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Technical Information

Surprise - your photographer is also an engineer! Here, you will find gathered links to various photography-related technical discussions by Marianne. These will gradually expand over time, so if this is an area of interest to you, check back occasionally.


Image Sensor Analysis

Marianne's guide to discovering the nuances of camera image sensor design and characteristics, and how the image data gathered from them is used.


Optical Simulation

Explore the sub-pixel realm and learn how defocus, diffraction, lens point-spread and AA filters interact and affect how the camera's sensor "sees" images.


Bayer 24Mpix RAW File

Comparison RAW file from the D800E at 25Mpix crop. Museum of History and Industry scene, Seattle, WA. Crop to 6012 x 4008 pixels to match sample photo taken by a Sigma DP2 Merrill. Processing tip: Using Raw Therapee with Unsharp Mask at 0.45 radius and 145 level, will match the default sharpening in Sigma's Photo Pro software.


D3s HPS Algorithm Examples

Astrophoto examples from the D3s, with and without the hot-pixel suppression (HPS) algorithm applied. Demonstrates loss of fine highlights. Exposure at 1/5 sec is without HPS, and exposure at 1/4 sec is with HPS - and many fewer visible stars!


D4 Long-exposure Process Examples

Astrophoto examples from the D4, with and without the long-exposure processing (LEP) which the D4 applies to RAW data at shutter speeds of 1 sec or longer. Note this is not the long-exp. NR selectable by the user; it's an automatic process that cannot be turned off. The good news: Quite unlike the HPS used by the D3s, this processing generally leaves stars intact. Exposure at 1/1.6 sec is without LEP, and exposure at 1 sec is with LEP.


D4 Black Frames

Black frames from the D4, at various ISO levels, with and without the long-exposure processing (LEP) applied. Offered for analysis by the curious.


D800E HPS Algorithm Examples

HPS test-chart from the D800E, with and without the hot-pixel suppression (HPS) algorithm applied. Demonstrates color-dependency in modification of "hot" pixel values. Exposure at 1/5 sec is without HPS, and exposure at 1/4 sec is with HPS. Without an AA filter, it is possible to create artificial hot pixels in the D800E, which it cannot distinguish from actual sensor hot pixels. The chart is designed with a slow phase shift between the test-chart dot matrix and the sensor matrix, producing many precisely-registered image dots which stimulate only one pixel.

 

Last Update:  Dec. 16, 2013.