Exposing to the Right? Help?

You are referring to the technique called "Expose To The Right" (ETTR) that was "developed" by Michael Reichman of Luminous Landscape back in 2003 following some conversations with Thomas Knoll, the "father" of Adobe Camera Raw.

Here's the article that Reichmann wrote which presented the technical facts and his findings:

http://www.luminous-landscape.com/tutorial​s/expose-right.shtml

Since that time, the technique has been widely talked about and practiced both here and all over the digital photography world -- a POTN search as well as a Google search will bring up plenty of results. Here's a google page from searching for "ettr expose to the right":

http://www.google.com …urceid=ie7&rlz=​1I7ADRA_en

You will note from just a glance down that page that ETTR has its detractors for one reason or another, so take your time to read both the original article and the counter-discussions!

Here in POTN we had a discussion not so long ago about a related topic dealing with Canon ISO output and how that can be effectively used with other ETTR ideas. A thread was born with a new POTN term, HAMSTTR. That thread is here:

https://photography-on-the.net/forum/showthre​ad.php?t=744235

In reading it, note that it references a thread that is long and became quite convoluted, but at the heart has good info on the use of ISO.

In a nutshell, ETTR has some facts to consider:

1) The digital sensor collects "noise" at the same time as it collects light. Starting in the individual pixel "sensels" (or wells), random noise is picked up and then added to by the camera circuitry. This happens with all exposures.

2) When low levels of light are collected (what you see on the Left side of your histogram) then you have a low "signal to noise ratio) -- less data is stored in each sensel along with the noise. The lower the light, the more this is "magnified". What this means is that if those low light levels are amplified, either by the cameras electronic ISO amplifier or by the in-camera "in-between ISO" software, or by something like Highlight Tone Priority, or by you in your processing software, then the signal noise will be amplified along with those low light tones and will become visible in your image. Those are the facts of life.

The reason why we observe noise when looking at a high ISO image is simply that -- you set your exposure as good as you can with the aperture and shutter speed but in low light you need a "boost" so you raise your ISO as much as you need to "brighten" the image, which also "brightens" the noise. As you will see in the HAMSTTR discussion, the high ISO is not the "bad guy" but rather the low level of light being collected not able to "drown out" the signal noise. In fact, at least with Canon cameras, a lot of work has been put into high ISO low noise performance so in fact a high ISO shot (such as ISO 1600) comes out a bit cleaner than if you had taken that shot at say ISO 100 (four stops underexposed) and then cranked that exposure up by four stops in post processing. If you find it hard to believe that an ISO 1600 shot can be cleaner than an ISO 100 shot, then go ahead and test it -- shoot in Raw, set to Manual Exposure, shoot a scene that when you set the camera to ISO 1600 is properly "bright" in overall exposure, then, leaving your aperture and shutter speed the same (to collect the same amount of light) lower the ISO to 100 and shoot the same scene. compare the two (obviously the ISO 100 shot will be "horribly underexposed" -- crank it up by four stops to match the brightness with the ISO 1600 shot and see how they compare!

Now, as to the ETTR/HAMSTTR technique, while ISO is a part of your overall exposure and so is worked into the technique, there is a fundamental understanding here that is is "light" which has to "compete" with the noise. Less light means more visible noise, so it stands to reason that more light means less visible noise. And, if you consider the fact that each major "notch" in a histogram represents a "stop" of light, and that a "stop" is actually twice as much as the stop preceeding it, then you can easily see why photogs prefer an image that is exposed to that as much as possible falls on the Right of the histogram before even considering the ISO.

Now, when following the desire for a good "To The Right" exposure, one important thing to watch out for is "blowing" needed highlights. This can show up if your camera is set to fire off highlight "blinkies", meaning that in those areas the highlights have been "flooded" with light, are just now white spots with no detail. That's the danger, not just of ETTR, but simply of any exposure that has bright highlights.

So then, the good news: as long as you can keep those needed highlights from blowing, your camera collects all the available light, meaning both color and luminosity tones, without the sensels flooding and losing detail. And, with Raw, you ensure that you retain all that detail in those highlights that, if you shot in jpeg, could be tossed out by the camera at the brighter parts.

A case in point: take a white piece of cloth -- something with good detail such as a white towel. The fact is that white can be exposed to up to +3 EV without losing details, even though many or most of our cameras don't show +3 EV in their meters! But, lay out that cloth and in Manual dial your aperture and shutter speed (at what ever ISO you are happy with) and set the exposure of that white cloth to +3 stops EV (if your meter shows 2 stops to the right go ahead and just click in one more stop) and take the shot. You will probably see the highlight blinkies but don't distress. Load the shot into Lightroom or DPP and you may still see some blinkies at the default levels of their processing but you will find that they quickly go away if you just pull back on the brightness/exposure sliders and you will see all that nice detail coming out.

Note, though, that you are working with Raw -- a jpeg would be a mess.

So, what are the learnings here? First of all you have more latitude when shooting "TTR" than you might imagine. And, if you can set your aperture and shutter speed to collect as much light as possible, your light will drown out more noise the more "to the right" you shoot.

But, we can't often just shoot at low ISOs and get a "great" +3 EV white towel image, especially when we are not working from a tripod, and that's where the ISO comes into play. You set your aperture/shutter speed to what you need for the shot, as much as possible nudging the planned exposure toward the right side of the histogram (chimping and/or Live View can be very good tools here) and then, if you find yourself at least a stop back from the right edge of the histogram, go ahead and increase your ISO by full/native stops. 100, 200, 400, 800, 1600 -- these use the electronic ISO amplifiers and are more efficient than the "in between" software stops or doing the boosing in post-processing.

So, that's a bit of a nutshell of both the ETTR idea and the HAMSTTR ideas rolled into one. I'm sure I've left important stuff out and probably botch some things up, so hopefully someone will come along and set things straight.

Now, to end, I'll ask: is ETTR all that important to use? Isn't it good just to "get it right in-camera"?

Well, I'd say "it depends!" -- sure, if you have a scene with good light and you can get a good exposure, fire away, I do it all the time! And, especially a scene with bright highlights won't give you the latitude to push things "to the right" -- in fact, you may struggle to get a decent overall exposure at all, which pushes many people to techniques like HDR and exposure blending.

Take a wedding, for example, with a white bridal gown. As we've seen, with Raw you can set your exposure for that gown to +3 EV, making it quite white without blowing the details. But is that using ETTR? Maybe just a touch -- if you were shooting a jpeg you would want to lower that down a notch or two, but still, you could just calling it "nailing the exposure" by telling the camera that that "white" is, in fact, "white". The groom's black tux will still be black, but at least you have let in the maximum amount of light allowed by the white dress so you will have some latitude in recovering the black tux details.

And then, consider another scene that you set your exposure and it shows up "looking good" on the histogram in the sense that the signal is spread across the graph around the middle -- "correct exposure", right? Well, look at the amount that spreads out from the center to the left -- that represents less and less light collected, meaning more and more visible noise showing if you need to boost highlights. And, as we've seen, noise is present at all ISO levels. So, analyze your scene and ask whether you really want those dark/shadowy areas to just fall into the digital black hole or not. If you can just tweak that aperture and shutter speed to let in more light, well, parts of the scene may turn out brighter than you "intend" but that is easy to recover in a Raw processor, and those shadows will also be easier to recover as well. And, if you have resorted to a high "working ISO", that means you are already shooting in low light, so nudging things up a bit can really pay off.

Well, I've been "long...winded" again, so I'll sign off!

Jay. wrote in post #12711530
Well, That just clarified everything for me..I guess I just suck @ searching -_-.

tonylong wrote in post #12711543
Heh! It's not always easy searching for exactly the right thing. But I hope it really did help you to understand things!

Jay. wrote in post #12711551
This article was really informative. When it says expose to the right it means that the right side of the histogram should be blank, correct?

Jay. wrote in post #12711571
Overexpose the image a tad bit, but don't blow out the highlights to the points you lose the detail. Got it! Thank you guys !

Jay. wrote in post #12711551
This article was really informative. When it says expose to the right it means that the right side of the histogram should be blank, correct?

tonylong wrote in post #12711581
Umm, OK, slow down -- "Expose To The Right" means quite the opposite. It means that as much as possible of your image "shows up" on the right side of the histogram. While histograms can be "tricky" in the sense that sometimes only a bit of critical highlights may be up against the right side, the point is that you nudge your exposure so that the image is as far "to the right" on the histogram as you can (without messing up your shutter speed and aperture needs). The "stopping point" is when your highlights get clipped -- at that point it's time to pull back a notch.

So, I'm not sure where you are getting the impression that the right side of the histogram should be blank? Can you point to a statement that gives that impression?

The in-camera settings can be useful in accurately interpreting the histogram, which can come in handy in a couple scenarios:

First, if you are using the Expose To The Right technique to maximize exposure up to the point of highlight clipping (blinkies) the setting you mentioned -- Neutral with -4 Contrast -- will give you an accurate warning of clipping, whereas using something with a higher Contrast will give you "early warning" -- in other words you aren't fully utilizing the latitude of the Raw data.

If you wonder about this, set up a test with a white subject -- good white paper will do for this (think of a wedding dress). Make sure you will have it in consistent light. Set your camera to Standard with standard Contrast, and dial up your exposure until the blinkies show up then dial your exposure down a notch (till the blinkies disappear) and note your Ev. The white should expose to "around" +2 Ev, maybe a bit higher.

Now, change your PS to Neutral and your Contrast to -4, and again, notch up your exposure until you hit the blinkies then dial back a notch and note your EV (it may be off the scale on your camera meter so you may just need to compare and calculate). Your Ev should show as just about +3 Ev, in other words, at +3 Ev you can get a "correct" or at least "contained" exposure of white. This could come as a bit of a surprise to those of use who have been used to the idea of white being about +2 Ev, but try it and see!

In practice, it can be "safe" to dial down whites to, say, +2 2/3 Ev, you are still doing a bit of "Expose To The Right" there, and even then your Standard Picture Style will "fib" to you that you are clipping highlights...

Another area where the histogram/ebedded jpeg can either give you an accurate or a misleading picture is with bright/saturated colors -- this can be tricky, but if your camera is in the sRGB color space the jpeg and the RGB histogram will be limited to sRGB values. If you are shooting and exposing bright, saturated colors (think bright colorful flowers or fabrics) your RGB histogram may give you a misleading indication that the colors are being blown. And furthermore, your Brightness histogram will likely look just fine, indicating that nothing is blown (but remember that histogram will indicate "blown" by a pure white 255,255,255 value, not one particular color channel -- you need the RGB histogram for that).

But note that in reality your sensor is able to capture a broader gamut than sRGB, which is why Canon provides the aRGB shooting color space -- you get a more accurate view of the range of colors, you can "shoot to the right" for the broader array of colors (and the jpeg will capture them and be in aRGB) but you should note that fine-tuning images that have colors that are outside of sRGB can be tricky and for many uses it can be safer and more efficient to stick with sRGB. And always, remember to use the RGB histogram when shooting bright colorful subjects!

Another tricky area where in-camera settings can affect your preview and RGB histogram is White Balance. A "bad" White Balance can through you RGB balance out the window and could mislead you to compensate in one way or another -- either to underexpose or over expose, perhaps. This may not trouble you in "normal" lighting situations -- after all if you're shooting Raw you can make a quick adjustment either to a preset or to a target. But there are settings where having your White Balance off could jeapordize your ability to analyze your histogram and make appropriate adjustments...

Hope that is a little helpful...!

Here's the article that Reichmann wrote which presented the technical facts and his findings:

http://www.luminous-landscape.com/tu...se-right.shtml

BigAl007 wrote in post #12712079
Tony I just tried to follow the link:

and It's not there any more.

Alan

tonylong wrote in post #12711609
]If you want something practical about how this works and how to set up your camera to work with you without misleading you (which the histogram and blinkies can do) here's another essay:

It goes beyond basic "Expose To The Right" but may be useful!