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http://www.luminous-landscape.com/essays/the_optimum_digital_exposure.shtml
Best to read and understand before making any comments.
In reply to ChrisJD:
I have come across the idea before. I understand the logic, but don't use it myself as it seems to require more processing than I am willing to put in for the average picture.
Software that knows the exact response of your camera would seem to be a given as well, although deriving that isn't exactly hard.
I have come across the idea before. I understand the logic, but don't use it myself as it seems to require more processing than I am willing to put in for the average picture.
Software that knows the exact response of your camera would seem to be a given as well, although deriving that isn't exactly hard.
In reply to davidbeynon:
yep - As with nearly everything, getting optimum outputs takes more effort.
> I have come across the idea before. I understand the logic, but don't use it myself as it seems to require more processing than I am willing to put in for the average picture.
yep - As with nearly everything, getting optimum outputs takes more effort.
In reply to ChrisJD:
I always ETTR to reduce the noise as my camera is m4/3rds, and with on-camera histogram / blinkies you only need to take one shot rather than bracketing as he does. Work out the aperture for required depth of field and then lower the ISO as far as it will go whilst keeping shutter speed within required parameters for sharpness and stopping blinkies occurring for anything other than pure white or the histogram falling off the righthand side. It works well. His method will work for cameras without histogram or configurable blinkies.
Essentially you're just looking to get as much light into the pixels without the 'wells' overflowing. Making images darker is easy, making them lighter means noise.
I always ETTR to reduce the noise as my camera is m4/3rds, and with on-camera histogram / blinkies you only need to take one shot rather than bracketing as he does. Work out the aperture for required depth of field and then lower the ISO as far as it will go whilst keeping shutter speed within required parameters for sharpness and stopping blinkies occurring for anything other than pure white or the histogram falling off the righthand side. It works well. His method will work for cameras without histogram or configurable blinkies.
Essentially you're just looking to get as much light into the pixels without the 'wells' overflowing. Making images darker is easy, making them lighter means noise.
In reply to Toerag:
Check what he says about Blinkies on camera versus Optimum exposure. ie you may not get Optimum by using Blinkies.
"An important thing to understand about highlight warnings is that they occur in two places: 1) on the back of your camera - the “Blinkies” and 2) in your software – highlight “Clipping”.
"These 2 warnings ARE NOT the same. Although the camera’s High-Alert “blinkies” provide some information, you can only use them as an indication of optimum exposure. The “Blinkies” on the back of your camera occur about 1 stop before the highlight warning in your software – highlight “Clipping”! !
“If you do not see camera blinkies… your exposure is sure not to be Optimum and…you’ve probably lost more than 50% of the scene’s data!”
Hence he recomends bracketing .... As with nearly everything, getting optimum outputs takes more effort.
Check what he says about Blinkies on camera versus Optimum exposure. ie you may not get Optimum by using Blinkies.
"An important thing to understand about highlight warnings is that they occur in two places: 1) on the back of your camera - the “Blinkies” and 2) in your software – highlight “Clipping”.
"These 2 warnings ARE NOT the same. Although the camera’s High-Alert “blinkies” provide some information, you can only use them as an indication of optimum exposure. The “Blinkies” on the back of your camera occur about 1 stop before the highlight warning in your software – highlight “Clipping”! !
“If you do not see camera blinkies… your exposure is sure not to be Optimum and…you’ve probably lost more than 50% of the scene’s data!”
Hence he recomends bracketing .... As with nearly everything, getting optimum outputs takes more effort.
Post edited at 15:10
In reply to ChrisJD:
I've started using it for most stuff now. It's easy, I set the body to +0.7EV, bracket 3 shots by +-0.7EV, ESP exposure. Then use LR to get the best out of the 3 via the exposure slider. The only hassle is to have to process the files, although I still have the 0.0EV shot if needs be. I process all my shots in LR anyway, if only to weed them and catalog them.
Using the blinkies doesn't work on my E-M5 as that's based on the 8 bit JPG image, and it shows mass blinkies when in fact all the highlights can be recovered.
I've started using it for most stuff now. It's easy, I set the body to +0.7EV, bracket 3 shots by +-0.7EV, ESP exposure. Then use LR to get the best out of the 3 via the exposure slider. The only hassle is to have to process the files, although I still have the 0.0EV shot if needs be. I process all my shots in LR anyway, if only to weed them and catalog them.
Using the blinkies doesn't work on my E-M5 as that's based on the 8 bit JPG image, and it shows mass blinkies when in fact all the highlights can be recovered.
In reply to ChrisJD:
I'm no expert, but this seems like fairly basic stuff?
Understanding how exposure works and how your own equipment responds to different situations is surely the name of the game?
If you get the exposure 'correct' in the average high contrast landscape shot, there won't be a lot of margin left to 'optimise' without blowing out large parts of the image. For real-life action portraits, the decision is also driven by aesthetics - the decision to lose information from a face or from a light/dark background is not not just down to 'optimisation'.
I can see how people who got to grips with digital photography in the early days might not think like this - I guess they had to deal with very limited dynamic ranges? As someone relatively new to taking pictures, I suppose I've always just thought in the same way as I might do with film - how do I get the most information (best density) ready for processing?
I'm no expert, but this seems like fairly basic stuff?
Understanding how exposure works and how your own equipment responds to different situations is surely the name of the game?
If you get the exposure 'correct' in the average high contrast landscape shot, there won't be a lot of margin left to 'optimise' without blowing out large parts of the image. For real-life action portraits, the decision is also driven by aesthetics - the decision to lose information from a face or from a light/dark background is not not just down to 'optimisation'.
I can see how people who got to grips with digital photography in the early days might not think like this - I guess they had to deal with very limited dynamic ranges? As someone relatively new to taking pictures, I suppose I've always just thought in the same way as I might do with film - how do I get the most information (best density) ready for processing?
In reply to JDal:
Apologies if this is obvious - have you dialed down the contrast/saturation etc on the jpg settings and turned down the sensitivity on the warnings? My NEX, shooting in RAW, has a much more useful histogram and blinkies when set up like this (though still a stop or so out if willing to really push the files).
> Using the blinkies doesn't work on my E-M5 as that's based on the 8 bit JPG image, and it shows mass blinkies when in fact all the highlights can be recovered.
Apologies if this is obvious - have you dialed down the contrast/saturation etc on the jpg settings and turned down the sensitivity on the warnings? My NEX, shooting in RAW, has a much more useful histogram and blinkies when set up like this (though still a stop or so out if willing to really push the files).
In reply to hamsforlegs:
Nah, I don't normally look at the screen, but I bet the blinkies would still be there. A shot can show massive truncation on the LR histogram & on the camera screen histogram, but be perfectly OK when you lower the exposure. Anyhow, why would I when the process is so simple? - I just use ESP and bracket, the E-M5 has enough headroom to cope with it. Mind you it's a bit annoying when you realise that all that knowledge you have about getting exposure right is now pointless
BTW this system starts fall apart when you need a fast shutter speed.
Nah, I don't normally look at the screen, but I bet the blinkies would still be there. A shot can show massive truncation on the LR histogram & on the camera screen histogram, but be perfectly OK when you lower the exposure. Anyhow, why would I when the process is so simple? - I just use ESP and bracket, the E-M5 has enough headroom to cope with it. Mind you it's a bit annoying when you realise that all that knowledge you have about getting exposure right is now pointless
BTW this system starts fall apart when you need a fast shutter speed.
In reply to hamsforlegs:
Well you appear to have completely missed the point of the approach. There is only one Optimum Exposure for a scene at capture, aesthetics doesn't enter into it 'at capture', but nailing that optimum is quite hard, hence the bracketing to minimise the margin by which you miss it..
If you don't want to adopt the approach, that is of course fine.
> the decision is also driven by aesthetics - the decision to lose information from a face or from a light/dark background
Well you appear to have completely missed the point of the approach. There is only one Optimum Exposure for a scene at capture, aesthetics doesn't enter into it 'at capture', but nailing that optimum is quite hard, hence the bracketing to minimise the margin by which you miss it..
If you don't want to adopt the approach, that is of course fine.
Post edited at 16:14
In reply to ChrisJD:
For me a major issue is that my current computer has been running Linux since its last hard disk died. The photo editing tools available are... not great.
Maybe it is time to build something.
For me a major issue is that my current computer has been running Linux since its last hard disk died. The photo editing tools available are... not great.
Maybe it is time to build something.
1
In reply to ChrisJD:
I have a home grown HDR stack already, so I guess plugging into dcraw with a curve inverter is the next step...
I have a home grown HDR stack already, so I guess plugging into dcraw with a curve inverter is the next step...
In reply to davidbeynon:
Yep - I remember you were quite handy with your programming.
> I have a home grown HDR stack already, so I guess plugging into dcraw with a curve inverter is the next step...
Yep - I remember you were quite handy with your programming.
In reply to ChrisJD:
I've been aware of ETTR for some time, what I don't understand is why the camera manufacturers don't introduce an ETTR exposure mode which automatically gives the longest exposure at which no part of the frame is> 99% brightness.
I've been aware of ETTR for some time, what I don't understand is why the camera manufacturers don't introduce an ETTR exposure mode which automatically gives the longest exposure at which no part of the frame is> 99% brightness.
In reply to ChrisJD:
You would actually - there's no evaluation of values from across the entire frame involved, you just look for the brightest area.
You would actually - there's no evaluation of values from across the entire frame involved, you just look for the brightest area.
In reply to ChrisJD:
That assumes that the 'scene' is a complete frame to be 'optimised' as a whole OR that you have equipment with such vast linearity and dynamic range that you can capture everything in any frame with full detail. The article does seem to lean the way of the former, but I will give the author some credit by hoping that he isn't that literal minded!
For many subjects where the dynamic range of the scene is very broad, ETTR across the fame without regard to the content will produce poor results. If I want to capture a lot of detail in someone's well exposed face, as well as lots of information in a darker, interesting foreground, then the 'scene' is those bits of the shot. Ideally it would also include the very bright background,but in many cases 'optimising' across all three of those elements would lead to a sub-optimal and noisy image where it counts.
Aesthetics only drops out of the equation if you have a sensor with absolutely vast dynamic range and no rolloff at the bottom end - we're getting there, but it's still not quite a reality yet. Otherwise you do need to make decisions about what part of the scene is being 'optimised'. This is like good B&W film photographers using zones and/or careful spot metering to push density to the limits of the film and then 'recompress' the image using development and processing techniques.
To say that the technique requires you to 'optimise' across the entire frame regardless of the content, aim, dynamic range, or where on the curve your point of interest lies is a bit silly? What if your camera has figured out that it wants to expose the foreground properly and that parts of the sky will start to clip? Exposing more will either be wrong if the sky is the subject, or accidentally correct if the foreground is the subject. Spot metering gives you control between these options, but you may still decide to sacrifice the highlights!
> There is only one Optimum Exposure for a scene at capture, aesthetics doesn't enter into it 'at capture',
That assumes that the 'scene' is a complete frame to be 'optimised' as a whole OR that you have equipment with such vast linearity and dynamic range that you can capture everything in any frame with full detail. The article does seem to lean the way of the former, but I will give the author some credit by hoping that he isn't that literal minded!
For many subjects where the dynamic range of the scene is very broad, ETTR across the fame without regard to the content will produce poor results. If I want to capture a lot of detail in someone's well exposed face, as well as lots of information in a darker, interesting foreground, then the 'scene' is those bits of the shot. Ideally it would also include the very bright background,but in many cases 'optimising' across all three of those elements would lead to a sub-optimal and noisy image where it counts.
Aesthetics only drops out of the equation if you have a sensor with absolutely vast dynamic range and no rolloff at the bottom end - we're getting there, but it's still not quite a reality yet. Otherwise you do need to make decisions about what part of the scene is being 'optimised'. This is like good B&W film photographers using zones and/or careful spot metering to push density to the limits of the film and then 'recompress' the image using development and processing techniques.
To say that the technique requires you to 'optimise' across the entire frame regardless of the content, aim, dynamic range, or where on the curve your point of interest lies is a bit silly? What if your camera has figured out that it wants to expose the foreground properly and that parts of the sky will start to clip? Exposing more will either be wrong if the sky is the subject, or accidentally correct if the foreground is the subject. Spot metering gives you control between these options, but you may still decide to sacrifice the highlights!
In reply to hamsforlegs:
OK I guessed this would turn into a **** waving exercise when you said "I'm no expert, but.."
... Never believe anything someone says before the word But. (I'll attribute that to TL-GOT)
Lets look at the credential of the guy who wrote the article:
"Bob DiNatale is an Adobe Certified Photoshop Lightroom Expert and an X-rite Coloratti. He has a US Patent in Color Printing; worked with experimental silver emulsions at Polaroid; taught both the Nikon and Time Life Schools of Photography and founded the Olympus School of Digital Photography. Bob is a photographer, lecturer, conducts workshops and specializes in 1-on-1 online training in digital photography."
He is clearly an expert, and you, by your own admission, are not.
mmm. So who should we listen to?
OK I guessed this would turn into a **** waving exercise when you said "I'm no expert, but.."
... Never believe anything someone says before the word But. (I'll attribute that to TL-GOT)
Lets look at the credential of the guy who wrote the article:
"Bob DiNatale is an Adobe Certified Photoshop Lightroom Expert and an X-rite Coloratti. He has a US Patent in Color Printing; worked with experimental silver emulsions at Polaroid; taught both the Nikon and Time Life Schools of Photography and founded the Olympus School of Digital Photography. Bob is a photographer, lecturer, conducts workshops and specializes in 1-on-1 online training in digital photography."
He is clearly an expert, and you, by your own admission, are not.
mmm. So who should we listen to?
Post edited at 17:27
In reply to ChrisJD:
If anyone still shoots Canon... Magic lantern has an excellent Auto-ETTR funtion - it takes the picture, anaylses the RAW, then takes another at optimum exposure. You can set the white percentage as you see fit.
If anyone still shoots Canon... Magic lantern has an excellent Auto-ETTR funtion - it takes the picture, anaylses the RAW, then takes another at optimum exposure. You can set the white percentage as you see fit.
In reply to John2:
That would be helpful - I'd use it, though I'd want to keep an eye on the blinkies in the dark spots. It would come with a high risk of confusion. Just one glasses lens reflecting the wrong thing and the whole frame would be dramatically under-exposed.
I suppose a basic problem with matrix metering is that it is doing a lot of complex second-guessing so is a bit mysterious. The 'nothing over 99' thing would give you uncomplicated spot metering as well as awareness across the frame.
> I've been aware of ETTR for some time, what I don't understand is why the camera manufacturers don't introduce an ETTR exposure mode which automatically gives the longest exposure at which no part of the frame is> 99% brightness.
That would be helpful - I'd use it, though I'd want to keep an eye on the blinkies in the dark spots. It would come with a high risk of confusion. Just one glasses lens reflecting the wrong thing and the whole frame would be dramatically under-exposed.
I suppose a basic problem with matrix metering is that it is doing a lot of complex second-guessing so is a bit mysterious. The 'nothing over 99' thing would give you uncomplicated spot metering as well as awareness across the frame.
In reply to Dan Arkle:
Cheers Dan - Sounds like a very useful function.
Been wanting to try ML for ages - but not yet available for the 70D I'm currently using
Cheers Dan - Sounds like a very useful function.
Been wanting to try ML for ages - but not yet available for the 70D I'm currently using
In reply to ChrisJD:
Based on credentials, the guy who wrote the article, surely?
I thought there might be some room to discuss what he wrote. In my ignorance and cynicism I leapt to the conclusion that he is trying to make a Unique and Special MegaFormula out of something quite basic. Perhaps his book setting out the OneZone method sets out a very useful and insightful new approach to photography.
I don't really understand what I've said that is incorrect - which may well be because I have, at best, a beginner's knowledge of this stuff. Perhaps you can point out where I'm missing some key concepts?
I like the suggestions from Dan and from John2 - seem like these do/would get us to the same place without any faffing.
> mmm. So who should we listen to?
Based on credentials, the guy who wrote the article, surely?
I thought there might be some room to discuss what he wrote. In my ignorance and cynicism I leapt to the conclusion that he is trying to make a Unique and Special MegaFormula out of something quite basic. Perhaps his book setting out the OneZone method sets out a very useful and insightful new approach to photography.
I don't really understand what I've said that is incorrect - which may well be because I have, at best, a beginner's knowledge of this stuff. Perhaps you can point out where I'm missing some key concepts?
I like the suggestions from Dan and from John2 - seem like these do/would get us to the same place without any faffing.
In reply to hamsforlegs:
I like the photography forum as its usually a bit gentler and less confrontational and less snidey than the rest of the UKC snakepit ....
I like the photography forum as its usually a bit gentler and less confrontational and less snidey than the rest of the UKC snakepit ....
In reply to ChrisJD:
Sorry.
I wasn't remotely attacking or crticising you, just flagging what I thought were some dubious elements in the article.
I confess I am cynical about folks with on photography websites selling definitive methods and systems. Had the article been called 'ETTR - two simple methods and some reasons to use them' I might have felt a bit less negatively about it!
I shall be more cautious in future - there are already enough snakes in the pit!
Sorry.
I wasn't remotely attacking or crticising you, just flagging what I thought were some dubious elements in the article.
I confess I am cynical about folks with on photography websites selling definitive methods and systems. Had the article been called 'ETTR - two simple methods and some reasons to use them' I might have felt a bit less negatively about it!
I shall be more cautious in future - there are already enough snakes in the pit!
In reply to hamsforlegs:
I'm inclined to agree with this to be honest. Bob just seems to be restating ETTR to me. Judging by his examples he either has a very different camera to mine or he is shooting very different scenes. The number of times a year I could take a shot where everything appears to be in zone 8 or 9 without blowing the highlights is pretty slim. And the suggestion that you could do that to his his black cat in a coal bunker without losing all data for the eyes seems downright misleading. As he says 'the optimum exposure cannot be determined in camera' so you must bracket every shot. Which again means it isn't applicable to the majority of shooting I do. I need to settle on an useful exposure at the time, and stick to it whilst trying to capture a moment. Which results in a histogram nothing like his examples...
Blown highlights are a far bigger issue in a shot failing, and to me the great achilles heel of digital compared to film. You need to make damn sure you haven't blown them. Agree it's be great it you could do that in camera, but I suspect it would still require two exposures to be sure. Whereas the ability to lift shadows is the great gain and with final versions nowadays are pretty much prints or web jpegs, in neither is shadow noise likely to be noticeable, let alone obtrusive to the point of a shot failing technically. But maybe this is because I haven't got a D810 or 645Z... or maybe it's the cultural differences, americans seems to love overstatement and simplification.
> In my ignorance and cynicism I leapt to the conclusion that he is trying to make a Unique and Special MegaFormula out of something quite basic.
I'm inclined to agree with this to be honest. Bob just seems to be restating ETTR to me. Judging by his examples he either has a very different camera to mine or he is shooting very different scenes. The number of times a year I could take a shot where everything appears to be in zone 8 or 9 without blowing the highlights is pretty slim. And the suggestion that you could do that to his his black cat in a coal bunker without losing all data for the eyes seems downright misleading. As he says 'the optimum exposure cannot be determined in camera' so you must bracket every shot. Which again means it isn't applicable to the majority of shooting I do. I need to settle on an useful exposure at the time, and stick to it whilst trying to capture a moment. Which results in a histogram nothing like his examples...
Blown highlights are a far bigger issue in a shot failing, and to me the great achilles heel of digital compared to film. You need to make damn sure you haven't blown them. Agree it's be great it you could do that in camera, but I suspect it would still require two exposures to be sure. Whereas the ability to lift shadows is the great gain and with final versions nowadays are pretty much prints or web jpegs, in neither is shadow noise likely to be noticeable, let alone obtrusive to the point of a shot failing technically. But maybe this is because I haven't got a D810 or 645Z... or maybe it's the cultural differences, americans seems to love overstatement and simplification.
In reply to hamsforlegs:
That immediately feels calmer If everyone was that gracious, UKC would be a whole lot nicer.
And you are into coffee - so we have a lot in common (just pulled a double shot, made some great milk, and all is good again with the world - suffering from a bit too much fun out last night) .
Been shooting RAW for 11 years now and absorbed ETTR from when Reichman first published his article on LulA 10 years ago.
I really liked the Bob DiNatale article and how he has laid out the definitions, Unlikely to suit all tastes mind. Has made me tweak the way I could approach exposure and ETTR and have set up the Custom mode on the 70D to implement the bracketing and will give it a go. Its always good to rethink the basics every now and then.
I tend to put on a pair of virtual "Protect me against American hyperism" goggles whenever I view US sites, which helps protect me from feeling too cynical!
That immediately feels calmer If everyone was that gracious, UKC would be a whole lot nicer.
And you are into coffee - so we have a lot in common (just pulled a double shot, made some great milk, and all is good again with the world - suffering from a bit too much fun out last night) .
Been shooting RAW for 11 years now and absorbed ETTR from when Reichman first published his article on LulA 10 years ago.
I really liked the Bob DiNatale article and how he has laid out the definitions, Unlikely to suit all tastes mind. Has made me tweak the way I could approach exposure and ETTR and have set up the Custom mode on the 70D to implement the bracketing and will give it a go. Its always good to rethink the basics every now and then.
I tend to put on a pair of virtual "Protect me against American hyperism" goggles whenever I view US sites, which helps protect me from feeling too cynical!
Post edited at 10:32
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