The Digital Sensor: A Guide to Understanding Digital Cameras
by Wesley Fink on April 21, 2008 1:00 AM EST- Posted in
- Digital Camera
Field of View
Now that you have some basic understanding of digital camera sensors, it is time to take a closer look at the practical considerations that are created by these differences in sensors. A very poorly understood concept is the lens multiplier with the smaller than 35mm sensor-size that is used in most digital SLR cameras. The best way to illustrate this is with actual photos taken by a range of digital SLR cameras from the same tripod location.
We shot the same view using the exact same tripod location on a range of current digital SLR cameras. Each camera used a lens with the same focal length of 50mm. Lighting was the same with a 100W high-right light source, camera aperture was f4.0 in all cases, and white balance was set to Tungsten. The purpose of this series is to illustrate what you can see with each camera with the same lens, so exposure data is somewhat irrelevant, but exposure conditions were kept as constant as possible for reference.
The Canon EOS 5D is a full-frame SLR, which means the sensor is the same size as 35mm film. This point of view is the way an image at this distance would look on the Nikon D3, Canon 1Ds III, Canon 5D, and 35mm film cameras. The APS-H sensor used in a few Canon pro models is 1.3X and falls between full frame and 1.5X in its field of view.
The 1.5X multiplier is typical of cameras based on the Sony and Samsung sensors. This includes the Sony A700/A350/A300/A200/A100, the Nikon D300/D200/D80/D60/D40x/D40, the Pentax K20D/K10D/K200D/K100D, and all Samsung digital SLRs.
Canon introduced the small APS C sensor in the pioneering D30 and they have kept this size for consumer cameras since. This field of view is typical of the Canon 40D/XTi/XSi. The Foveon sensor Sigma SD14 has a 1.7X lens multiplier and falls between this small APS C Canon sensor and the 4/3 system.
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andrewln - Monday, April 21, 2008 - link
This was followed in about 6 months by the introduction of the Samsung 14.6MP CMOS sensor in the Pentax D20.should be Pentax K20D
Wesley Fink - Monday, April 21, 2008 - link
Typo corrected. Unfortunately spell check can't catch model numbers that are misstated.araczynski - Monday, April 21, 2008 - link
now i know what pc tech illiterate people feel like :)its a good thing i don't care about photography, interesting read none the less.
finbarqs - Monday, April 21, 2008 - link
the thing is, I've read the reviews and saw the comparisons between the 5D and the D200 (I believe that was the last CCD sensor that Nikon used). The 5D has way better per-pixel sharpness than the D200. Perhaps the technology of the CMOS made it so it finally "looks" better than the CCD. Or at least on the Canon side of things. I'm not biased towards any camera. I've own an XTi, 5D, Panasonic DMC-L1, and now a D300. I'm hoping to own the next 5D MKII (or whatever they call it).Even the D2X used a CMOS sensor, and I thought Nikon made the D300 sensor, as well as the D3 sensor (FF). What I also find "funny" is that Sony doesn't have a FF sensor yet, but nikon does, thus leaving me to believe that Nikon came up with their own FF sensor.
melgross - Monday, April 21, 2008 - link
It's Nikon's own design, though I don't remember who makes it.haplo602 - Monday, April 21, 2008 - link
Nice article Wesley, finaly one Anandtech photo related article I enjoyed reading.On note on the growing megapixel count. Sooner more than later, DSLR in APS-C (and later full frame ones) will hit the same technology wall P&S are facing (too small photosite).
This is one factor that makes me a happy film shooter :-) I know that my limit is the scanner up to around 10MP and I have less flexibility in shooting conditions (either 2 bodies or limited by ISO and film type), in every other situation I am equal or better off.
I am waiting for an affordable Nikon full frame body and then I will make my switch to digital (but that is yet years to come).
wally626 - Monday, April 21, 2008 - link
A sensor technology improves APS-C will be able to go to high enough pixel counts and have very good quality. For most consumers some where around 12 MP is enough, if the sensors improve to where this can hit 3200 ISO with low noise 99 percent of the market would be satisfied.The full frame bodies will replace the medium formats of the film world. There have been some really good medium format cameras that take much better images than 35mm but very few are sold. I think the article is correct in saying the full-frame DSLR will be the PRO cameras and priced as such.
melgross - Monday, April 21, 2008 - link
The number ofpixels is directly related to the print size.If you go by the oft quoted 300 dpi on the final print for maximum quality, you will need a sensor with 2400 x 3600 resolution for a full frame 8 x 12 print, or 8.64 MP. For an 8 x 10, it would be 7.2 MP (4/3 sensor).
For a larger 11 x 17, it would be 3300 x 5100, or 16.83 MP, or 13.86 for the 11 x 14 4/3 sensor print.
You can figure the rest of the sizes my multiplying the inch size of the print edges L x W by 300 to come up with a number.
But the truth is that 240 dpi is going to be good enough fot most prints, and youcan do the numbers that way.
When you know the numbers, you can figure out what size sensor you will need for the highest quality work.
But for most people, even 180 dpi will be enough for their prints. Going to that gives more flexibility, as the sensor pixel count is much smaller.
It's better to get a camera with a longer OPTICAL zoom rather than to go for the biggest number of sensor pixels.
haplo602 - Tuesday, April 22, 2008 - link
^ this ^It's all a matter of print size. I am an amateur/hobbyist, and anything past A4 is large for me. I have printed reasonable quality 8x12 prints from a consumer slide film and home film scanner.
I can hang them up on the wall in a nice frame and they will serve their purpose :-)
Idealy I'd need a 12-14MP full frame Nikon with goot ISO/Noise characteristics (f.e. D3) and it will satisfy my needs for years to come.
Heidfirst - Monday, April 21, 2008 - link
especially as I was wondering the other day what smaller process technology would do for digital sensors?Normally of course smaller process means cooler & more importantly smaller>cheaper to make but of course with sensors you are talking a fixed size so not any cheaper.
But would the potential increased precision of circuitry mean any better image quality?
& a little nitpicking:
Sony didn't buy Konica Minolta (which continues in business) but certain assets from the Photo Imaging division of KM. As to what that actually means there is little hard knowledge outside the 2 companies as it seems that KM still retain some IP & indeed a shareholding in some of the production facilities.
Also, current thinking seems to be that the "A900" may not be called that but something else to differentiate it from the APS-C models.