Canon 5D Mk2

[DeanNewman]

How does the Canon 5D MK2 perform in reducing noise at high ISO? Is it comparable to the Mk3?

[arash_hazeghi]

5D MKII has lower noise than any EOS camera built to date.

you can go to http://www.imaging-resource.com/ and download RAW files from their standard test scene with 1DMKIII and 5D MKII (and other cameras)and convert them using your favorite converter, then put them side by side in PS, compare and decide :)

[Roger Clark]

How does the Canon 5D MK2 perform in reducing noise at high ISO? Is it comparable to the Mk3?


5D MKII has lower noise than any EOS camera built to date.


It is more complicated than that.

First, what people call noise is more correctly the signal-to-noise ratio, not the noise directly. For example, many P&S cameras with small sensors have lower noise from the highlights to the shadows than most DSLRs with larger sensors. The problem is the P&S cameras have tiny signals, whereas the DSLRs have huge signals (for example, measured in photons captured). So the large pixels of large sensor DSLRs collect the most photons and therefore have the highest signal-to-noise ratios, producing the cleanest images.

The photons collected by a digital camera pixel is controlled by the collection area (mostly the size of a pixel), the quantum efficiency of the sensor and the transmission of the optics. Quantum efficiencies and transmission of the blur filter, IR and RGB filters on the sensor are very close in most all digital cameras, whether CCD or CMOS. That leaves fill factor and pixel size. With the micro lens arrays that have been refined in the last few years fill factors are very high and won't change much (the technology is mature). That leaves pixel size.

So the dominant metric in signal-to-noise ratio in digital camera images is pixel size. The signal-to-noise ratio is very close to the photon noise limit at high signals (everything in your images except the deep shadows or very ighest ISOs). The signal-to-noise ratio is the square root of the number of photons collected by each pixel.

At the low end, other factors come into play, and here is where technology has been advancing rapidly, giving the impression of better shadow and better high ISO performance. The noise sources include:
1) apparent read noise from the electronics (this is a combination of noise from the on chip amplifiers to the A/D converter), 2) fixed pattern noise, and 3) thermal noise (only a factor on long exposures of minutes or more, or at high temperatures).

You can see details of where sensors plot at:
http://www.clarkvision.com/imagedetail/digital.sensor.performance.summary

For example, look at Figure 2 which shows ISO 100 signal-to-noise ratio on an 18% gray card. The 5DII and other recent cameras do not plot with the highest signal-to-noise ratios because they have smaller pixels. Older cameras, like the 1D Mark II do better and have signal-to-noise ratios.

Now look at Figure 3, the read noise at high ISO and you'll see the read noise is very low for the 5DII and other recent cameras like the 50D.

So for highlights, middle gray and a few stops lower, the 5DII has lower signal-to-noise ratios than older cameras like the 1D Mark II. But the read noise is much better at high ISO giving better overall high ISO performance. The fixed patter noise is also much better in the newer cameras, also helping high ISO performance.

But if we had 1D Mark II sized pixels with present day electronics performance, it would be stunning at high ISO in low light.

Roger

[DeanNewman]

Thanks for the info. That Image Resource web site is pretty amazing and I learned a "ton" about photographic noise from Roger's post. I'm indebted to you both. Again, thanks.