ISO Sensitivity / Noise levels (contd.)

ISO bracketing

The EOS-1Ds inherits the EOS-1D's ability to use ISO to exposure bracket rather than changing the aperture or shutter speed. Holding the ISO modify combination (AF+Meter) you can use the quick command dial (rear of the camera) to select ISO bracketing of between -3 and +3 EV in 0.3 EV steps. The camera won't however exceed the minimum ISO 100 or maximum ISO 1250 during bracketing. With drive mode switched to continuous the camera will automatically take three (or more - custom function) frames. Shutter speed and aperture will remain the same for each of the bracket shots.

Although the ISO sensitivity is changed that is not reflected in the EXIF header (a little confusing).

Settings: ISO 400 / Parameters: Standard / Color matrix: 1 (sRGB) / Small, Fine

ISO 400
1/13 sec, F8.0
ISO 400 -1 stop
1/13 sec, F8.0
ISO 400 +1 stop
1/13 sec, F8.0

ISO 50 dynamic range

The reason ISO 50 is only provided as a custom function option is that although it provides 'buttery smooth' noise free images it is outside the designed sensitivity range of the sensor. This means that dynamic range is compromised at ISO 50. The results of this can be seen below, these two shots were taken with the same equivalent exposure value by varying aperture (F9 to F13 is one stop) and ISO (50 to 100 is one stop).

Settings: Parameters: Standard / Color matrix: 1 (sRGB) / Small, Fine

ISO 50
1/160 sec, F9
ISO 100
1/160 sec, F13

White balance

The EOS-1Ds provides a wide range of white balance options. On top of all of the normally selectable pre-programmed white balance settings (incandescent, fluorescent, shade, sunny etc.) there is also a Kelvin temperature selectable white balance (2800 - 10000 K in 100 K steps), manual preset white balance and three 'personal white balance' presets which can be programmed via the File Viewer Utility.

Automatic white balance works best under natural light, despite having an additional external white balance detector the 1Ds still couldn't quite get a perfect balance under incandescent light (still it's not too bad). The pre-programmed settings worked well and offer the nearest thing without setting manual (which is of course the best).

Settings: ISO 200 / Parameters: Standard / Color matrix: 1 (sRGB) / Small, Fine

Daylight: Auto Daylight: Shade (Cloudy / Sunny) Daylight: Manual
Incandescent: Auto Incandescent: Incandescent Incandescent: Manual
Fluorescent: Auto Fluorescent: Fluorescent Fluorescent: Manual

Kelvin temperature white balance

Below you can see an example of manually selecting the Kelvin temperature for white balance. Here the samples were shot in incandescent light and the optimum white balance would be approximately 2800 K.

Settings: ISO 400 / Parameters: Standard / Color matrix: 1 (sRGB) / Small, Fine

2800 K 3200 K 3600 K

White balance bracketing

Another useful feature of the EOS-1Ds is the ability to bracket white balance. This is enabled by holding the white balance and DISPLAY buttons and turning the quick command dial. You can select up to three levels of white balance adjustment plus and minus the selected white balance. Each level of adjustment equates to 5 mired (as would be produced by a colour conversion filter).

Settings: ISO 400 / Parameters: Standard / Color matrix: 1 (sRGB) / Small, Fine

Normal Minus Plus

Night Exposures

The EOS-1Ds provides timed long exposures up to 30 seconds, beyond that we must use Bulb exposure mode with a remote release. The 1Ds has noise reduction which when enabled (menu option) reduces noise in exposures with a shutter speed of one second or longer. It does so by taking a second equal exposure with the shutter closed and uses the noise information gathered from this exposure to remove noise from the first. Our experience of taking night exposures with the 1Ds was very positive, it produces great results up to and beyond the maximum timed exposure of 30 seconds.

Canon EF 50 mm F1.4
ISO 100, 10 sec, F16
3,761 KB JPEG
Canon EF 50 mm F1.4
ISO 100, 10 sec, F8
3,838 KB JPEG

The fifteen minute exposure

Not the most creative shot ever but it was really a test more than anything, the image below was taken using Bulb exposure mode and a remote release. The shutter was opened for fifteen minutes, the camera then took a further fifteen minute exposure afterwards. The result however is very impressive. There are a few small white speck 'hot pixels' but nothing that would distract from the overall image. Note the star trails...

Canon EF 17-35 mm F2.8 L
ISO 100, 905 sec, F19
3,742 KB JPEG
(100% crop from image on the left)