A tweet of @PhilipBloom drew my attention to the blog of @AndrewSchar about video noise on a Canon 60D. My idea immediately was to digg in a little bit deeper to be able to compare a 5D MkII at different ISO settings and even more to compare the amount of noise generated by other cameras.
And there is also the question, whether and how noise gets influenced by different picture profiles. Several weeks ago Technicolors CineStyle was presented and spread out all around the globe. So I also wanted to find out whether there are any differences between a neutral setting and the CineStyle.
You’ll find recommendations in the web that on a Canon 5D Mk II you should always use ISO multiples of 160. In fact 160 is way better than 100 or 125, but what’s the difference for example between ISO 1250 and 125? Continue reading, you’ll be surprised!
So the idea is to see more than just a comparison of framegrabs with raw noise. I wanted to see the level and nature of noise and so I thought about tools to measure video noise. Finally I came up with a solution that only requires After Effects CS5.

Shooting noise is quite easy, keep the cap on the lens and assure no light gets in, select one ISO after another and record a few seconds of each. I set the camera to manual mode, 1/50 and Daylight WB. To get the feeling about typical low light situation I also did a complete series with tungsten setting. Both of them with the neutral profile and CineStyle.

When placing the clips in a new After Effects Composition you see the noise, but it is very dark. Luckily, who wants bright and highly visible noise?! In our case althoug we want to see the noise better. So we add an adjustment layer with the Levels Effect applied. Setting the input range from 0 to 32 and the output from 0 to 256 makes it’s easy to calculate the RGB Values. In an 8bit RGB colorspace 0 remains 0, 1 will be 8, 2 wil be 16 and so on. With the adjustment layer active the noise is way better visible now.

For better comparison I added a reference chart in a precomposition. The chart consists of 17 squares with RGB values starting at [0,0,0] up to [16,16,16]. I used short scripts to calculate position and color of the squares. So I had just to set up one square and then duplicate that layer 16 times.

Now is the time to take a look at the noise in a monitor. Packed with After Effects CS5 you get the plugin Synthetic Aperture Color Finesse 3 for color grading. This plugin also features a waveform monitor, a vectorscope and a histogram. These are the tools we need.
There are some tutorials for color finesse out there, the one which inspired me for using a color correction plugin as waveform monitor is from Andrew Cramer (http://aeportal.blogspot.com/2011/01/vectorscope-and-basic-color-correction.html).
In the AE Comp I placed Color Finesse in a separate adjustment layer at the top of the composition.

So what do we have right now? Well – we have the amplified noise and our reference chart at the bottom of the frame. In the example you see the noise at ISO 6400. What is quite strange, that my 5D sensor produces more and “greener” noise on the right side. So first I thought light has got in, but then I found reports in the Internet about this phenomen, so I just accepted it without further investigation.

To access the different monitors you have to launch the Full Interface of color finesse.

When looking at “cinestyled noise” we add one more adjustment layer with LUT buddy.

Picture profiles and noise

This is a comparison between 5D and 550D with and without CineStyle, in this example at ISO 1250. Monitor-Charts of all ISOs you find in detail after the summary.

	5D	550D
1250, Neutral
1250, CineStyle

Summary

• On a 5D Mk II always use the old “multiples of 160″-rule, avoid especially 125 and multiples. As you can see ISO 1250 has same amount of noise as 125! Above 1250 noise continuously growing and there are no significant bad or good ISOs. So order is: 160 320 640 1250 …
• Cinestyle generally raises the blacks level when recording and LUT brings the blacks back down including the noiselevel, so it effectively reduces noise! There’s a price to pay for that, read about in an upcoming blog.
• On a “normal” 550D you can select only multiples of 100. With magic latern you also get the ISOs in-between. I’ve tried the 160′s series but the difference not that big as it is on a 5D.
• A 550d shows – as expected – generally more noise.

Comparison 5D vs 550D with “Neutral” Profile

	5D Neutral	550D Neutral
100
125
160
200
250
320
400
500
640
800
1000
1250
1600
2000
2500
3200
4000
5000
6400

Comparison 5D vs 550D with Technicolor CineStyle Profile

	5D CineStyle	550D CineStyle
100
125
160
200
250
320
400
500
640
800
1000
1250
1600
2000
2500
3200
4000
5000
6400