What is the best exposure for your Olympus? (ETTR and other techniques)

pdk42

One of the "Eh?" team
Joined
Jan 11, 2013
Messages
6,730
Location
Leamington Spa, UK
Incidentally, some people say that using the extended low ISOs on Olympus cameras (64 and 100) is the same as over-exposing at ISO 200 and pulling back the raw file in post (as I've done here). I think in fact that this is not 100% accurate. I haven't been able to find definitive information, but it seems that when you use these extended low ISO values, there is some electronic or processing tweak being done to the sensor such that the sensor response becomes non-linear in the highlights. It tails off, giving a shoulder to the curve. The outcome of this is that highlight headroom is actually a little better at ISO 100 than at ISO 200. In effect, this probably means that you're losing only a half-stop of highlight capacity for the one stop gain in shadow capacity. Net, net - an extra half stop of DR. You can see this in fact in the DR curves on DxO - this one for the Pen F:

1581275130032.png
Subscribe to see EXIF info for this image (if available)


Half a stop ain't much and I don't usually bother with low ISO - but when I do use it, I'm usually quite surprised with the extra detail I get in the shadows.
 

Machi

Mu-43 Top Veteran
Joined
May 23, 2015
Messages
657
Incidentally, some people say that using the extended low ISOs on Olympus cameras (64 and 100) is the same as over-exposing at ISO 200 and pulling back the raw file in post (as I've done here). I think in fact that this is not 100% accurate. I haven't been able to find definitive information, but it seems that when you use these extended low ISO values, there is some electronic or processing tweak being done to the sensor such that the sensor response becomes non-linear in the highlights. It tails off, giving a shoulder to the curve. The outcome of this is that highlight headroom is actually a little better at ISO 100 than at ISO 200. In effect, this probably means that you're losing only a half-stop of highlight capacity for the one stop gain in shadow capacity. Net, net - an extra half stop of DR. You can see this in fact in the DR curves on DxO - this one for the Pen F:

View attachment 801638

Half a stop ain't much and I don't usually bother with low ISO - but when I do use it, I'm usually quite surprised with the extra detail I get in the shadows.
Actually extended ISO in Olympuses is the ETTR. Graph from DXOmark shows on the left ISO200 (not extended ISO100) and ISO400.

penfDR.jpg
Subscribe to see EXIF info for this image (if available)


But DXOmark has much more useful tool and that's Full SNR measurements.
Here it shows SNR for both ISO64 and ISO200 in case of E-M1II and they are the same (as expected).

OlympusE-M1IIsnrDXOmark.jpg
Subscribe to see EXIF info for this image (if available)


And here is the same for PEN-F. Now in this graph ISO80 isn't even visible because it's in perfect overlay with ISO200.

OlympusPenFsnrDXOmark.jpg
Subscribe to see EXIF info for this image (if available)
 
Last edited:
Joined
Mar 31, 2015
Messages
224
Location
Switzerland
Real Name
Siegfried
OK, so let's try some controlled experiments.

Here's the rather messy scene in my home office. It's not a very high contrast scene, so definitely a candidate for ETTR.

View attachment 801611

The above shot, and all the following were shot on a Pen-F in raw with the Oly 17mm f1.8 @ f1.8; then processed in Lightroom using default settings apart from changes to exp comp and shadows as indicated later. No NR applied to any shots. Sharpening was at default value of 40.



1) This shot was taken at ISO 200 and used the camera's suggested exposure (it's the same as the above, I'm just repeating it for clarity):

View attachment 801612



2) Here's the same scene, shot this time with +1.5 stops of exp correction. The white on the binder on the right of the bottom shelf was just showing as overexposed on the blinkies display:

View attachment 801613



3) Here it is again, but pulled back by -1.5 stops in LR:

View attachment 801614



This now looks the same the first shot - so, we've done +1.5 stops of ETTR. Has it made a difference? It's hard to tell at this size (1024 pix), so let's try a bit harder. Let's add +100 to the shadows on them both and go peering into some dark areas at 200% in Lightroom. The ETTR shot is on the right:


4) ETTR comparison:

View attachment 801615


Wow - big difference. It's as if I've got 1.5 stops better noise - since I have!! That's ETTR. Now look at the exposures:

- Left shot (non-ETTR): 1/30 at f1.8.
- Right shot (ETTR): 1/10 at f1.8

So, more light in the right shot - so better filled wells, lower noise. The result matches the theory. Yay!!

Now let's try it at ISO 3200.


4) ISO 3200, camera's suggested exposure:

View attachment 801616



5) ISO 3200, +1.5 exp comp, pulled back -1.5 in LR:

View attachment 801617


Now let's do the same trick - raise shadows by +100 and go peering in the dark areas. Left is normal, right is "ETTR":


6) ETTR Comparison at ISO 3200

View attachment 801618


So - ETTR is working then?

No - it isn't. The exposure of the "ETTR" shot is 1/180s at f1.8 at ISO 3200 (+1.5 EC in camera, -1.5 EC in LR) . Now let's shoot the same shot at 1/180s, f1.8 at ISO 1250. This is now the same exposure as the "ETTR" ISO 3200 shot, but now shot at EC 0 according to the camera's meter. Let's push the shadows +100 again and go peering into the same dark area:


7) ETTR at ISO 3200 vs regular exposure at ISO 1250

View attachment 801619


So, virtually the same. The ISO 3200 is perhaps very, very marginally better - but the difference is negligible. We've won nothing by dialing in ISO 3200 and playing around with over exposure and pulling back in post processing.

Why? - because the exposure (1/180 at f1.8) is the same in both. The sensor has received the same total light, the wells are filled the same. All we've done on the ISO 3200 shot compared to the ISO 1250 shot is to add amplification in the camera and then reduce the amplification in LR. We've not made the slightest difference to the sensor's performance.

There may be some small differences due to the way that ISO amplification is done (determined by how electronic gain is being done vs ADC vs digital gain) - but whilst it may be helpful to know these details, the magnitude of the change will likely be small, and of course very camera dependent. It may even be the case that the order of noise effects will swap according to what strategy the camera is adopting (i.e. "ETTR" at higher ISOs might be worse). These are all second order effects compared to ETTR (at base ISO) which will make a big difference because we are giving the sensor more light.
My 1st comment:-
You proofed that one should not apply ETTR by changing the ISO setting... 😟 The ISO setting does not change exposure (the "E" in ETTR)

First image:
1/180, f1.8 @ ISO1250

Second "ETTR" image
1/180, f1.8 @ ISO3200

Result? You proofed that changing image brightness (ISO), is NOT changing exposure....

My second comment:
The conditions you selected to test the ISO3200 test was not ideal but its OK for this test purposes. Why? Well I do not think one would use ISO3200 with a shutter speed of 1/500sec? Maybe in a sports setting but then without ETTR because 1/180 sec might then be too slow?

Try and simulate a more realistic condition. Wait until evening and try f1.8 with something like 1/20 sec at ISO3200 (similar to a street scene or city scape in low light). Now you could change the shutter speed with +1 stop or +1,5 stops (ETTR). All handheld.....thats why we selected ISO3200, right?

Now if you feel you like to repeat your image brightness ETTR test dropping the ISO to 1250 and take an image handheld..... 😎

Have fun....
 
Last edited:

pdk42

One of the "Eh?" team
Joined
Jan 11, 2013
Messages
6,730
Location
Leamington Spa, UK
My 1st comment:-
You proofed that one should not try ETTR with changing the ISO setting... 😟 The ISO setting does not change the exposure (the "E" in ETTR)

First image:
1/180, f1.8 @ ISO1250

Second "ETTR" image
1/180, f1.8 @ ISO3200

Result? You proofed that changing image brightness does NOT changing exposure....
Sorry, but I just don't understand your point here at all.

My second comment:
The conditions you selected to test the ISO3200 test was not ideal but its OK for this test purposes. Why? Well I do not think one would use ISO3200 with a shutter speed of 1/500sec? Maybe in a sports setting but then without ETTR because 1/180 sec might then be too slow?

Try and simulate a more realistic condition. Wait until evening and try f1.8 with something like 1/20 sec at ISO3200 (similar to a street scene or city scape in low light). Now you could change the shutter speed with +1 stop or +1,5 stops (ETTR). All handheld.....thats why we selected ISO3200, right?

If you now feel like you like to repeat your image brightness ETTR test dropping the ISO to 1250 and take an image handheld..... 😎

Have fun....
I accept that lower light would exacerbate the noise issues, but I don't think it invalidates my point.
 

Machi

Mu-43 Top Veteran
Joined
May 23, 2015
Messages
657
My aim was:
- To keep it as simple as possible (its still way to complex in terms of lingo and text)
- Develop a profile/model photographers can apply to improve IQ and image noise
- From statements we see on the web, image noise, ISO, technology and exposure are probably the most confused subjects on digital photography - that means 15 years of digital photography resulted in a generally poorly educated photography community - not a great report?
I think that trying to do everly simplified explanation is what caused your last point about confusing topics in the photography (with which I agree).
Also I doubt that there is a simple model to improve IQ and image noise at least until the time where manufacturers decide to give us RAW histogram and RAW overexposure/underexposure warnings ("blinkies").
Personally I shoot most of my images as fast sequence of three images with varying exposure through exposure bracketing with 1EV difference. I've learned that because my older camera E-PM2 has serious issues with shutter shock and with this style I know that at least one of my images will be sharp and it has other benefits too. At least one of them will be perfectly exposed in 95% of cases and three images can be stacked for better IQ.
With E-PM2 I normally have 1-2 sharp images, same technique with my newer E-M10II gives better results as mostly all three of them are properly sharp. But on other side it has one disadvantage - IBIS doesn't works well with sequence shootings, so in the dark conditions I'm using single frame shooting mode.
 
Last edited:
Joined
Mar 31, 2015
Messages
224
Location
Switzerland
Real Name
Siegfried
Sorry, but I just don't understand your point here at all.

Your first ISO200 test was good and the second ISO3200 also for the simple reason you increased the exposure (shutter speed) in both examples.

Then you were confused trying to proof a point by dropping the ISO to ISO1250. To understand what you really did I showed you that one cannot apply ETTR by changing the ISO because that is what you did. That is why I suggested you do the test again in more realistic conditions - all handheld.... try tonight and let me know....

I accept that lower light would exacerbate the noise issues, but I don't think it invalidates my point.


This was the point I was asking about - what is your point please?
 

pdk42

One of the "Eh?" team
Joined
Jan 11, 2013
Messages
6,730
Location
Leamington Spa, UK
This was the point I was asking about - what is your point please?
I'll try to be more explicit...

"You profed that one should not try ETTR with changing the ISO setting..."
Actually, I didn't prove that at all. I showed that over-exposing at ISOs above base and pulling back in post is no different to using a lower ISO and exposing normally.


"You proofed that changing image brightness (ISO), is NOT changing exposure..."
I don't think I showed that at all. Image brightness is a function of exposure, ISO, post-processing, output medium, ... Your point makes no sense.


Try and simulate a more realistic condition. Wait until evening and try f1.8 with something like 1/20 sec at ISO3200 (similar to a street scene or city scape in low light). Now you could change the shutter speed with +1 stop or +1,5 stops (ETTR). All handheld.....thats why we selected ISO3200, right?
As I said, I accept that lower light would exacerbate the noise issues - but that doesn't change the basic argument I made, not its conclusions. You are complicating the principle. To understand principles, we need to reduce the problem to its basics - that's how science works!! :)
 
Last edited:

Machi

Mu-43 Top Veteran
Joined
May 23, 2015
Messages
657
@pdk42 I generally agree that ETTR at different than base ISO for most conditions is lets say unwise :) (as your images showed) but there aren't absolute rules for what ETTR is and what it isn't.
And there is one area where ETTR is viable even at higher ISO settings in case of non-ISOless cameras and that's photography at so called photon-starving regimes where camera works with few photons per pixel at given exposure. That can happen in case of astrofotography and photography at night in general (possible improvement is showed in my example here).
 

pdk42

One of the "Eh?" team
Joined
Jan 11, 2013
Messages
6,730
Location
Leamington Spa, UK
@pdk42 I generally agree that ETTR at different than base ISO for most conditions is lets say unwise :) (as your images showed) but there aren't absolute rules for what ETTR is and what it isn't.
And there is one area where ETTR is viable even at higher ISO settings in case of non-ISOless cameras and that's photography at so called photon-starving regimes where camera works with few photons per pixel at given exposure. That can happen in case of astrofotography and photography at night in general (possible improvement is showed in my example here).
I'm not going to dispute that. Real-world cameras and sensors will add complexity and subtlety. But in most normal photography these will be second-order problems compared to just getting more light on the sensor and that is what ETTR, for most people, should mean. Using ETTR at higher ISOs is not notably different to lowering the ISO and exposing normally. I accept that the rules changes in astrophotography - but that deserves a whole different thread!
 
Joined
Mar 31, 2015
Messages
224
Location
Switzerland
Real Name
Siegfried
I think that trying to do everly simplified explanation is what caused your last point about confusing topics in the photography (with which I agree).
Also I doubt that there is a simple model to improve IQ and image noise at least until the time where manufacturers decide to give us RAW histogram and RAW overexposure/underexposure warnings.
Personally I shoot most of my images as fast sequence of three images with varying exposure through exposure bracketing with 1EV difference. I've learned that because my older camera E-PM2 has serious issues with shutter shock and with this style I know that at least one of my images will be sharp and it has other benefits too. At least one of them will be perfectly exposed in 95% of cases and three images can be stacked for better IQ.
With E-PM2 I normally have 1-2 sharp images, same technique with my newer E-M10II gives better results as mostly all three of them are properly sharp. But on other side it has one disadvantage - IBIS doesn't works well with sequence shootings, so in the dark conditions I'm using single frame shooting mode.
- If I understand correctly, you did not really use ETTR....the three shots per image was an effort to manage shutter shock? That said - you benefitted in many respects...
- I wonder if the shutter in the EPM2 is the same as the first EM5? Have you tried the 1/8 sec delay function?
- I agree having a RAW histogram (luminance) will be great. That said there is a direct relationship between the jpeg histogram and the "nice to have" RAW histogram. Also the tiny histogram does not show much detail. In most cases it's better to use the display over/under exposure warning.
- IBIS - you referring to the EPM2? - Any of the 5 axis IBIS units are great if used correctly....
- Having a simplified model is possible - in fact its more simplistic than expected. Reason is we working with a linear graph (photons to electrons) within the sensor DR. The bigger challenge, is photographers ready to view the challenge from another view point....

Best :)
 
Joined
Mar 31, 2015
Messages
224
Location
Switzerland
Real Name
Siegfried
I'll try to be more explicit...


Actually, I didn't prove that at all. I showed that over-exposing at ISOs above base and pulling back in post is no different to using a lower ISO and exposing normally.



I don't think I showed that at all. Image brightness is a function of exposure, ISO, post-processing, output medium, ... Your point makes no sense.



As I said, I accept that lower light would exacerbate the noise issues - but that doesn't change the basic argument I made, not its conclusions. You are complicating the principle. To understand principles, we need to reduce the problem to its basics - that's how science works!! :)
You mix exposure with image brightness (ISO)
- Exposure is ONLY shutter speed and aperture
- In its most simplistic form ISO only adjust image brightness
This principle is key....
 
Last edited:

pdk42

One of the "Eh?" team
Joined
Jan 11, 2013
Messages
6,730
Location
Leamington Spa, UK
Actually extended ISO in Olympuses is the ETTR. Graph from DXOmark shows on the left ISO200 (not extended ISO100) and ISO400.

View attachment 801640
Yes, I'd forgotten that DxO use measured ISO and not manufacturer-declared ISO on their graphs, so the left-most point on the plot I referenced is actually ISO 200 on the dial. However, Bill Claff's site does go down to extended low (which is actually ISO 80 on the Pen-F):

1581281569665.png
Subscribe to see EXIF info for this image (if available)

http://www.photonstophotos.net/Charts/PDR_HighResShotMode.htm#Olympus PEN-F

You'll see that the DR is flat to the left of ISO 200. Must have been my imagination that it was better!! At least it's no worse!
 

pdk42

One of the "Eh?" team
Joined
Jan 11, 2013
Messages
6,730
Location
Leamington Spa, UK
This is frustrating....

You mix exposure with image brightness (ISO)
I DID NOT "mix exposure with image brightness (ISO)". Why are you saying this????

- Exposure is ONLY shutter speed and aperture [for a given scene & lighting]
- In its most simplistic form ISO only adjust image brightness [all other things being constant and assuming the sensor isn't clipping]
Yes, I agree with this (phew!).
 

Machi

Mu-43 Top Veteran
Joined
May 23, 2015
Messages
657
- If I understand correctly, you did not really use ETTR....the three shots per image was an effort to manage shutter shock? That said - you benefitted in many respects...
It was both effort to manage shutter shock and to do ETTR (for at least one of the images).

- I wonder if the shutter in the EPM2 is the same as the first EM5? Have you tried the 1/8 sec delay function?
I'm not sure if it's the same shutter. I tried 1/8 sec delay and after I lost some shots because of that (yes, even 1/8sec delay is sometimes too much), I've stopped using it.

- I agree having a RAW histogram (luminance) will be great. That said there is a direct relationship between the jpeg histogram and the "nice to have" RAW histogram. Also the tiny histogram does not show much detail. In most cases it's better to use the display over/under exposure warning.
Blinkies works in mysterious ways on my E-M10II, so I have not much confidence in them.

- IBIS - you referring to the EPM2? - Any of the 5 axis IBIS units are great if used correctly....
It doesn't work for fast sequential shooting (my most used setting for exposure bracketing) and I'm not sure how effective is it slow sequential shooting as I didn't tested it properly in these conditions but after some bad experiences I'm only using it in single mode in landscape orientation where it works fabulously (up to 5.5EV with E-M10II+Panasonic 20mm). In vertical (portrait orientation) effectivity is much lower.

- Having a simplified model is possible - in fact its more simplistic than expected. Reason is we working with a linear graph (photons to electrons) within the sensor DR. The bigger challenge, is photographers ready to view the challenge from another view point....
Best :)
There is a "simple" model and it's called "photon transfer curve" but it's in graph form, some doesn't know how to read it because for that one must have some knowledge about how to read a graphs, how sensor works, what's a noise and how it affects image etc. and now it's not so simple anymore! :)
But there is a simple version for ETTR if one doesn't need explanation - push exposure as far as you can as long you don't ruin your photo! :)
 
Last edited:

Machi

Mu-43 Top Veteran
Joined
May 23, 2015
Messages
657
Must have been my imagination that it was better!! At least it's no worse!
I think you've confused Olympus and Panasonic.
(Some) Panasonic cameras have better results in extended ISO and it's a little mystery how they did it.
 

pdk42

One of the "Eh?" team
Joined
Jan 11, 2013
Messages
6,730
Location
Leamington Spa, UK
I'm not sure if it's the same shutter. I tried 1/8 sec delay and after I lost some shots because of that (yes, even 1/8sec delay is sometimes too much), I've stopped using it.
No Olympus shutter up to the one on the E-M5ii was immune to shutter shock. Some cameras were worse than others, and the effect would be dependent to some degree on the lens fitted (for mass damping reasons, not optical). However, the E-PL5, E-PM2, and EP5 were all pretty bad.

The underlying problem was the "ringing" caused by the opening of the first curtain. As the blade slammed open, the impact would cause a damped vibration (ringing) in the camera body (incl sensor assembly) with the inevitable consequence of image blur. Long exposures weren't impacted since the ringing damped down early in the exposure so the overall result was not impacted. Shorter exposures weren't impacted since the vibration period would be short compared to the exposure. Around the 1/125 to 1/180 it was most marked.

The 1/8s delay you could add on the older Oly cameras introduced a delay BEFORE the first curtain - it was trying to fix camera shake caused by the photographer jabbing the shutter release. As such, it did nothing to help shutter shock.

Olympus in the end did two fixes:

- Damp the first curtain better - E-M5ii and later cameras.

- Introduce a delay between the curtain opening and the exposure starting (electronic first curtain shutter - EFCS, or "0s anti-shock" as Oly call it)

The latter was introduced as a retrospective kludge/fix on the EP5 and E-M1; but done properly on E-M5ii and later cameras.

The E-P5 and E-M1 kludge worked like this:

The shutter sequence is:
- Shutter closes (Live View terminates)
- First curtain shutter opens
- Electronic "0-sec" delay starts
- Exposure starts electronically after 20ms (so 0s = 20ms !)
- Shutter closes

This little video shows the EP5 shutter. Both are at the same shutter speed. Left hand side is without 0s anti-shock. Right side is with 0s anti-shock. You'll see that there is a delay (ca 20ms) for closing the 2nd curtain shutter on the right. This would result in a longer exposure but the start is delayed by EFCS. Basically, it allows the vibrations from the first curtain opening to die down and then starts the exposure electronically. It's EFCS, but the shutter goes through the whole close/open/close/open sequence anyhow - I guess because it was designed that way and can't be changed by programming.

Subscribe to see EXIF info for this image (if available)
 
Last edited:

saladin

Mu-43 All-Pro
Joined
May 29, 2015
Messages
1,814
Location
Melbourne
Real Name
jason
This thread is breaking my brain.....


All I want to know is how far can I push the Em5iii jpeg highlights (histogram) without blowing the raw headroom out of the photo? The shadows can fall wherever they do.
 
Links on this page may be to our affiliates. Sales through affiliate links may benefit this site.
Mu-43 is a fan site and not associated with Olympus, Panasonic, or other manufacturers mentioned on this site.
Forum post reactions by Twemoji: https://github.com/twitter/twemoji
Copyright © 2009-2019 Amin Forums, LLC
Top Bottom