Exercise: Sensor linear capture
Prior to starting this exercise I read of a fellow DPP student's problem understanding the expected outcome of the exercise on the OCA Flickr group. I am glad I was made aware the coursework text is incorrect as I too would have thought I was totally dim ! http://www.flickr.com/groups/ocarts/discuss/72157628955228629/
Digital sensors respond to light in a different way to film and also how our own eyes react. The sensor responds to light in a linear, proportional, way and then performs a series of in-camera actions. Unlike the human eye it is unable to distinguish detail in the shadows and highlighted areas , this information is lost.
This exercise examines what an image looks like prior to the in-camera process and how the camera performs gamma correction curves to alter an image and make it appear more customary. I used a 16 bit Tiff as instructed (on my old PC using Elements not PS) and created a new darker image .
Prior to starting this exercise I read of a fellow DPP student's problem understanding the expected outcome of the exercise on the OCA Flickr group. I am glad I was made aware the coursework text is incorrect as I too would have thought I was totally dim ! http://www.flickr.com/groups/ocarts/discuss/72157628955228629/
Digital sensors respond to light in a different way to film and also how our own eyes react. The sensor responds to light in a linear, proportional, way and then performs a series of in-camera actions. Unlike the human eye it is unable to distinguish detail in the shadows and highlighted areas , this information is lost.
This exercise examines what an image looks like prior to the in-camera process and how the camera performs gamma correction curves to alter an image and make it appear more customary. I used a 16 bit Tiff as instructed (on my old PC using Elements not PS) and created a new darker image .
 Original image |  Using a curve adjustment to demonstrate what the image looked like at time of capture. The altered image is now much darker , the colours are flat and dull. |  The histogram indicates a dark image and shows how it looks prior to in-camera processing. |
 The original file saved as a new "linear" version: showing how the camera sees. |  Using a curve adjustment to demonstrate the gamma correction performed in-camera.The altered image has now become brighter. |  The histogram demonstrates how in-camera processing alters tonal values. |
I found the image emulating the in-camera gamma correction process greatly increased digital noise, something I hate.
How I understand the exercise, and what it means in terms of creativity, is that the sensor records lines of light (linear capture). I need to be able to pre-visualise a scene as the camera sees it , ignore what I see, and use this knowledge to gain control over the final image. The projects in the remainder of Part 2 look at ways of how this may be achieved.
How I understand the exercise, and what it means in terms of creativity, is that the sensor records lines of light (linear capture). I need to be able to pre-visualise a scene as the camera sees it , ignore what I see, and use this knowledge to gain control over the final image. The projects in the remainder of Part 2 look at ways of how this may be achieved.
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