We're all doing it wrong (unless you ETTR)

robertgilbert86

robertgilbert86

robertgilbert86

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Just read this essay about metering for digital sensors and it seems you can capture ~10^3 times more tonal range if you Exposure To The Right without clipping and then under-expose in PP (RAW only). I've haven't tried it in the field but wonder if anyone else has and noticed an impact?

http://www.luminous-landscape.com/tutorials/optimizing_exposure.shtml
 
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Ive always instinctively known to over-expose a light scene like a snow scene & under-expose a dark scene -else it will look grey.
Ive never heard of ETTR, but after reading that article it makes sense.
Obviously theres more noise in the dark areas of a digital image, you only have to use a cheap webcam in a dark room to notice this. No matter the camera, this will always be true (just less on pro cameras).

Basically: over-expose a RAW as much as you can without clipping the highlights too much & then pull back the exposure in post.
Obviously this will not work with every scene, but should otherwise improve the tonal values which would have been lost in a before; correctly exposed dark area.
 
Interesting stuff - so if I've understood right, overexposure up to (but not including) the point at which highlights start blowing - then adjust the raw file afterward. Will have to give it a go.
 
Yup, read up on it maybe a year ago. I always try and expose as much as I can without overexposing and without jeopardising my shutter speed depending on what I'm shooting.
 
The crazy thing is that it sounds like manufacturers could implement this with a firmware update (over exposing for x% clip and then pulling it back) and that DNG has already got capacity for it.

I know it's old but it's new to me!
 
I dunno about Expose to the right for every shot.

I expose to what I think it looks right...sometimes i dial 1/3, sometimes a stop, at times 2 stops, sometimes none.

It's not an absolute.
 
robertgilbert86 said:
The crazy thing is that it sounds like manufacturers could implement this with a firmware update (over exposing for x% clip and then pulling it back) and that DNG has already got capacity for it.

I know it's old but it's new to me!
Click to expand...

I thought RAW is how the scene IS and the RAW cant be tinkered with other than how it was originally shot. Thats the point of a RAW image, but theres nothing stopping you from over-exposing at the time of shooting and being as the camera does not know if a scene needs ETTR applying then how can a camera expose with ETTR ? Am I making sense?
Maybe a camera jpg could have ETTR applied, but jpg is only 8bit & has 256 tones compared to 4098 with RAW, plus would need a different exposure than an accompanying RAW shot.
 
Good point juno, the camera could still provide a corrected JPEG preview though. The essay does goes into how cameras could actually expose for ETTR by exposing for a small percentage of highlight clipping using a live-view derived histogram.

I think the point from the essay is that you don't expose for what you want to achieve, you expose for highlights at the point of clipping, always. That way you come home with the maximum amount of data. If you haven't read the essay Johnny take a look, it's interesting hearing about how many more 'steps of tone' you can get out of something if it's ETTR.
 
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Johnny|lucidcomposure said:
Yeah this is photography 101 for me. V old news.
But not always relevant. Expose for what you want to achieve. The histogram tells you if you have enough light data in shadows etc and highlights is a given
Click to expand...

I agree, although one of the things I'v enjoyed with my D7K since upgrading from a 50 & 550D, is to be able to expose to the left and raise exposure of shadows without much noise and with ZERO banding, something that Canon bodies just can't do very well.
This technique comes in very handy in contrasty areas.

I have my D7k exposure micro-adjusted 0.5 stops under, and then sometimes manually add -0.3 stops.

Exposing to the left and raising shadows also help even out the exposure on something, and it becomes closer to what the eye sees.

Below is 4 stops under exposure according to camera meter.

4stops.jpg


Recovered, with only colour noise reduction applied.

4stopsrec.jpg
 
You don't see noise in those? I can see noise in those.

Every adjustment you make in the exposure slider in LR introduce noise. What you are doing is digging a hole for yourself and then try to climb out of it in post.

Basically doing it backwards and creating problems for yourself.
 
Raymond Lin said:
You don't see noise in those? I can see noise in those.

Every adjustment you make in the exposure slider in LR introduce noise. What you are doing is digging a hole for yourself and then try to climb out of it in post.

Basically doing it backwards and creating problems for yourself.
Click to expand...

In which ones? the first two yes of course, but that was simply an extreme example, but the second set is pretty clean imo...

100% Crop with no noise reduction.

under3.jpg


Tbh, I'd rather introduce a tiny bit of noise than risk losing texture altogether which is easily done when your shooting a scene with high contrast on the exposure limit, and don't want to be checking your LCD after every shot...

Below is an example of one of yours...
http://www.flickr.com/photos/raymondlin/4212313775/in/set-72157622941955077
 
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