#thursdayvibes: What Is a “Crop Sensor”

by | Jul 27, 2023

Today’s Post by Joe Farace

Initially, I studied philosophy, because it claimed to give you answers to the meaning of existence, but it didn’t: It was basically a semantics game.—Talulah Riley

in 1925, when Oscar Barnack developed the camera that came to be known as Leica he wanted to use movie film that would move sideways through the camera  effectively doubling it’s 18x24mm format into 24x36mm. Trivia: One story about the 35mm motion picture film format itself, perhaps apocryphal, was that when Thomas Edison was asked by his workers how wide to cut the film, he held up his thumb and forefinger and said, “about this wide.”

Lately, with new full frame mirrorless cameras popping up all over the place, 24x36mm is being treated like the Holy Grail of imaging. It’s not. Those first Leicas may have used the 24x36mm format but other early 35mm cameras, including the original film-based Olympus Pen, used 18x24mm and early Nikon, Minolta and other Japanese rangefinder cameras initially used 24x32mm before standardizing on 24x36mm.

 

What’s talking about film cameras have to do with sensor size?

Everything. When Nikon’s D1 was introduced in 1999 it used a 23.7×15.6mm sensor. When Canon introduced its D30 DSLR in 2000, that camera’s sensor size was 22.7×15.1mm. Even after Canon introduced the full frame EOS 1D in 2001, Nikon insisted their 23.7×15.6mm was more than adequate and didn’t join the full-frame parade until 2007’s launch of the D3.

Olympus, on the other hand, was always willing to go their own way and introduced their Four-Thirds system at photokina in 2012. I was there at the launch looking at a wooden prototype while listening to a German professor explaining why 18×13.5mm was the “perfect sensor size” for digital imaging. The Four-Thirds system is now long dead but the format lives on in sensors used by new Micro Four-thirds mirrorless cameras from OM Systems and Panasonic.

For a long time people, like my friend Jack, thought that the term “mirrorless camera” was synonymous with Micro Four-thirds but it’s obviously not. That’s because some mirrorless cameras use full-frame sensors, others use APS-C while yet other have a 23.5×15.6mm formats. For my younger readers the term APS refers to the Advanced Photo System a format that Kodak launched in 1996 under the Advantix brand. It was an interesting experiment in film formats but before it could catch on with the public was overtaken by digital capture and quickly became obsolete. The APS system used multi-format capture, including APS-C or 25.1×16.7 mm, which as you can see is not quite the same as what digital camera makers call this same format today.

And so, dear readers what does “crop sensor” mean? If film shooters refer to roll film as 6×6, 6×7, and 6×9 and sheet film as 4×5, 5×7, and 8×10, why can’t we refer to the sensor size by its actual measurements because as you can see, their ain’t nothing standard about ”crop.”


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