It appears that the new $5000 Leica M8 uses glass over the sensor that is quite inadequate to block infrared light—great for infrared shooters, a serious problem for visible-light shooting. I don’t have my own Leica M8 to test, but pictures posted on the Leica Camera forum [thread] show the characteristic problems associated with infrared contamination. I have also confirmed the issue with a friend that owns a Leica M8.
Having experienced serious headaches with the infrared sensitivity of the Nikon D2H, I have canceled my Leica M8 order until I learn more of this issue, because for me it is an absolute show-stopper, completely unacceptable, especially for a $5000 camera.
The Nikon D2H had eerily similar problems, and it is simply mind-boggling that Leica chose sensor glass with weak IR-blocking qualities. The D2H caused enormous headaches to wedding photographers and similar professionals, especially those shooting with flash (which emits a massive amount of infrared). I have more than a few photos taken with the D2H with people’s faces that look like they are sunburned. In other cases, clothing or furniture or upholstery turns purple, like the entire interior of a BMW X5 (sorry, I threw those images out in disgust a few years back).
Only by using a B+W 489 or similar infrared-blocking filter can the influence of infrared be eliminated. While the B+W 489 introduces its own slight cyan cast, it is easily corrected because the entire image is affected uniformly. Try removing 3-6 points of cyan in Photoshop, or adding the same amount of magenta.
With Leica lenses, having to use a filter can be problematic, because Leica uses multiple filter sizes eg 39mm, 46mm, 55mm, 60mm—and too, Leica fans look askance at using filters (and why shouldn’t they, after paying $1500-$3500 for just one lens?!). The B+W 489 isn’t exactly cheap, it’s single-coated only, and often takes 10 weeks or more to obtain (personal experience). Still, if you want one, click on any of the images below to go the B&H site, one of the few vendors that offers them:
Infrared reflectivity is highly dependent on the subject matter. This means that no color profile or white balance can correct the problem, because different items within the same frame are affected differently! Items that are coal-black in visible light might be extremely bright in infrared. Consider these Halloween wreaths, which are coal-black in visible light (infrared photo taken with an IR-modified camera). They are relatively bright in infrared (the door is bright white in visible light).
When a particular item in an image is highly reflective of infrared, yet very dark in visible light, a sensor whose cover glass doesn’t block infrared adequately will “see” the item as a very bright... something. Color rendition will depend on the sensor, but typically magenta is the resulting color. (In the shot above, the camera has been modified to respond only to infrared, so color rendition is strictly due to infrared light). See Digital Infrared for more on infrared shooting.
The upshot is that under some conditions, faces will look sunburned, black velvet will look magenta, brown fabrics will look purple, etc. And at the same time, other objects will be perfectly normal. Such problems can be extremely difficult to deal with without lots of laborious Photoshop work; the only solution is to block the infrared before the picture is taken.
In short, unless you’re willing to apply filtration on the lens, the Leica M8 appears to be a risky choice for those with varied shooting situations, where the unpredictable infrared characteristics of the subject matter can spell serious problems.
UPDATE: Sean Reid has posted an unofficial response from Leica in the Leica Camera Forum (Nov 8, 2006). [One wonders why Leica can’t post this on their M8 website!]. In short, Leica says they’re aware of the issue, and that’s the way the M8 was designed, and it’s why a “special IR barrier filter” is offered. I doubt that this special filter will be free, or even inexpensive, so add a C-bill or so to the price of each lens you plan to use with the M8. Why should users have to pay to fix an inherent defect? At the least, M8 users should get a rock-bottom price to buy these filters.
As one poster (“clayh”) quipped: “It’s not a bug, it’s a feature—It'll cost you some extra money to turn off the feature, though.”