Canon today has released a firmware update for the EOS-1D that is designed to diminish the appearance of noticeable light/dark striations running through images generated by the company's flagship digital SLR. The condition, commonly referred to as the "banding problem" on Internet forums, is most noticeable in certain darker backgrounds and at higher ISO settings in particular.
The user-installable update, which may be loaded into the camera from a CompactFlash card, brings the firmware version in the camera to 1.2.0. The primary or only change in the firmware release is an adjustment in the amount of gain applied to the image data at certain points as it's being whisked from CCD to camera storage media. Specifically, after v1.2.0 is loaded, gain during the analog-to-digital conversion step is increased, while gain during a later digital processing step is decreased, relative to firmware v1.0.1.
Whatever the geeky underpinnings of the change, a quick look at before-after photos taken at ISO 800 and ISO 1600 reveals a welcome reduction in the light/dark striation effect. Not eliminated, however, is a single thin line across the top (horizontal) or side (vertical) of certain high-ISO frames.
To properly get a handle on the degree of improvement offered by v1.2.0 means first getting out and shooting the sorts of assignments that have previously revealed the banding problem. My initial impression, however, is that Canon has engineered a change that will likely improve the lot of EOS-1D photographers whose work consists of mostly upper ISO shooting. The first big test of the new firmware in North America may be this weekend's Superbowl XXXVI.
Canon has also released two Custom Tone Curves for the EOS-1D, both of which are designed to diminish the appearance of noise, but with a loss of some dynamic range too. At a glance this loss appears to be in the form of denser, noise-muting shadows. The two curves differ in the amount of noise reduction they provide, and each can be loaded into the camera as part of one of three user-selectable parameter sets. Canon recommends applying +1/3 stop of meter compensation for the milder 1_3.tcd curve, and +2/3 stop for the stronger 2_3.tcd curve.
To download the v1.2.0 firmware update, have your camera's serial number handy. Canon's web site requires it be entered before the download commences. Also online is a detailed PDF describing the firmware update process, as well as the Custom Tone Curve files.