Sunday 27 September 2015

digital vs film - Why don't cameras capture dynamic range as our eyes do?


When sitting in a room with no lights on, and I look out the window, I can easily see the interior of the room even if I focus on a tree outside.


Why can a camera not capture a similar image to what my eyes can see? I would think that newer cameras should be able to capture this much dynamic range easily. I do not believe that display is a problem if this much dynamic range is captured, because it can be normalized. In a digital camera I have to set exposure which will only capture outer scene or inside scene correctly.


Is this only an issue with digital cameras or is it same for film cameras?


A similar question is already discussed here How to capture the scene exactly as my eyes can see?. I am not talking about resolution, focusing or detail. I am interested in exposure or dynamic range similar to when we fix our eyes on a single scene.



Answer



The reason you can see such a large dynamic range isn't that the eye, as an optical device, can actually capture such a range - the reason is that your brain can combine information from lots and lots of "exposures" from the eyes and create an HDR panorama of the scene in front of you.


The eye is pretty poor from an image quality standpoint but it has a very high "frame rate" and can change sensitivity, direction and focus very quickly.


The brain takes all those images from the eye and create the image you think you see - this includes details from images at different sensitivity and even details that are completely made up based on what you expected to see. (This is one reason why there are optical illusions - the brain can be fooled into "seeing" things that aren't really there).


So, you can see with your camera just like with your eye, just take lots of exposures at different settings then load everything into Photoshop, create an HDR panorama and use "content aware fill" to fill the gaps.



By the way, why cameras "should" be able to capture that range but monitors shouldn't be able to reproduce it? If technology that doesn't exist should exist then monitors should be able to reproduce anything we can see (and I should be able to take a vacation at a low gravity hotel on the moon)


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