mm)
|
Focal
length Factor
|
Medium
Format
|
Various
|
Various, about
44x33
|
Various
about 55
|
Various
about 1452
|
Various
about 0.78
|
Full Frame
|
3:2
|
36x24
|
43
|
864
|
1.0
|
APS-C
Sony et al
|
3:2
|
23.5x15.6
|
28
|
367
|
1.5
|
APS-C
Canon
|
3:2
|
22.3x14.9
|
27
|
332
|
1.6
|
Four
Thirds,
Micro 4/3
|
4:3
|
17.3x13
|
21.6
|
225
|
2.0
|
One inch
|
3:2
|
13.2x8.8
|
15.9
|
116
|
2.7
|
2/3"
|
4:3
|
8.8x6.6
|
11
|
58
|
3.9
|
1/1.7"
|
4:3
|
Various about
7.5x5.6
|
Various
about 9.3
|
Various
about 42
|
4.6
|
1.2"
|
4:3
|
6.4x4.8
|
8
|
30
|
5.4
|
1/2.3"
|
4:3
|
6.1x4.6
|
7.7
|
28
|
5.6
|
So, instead of
calling the sensor in the Panasonic FZ1000 and several other cameras, "one
inch" which means nothing it can be described by the diagonal which is
15.9mm which is at least something real and useful for those consumers who
might want to know the size of the sensor in their camera.
I really don't know why this simple naming system has not become
universal, it seems so completely obvious to me. Not to others apparently.
I agree, the diagonal dimension is a good measure for the sensor size. But there is an even better one: the focal length factor - compared to 35mm. The reason is, that 35mm was so common, that it is still used today, even for other formats. A lot of camera makers state the focal length in 35mm equivalent to describe their lenses. To get a matching system, stating the sensor size as a factor to 35mm would be the right match.
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