Norman Koren’s Google TechTalk, Image Quality Measurement: Real world challenges, is now available online. For a clearer view of the image quality factors, download the the Presentation (PDF format) (2.8 MB).
RAW files are supported for a large number of digital cameras using Dave Coffin’s dcraw program. Files are converted with minimal signal processing— no sharpening or noise reduction. This allows the true performance of cameras and the behavior of raw converters to be analyzed.
Chromatic Aberration is now measured as percentage of the distance from the image center. This is an improvement over area in pixels because CA tends to be proportional to that distance. The new measurement is relatively independent of camera pixel count and measurement location.
A checkbox on the main window allows you to turn off automatic expansion of the figures for high resolution screens (>1280 pixels wide). The smaller figures are better for posting on the web.
Greatly expands noise and dynamic range calculations in Q-13 Stepchart and noise calculations in Colorcheck. Noise measurements in f-stops have been added to both programs. These are relative measurements, which correspond closely to the workings of the eye. Q-13 Stepchart now calculates total dynamic range (using a more sensitive detection algorithm) as well as noise-limited dynamic ranges for several quality levels. Colorcheck now includes noise measurements for the third Colorchecker row, which includes Blue, Green, Red, Yellow, Magenta, and Cyan.
In evaluation mode, multiple region SFR runs now count as two runs (even if more than two regions are selected).
September 3, 2004 -Imatest LLC announces the release of Imatest 1.0, a software package that measures the sharpness and image quality of digital camera images and digitized film images using inexpensive widely-available targets. Never before has it been possible for photographers to measure the performance of their cameras and lenses with such accuracy and convenience. You had to rely on subjective judgments or published test results. Now you can perform your own measurements, simply and easily, by photographing a target and analyzing the results with Imatest software.
Imatest consists of three modules.
- SFR measures the sharpness of cameras and lenses using a simple slanted-edge target (either the industry-standard ISO 12233 chart or a target you can print yourself on a high quality inkjet printer). Its standardized sharpening algorithm allows digital cameras to be compared on a fair basis. SFR also analyzes Chromatic Aberration and noise and estimates the Shannon information capacity— an indicator of image quality based on sharpness and noise.
- Q-13 measures a camera’s tonal response and noise using the Kodak Q-13 Gray Scale. It also measures camera or scanner dynamic range using transmission step wedges from Stouffer or Kodak.
- Colorcheck measures a camera’s color quality, tonal response, and noise using the GretagMacbethTM ColorChecker®.
With Imatest you can
- test lens performance at different focal lengths and apertures;
- measure your camera’s tonal response and dynamic range;
- examine the effects of camera and post-processing settings, such as mirror lock, ISO speed, white balance, RAW converter, and sharpening;
- compare the performance of different cameras, even if they have different amounts of built-in sharpening;
- compare your camera and lenses with results derived from websites such as imaging-resource.com, dpreview.com and others. This is important because quality control is far from perfect. Even premium lenses may fail to meet expectations. With Imatest you can find out fast and return them if they are substandard.
The tour on www.imatest.com/tour is an excellent introduction to Imatest’s capabilities.. Full documentation is available online at www.imatest.com/docs. Imatest runs under Windows 98, 2000, XP, and later, with a recommended
minimum of 128 MB RAM and 1024×768 pixel screen resolution. The introductory price is only $59 US.
An evaluation version that allows up to 20 runs of individual modules maybe downloaded from www.imatest.com/download.
Secure online purchase is available through Regsoft.com. Purchase entitles you to one year of upgrades. An affiliate program will be available.
Imatest was founded in Boulder, Colorado in 2004 to develop software that enables photographers to test the performance of their digital cameras and the sharpness of their lenses. It is a spinoff of the highly informative digital photography website, normankoren.com.
For more information, visit www.imatest.com or contact Norman Koren at .