Short Description
Image Sensor
Photo of a Canon CMOS
sensor
The sensor size is the physical dimensions of the cameras image sensor. This is the heart of the digital camera,
this is essentially your "film". Typically the larger the sensor the better. Larger sensors permit more light per
pixel permitting lower noise and higher quality conversion of light to a RGB value that is most accurate and
contains the highest range of contrast and color depth. There are 7 main sensor sizes but you can primarily group
all the sensors into two groups: small and large.
Small Digital Camera Sensors
Small sensors range between 1/3.6" (4x3mm) and 1/1.7" (7x5mm). Although the differences seem small 1/1.7"
sensors offer 35mm² of sensor area while 1/3.6" only offer 12mm². 1/1.7" sensors are typically used in high end
digicams that tend to produce better quality photos, largely because their sensors large (3X larger than 1/3.6")
permitting cleaner pixels and lower noise at higher ISOs. Small sensors are only used in digicams, no SLRs use
them, they are simply too small of a sensor even at the top of the size range. The major advantage of a small
sensor is it permits smaller lenses and camera bodies, stuffing a full frame sensor into a ultra compact with
decent zoom just isn't going to happen. If you want small portable size and zoom lenses that can slide inside a
tiny camera you trade off having a small sensor.
Large Digital Camera Sensors
Cheapest Full Frame DSLR
The
Nikon D4 is the least expensive full frame SLR digital camera at $5,999.99.
Large sensors range between 18x14mm(Four Thirds) and 36x24mm(full frame). These sensors are typically reserved
for SLRs but there is a demand by enthusiasts for large sensors in small packages and as such you can find these
sensors in select few boutique digicams as well as most mirrorless interchangeable lens cameras. These sensors are
much larger than the small sensor group, the smallest large sensor, Four Thirds @ 18x14mm is still 7X larger than
the largest small sensor - 1/1.7" @ 7x5mm. Large sensors inherently provide better cleaner images, they offer
higher true resolution, larger pixels, better color depth and great dynamic range. For these reasons they are
favored in SLRs which place a focus on quality over convenience.
Crop Factor on Large Sensors
When using interchangeable lenses the crop factor is important, because most large sensor cameras have
interchangeable lenses the crop factor should be considered. The crop factor section provides a good overview.
Top Small Sensor Cameras
The following are the top small sensor cameras, providing a strong mix of size, feature, convenience and
quality.
Compact Large Sensor Cameras that Shoot Video
The following are the top large sensor cameras that are mid size or smaller and also shoot video. These
represent high quality portable digital cameras that are a strong middle ground between large SLRs and compact
digicams.
Showing 6 comments
http://pentax.ca/en/digital_slr/645D/
It's only relevant if you're using lenses designed for a different camera.
Actually, this whole page is confusing. It says "Larger sensors permit more light per pixel", which is wrong. It actually permits LESS light per pixel, which allows the pixel to function without being overloaded ("clipping").
The only relationship I can find between sensor size and image quality is that a larger sensor allows larger pixels, and larger pixels are less sensitive to the blur caused by overlapping light waves. The light waves are spread out more so they don't interfere with each other. I can't think of any other reason why a larger sensor would be better than a small one.
Small sensors are better, if all other things are equal, because they make it possible for the camera to have much more capability in a smaller size (depth of field, zoom, etc). If the sensor is big, but doesn't have large pixels, then I don't think there's any advantage, but it will have many disadvantages.