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A new sensor size taxonomy

Doug Kerr

Well-known member
For many decades now, we have often spoken of format size ranges for film cameras in the following taxonomy:

• Large format: Format sizes of 4" × 5" or above.

• No category name: Format sizes such as 3-1/4" × 4-1/4" and 2-1/4" × 3-1/4 inch; sometimes considered medium format

• Medium format: Formats such as 6 cm × 4.5 cm, 6 cm × 6 cm, 9 cm × 6 cm, etc. (generally using 120- or 220-type film).

• Miniature: Format size of 36 mm × 24 mm (using 135-type film).

• Half-frame 135: Format size of 24 mm × 18 mm (using 135-type film).

• Subminiature: Smaller than that (often using 9.5 mm or 16 mm film).​

This scheme developed over a period of 50 years or more. But now we have digital cameras, and we are in the third millennium, CE (to use a revolting nomenclature, fortunately not often heard).

Today, we classify digital format sizes into these categories:

• Medium format: format sizes larger than 36 mm × 24 mm.

• Full frame: Format size of approximately 36 mm × 24 mm. (This is actually a format size name,. not a category name, but it has taken on great mystical significance, so I treat it as a category name.)

• No category name: Everything smaller than that. (Yes, there are names for specific format sizes.)​


I suggest a new taxonomy of format sizes, as follows (here I will designate sizes in terms of their diagonal dimension):

• Digital Extra Large Format (DXLF): Larger than 45 mm.​

• Digital Large Format (DLF): 26 mm - 45 mm. This includes format sizes often called:
• "Full frame" (would be better called "full-frame 35-mm") - 43.3 mm.
• APS-H - 33 mm
• APS C - 27 mm​

• Digital Medium Format (DMF]: 10 mm - 25 mm. This includes format sizes often called:
• 1.5" - 24.5 mm
• Four Thirds System/Micro Four Thirds System - 22.5 mm
• 4/3" - 22 mm
• 1" - 16.5 mm
• 2/3" - 11 mm [This is where this silly convention got started.]​
• Digital Small Format (DSF): Smaller than 10 mm. This includes format sizes often called:
• 1/1.8 inch - 9.2 mm [often inexplicably spoken, "one over one and one-eighth inch"]
• 1/2.3 inch - 7.2 mm [often inexplicably spoken, "one over two-thirds inch"] [Some cameras said to have this size sensors actually have sensors that would, under this convention, be properly (!) called "1/2.1 inch)​

************

Well, now I await the arrival of my new DMF camera, the Panasonic DMC-FZ1000, with a 15.9 mm sensor.

Best regards,

Doug
 

Dr Klaus Schmitt

Well-known member
APS and FF summed up in one category seems a bit odd to me, as the results and behaviour of such bodies is quite different.

Actually it is THE biggest difference in the (current) market of cameras IMHO.
 
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