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 . 

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Original image

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 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.

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The histogram indicates a dark image and shows how it looks prior to in-camera processing.

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The original file saved as a new "linear" version: showing how the camera sees. 

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Using a curve adjustment to demonstrate the gamma correction performed in-camera.The altered image has now become brighter. 

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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. 

 


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