Red One Camera Testing
by John Beale  Jan. 2008

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I was fortunate to have the opportunity to do some tests with Red #103 (firmware #12) on Jan. 8 2008.  Careful testing takes time; analyzing and understanding the results takes quite a bit more time.  I will add to this page as I am able.  There may be discussion of this test at Reduser and DVInfo.

Many of the raw files were taken in 2k 16:9 mode ("Red 2k" at 2048x1152), which uses a cropped or windowed central portion of the sensor that is half-size in X and Y, so that is 1/4 the total number of pixels available in 4k mode.  Using the 2k mode saves storage space and processing time, and is useful for evaluating technical details at the per-pixel level (noise, sharpness, color, etc). To compare image quality overall, of course the 4k mode is better.  To open Redcode Raw (.R3D) files you need an application such as Redcine.   The Red Alert and Redcode Quicktime plug-ins (as of Jan. 2008) don't support 16:9 format.

NOTE: in August 2014 I had to remove all R3D files after my site was suspended for over-large files. Sorry.

Test #1: Lens Cap On 2k 16:9 lens cap on

RAW:  2k-Dark-5600k-1-1.R3D  2k-Dark-4200k-1-3.R3D

This test shows the dark level of the camera and the nature of the noise with no light. Since the RED does not have variable analog gain between sensor and A/D, I do not expect the recorded dark noise level in the raw file to change with camera settings. On this camera, ISO/ASA setting and color correction is all done in post, after the shoot.  Just to check this I did another dark clip with the color temperature manually set to 4200 K.  This test was done immediately after turn-on, indoors at about 25 degrees C.  In the full day of testing the camera became only barely warm to the touch, but it was mostly in standby and recording only very brief clips.

Redcine allows export to TIFF or other standard formats with a selection of RGB color models, exposure and color adjustments. At the default settings, the dark level sits well above R,G,B=0. For normal image processing you would adjust it downwards ("crushing the blacks"). Regardless of settings, the noise level appears good to me with very little fixed-pattern noise.  Apparently there was an improvement made with firmware #12, as cameras running earlier versions of the firmware showed more noisy dark areas in low-light conditions.

Test #2: Color Charts A Chart A setup  Canon 20D: Charts A

RAW:  4k-ChartA-T56-1-3.R3D  2k-ChartA-T3-1-12.R3D  2k-ChartA-T56-1-13.R3D  2k-ChartA-T8-1-14.R3D
Photo with Canon 20D + 24-70L: Canon20D-ChartsA_9207.jpg   (note: 20D was not aligned to exact same location as Red)

Setup: For the 2k shots the red camera was 8' 7" from the charts measured from the front of the PL mount (the lens extends in front of this plane). The lens was the Red 18-50mm set at T3, T5.6 and T8. For the 4k version camera was moved closer and zoom adjusted to frame approximately the same area. In all tests, focus was by eye, with the lens at T3, using the LCD viewscreen in 2x expanded view ("Focus Check" user key 2). Note, in 2k mode, the view magnification is less than 2x. The main goal of this test was to examine color response, not resolution.

The center color chart is the A4 size non-glossy IT8.7/2 from Wolf Faust at, charge R060101. Colorimetric data: R060101.txt  The bottom color chart is the Gretag-Macbeth color checker.  The monochrome resolution patterns were printed by an Epson Photo R320 at 1440 dpi on matte paper. The patterns were generated using Imatest, and the specific images I used can be downloaded here. The charts are pinned to a black 30x40" foamcore sheet.

Light was from two Lowel Tota lights with 650 W bulbs, placed at roughly 45 degrees on each side. The light stands were 4' 8" from the center of the chart. The light on camera right was gelled Rosco 3202 (CTB), light on camera left was gelled 3202 + 3216 (CTB, +1/8 CTB) to balance the measured color temperature between the two. Both lights were on electronic dimmers to allow for adjustable color temperature, but in all cases were used with the dimmers set to full-on.  A length of  24" wide black wrap was used around each fixture to reduce stray light to the sides.

Incident exposure at center of chart: f5.6 + 2/10 at ISO 320, 24 fps, 180 degree shutter.  
Lighting color temperature: 5150 K, CC-4 from left fixture and 5150 K, CC-1 from right fixture.  (CC units in deca-mireds)  [units corrected 4/15/08]

Exposure measured by Spectra IV (s/n 072664) calibrated 10.3.07 by Quality Light-Metric Co, Hollywood CA
Color measured by Minolta Color Meter II (s/n 119859), calibrated 10.3.07 by Quality Light-Metric Co, Hollywood CA

Test #3: Zone Charts B Chart B setup  Canon 20D: Charts B  

RAW:   4k-ChartB-T8-1-12.R3D  2k-ChartB-T8-1_4.R3D
Photo with Canon 20D + 24-70L: Canon20D-ChartsB_9215.jpg  (note: 20D was not aligned to exact same location as Red)

The goal of this test was to examine aliasing with high-frequency detail, at different contrast levels, with B/W, grey and color patterns. Lighting was the same as above (Test #2) in this case. An in-camera manual white balance to a grey card indicated 6218 K, but my grey card is old and probably bad.  The Red display has a "traffic light" exposure aid which has red, green and blue lights indicating if any area is clipping in the R, G or B channel. The exposure in this test at which all three clip lights just disappeared was T4.0 + 2/3.  However, the 2k and 4k shots were taken at T8 in an attempt to minimize any focus problems. Consequently, the raw image is somewhat underexposed.

The 20D image was f/8, 1/10 sec, ISO 200. The aliasing on my 20D is so bad I suspect a problem (Jan.2 2009: there is a problem). It was once repaired by Canon, about two years ago (it was writing corrupted images on the CF).  If anyone else wants to try this test with a 20D (or any other camera), I'd be interested in your results.

The background is 36x48" white foamcore (Office Depot 575514). The uppermost zone plate looks washed out due to overexposure, but it is not. That pattern is just printed with low contrast (2:1). The center zone plate has a sinusoidal pattern, the left zone plate and the bottom colored plates are hard-edged patterns.  The basic versions of these patterns can be downloaded here. I made the color versions from the hard-edged B/W version by RGB levels adjustment in Photoshop.

Each of the seven resolution test patterns is printed on US letter size (8.5x11") paper. Top (light) and bottom (color) zone plates are on Epson S041568 Matte Double-Sided. Center and left zone plates are on Epson S041667 Premium Glossy. Right pattern (3x5 squares) is on Alpha Cellulose 315 gsm soft-textured (MIS Associates / Inksupply ALPHA-8511-25), this paper has no optical brighteners. All patterns printed by Epson Photo R320 inkjet at 1440 dpi (except the 3x5 squares were 720 dpi).  

Exact materials are listed in the interest of recording the details of this test. No commercial endorsement is intended, and no business relationship exists, except as a customer since I bought the items mentioned for the test.

UPDATE Jan.2 2009:  More about my Canon EOS 20D RAW problem (JPEGs are OK, but RAW images show mosaic noise; it started after a Canon repair for a different problem). The fix is to use the raw converter DCRAW with the -f option.  The DCRAW man page says only: "-f : Interpolate RGGB as four colors".  I might guess that somehow, the two green channels in my 20D sensor's RGGB bayer pattern do not have the same gain? Anyway, it certainly makes a difference. Here is a 200% crop of the same image converted from RAW, both with and without the -f flag. USM was added to show the problem; same amount for both frames:

More Tests: Page Two

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