Exposure Compensation Question

[Dennis]

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19 minutes ago, MikeMyers said:

what will you set your ISO to?  .....and why???

Don't struggle so much with this. You should start maybe to work on just three vales. While the aperture affects the DOF, and the shutter speed the motion, what does the ISO do? Absolutely nothing 🙂 The amount of exposure is set by aperture and Shutter speed. The cons of the ISO, is that a higher iso, lower quality, right? Because the noise. 

So what about this Mike: Sunny day? 100/160 or 200 ISO (native or tot, up to you). Indoor or dark? 1600 ISO. Very dark or night shot, 6400 ISO.

Don't overwhelm yourself with all these numbers 😅If you set to yourself some limitations, IMHO, you can be freer Mike, by some technicalities and the paradox of choices.

In order, for me, it's working in this way:

1. ISO 
2. Aperture
3. Shutter speed

Iso first because I know what the situation need. Aperture, because I want that special DOF, right? Finally, shutter speed, which for me is the less important. Do you shoot F1 race? of course you need an higher shutter speed. You want to play with the movement of water? Lower shutter speed. But for many cases, any value upper than 1/250 is working for me.

Sometimes, I shoot at 3200 ISO by day because i need huge DOF and a fast enough shutter speed. But answering to your ISO question, despite the first setting i put when I shoot in manual, it's the easier to set.

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[evikne]

16 minutes ago, MikeMyers said:

I was just reading the other link up above from a.noctilux, and half way through it I came to the same conclusion as what you just wrote.  Select Manual mode, select ISO 200, select an aperture based on depth of field, and select a shutter speed based on motion within the image (more or less desired).  Then adjust the image in whatever image editor I'm using, perhaps Lightroom or DarkTable.

Will try this today, and see how well it works, or what issues I need to deal with.

(......and if I'm shooting in a dark room, I may select something other than 200, as I would have before my world got all discombobulated.)

Here is an example I shot in a dark room. I used f/1.4 and 1/60 sec. shutter speed to get maximum light on the sensor, but I left the ISO at 200. The result was a very dark image which I raised with 3 stops in LR (equivalent to ISO 1600), but still completely free from noise. 

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Edited March 6, 2020 by evikne

[MikeMyers]

2 hours ago, Dennis said:

........Ending this, I'm with you, Mike. I own Leica since last year and, although I have no problem with the exposure, I'm struggling with the focus. I'm still learning how to be faster ... Step by step.....

One tip I learned from watching a few gazillion YouTube videos - when focusing, just turn the lens one way until the images are aligned, and stop.  Do not go back and forth, trying to make it "perfect".  This speeds things up, and is easier for me.  I used to go back and forth and back and forth until it looked perfect, but the video said to do it once and stop.  

I'm still trying to find the position(s) for my left hand, and to remember to keep the lens at a setting I know for a starting point.  I typically "zone focus" the lens, so if I don't have time to focus correctly, I'll still hopefully get a good image.  Focusing is still my "weakest" part of using the M.

[MikeMyers]

2 hours ago, Dennis said:

Don't struggle so much with this. You should start maybe to work on just three values. While the aperture affects the DOF, and the shutter speed the motion, what does the ISO do? Absolutely nothing 🙂 The amount of exposure is set by aperture and Shutter speed. The cons of the ISO, is that a higher iso, lower quality, right? Because the noise. 

When I read what you wrote, and that the ISO setting doesn't matter, I come to two conclusions:

a) I can leave the ISO at 200 for most of my photos, and correct the brightness later in an editor, or..

b) I cal leave the ISO at "Auto ISO", knowing that it won't make any difference once I get into the image editor.

 

If it really and truly makes no difference, why not leave it in a setting where "image review" can show me a quick view of what I shot?  And while the editor can adjust all those many stops of corruption, the image will still look reasonably good "out of the camera".  

Also....   not sure how many of you have tried it, but I use Photo Mechanic to move my images from the memory card into the computer.  The software provides a pretty good idea of the quality of the image, and does this very quickly.  Photo Mechanic is going to make it difficult to select the images I want to keep, if some are too light or too dark to see them well enough.  To me, the aperture, the shutter, and the focus are all I need to do "manually".  (I'm thinking of typical images that I create - for special situations, maybe I need to re-evaluate this.

.......and back to where we started, if Exposure Compensation is ONLY going to make changes to the ISO setting, again, who cares?  I guess I now accept that it's not that critical, but UNLESS the situation means I'm going to be creating a lot more noise, does it matter?

 

(Photo Mechanic is a wonderful program for SO many reasons - if you're not familiar with it, check it out on the internet.  https://home.camerabits.com  It will work with any images, whether correctly exposed or over/under, but evaluating excessively incorrectly images will probably be difficult.)

[jdlaing]

8 minutes ago, MikeMyers said:

When I read what you wrote, and that the ISO setting doesn't matter, I come to two conclusions:

a) I can leave the ISO at 200 for most of my photos, and correct the brightness later in an editor, or..

b) I cal leave the ISO at "Auto ISO", knowing that it won't make any difference once I get into the image editor.

 

If it really and truly makes no difference, why not leave it in a setting where "image review" can show me a quick view of what I shot?  And while the editor can adjust all those many stops of corruption, the image will still look reasonably good "out of the camera".  

Also....   not sure how many of you have tried it, but I use Photo Mechanic to move my images from the memory card into the computer.  The software provides a pretty good idea of the quality of the image, and does this very quickly.  Photo Mechanic is going to make it difficult to select the images I want to keep, if some are too light or too dark to see them well enough.  To me, the aperture, the shutter, and the focus are all I need to do "manually".  (I'm thinking of typical images that I create - for special situations, maybe I need to re-evaluate this.

.......and back to where we started, if Exposure Compensation is ONLY going to make changes to the ISO setting, again, who cares?  I guess I now accept that it's not that critical, but UNLESS the situation means I'm going to be creating a lot more noise, does it matter?

 

(Photo Mechanic is a wonderful program for SO many reasons - if you're not familiar with it, check it out on the internet.  https://home.camerabits.com  It will work with any images, whether correctly exposed or over/under, but evaluating excessively incorrectly images will probably be difficult.)

If you set the base ISO to 200 and use exposure compensation changes will still be made but not to iso.

[IkarusJohn]

29 minutes ago, jdlaing said:

If you set the base ISO to 200 and use exposure compensation changes will still be made but not to iso.

Only to the meter reading, if you’re in manual mode; and to shutter speed, if you’re in aperture priority.

[Dennis]

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56 minutes ago, MikeMyers said:

when focusing, just turn the lens one way until the images are aligned, and stop.  Do not go back and forth, trying to make it "perfect".  This speeds things up, and is easier for me.

It's a very nice tip. Obvious for many people I guess. I struggle a little when I'm working on something more "artistic" ... For documentary, street and PJ I'm fast, because I don't really care about focus 😂 But for the other situation, I'll follow your advice.

47 minutes ago, MikeMyers said:

I can leave the ISO at 200 for most of my photos, and correct the brightness later in an editor, or.

I don't agree with. The editing, it's another step of process. But it's intended to give your own style signature style, that it. Not to compensate a wrong exposure. I guess this is hot topic 🙂

That's why also, I really love the culling process in PhotoMechanic. It's one of my favorite part, and the software is really helping me. Not sure I understood why you think it can be difficult.  

[NigelG]

Without wishing to add any further confusion - if you are considering that increasing ISO only “adds noise” or ultimately “doesn’t matter” you might want to also look at the impact of increased ISO on available Dynamic range....

 

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This is for the M10 from Photonstophotos.net

[Jeff S]

9 minutes ago, NigelG said:

Without wishing to add any further confusion - if you are considering that increasing ISO only “adds noise” or ultimately “doesn’t matter” you might want to also look at the impact of increased ISO on available Dynamic range....

 

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This is for the M10 from Photonstophotos.net

This and lots more covered well in the link that the OP ignored...post #53.

https://clarkvision.com/articles/iso/

Jeff

[Dennis]

3 minutes ago, NigelG said:

Without wishing to add any further confusion - if you are considering that increasing ISO only “adds noise” or ultimately “doesn’t matter” you might want to also look at the impact of increased ISO on available Dynamic range....

Got your point. And this is true. I know that increasing ISO do matter. But I don't know practically does.

I'm thinking out loud ... So if I expose for the highlights, using for example the following settings: F/16 - 1/4000 and 3200 iso, this means that my dynamic range decreases from 10EV to 7EV? This mean also that, if I have the exactly same quantity of exposure but I decide to use the F/4 - 1/4000 and 200 iso instead , the dynamic range will be much worst? I mean something you can really appreciate it in an image? I'm very curious...

[Dennis]

6 minutes ago, Jeff S said:

https://clarkvision.com/articles/iso/

Can't right now, got to go. But be sure I'll carefully read this later. Thanks for share

[MikeMyers]

The OP didn't intentionally "ignore" anything - postponed would be a better word, as in he is still trying to catch up.  There is one thing he, er, I did this evening - changed the ISO knob from "A" to 200 and left it there.  So as of that moment, I'm in full manual mode.  I've got a lot more reading to do, and a lot more understanding.

I will say one thing - at my brother's house, I went into a somewhat dark room, and tried to take photos of his cat in an interesting pose.  With my Nikon, I'd get a fine image, that would be grainy.  With the M10, manually adjusting shutter and aperture, leaving ISO at 200, I (eventually) got the image copied below. I am pretty sure it is better than I would have gotten with the D750.  As to the other photos I captured in full Manual, I didn't use the meter at all - just guesstimated, and while I wasted a few frames testing, the results were fine. 

I'll "grudgingly" leave the ISO at 200, and I'll read all the new information posted here, but deliberately creating an image that is way too light, or way too dark, thinking I'll fix it in processing, just goes against what I feel I should do.

(Regarding my comment about PhotoMechanic, how am I going to evaluate images in that software, if they're too dark to see clearly?  The point of Photo Mechanic is do do much of the selection before importing images into Lightroom, or whatever....)

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[MikeMyers]

11 hours ago, Jeff S said:

https://clarkvision.com/articles/iso/

Jeff

Not sure what to think of this article.  I read part of it earlier today, and read a lot more, along with the follow-up articles tonight.  He says things that I don't feel comfortable accepting.  For example:

"If you have a very old digital camera, e.g. made before circa 2009, a newer cameras with a more modern sensor will help a small amount, but usually not as much as a lens upgrade. "

To me, that's backwards.  I now own a Leica M8.2 and an M10, with a 50mm f/2 Summicron.  Moving from the M8.2 to the M10 was overwhelmingly better than what I could do with the M8.2 camera.  If I bought a faster f/1.4 or even faster lens, it wouldn't come close to the benefit of upgrading cameras.  I've noticed this with my Nikon cameras as well - old gear had limitations, and newer gear is usually so much better.

Also, he says that changing the ISO doesn't change the sensor sensitivity, and he and others prove the point.  But still, for as long as I can remember, going from 25 to 120 to 200 to 160 to any higher ASA or ISO speed allows me to shoot in less and less light.  That is true, regardless of how one does or doesn't define "sensitivity".  The practical effects of going to a higher ISO are that I can shoot in less light, or use a higher shutter speed.

The chart as to how ISO is "counted" is misleading.  He explains how it's more of how light and pixels are "counted", rather than the sensor becoming more sensitive to light, which I accept, but in the real world, again, making a change to a faster ISO gives me the benefits of a more sensitive sensor.  Technically he is correct, but in practice, the sensor acts as if it was in fact more sensitive, even though it's other components in the camera that are changed.

There are other considerations too.  I used to use image preview (chimping).  That wouldn't work too well if many of the images are so dark I can't tell much, even though Lightroom would be able to correct them.  And there's software like Photo Mechanic, which won't work as intended if the images are too dark to select which are better.

Reminds me of taking a shortcut when going somewhere, which is many fewer miles, but if the 'fewer miles" happen to go up and down a mountain, or if they're an unpaved dirt road, they're not going to get me someplace faster.

 

Back to the M10.  After all this discussion, I'm likely to use M(anual) mode when I have time, and if I'm pressed for time, to switch to auto-ISO.  I want to try using "exposure compensation", turning it on and off, with the aperture and shutter already set, and find out for sure what happens if I enable -0.7 for exposure.  I hope it changes the ISO speed, not the shutter.  Will find out for sure.

[MikeMyers]

This is a much easier to read page explaining ISO, etc.  Most of this page seems in agreement with the other websites listed above on this topic.  But here they say it's better to bump the ISO on your camera, rather than doing so later in Lightroom.

https://photographylife.com/what-is-iso-in-photography 

[mujk]

4 hours ago, MikeMyers said:

This is a much easier to read page explaining ISO, etc.  Most of this page seems in agreement with the other websites listed above on this topic.  But here they say it's better to bump the ISO on your camera, rather than doing so later in Lightroom.

https://photographylife.com/what-is-iso-in-photography 

There is something (popularly) called ISO invariance. If a camera is highly invariant, noise will not increase more when underexposing on purpose and then increasing exposure in post-processing than when bumping up ISO in camera. There seem to be slightly differing opinions on how ISO invariant the M10 is.

Personally, I don't rely on post-processing only, so I increase ISO in camera and often even use auto-ISO. But I'm quite comfortable with underexposing somewhat on purpose, particularly to avoid blowing highlights, knowing that I can successfully lift the shadows in post.

[jaapv]

Yes, you can do so and it works quite well - most of the time. But in high contrast situations you should be aware that you lose dynamic range by the amount that you underexpose. That is when the histogram and clipping warning in Live View or EVF come in handy.

[MikeMyers]

3 hours ago, jaapv said:

Yes, you can do so and it works quite well - most of the time. But in high contrast situations you should be aware that you lose dynamic range by the amount that you underexpose. That is when the histogram and clipping warning in Live View or EVF comes in handy.

'Jaapv', would it be correct to change your words slightly, but I think with the same meaning - if the histogram of the image you have captured does not show any "clipping" on the left edge of the histogram, you have not lost any of the dark tones?  (If I'm over-simplifying, please correct me.)

I didn't use histograms very much in the past, but with all this new information that has been discussed here, I expect that to change.  Also, this implies it is a bad idea to underexpose images, thinking that they can be corrected in post processing.  From what you just reminded us of, data that is lost during/from clipping, that data is gone forever.

I guess this thread, about exposure compensation, should tell us to check the histogram, to see if exposure compensation is needed or not, and to warn us that we might be losing data if we're not careful.  (....and for me, that implies I should start using the "Live View" function more often.

[jaapv]

No, your highlighted  is not necessarily  the case. A sensor is the opposite of negative film. Whereas film can block the shadows (i.e. no halide crystals have been activated, so less light will not make a difference), a sensor will reach a limit of photons it can absorb. So the left hand side is a "soft" limit, i.e. the photon-induced signal drowns in random noise, and the right-hand side a "hard" limit, i.e. details will be recorded up to 100% of saturation and not one photon more.

The result is that it is of advantage to expose as far to the right as highlight clipping will allow. In fact, specular highlights, which will be without detail anyway, may be clipped. My system (using an EVF camera) is to watch for a spike on the right-hand side, avoiding a gap, at the same time ensuring that the "bulge" in the middle is as full as possible.  I more or less ignore the left-hand side, unless I have a narrow (i.e.low-contrast) histogram that benefits from leaving a gap at both left- and right-hand side; then you can shift to the left to record a few highlight blips. My EV settings turn out to to vary between -3 and +2 in practice.

Note that the histogram is generated from the JPG, which means that it leaves you a bit of leeway.

BTW, changing ISO does indeed only change the gain in the camera electronics in general, but that is not always the case, as digital algorithms are involved. This will show up as a discontinuity in the DR curve in PhotonsToPhotos. Secondly, there a various ways of changing brightness in postprocessing, for instance, there are the exposure, brightness and contrast sliders, but using a layer mask in "screen" blending mode  gives a different (and usually better) result.

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Hallo,

Look here: Leica M

[willeica]

A digital M has fairly centre-weighted metering. You can hold the results of any particular auto metering by a half press on the shutter and then recompose the scene. Alternatively you can set the metering you want manually. A scene like the one above with a lot of sky and water will give all kinds of results depending on where you take your meter reading. It helps to use a set ISO rather than auto-iso. Exposure compensation only helps where you are sure of your meter reading and want a bit less or a bit more. All of the exposure variables can be altered in post processing. There is no point in having a sophisticated digital camera and not being able to do this. Also there is no point in purchasing an M10 just to use auto everything unless you fully understand how to work around the auto system, in which case you are better learning how to work in manual mode. Defeating the auto system is actually harder than working in manual.

William

[Jeff S]

48 minutes ago, jaapv said:

Secondly, there a various ways of changing brightness in postprocessing, for instance, there are the exposure, brightness and contrast sliders, but using a layer mask in "screen" blending mode  gives a different (and usually better) result.

Or by adjusting the tone curve, which can be more effective than individual sliders. It’s a powerful tool, one that often seems ignored, especially now that I see some who complain about flat out-of-camera files with high MP cameras, and don’t recognize the contrast characteristics of film vs digital (or the effects of larger dynamic range).

Jeff

Edited March 7, 2020 by Jeff S