To ETTR or not to ETTR...?

Started 4 months ago | Discussions
TomFid Veteran Member • Posts: 3,146
example
2

Jeepit wrote:

TomFid wrote:

Many pieces on this topic that I have read states to have the ISO as low as you can get it. Interesting yours was at 200 & 640.

200 is base for my EM5ii. 640 was just carelessness.

I'll try again later.

Here's an example. I shot a sequence at f7.1, ISO 200, varying shutter speed for exposure compensation.

Sequence as imported into LR. Note that I mislabeled the top right shot - it's +1EV.

The 0EV exposure would make a decent jpeg but looks a little under to me. OTOH the +1 shot is a little washed out.

The +2 shot roughly pinned the camera histogram to the right edge without visible clipping. The +3 shot looks pretty hopeless.

In LR, I used the exposure slider to roughly normalize everything to look like the +1 shot (i.e. the +3 shot got -2, etc.). Then they all look similar. It turns out that the jpeg histogram is too conservative, and even the +3EV shot is not clipped:

Same sequence, after rough leveling using the LR exposure slider.

However, if you zoom in, they look pretty different:

Left: the metered exposure (no compensation). Right: the +3EV shot.

The +3 shot is much cleaner in the mids and shadows, as expected (illustrating knickerhawk's point above).

On a day that's not so hazy, you wouldn't get away with this much compensation.

FingerPainter Veteran Member • Posts: 7,902
Re: ETTR is an esthetic decision

TomFid wrote:

I'm learning too. See for example knickerhawks refinement of my comments just above.

I also just reminded myself of a limitation I don't often think about. When you ETTR, you have to adjust the exposure, i.e. the amount of light hitting the sensor. Just cranking up the ISO doesn't accomplish anything, though it does move the histogram to the right.

Here's how that happened. I went outside to shoot an example - the mountains across the valley in evening light, much brighter than the surrounding area. I squeezed off a couple shots, first at the metered exposure, then +1EV and +1.7 (which is what it took to pin the histogram to the right). What I didn't notice is that I was in A mode, and the light was pretty low, so the first shot (0EV) was 1/20th, f7.1 at ISO 200 (gotta love IBIS). The last shot (+1.7) was also 1/20th, f7.1, but ISO 640. So, there was zero benefit - both shots received identical light; they just look different because one cranked up the gain. If you adjust the levels in LR to look the same, they're hard to tell apart.

Yeah, you didn't really expose more to the right.

But you were more right when you said "they're hard to tell apart" than when you said "they're hard to tell apart", because if your camera does indeed use gain to implement an ISO increase, there probably was a small increase in SNR from the increased gain.

DLGW Senior Member • Posts: 1,197
It's rarely really 'needed' at all. It's all about maximizing potential image quality...

,.. under certain sets of circumstances.

Jeepit wrote:

so are you saying ETTR is not really needed for mFT cameras? Is that small boost in image quality really worth the end results, if a photographer has to change his/ her way of shooting and start wondering about if every shot should be ETTR?

Think of it as a potential tool - like shooting a panoramic or shooting multi-exposure to eventually blend into and HDR image. It does require you to evaluate what you are shooting and how, and to make a decision as to how get the best image quality out of a particular shoot.

As to whether or not the improvement is worth a small bit of effort - that is for the photographer to decide.  I rarely use to be honest, but since I'm already shooting full manual exposure and watching my histogram, the amount of additional effort when capturing is about zero. Any image I actually do something with is processed from RAW as well, so again, about 3 seconds of additional time to 'fix' the exposure.

 DLGW's gear list:DLGW's gear list
Olympus E-M1 Olympus E-M5 II Olympus Zuiko Digital ED 7-14mm 1:4.0 Olympus Zuiko Digital ED 8mm 1:3.5 Fisheye Olympus 12-40mm F2.8 Pro +6 more
The Ghost of Caravaggio Contributing Member • Posts: 704
Re: Have I got it right?
1

timo wrote:

...

If, using the camera's metering system and with your EV dial set to 0, your shot is already just about triggering blinkies,

...

What have I missed?

Blinkies are better than nothing, but –

Blinkies come and go based on in-camera JPEG settings. One could choose in-camera rendering settings that would unnecessarily underexposure the sensor compared to other settings – underexpose and then over brighten in-camera. In-camera JPEG options that offer pull-push automation (Active D-Lighting for Nikon, DRO for SONY, DR for FUJIFILM, etc.) intentionally underexposure the sensor. These automation tools are useful because they protect inexperienced in-camera JPEG users from unintentional over exposure. However with raw files these data are always less informative compared to just than maximizing exposure. Using blinkies and automated pull-push invoked would be self defeating.

Blinkies can indicate both sensor over exposure and signal clipping caused by an unnecessarily high camera ISO setting. To maximize exposure only the former counts as ISO signal gain occurs after the shutter closes. This is typically most important when using base ISO.

Blinkies will appear for specular reflections from sunlight and other very bright point-source light sources. The light from these is uninformative. Even if you use a 6 stop ND filter and sunlight reflections are not overexposed, they will render as white. If the on-camera LCD resolution is insufficient to distinguish between blinkies caused by uninformative bright light sources and blinkies in regions of interest, you may unnecessarily underexposue the sensor.

ISO Is An Important Parameter

Use the lowest practical ISO consistent with practical shutter times and or aperture settings. This maximizes sensor exposure. If your camera happens to use dual conversion-gain sensor technology there will be two minimum ISO settings. One for low gain (bright light) to optimize sensor analog dynamic range in bright light and another for high gain to maximize sensor sensitivity in low light.

-- hide signature --

"The belief that ‘randomness’ is some kind of real property existing in Nature is a form of the mind projection fallacy which says, in effect, ‘I don’t know the detailed causes – therefore – Nature does not know them."
E.T Jaynes, Probability Theory: The Logic of Science

 The Ghost of Caravaggio's gear list:The Ghost of Caravaggio's gear list
Fujifilm X100T Fujifilm X-Pro2 Fujifilm XF 18mm F2 R Fujifilm XF 35mm F2 R WR Fujifilm XF 27mm F2.8 +2 more
Tom Axford Veteran Member • Posts: 6,287
Re: example

TomFid wrote:

In LR, I used the exposure slider to roughly normalize everything to look like the +1 shot (i.e. the +3 shot got -2, etc.). Then they all look similar. It turns out that the jpeg histogram is too conservative, and even the +3EV shot is not clipped:

Same sequence, after rough leveling using the LR exposure slider.

Try processing the +3 shot with the Exposure slider around -2.5 to -3.0 and the Whites slider around +70.  That should bring out much more detail in the highlights and be much closer to what the sensor actually recorded.

FingerPainter Veteran Member • Posts: 7,902
Re: Have I got it right?

timo wrote:

This thread seems to have got super-complicated. Have I misunderstood ETTR?

My understanding is that the further up the histogram you go (i.e. to the brighter end), the more useful data the file can contain, and that includes finer distinctions of tonal values.

Yes, as long as you move to he right by increasing exposure - the amount of light per unit area falling on the sensor.

In many cameras, you can also make a (usually much) smaller improvement by moving up the histogram by increasing the ISO setting for the first few stops above base ISO.

So for the purposes of taking the photo, you push the exposure up as far as you can SHORT OF blowing the highlights to the point where they are unrecoverable.

Yes.

The image will look overexposed at that point.

The image will probably look too light. It won't actually be exposed too much. It is useful to avoid calling an image "overexposed" when it might be too light for a reason other than too much exposure. The mis-use of the term "overexposed" is a holdover from roll-film, where there was often a close to one-to-one mapping between lightness and exposure. This is not the case for digital images.

Then in post-processing, you bring the 'exposure', or 'brightness', or whatever you want to call it,

Call it "lightness". "Exposure" is the amount of light that fell on the sensor per unit area. You cannot change that after capture.  "Brightness" is a property of an image displayed by a light-emitting device, like a monitor or  television. You can increase the brightness of an image displayed on your computer monitor by increasing the brightness setting of the monitor without affecting the image file. Prints do not, AFAIK, have a brightness, Just a lightness.

back down to whatever reflects you visual intentions. That way you will get more subtle, more accurate, shadow tones. And better S/N ratio,

Yes

provided you haven't had to adjust the ISO upwards, which would have defeated the purpose.

Adjusting ISO upward only defeats the purpose if it is done instead of increasing exposure. If you got the maximum exposure you can tolerate (not too much motion blur, too shallow DoF or too much lens aberration blur), then incrasiog ISO can make a samll improvement to SNR on many cameras, at least for the first few stops above base ISO.

If, using the camera's metering system and with your EV dial set to 0, your shot is already just about triggering blinkies, you are already 'exposing to the right', and you don't have to adjust anything.

In fact, when desired highlights are blown at the metered exposure, ETTR requires negative EC.

ETTR is most relevant in situations where there are no important extreme highlights, and you have a lot of shadow detail that you want to maintain.

Hmm, given that ETTR is essentially exposing for the hightlights, I don't think it becomes less relevant in situation where there are no important extreme highlights. It just doesn't give as much SNR improvement. It is still relevant because ETTR is as much about preserving desired highlight detail as it is about increasing SNR. Fundamentally it is about maximizing usable data. It does this both by trying to increase light capture and also by trying to avoid throwing away data in highlights.

What have I missed?

See above?

FingerPainter Veteran Member • Posts: 7,902
Am I missing something?

The Ghost of Caravaggio wrote:

...

ISO Is An Important Parameter

Use the lowest practical ISO consistent with practical shutter times and or aperture settings. This maximizes sensor exposure. If your camera happens to use dual conversion-gain sensor technology there will be two minimum ISO settings. One for low gain (bright light) to optimize sensor analog dynamic range in bright light and another for high gain to maximize sensor sensitivity in low light.

I'm not sure what you are advising here.

Assume a dual conversion gain camera that switches at ISO 800 and has a base ISO of 100. Assume a scene luminance and highlights such that there are two stops of highlight headroom at the slowest shutter that won't give unwanted motion blur and the widest aperture of the lens.

Are you suggesting the user will get better results at ISO 100 than at ISO 400? Isn't ISO 100 "the lowest practical ISO consistent with practical shutter times and or aperture settings"?

I would have thought one should use the highest ISO consistent with not blowing desired highlight detail at the slowest practical shutter and widest practical aperture.

bobn2
bobn2 Forum Pro • Posts: 62,019
Re: To ETTR or not to ETTR...?
3

tomhongkong wrote:

Some facts

None of the below is a fact.

Most people use an average auto exposure setting which is based on averaging the light measured and having an 18% greyscale exposure correct. That means that bright portion of a bright image is going to be underexposed (of course if you are using spot or centre weighted exposure that may not apply). A predominately dark image might similarly be underexposed

With most digital sensors there is around one stop of 'headroom' for highlights, when the auto exposure is used. Even blinkies typically start flashing at a maximum setting of 125% so there is plenty of headroom left when they are blinking.

If you don't believe this, try taking a photo in RAW with 'blown' highlights and reducing the exposure in PP. You will be surprised at how much latitude is built in to your camera, which is not used when taking JPEG. Having a feeling for how much you can overexpose is a good thing.

So there is a lot of scope for 'overexposing' based on what the camera meter believes.

Getting the right exposure (and I don't mean correcting a dark image by winding up brightness with a higher iso, which does nothing for exposure) is important to improve the SNR and reduce noise, and to capture more detail in the whole image, in particular in the shadows. To be safe, and underexpose "to protect the highlights' does the reverse.

Of course if you only use JPEGs, and I accept the convenience of this strategy, you pay the price in reducing potential DR.

Just try it

Tom

-- hide signature --

263, look deader.

Pixnat2
Pixnat2 Veteran Member • Posts: 5,767
Re: All depends on your expected output
1

Jeepit wrote:

Pixnat2 wrote:

You shoot landscapes in difficult light and are adept of squeezing out all the DR and shadow details you can in post processing?

You can't stand a bit of noise in your shadows?

In those cases, mastering ETTR could be helpful.

But for casual shooting, I wouldn't worry about it. Our modern cameras have excellent metering system and enough DR to cope with nearly all situations.

That said, it's a nice technique to learn and use in some cases.

Thanks for your post. What would those cases be?

You're welcome.

Lanscapes with high contrast (deep shadows and strong highlights) is probably the main case where ETTR can be useful.

In this scenario, camera tend to protect highlight for the JPEG, thus it underespose a bit. This will introduce noise in the shadows which will be visible when you try to recover your RAW files. In a landscape picture, you would lose fine details in the shadows and get a mushy result.

ETTR will burn your JPEG, but less noise will be present in the shadows. If correctly done, you could recover your highlights, and you'll get a landscape with clean shadows and fine details.

Peronally, that's the only case where I use ETTR.

But all pictures with high contrast, where you need a wide Dynamic Range, would benefits form ETTR.

-- hide signature --
 Pixnat2's gear list:Pixnat2's gear list
Fujifilm X-T2 Panasonic Lumix DMC-GM5 Panasonic Lumix DMC-GM1 Sony a7R II
TomFid Veteran Member • Posts: 3,146
Re: Am I missing something?

FingerPainter wrote:

The Ghost of Caravaggio wrote:

...

ISO Is An Important Parameter

Use the lowest practical ISO consistent with practical shutter times and or aperture settings. This maximizes sensor exposure. If your camera happens to use dual conversion-gain sensor technology there will be two minimum ISO settings. One for low gain (bright light) to optimize sensor analog dynamic range in bright light and another for high gain to maximize sensor sensitivity in low light.

I'm not sure what you are advising here.

Assume a dual conversion gain camera that switches at ISO 800 and has a base ISO of 100. Assume a scene luminance and highlights such that there are two stops of highlight headroom at the slowest shutter that won't give unwanted motion blur and the widest aperture of the lens.

Are you suggesting the user will get better results at ISO 100 than at ISO 400? Isn't ISO 100 "the lowest practical ISO consistent with practical shutter times and or aperture settings"?

There may be a couple of dual gain m43 cameras, but looking at http://www.photonstophotos.net/Charts/PDR.htm I don't see anything with enough of a step in performance to justify shooting above the base native ISO, unless you're short on light. Am I missing something?

I would have thought one should use the highest ISO consistent with not blowing desired highlight detail at the slowest practical shutter and widest practical aperture.

The theoretical benefit of this isn't normally visible on my EM5ii, but other bodies might differ. There's no substitute for personal testing, I think.

FingerPainter Veteran Member • Posts: 7,902
Re: Am I missing something?

TomFid wrote:

FingerPainter wrote:

The Ghost of Caravaggio wrote:

...

ISO Is An Important Parameter

Use the lowest practical ISO consistent with practical shutter times and or aperture settings. This maximizes sensor exposure. If your camera happens to use dual conversion-gain sensor technology there will be two minimum ISO settings. One for low gain (bright light) to optimize sensor analog dynamic range in bright light and another for high gain to maximize sensor sensitivity in low light.

I'm not sure what you are advising here.

Assume a dual conversion gain camera that switches at ISO 800 and has a base ISO of 100. Assume a scene luminance and highlights such that there are two stops of highlight headroom at the slowest shutter that won't give unwanted motion blur and the widest aperture of the lens.

Are you suggesting the user will get better results at ISO 100 than at ISO 400? Isn't ISO 100 "the lowest practical ISO consistent with practical shutter times and or aperture settings"?

There may be a couple of dual gain m43 cameras, but looking at http://www.photonstophotos.net/Charts/PDR.htm

I don't see anything with enough of a step in performance to justify shooting above the base native ISO, unless you're short on light. Am I missing something?

Perhaps. Those charts may indicate that the E-M5 II and E-M10 II are dual gain with the switch occurring at ISO 400,

Now look at http://www.photonstophotos.net/Charts/PDR_Shadow.htm

It shows a 1 stop increase in ISO above base gives a half stop improvement in PDR for the E-M5 II and a bit more for the E-MI II and the E-M10 II. Is a half stop of improvement negligible? It seems any other increase on these two cameras does not give enough improvement to be worth the effort.

The E-M1 II's sensor does not appear to be dual gain, yet it too shows > 1/2 stop improvement in PDR from ISO 200 to ISO 400, and another 1/2 stop available above ISO 2000.

I would have thought one should use the highest ISO consistent with not blowing desired highlight detail at the slowest practical shutter and widest practical aperture.

The theoretical benefit of this isn't normally visible on my EM5ii, but other bodies might differ.

Other than from ISO 200 to ISO 400, I'd be inclined to agree, for that particular camera.

There's no substitute for personal testing, I think.

I think that there's no substitute for properly conducted testing. Sadly, a lot of personal testing is not properly conducted.  Most people don't have the proper setup or knowledge to properly control the tests. Perhaps your situation differs from the norm.

TomFid Veteran Member • Posts: 3,146
Re: Am I missing something?

FingerPainter wrote:

Perhaps. Those charts may indicate that the E-M5 II and E-M10 II are dual gain with the switch occurring at ISO 400,

Now look at http://www.photonstophotos.net/Charts/PDR_Shadow.htm

It shows a 1 stop increase in ISO above base gives a half stop improvement in PDR for the E-M5 II and a bit more for the E-MI II and the E-M10 II. Is a half stop of improvement negligible? It seems any other increase on these two cameras does not give enough improvement to be worth the effort.

The E-M1 II's sensor does not appear to be dual gain, yet it too shows > 1/2 stop improvement in PDR from ISO 200 to ISO 400, and another 1/2 stop available above ISO 2000.

Thanks for the useful link. I couldn't see the effect at all in the quick test I shot yesterday. I'll have to give it another try, more carefully.

There's no substitute for personal testing, I think.

I think that there's no substitute for properly conducted testing. Sadly, a lot of personal testing is not properly conducted. Most people don't have the proper setup or knowledge to properly control the tests. Perhaps your situation differs from the norm.

I think there are two aspects to this. Developing generalizable knowledge is hard. I know from mtf testing multiple lenses to see what stabilization settings worked best that it can be a ton of work, and I'd have to do it all over if I switched bodies.

But if you're just trying to figure out what works for you, the bar is a little lower. If you're making a mistake in your testing, you're likely to make the same mistake in the field, so it's not necessarily a great loss if you rule out whatever it was you tried for the wrong reasons. Also, you may learn something about your own preferences - for example that even though ETTR gets you 2 stops of noise reduction, it's kind of a PITA, and not worth bothering about much of the time.

knickerhawk Veteran Member • Posts: 6,349
Re: Am I missing something?
1

TomFid wrote:

FingerPainter wrote:

Perhaps. Those charts may indicate that the E-M5 II and E-M10 II are dual gain with the switch occurring at ISO 400,

Now look at http://www.photonstophotos.net/Charts/PDR_Shadow.htm

It shows a 1 stop increase in ISO above base gives a half stop improvement in PDR for the E-M5 II and a bit more for the E-MI II and the E-M10 II. Is a half stop of improvement negligible? It seems any other increase on these two cameras does not give enough improvement to be worth the effort.

The E-M1 II's sensor does not appear to be dual gain, yet it too shows > 1/2 stop improvement in PDR from ISO 200 to ISO 400, and another 1/2 stop available above ISO 2000.

Thanks for the useful link. I couldn't see the effect at all in the quick test I shot yesterday. I'll have to give it another try, more carefully.

There's no substitute for personal testing, I think.

I think that there's no substitute for properly conducted testing. Sadly, a lot of personal testing is not properly conducted. Most people don't have the proper setup or knowledge to properly control the tests. Perhaps your situation differs from the norm.

I think there are two aspects to this. Developing generalizable knowledge is hard. I know from mtf testing multiple lenses to see what stabilization settings worked best that it can be a ton of work, and I'd have to do it all over if I switched bodies.

But if you're just trying to figure out what works for you, the bar is a little lower. If you're making a mistake in your testing, you're likely to make the same mistake in the field, so it's not necessarily a great loss if you rule out whatever it was you tried for the wrong reasons.

There's a nice middle ground between formal ETTR testing (boring, time consuming and usually not very "real life") and just winging it (that's a recipe for disappointment with ETTR). If you make a point of exposure bracketing when shooting in ETTR-appropriate situations, you can learn a lot about your camera's behavior and arrive at some pretty reasonable conclusions about what works well for your particular mix of camera, setting and processing. The only downside here is that you'll burn through your memory cards somewhat faster than would otherwise be the case and you'll need to spend more time analyzing your raw images and processing options than you otherwise would with a one-frame-per-shot workflow, but you'll learn some interesting stuff along the way and begin to train your eye for when to use ETTR and how much...

Also, you may learn something about your own preferences - for example that even though ETTR gets you 2 stops of noise reduction, it's kind of a PITA, and not worth bothering about much of the time.

Cleaning up noise in conversion/post-processing is a PITA too! But I agree that ETTR ain't for everyone and ain't for every situation.

Xasan Contributing Member • Posts: 829
Re: To ETTR or not to ETTR...?

tomhongkong wrote:

Some facts

Most people use an average auto exposure setting which is based on averaging the light measured and having an 18% greyscale exposure correct.

You are missing at least one important fact, AE determines what it is in the scene to be assigned 18% to, and in certain modes it doesn't bother to do even this. 18% greyscale exposure of what is going to be correct? Of an 18% card filling the frame? How useful is that IRL?

Before you go into explanations you need to have a clear idea what is AE and how it works, and what you know about the multitude of AE algorithms in use.

That means that bright portion of a bright image is going to be underexposed (of course if you are using spot or centre weighted exposure that may not apply). A predominately dark image might similarly be underexposed

With most digital sensors there is around one stop of 'headroom' for highlights, when the auto exposure is used. Even blinkies typically start flashing at a maximum setting of 125% so there is plenty of headroom left when they are blinking.

If you don't believe this, try taking a photo in RAW with 'blown' highlights and reducing the exposure in PP. You will be surprised at how much latitude is built in to your camera, which is not used when taking JPEG. Having a feeling for how much you can overexpose is a good thing.

So there is a lot of scope for 'overexposing' based on what the camera meter believes.

Getting the right exposure (and I don't mean correcting a dark image by winding up brightness with a higher iso, which does nothing for exposure) is important to improve the SNR and reduce noise, and to capture more detail in the whole image, in particular in the shadows. To be safe, and underexpose "to protect the highlights' does the reverse.

Of course if you only use JPEGs, and I accept the convenience of this strategy, you pay the price in reducing potential DR.

Just try it

Tom

Xasan Contributing Member • Posts: 829
Re: To ETTR or not to ETTR...?

bobn2 wrote:

tomhongkong wrote:

Some facts

None of the below is a fact.

If I may, some of us would enjoy your answer past the headline above.

Most people use an average auto exposure setting which is based on averaging the light measured and having an 18% greyscale exposure correct. That means that bright portion of a bright image is going to be underexposed (of course if you are using spot or centre weighted exposure that may not apply). A predominately dark image might similarly be underexposed

With most digital sensors there is around one stop of 'headroom' for highlights, when the auto exposure is used. Even blinkies typically start flashing at a maximum setting of 125% so there is plenty of headroom left when they are blinking.

If you don't believe this, try taking a photo in RAW with 'blown' highlights and reducing the exposure in PP. You will be surprised at how much latitude is built in to your camera, which is not used when taking JPEG. Having a feeling for how much you can overexpose is a good thing.

So there is a lot of scope for 'overexposing' based on what the camera meter believes.

Getting the right exposure (and I don't mean correcting a dark image by winding up brightness with a higher iso, which does nothing for exposure) is important to improve the SNR and reduce noise, and to capture more detail in the whole image, in particular in the shadows. To be safe, and underexpose "to protect the highlights' does the reverse.

Of course if you only use JPEGs, and I accept the convenience of this strategy, you pay the price in reducing potential DR.

Just try it

Tom

OP Jeepit Regular Member • Posts: 168
Re: All depends on your expected output

Pixnat2 wrote:

Jeepit wrote:

Pixnat2 wrote:

You shoot landscapes in difficult light and are adept of squeezing out all the DR and shadow details you can in post processing?

You can't stand a bit of noise in your shadows?

In those cases, mastering ETTR could be helpful.

But for casual shooting, I wouldn't worry about it. Our modern cameras have excellent metering system and enough DR to cope with nearly all situations.

That said, it's a nice technique to learn and use in some cases.

Thanks for your post. What would those cases be?

You're welcome.

Lanscapes with high contrast (deep shadows and strong highlights) is probably the main case where ETTR can be useful.

In this scenario, camera tend to protect highlight for the JPEG, thus it underespose a bit. This will introduce noise in the shadows which will be visible when you try to recover your RAW files. In a landscape picture, you would lose fine details in the shadows and get a mushy result.

ETTR will burn your JPEG, but less noise will be present in the shadows. If correctly done, you could recover your highlights, and you'll get a landscape with clean shadows and fine details.

Peronally, that's the only case where I use ETTR.

Landscapes was one of the main questions I had regarding ETTR.

What about street shooting in b/w, where there are shadows?

Wildlife?

But all pictures with high contrast, where you need a wide Dynamic Range, would benefits form ETTR.

 Jeepit's gear list:Jeepit's gear list
Olympus E-M1 II Olympus E-330 Olympus E-M1 Olympus Zuiko Digital ED 18-180mm 1:3.5-6.3 Olympus Zuiko Digital ED 12-60mm 1:2.8-4.0 SWD +16 more
bobn2
bobn2 Forum Pro • Posts: 62,019
Re: To ETTR or not to ETTR...?
1

Xasan wrote:

bobn2 wrote:

tomhongkong wrote:

Some facts

None of the below is a fact.

If I may, some of us would enjoy your answer past the headline above.

Nothing too much to take exception to - it's just that when someone declares their opinions to be facts, they set themselves a high bar.

Most people use an average auto exposure setting which is based on averaging the light measured and having an 18% greyscale exposure correct. That means that bright portion of a bright image is going to be underexposed (of course if you are using spot or centre weighted exposure that may not apply). A predominately dark image might similarly be underexposed

I think 'most people' likely use their camera's default evaluative exposure modes, which don't at all work as described.

With most digital sensors there is around one stop of 'headroom' for highlights, when the auto exposure is used. Even blinkies typically start flashing at a maximum setting of 125% so there is plenty of headroom left when they are blinking.

Depends where you're measuring headroom from. Most digital cameras don't leave a whole stop above JPEG 100%. In the context of this forum particularly, many Panasonic sensored cameras have very little, or even negative headroom.

If you don't believe this, try taking a photo in RAW with 'blown' highlights and reducing the exposure in PP. You will be surprised at how much latitude is built in to your camera, which is not used when taking JPEG. Having a feeling for how much you can overexpose is a good thing.

He's talking about raw headroom, varies a lot from camera to camera.

So there is a lot of scope for 'overexposing' based on what the camera meter believes.

Getting the right exposure (and I don't mean correcting a dark image by winding up brightness with a higher iso, which does nothing for exposure) is important to improve the SNR and reduce noise, and to capture more detail in the whole image, in particular in the shadows. To be safe, and underexpose "to protect the highlights' does the reverse.

The best exposure is pretty much always the largest exposure, subject to technological and aesthetic constraints. Once you've maximised exposure the task is selecting the best ISO setting to go with it.

Of course if you only use JPEGs, and I accept the convenience of this strategy, you pay the price in reducing potential DR.

Not sure which is 'this strategy'. If you use OOC JPEGs, there's a lot to do with actually choosing the lowest ISO and not being lazy and letting yourself be stuck in the ISO you first thought of. Whether you think of it as maximising exposure or minimising ISO, you need to pay attention to maximising exposure.

-- hide signature --

263, look deader.

OP Jeepit Regular Member • Posts: 168
Re: It's rarely really 'needed' at all. It's all about maximizing potential image quality...

DLGW wrote:

,.. under certain sets of circumstances.

Jeepit wrote:

so are you saying ETTR is not really needed for mFT cameras? Is that small boost in image quality really worth the end results, if a photographer has to change his/ her way of shooting and start wondering about if every shot should be ETTR?

Think of it as a potential tool - like shooting a panoramic or shooting multi-exposure to eventually blend into and HDR image. It does require you to

evaluate

This is area I need to concentrate on since this ETTR is new to me.  Hence all the questions I have been asking in this learning process.

what you are shooting and how, and to make a decision as to how get the best image quality out of a particular shoot.

Well said...and part of that 'decision' making process is learning to decide if I need to ETTR for every shot I take with my EM1 mkII. and maybe the new EM1x.

As to whether or not the improvement is worth a small bit of effort - that is for the photographer to decide. I rarely use to be honest, but since I'm already shooting full manual exposure and watching my histogram, the amount of additional effort when capturing is about zero. Any image I actually do something with is processed from RAW as well, so again, about 3 seconds of additional time to 'fix' the exposure.

 Jeepit's gear list:Jeepit's gear list
Olympus E-M1 II Olympus E-330 Olympus E-M1 Olympus Zuiko Digital ED 18-180mm 1:3.5-6.3 Olympus Zuiko Digital ED 12-60mm 1:2.8-4.0 SWD +16 more
knickerhawk Veteran Member • Posts: 6,349
Re: All depends on your expected output

Jeepit wrote:

Pixnat2 wrote:

Jeepit wrote:

Pixnat2 wrote:

You shoot landscapes in difficult light and are adept of squeezing out all the DR and shadow details you can in post processing?

You can't stand a bit of noise in your shadows?

In those cases, mastering ETTR could be helpful.

But for casual shooting, I wouldn't worry about it. Our modern cameras have excellent metering system and enough DR to cope with nearly all situations.

That said, it's a nice technique to learn and use in some cases.

Thanks for your post. What would those cases be?

You're welcome.

Lanscapes with high contrast (deep shadows and strong highlights) is probably the main case where ETTR can be useful.

In this scenario, camera tend to protect highlight for the JPEG, thus it underespose a bit. This will introduce noise in the shadows which will be visible when you try to recover your RAW files. In a landscape picture, you would lose fine details in the shadows and get a mushy result.

ETTR will burn your JPEG, but less noise will be present in the shadows. If correctly done, you could recover your highlights, and you'll get a landscape with clean shadows and fine details.

Peronally, that's the only case where I use ETTR.

Landscapes was one of the main questions I had regarding ETTR.

Yes, landscape is generally the best use case for ETTR.

What about street shooting in b/w, where there are shadows?

Wildlife?

Use cases involving fast moving subjects are tricky because metering on your critical highlights (or otherwise monitoring highlight blinkies and the histogram) is hard to control in a timely way. Plus, action shots are more often shutterspeed constrained and perhaps also aperture constrained, which limits your flexibility for pushing up exposure.

With respect to B/W, there are additional pluses and minuses. On the plus side, you're less worried about adverse color issues from blowing one or even two of the channels. In general B/W street shooters aren't so concerned about blown highlights either (as long as it's not affecting the subjects' faces). Plus, the improved tonality resulting from ETTR done right can be very important in some B/W work. However, lots of street shooters like the gritty/grainy look that's reminiscent of fast film. For them, ETTR might be counterproductive, especially when considering the noted exposure limitations.

But all pictures with high contrast, where you need a wide Dynamic Range, would benefits form ETTR.

Xasan Contributing Member • Posts: 829
Thank you

bobn2 wrote:

Xasan wrote:

bobn2 wrote:

tomhongkong wrote:

Some facts

None of the below is a fact.

If I may, some of us would enjoy your answer past the headline above.

Nothing too much to take exception to - it's just that when someone declares their opinions to be facts, they set themselves a high bar.

Most people use an average auto exposure setting which is based on averaging the light measured and having an 18% greyscale exposure correct. That means that bright portion of a bright image is going to be underexposed (of course if you are using spot or centre weighted exposure that may not apply). A predominately dark image might similarly be underexposed

I think 'most people' likely use their camera's default evaluative exposure modes, which don't at all work as described.

Agree and agree.

With most digital sensors there is around one stop of 'headroom' for highlights, when the auto exposure is used. Even blinkies typically start flashing at a maximum setting of 125% so there is plenty of headroom left when they are blinking.

Depends where you're measuring headroom from. Most digital cameras don't leave a whole stop above JPEG 100%.

Agree, and depending on the tone curve applied to raw in DSP, can be less than .5 stop.

In the context of this forum particularly, many Panasonic sensored cameras have very little, or even negative headroom.

If you don't believe this, try taking a photo in RAW with 'blown' highlights and reducing the exposure in PP. You will be surprised at how much latitude is built in to your camera, which is not used when taking JPEG. Having a feeling for how much you can overexpose is a good thing.

He's talking about raw headroom, varies a lot from camera to camera.

Agree, and he's not specifying what latitude is that, part of it is because of calibration, part of it is due to channel extrapolation using AI algorithms. Quality-wise it matters.

So there is a lot of scope for 'overexposing' based on what the camera meter believes.

Getting the right exposure (and I don't mean correcting a dark image by winding up brightness with a higher iso, which does nothing for exposure) is important to improve the SNR and reduce noise, and to capture more detail in the whole image, in particular in the shadows. To be safe, and underexpose "to protect the highlights' does the reverse.

The best exposure is pretty much always the largest exposure, subject to technological and aesthetic constraints. Once you've maximised exposure the task is selecting the best ISO setting to go with it.

No doubt.

Of course if you only use JPEGs, and I accept the convenience of this strategy, you pay the price in reducing potential DR.

Not sure which is 'this strategy'. If you use OOC JPEGs, there's a lot to do with actually choosing the lowest ISO and not being lazy and letting yourself be stuck in the ISO you first thought of. Whether you think of it as maximising exposure or minimising ISO, you need to pay attention to maximising exposure.

Definitely so.

Your systematic answers are as helpful as a steady tripod. They anchor things to their proper places. Steady tripods are usually not light-weighted, too.

Keyboard shortcuts:
FForum MMy threads