MP and Bit depth?

slackercruster

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If a standard dslr sensor is 23.1 x 15.4 and a full frame sensor is 36 x 23.9 and both are in the 12 MP range. Does that mean the pixels are bigger on the larger sensor since they have the same amount of pixels as the smaller sensor? If this the case, is there slight loss of benefit with the larger sensor since the pixels are larger?

What is bit depth?

One camera may have a bit depth of 8 another has 14. How does this translate to real world photography? Will you see the difference on the screen or an 8 x 10?
Thanks
 

SCraig

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The pixels on the full-frame sensor are larger. There are numerous arguments for either full-size or crop sensors. Look around and take your choice.

Bit depth is the number of tones the sensor can resolve. 8-bit depth can resolve only 256 shades per channel, 12-bit depth can resolve 4,096, and 14-bit depth can resolve 16,384 shades per channel.

The sensor itself only sees light levels, it does not see red, green, or blue. The filter array over the top of the sensor filters out two colors of light so that each pixel on the sensor only sees one color.
 

Big Mike

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I'm no photographic engineer, but I think one of the main differences between sensors of the same MP count, but different size, is the 'pixel pitch'. In other words, how tightly packed the photosites are. The more photosites you cram onto a sensor, the more heat that can build up, and thus the more interference and thus the more digital noise in the image.

This is why cameras with larger sensors can give us images with less digital noise (especially at high ISO) and why cameras with smaller sensors give more digital noise. Consider P&S digital cameras, they have tiny sensors and usually give very noisy images when the ISO gets up to 400 or 800 etc.

Check out this article. Part one has a nice write up about bits.
Why Raw -- Part I
 

480sparky

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If a standard dslr sensor is 23.1 x 15.4 and a full frame sensor is 36 x 23.9 and both are in the 12 MP range. Does that mean the pixels are bigger on the larger sensor since they have the same amount of pixels as the smaller sensor?

Yep.

If this the case, is there slight loss of benefit with the larger sensor since the pixels are larger?

Better noise issues.

What is bit depth?

Basically, how many shades of a color that are possible. 8-bit images containt 256 levels of a color (2x2x2x2x2x2x2x2 = 2^8 = 256). 14-bit images have 16,384 levels (2x2x2x2x2x2x2x2x2x2x2x2x2x2 = 2^14 = 16,384) levels of color.

One camera may have a bit depth of 8 another has 14. How does this translate to real world photography? Will you see the difference on the screen or an 8 x 10?
Thanks

At a 12mp level, there won't be an issue printing an 8x10. The difference will appear when you start to edit them. An 8-bit image have very limited editing options before the image starts to degrade. 14-bit opens up far far more editing abilities.
 

KmH

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If a standard dslr sensor is 23.1 x 15.4 and a full frame sensor is 36 x 23.9 and both are in the 12 MP range. Does that mean the pixels are bigger on the larger sensor since they have the same amount of pixels as the smaller sensor? If this the case, is there slight loss of benefit with the larger sensor since the pixels are larger?

What is bit depth?

One camera may have a bit depth of 8 another has 14. How does this translate to real world photography? Will you see the difference on the screen or an 8 x 10?
Thanks
There are many DSLR image sensor sizes, none of them 'standard'.

Most DSLR cameras have an APS-C size image sensor. Canon's APS-C size image sensor is smaller than Nikon's APS-C size image sensor but both companies have some APS-C image sensor size variances.

In addition to the full size 24 mm x 36 mm (35 mm) image sensor size, there is the APS-H, 1.3x crop ratio image sensor, the 1.5x and 1.6x crop ratio APS-C size image sensors, and the 4/3rds, 2x crop ratio image sensor.
 

Garbz

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To qualify what has been said about the sensors capabilities, with a larger sensor of the same pixel count the pixels themselves are larger.

In any digital signal system be it photographic or something like music, one of the most important aspects is the Signal to Noise ratio. i.e. there's no point in having a 14bit signal if the bottom 64 values are white noise. It would effectively make it no better than an 8bit signal. So these two combined (the signal - noise, and the bitdepth) determine how much useful data you have.

Back to the sensor, noise comes from electronics, and it occurs randomly in some as dictated by physics. Signal comes from light. To increase signal we need to convert the maximum number of photons (light) into electrons (electricity), and by far the easiest way to do this is to make the pixel larger so that more photons hit it.

i.e. Larger sensors produce more usable data, which equates to better pictures.
 

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