Thursday, November 09, 2006


Leica M8 Infrared IR and 6-bit coding woes

It appears that many Leica M8 owners, and prospective owners are getting ready to return or cancel their orders for the M8 due to the M8 possibly needing both a filter, and lens 6-bit coding to properly work in JPG mode without post processing.

Previously it was thought that the lens encoding was primarily for vignetting correction with very wide lenses as well as for lens identification for insertion into the EXIF data fields.

It turns out that the lens identification, and interaction with the firmware in the camera may be required for additional corrections.

The requirement of an IR filter proposed by Leica as a corrective measure has thrown many folks off. Even this Kodak press release from Sept. indicates that the IR issues are being handled by a thin coating on the sensor:

[Excerpt of Kodak Press Release for sensor]:
September 18, 2006 – Last Friday, Eastman Kodak Company announced the new Kodak KAF-10500 image sensor found in the first digital Leica rangefinder camera, the M8. As the second collaboration between the two companies, the Kodak CCD sensor promises low noise, high sensitivity, and wide dynamic range for the Leica M8, according to Kodak’s press release.

Kodak, who has provided sensors for Hasselblad in Phase One digital backs, partnered with Leica for a second time for the digital M8. Kodak and Leica first joined ranks in making the repeatedly delayed Leica Digital-Module-R, the world’s first digital and analog camera that takes film and SD memory cards.

Leica, who also released its first DSLR last week - which uses a live view-enabled Olympus NMOS sensor, also found in the Olympus E-330 and Panasonic L1 - elected to fit the M8 with the new 10 megapixel 27 x 18 mm Kodak KAF-10500 CCD sensor based on the low noise characteristics of the chip and its ability to confirm to the M8's physical design parameters.

The design of the Leica M8 and Kodak sensor took a couple years, said Mike DeLuca, Kodak market segment management for image sensor group, in an interview with

“Kodak designed and optimized the new image sensor to meet the demanding needs of Leica photographers,” stated the release. Kodak specifically modeled the new KAF-10500 image sensor with the Leica M8 in mind.

Kodak used Indium Tin Oxide (ITO) on the CCD sensor to create low noise, high sensitivity, and a wide dynamic range. The sensor also has anti-blooming protection to preserve image information in high light situations, stated the release.

The M8's KAF-10500 imager is designed with a microlens to prevent vignetting. Unlike DSLRs, the Leica M8 lacks a mirror reflex box to preserve the body’s compact design. To conserve space, the sensor sits close to the lens. When used with a wide angle lens, a compact body without a mirror box allows light in through sharp angles, creating the problematic vignettes. The Kodak sensor, however, as DeLuca explains, compensates for proper light allowance and thwarts lens vignettes.

In addition to the micro lens, the Kodak sensor helps keep the Leica body small applying with its infrared light filter coating directly on its glass. Unlike other cameras that contain an extra element to filter IR light, the Leica M8 contains the IR filter right on the sensor to conserve space. “There is not an additional element in place,” said DeLuca, “but [the camera sensor] still has the IR-absorbing characteristics.”

When asked why Kodak and Leica opted for a CCD sensor over a CMOS sensor, DeLuca said, “It was very clear the full frame CCD was the path to go down because of the performance it was able to provide.”

Although Kodak sensors have been used in a respectable list of high-performance cameras, DeLuca notes, “the achievement is working closely with a customer that is so well known for the quality of devices that they deliver. To work with Leica…we are as proud of that as we are the technology we deliver.”

Link to PDF datasheet of Kodak KAF-10500 CCD Imager:

From one of the early reviewers of the M8, but not an official beta tester, posted here:

In response to my requests, Leica USA's Christian Erhardt recently provided me with two official statements related to the M8. I've already integrated a discussion of the first into my M8 review series and will be integrating the second as well. I'm publishing these here as well as on my site because I know this is important information. To my knowledge, they have not yet been released generally.

Christian Erhardt Statement 1:

Background information on the IR barrier filter of the LEICA M8 and its positive effect on color fringing, image resolution and the rendering of black synthetic fibers:

The glass cover of the image sensor of the LEICA M8 is a combination of the IR barrier filter and a specially coated protective glass. The transmission in the red and infrared region of the spectrum can be controlled by the layer thickness of this filter. In the case of the Leica M8, which is a very compact system, the thickness of the filter, 0.5 mm has proved to be ideal. The short back focal length is the base for the compactness and the high quality of the standard and wide-angle lenses. However, the resulting oblique angle of the incident light on the sensor requires special adaptations of the filter.

Absence of color fringing / Image Resolution
The extremely thin layer of the filter, 0.5 mm prevents color fringing at the corners of an image. This phenomenon, which is also known as astigmatism and is frequently encountered with digital SLR cameras, is not a problem for the LEICA M8 because of the thin glass cover on the image sensor. This feature, plus the particularly high imaging quality of Leica M lenses, is the reason for the high corner-to-corner image resolution.

Rendering of black synthetic fibers
The elimination of color fringing and the improvement of image resolution results in higher IR sensitivity. This causes some synthetic textiles to appear an artificial-looking purple.

If the higher IR sensitivity has a disturbing effect in certain applications, e.g. fashion photography, LEICA Camera AG offers its customers a special IR barrier filter. This is screwed on in front of the lens and is an ideal combination of IR, UV and protection filter.

The use of the additional IR filter in front of the optical system has big advantages, as the filter does not create reflections inside the optical system. This enables the reproduction of the finest tonal values even in shadows.

The filter is supplied as an accessory with a special firmware adjustment, which will be available shortly after the planned market launch of the camera at the end of November 2006.

The IR/UV filter is only suitable for use with digital M cameras and 6-bit coded lenses.

The high IR transmission may also be a creative advantage for applications in the area of infrared photography.

Christian Erhardt Statement 2:

White balance ensures neutral rendition of color in any light. It is based on the M8 being preset to reproduce a particular color as white. The AUTO WB provides neutral results in most situations.

Leica is currently working on fine-tuning the Auto-White-Balance. Future Firmware updates will show the improvements achieved.

For the best image quality, Leica recommends the use of the RAW mode (DNG). When working in the DNG mode, customers have the option to change the Kelvin temperature to their desired WB. For best results, it is further recommended that the specific lighting situation within the WB setting is selected.

Capture One is the ideal software for converting the Leica DNG files.


I'm happy to provide this kind of information specifically to this forum. I don't believe that this information has yet been issued as a general release. I hope it leads to productive discussion. If it instead simply leads to a series of attacks on Leica, I doubt that I will publish statements like this to a forum again.

BTW, to make things crystal clear....I was not an official beta tester for Leica. Along with many journalists, I had the opportunity to twice work with pre-production examples of the M8 this past August in order to write about the physical camera (viewfinder, speed, ergonomics, etc.). These cameras used pre-production firmware and file quality was not at "shipping" level (as defined by Leica). My file quality assessments of the M8 are all based on the test unit I received October 20, 2006 and have been testing since, as time allows. No one person will discover all there is to know about the M8 so let's use this forum to educate each other about the camera, not to attack each other.



Sean Reid

This digital Leica is more like a traditional film camera than a digital camera. You must be totally in control of focus and exposure, change lenses rather than zoom, and THINK when you shoot. The images that result can be stunning. After 40 years of shooting with Leicas and loving every moment of it, this was an exciting break through. It is a real Leica camera that just doesn't use film. It is expensive, but some things are worth the money.
Post a Comment

<< Home

This page is powered by Blogger. Isn't yours?