Manual iso

[4dampadac]

Is there any reason why others use manual iso in manual mode instead of auto ?

 

[FingerPainter]

Just to modern hi tech photographers maybe. To a lot of us old guys, for 40 years or so I and any of my friends would have called a photo that was too dark underexposed and a photo that was too light overexposed and some of us still do. Things used to be so much simpler.

It would be correct, relative to the ISO used. ISO specifies the correct exposure, and too dark is under exposure at that ISO.

That may be how it was with film, but that's a sub-optimal way of treating digital. With roll film your ISO was a constant, until you changed the roll. It was set before yo stated taking pictures. With digital, there is no need to have ISO dictate exposure, setting ISO first just opens up the possibility of unnecessary noise.

With digital the best exposure is the one that maximizes light capture while controlling lens sharpness, DoF and motion blur to match artistic intent, and avoids blowing desired highlight detail. in an invariant camera, Unless you set ISO manually first, ISO merely controls SOOC lightness, something which is easier to adjust than DoF, blur or noise after the shot has been taken. IF you do se ISO manually first, to anythign above base, you risk needless noise. For a non-invariant camera after you hav maximized exposuem, you want to maximize ISO just to the point before blowign desired highlight detail.

 

[Barry Twycross]

Just to modern hi tech photographers maybe. To a lot of us old guys, for 40 years or so I and any of my friends would have called a photo that was too dark underexposed and a photo that was too light overexposed and some of us still do. Things used to be so much simpler.

It would be correct, relative to the ISO used. ISO specifies the correct exposure, and too dark is under exposure at that ISO.

That may be how it was with film, but that's a sub-optimal way of treating digital. With roll film your ISO was a constant, until you changed the roll. It was set before yo stated taking pictures. With digital, there is no need to have ISO dictate exposure, setting ISO first just opens up the possibility of unnecessary noise.

With digital the best exposure is the one that maximizes light capture while controlling lens sharpness, DoF and motion blur to match artistic intent, and avoids blowing desired highlight detail. in an invariant camera, Unless you set ISO manually first, ISO merely controls SOOC lightness, something which is easier to adjust than DoF, blur or noise after the shot has been taken. IF you do se ISO manually first, to anythign above base, you risk needless noise. For a non-invariant camera after you hav maximized exposuem, you want to maximize ISO just to the point before blowign desired highlight detail.

We're not talking about best exposure, we're talking about correct exposure. The ISO standard has a correct exposure for each ISO value.

Whether it's optimal or not is not addressed by the ISO standard.

 

[FingerPainter]

Just to modern hi tech photographers maybe. To a lot of us old guys, for 40 years or so I and any of my friends would have called a photo that was too dark underexposed and a photo that was too light overexposed

With roll film pretty well all overexposed photos were too light and pretty well all photos that were too light were overexposed. That's why it became common in the roll film era to use "overexposed" as a synonym for "too light" and "underexposed" as a synonym for "too dark". It may not have been technically correct to treat the terms as synonyms, but there was little practical difference.

It's not the same with digital. With digital it is quite easy to get an underexposed image that is too light. When ISO setting is no longer a constant, but one of the settings that can vary from one photo to the next, it is no longer so harmless to fail to distinguish between lightness and exposure.

and some of us still do.

Old habits die hard.

Things used to be so much simpler.

Indeed. Often all you could afford to worry about was getting a reasonably correct exposure for the roll of film you had loaded, where "correct" meant one that gave reasonable lightness under standard processing. As a result, aperture was often adjusted to obtain a particular exposure, as opposed to setting a DOF or optimizing lens sharpness. Shutter speed was used primarily as an exposure control, as opposed to a motion blur control. It was rare indeed that one could afford to consider both DoF and motion blur in the same shot. One worried less about DoF, lens sharpness, and motion blur. Noise wasn't even a concern. It was masked by grain and grain was set by the film emulsion used, not by the exposure.

If you want to, you can treat your digital camera as if it is just a film camera with an unlimited roll of adjustable ISO film, but that approach gives up some of the advantages of digital. Digital gives you better control over more of the visual aspects of your image.

I learned on roll fill too. With it, I was mostly concerned about framing and getting an exposure that was right for the ASA rating of the film. With digital, lightness is the least of my concerns, and my settings choices are based upon concerns about DoF, lens sharpness, motion blur and nosiness. Lightness is hardly ever a concern. If it is wrong OOC, I just adjust in software. It is much easier to correct than DoF, blur or noisiness.

As you say, it was simpler back then, because there were fewer aspects of the photo that you could effectively control, so there was less to think about. Now for the price of a bit more thought, one can more finely control one's end product.

 

[FingerPainter]

Just to modern hi tech photographers maybe. To a lot of us old guys, for 40 years or so I and any of my friends would have called a photo that was too dark underexposed and a photo that was too light overexposed and some of us still do. Things used to be so much simpler.

It would be correct, relative to the ISO used. ISO specifies the correct exposure, and too dark is under exposure at that ISO.

That may be how it was with film, but that's a sub-optimal way of treating digital. With roll film your ISO was a constant, until you changed the roll. It was set before yo stated taking pictures. With digital, there is no need to have ISO dictate exposure, setting ISO first just opens up the possibility of unnecessary noise.

With digital the best exposure is the one that maximizes light capture while controlling lens sharpness, DoF and motion blur to match artistic intent, and avoids blowing desired highlight detail. in an invariant camera, Unless you set ISO manually first, ISO merely controls SOOC lightness, something which is easier to adjust than DoF, blur or noise after the shot has been taken. IF you do se ISO manually first, to anythign above base, you risk needless noise. For a non-invariant camera after you hav maximized exposuem, you want to maximize ISO just to the point before blowign desired highlight detail.

We're not talking about best exposure, we're talking about correct exposure. The ISO standard has a correct exposure for each ISO value.

I don't think the standard addresses "correctness". For at least one of the multiple calibration methods available in the standard, it addresses JPEG values relative to shades in the scene. For at least one, it doesn't. It doesn't claim that a particular correspondence is "correct". And given the latitude the standard allows manufacturers, there can be many exposures that you would call "correct" for the same ISO setting.

Even with film there wasn't a 1:1 mapping between ISO and exposure when it came to final print lightness.

But whether there is something that could be considered a "correct' exposure is not really the point. The issue is whether that so-called correct exposure gives one the best photo. Quite often, it does not. Therefore it is counter-productive to cling to the old conception of correct exposure.

Whether it's optimal or not is not addressed by the ISO standard.

That's for sure.

 

[FingerPainter]

Is there any reason why others use manual iso in manual mode instead of auto ?

Sometimes I want to expose a picture in a different way than my camera's metering would default to,

You mean you want a lighter or darker outcome than the default metering would provide? Just adjust the EC setting.

so I pick all three exposure properties.

I know how you pick the aperture and shutter speed. How do you pick the scene luminance?

Not every photo is exposed the same way, and my camera can only guess.

Sure. You should tell it what you want. The most direct way to do that is to set the aperture for the DoF or lens sharpness you want, the shutter for the motion blur you want, and the EC for the lightness you want relative to a default metering solution. If this combination of settings blows desired highlight detail, increase the shutter speed, (or if you actually want motion blur, use an ND filter). Let ISO adjust itself for the EC-adjusted metering, because there is no point in wanting a particular ISO setting.

 

[David1961]

If the scene lighting isn't changing, the Auto ISO should set a constant ISO anyway.

Remember that the situation ericbowles offered was, "Think about a bird that flies across a landscape. Matrix and Center weighted metering consider the background. It starts out with tan grasses in the background, then has dark green trees as the background, and finally has a light blue sky with puffy white clouds." In that situation, auto ISO will change the ISO setting in keeping with the brightness of those varying backgrounds.

That is different to what you said about constant lighting.

Even with constant lighting, if the part of the scene you are metering changes then of course the ISO will vary according to the lighting the meter sees in that part of the scene.

And that is exactly what I want to happen when I use manual with Auto ISO.

 

[BrentSchumer]

Is there any reason why others use manual iso in manual mode instead of auto ?

Sometimes I want to expose a picture in a different way than my camera's metering would default to,

You mean you want a lighter or darker outcome than the default metering would provide? Just adjust the EC setting.

so I pick all three exposure properties.

I know how you pick the aperture and shutter speed. How do you pick the scene luminance?

Not every photo is exposed the same way, and my camera can only guess.

Sure. You should tell it what you want. The most direct way to do that is to set the aperture for the DoF or lens sharpness you want, the shutter for the motion blur you want, and the EC for the lightness you want relative to a default metering solution. If this combination of settings blows desired highlight detail, increase the shutter speed, (or if you actually want motion blur, use an ND filter). Let ISO adjust itself for the EC-adjusted metering, because there is no point in wanting a particular ISO setting.

Why would I bother with EC instead of just setting ISO exactly? I get that it allows the cameras to "guess" first, and sometimes that's valuable. Otherwise I like setting my ISO exactly.

 

[Bill Ferris]

Is there any reason why others use manual iso in manual mode instead of auto ?

I manually select ISO because I make better choices than the camera.

 

[David1961]

Why would I bother with EC instead of just setting ISO exactly? I get that it allows the cameras to "guess" first, and sometimes that's valuable. Otherwise I like setting my ISO exactly.

Whether you use EC to adjust ISO or adjust ISO manually is essentially a personal choice.

The important thing in terms of maximising exposure to minimise visible noise is that ISO should be the last thing to set after setting your widest aperture to give the required DOF and the slowest shutter speed that meets your motion blur requirements without clipping highlights.

Personally I prefer to use EC to adjust ISO.

If I see I have, for example, 1 stop of highlight headroom on my histogram it is quicker and easier for me to use EC to add 1 stop of lightness than to check the current ISO setting, mentally add 1 stop and then adjust the ISO manually.

Whether I use EC or adjust ISO manually, the adjusted ISO setting will be the same.

 

[David1961]

• Bob A L wrote:

Just to modern hi tech photographers maybe. To a lot of us old guys, for 40 years or so I and any of my friends would have called a photo that was too dark underexposed and a photo that was too light overexposed and some of us still do. Things used to be so much simpler.

Before joining DPR forums I used to think like you until I had it drummed into me what exposure actually is and that ISO is not an exposure control.

Suddenly things became much clearer in terms of the roles aperture, shutter speed and ISO play.

Using incorrect terminology, although yes it is common, does not make it correct and should not be thrust upon newbies to photography.

I just wish that the "old guys" you refer to updated their knowledge on what exposure actually is in reality otherwise they leave themselves wide open to justifiably being corrected, at least for the sake of correctly educating newbies.

I posted the definition of exposure I accept and I see you are still unable to answer my question to you regarding what definition of exposure you accept.

Maybe you don't have one?

 

[Pocket Lint]

Is there any reason why others use manual iso in manual mode instead of auto ?

When your camera meter isn’t exposing the scene how you want it and you are blowing out details in highlights or losing details in shadows... n/t

 

[FingerPainter]

Is there any reason why others use manual iso in manual mode instead of auto ?

Sometimes I want to expose a picture in a different way than my camera's metering would default to,

You mean you want a lighter or darker outcome than the default metering would provide? Just adjust the EC setting.

so I pick all three exposure properties.

I know how you pick the aperture and shutter speed. How do you pick the scene luminance?

Not every photo is exposed the same way, and my camera can only guess.

Sure. You should tell it what you want. The most direct way to do that is to set the aperture for the DoF or lens sharpness you want, the shutter for the motion blur you want, and the EC for the lightness you want relative to a default metering solution. If this combination of settings blows desired highlight detail, increase the shutter speed, (or if you actually want motion blur, use an ND filter). Let ISO adjust itself for the EC-adjusted metering, because there is no point in wanting a particular ISO setting.

Why would I bother with EC instead of just setting ISO exactly? I get that it allows the cameras to "guess" first, and sometimes that's valuable. Otherwise I like setting my ISO exactly.

It seems to me to make sense set the control that actually controls what it is you want to control. You set the EC directly, to something other than 0, when you know that you want the image lightness to be different from what it would be with the default metering solution, and you set the EC to 0 when the default solution is what you want.

Why do you care what exact ISO you have? What reason do you have for wanting to control the ISO setting?

An exact ISO, unlike an exact f-number or an exact shutter speed or an exact EC setting, doesn't correspond directly to any visible aspect of a photo.

I'd have thought you'd care about how light or dark the image was, relative to the typical metering solution.

 

[FingerPainter]

Is there any reason why others use manual iso in manual mode instead of auto ?

I manually select ISO because I make better choices than the camera.

A lot of people believe this to be true of themselves. Based on what I've seen in these fora, only a few are correct. You may be one of the few.

 

[Bill Ferris]

So with your cameras you can just set the shutter speed and aperture to the settings you want, ignore ISO setting and everything will be fine (whether the iSO is set at 100 or 1000) and resulting images will all exhibit the same exposure and quality when viewed or printed? Maybe me and my wife need one of those cameras.

If your camera was manufactured in the last five years, you probably do. Which model camera do you have? There's probably a range of ISOs within which it is invariant. In other words, you can choose your exposure settings (shutter speed and f-stop) and use any ISO within that range to make the photo. As long as you shoot raw and don't choose an ISO that blows out the highlights, the image can be lightened or darkened in your photo editing app to make an image indistinguishable from one made using an ISO that would've produced the same lightness image in camera.

That's the beauty of a camera setting that manages post-exposure image processing. Whether you do the processing in camera or on a home computer, the final image looks the same.

--
Bill Ferris Photography
Flagstaff, AZ
http://www.billferris.photoshelter.com

 

[FingerPainter]

Is there any reason why others use manual iso in manual mode instead of auto ?

When your camera meter isn’t exposing the scene how you want it and you are blowing out details in highlights or losing details in shadows... n/t

That's what the EC control is for.

 

[jrtrent]

If the scene lighting isn't changing, the Auto ISO should set a constant ISO anyway.

Remember that the situation ericbowles offered was, "Think about a bird that flies across a landscape. Matrix and Center weighted metering consider the background. It starts out with tan grasses in the background, then has dark green trees as the background, and finally has a light blue sky with puffy white clouds." In that situation, auto ISO will change the ISO setting in keeping with the brightness of those varying backgrounds.

That is different to what you said about constant lighting.

I don't see how. In the ericbowles bird and background example, the light falling on the scene is constant. In the article I linked to from Sekonic, the light falling on the plates of fruit is constant. The idea is that I don't want auto-ISO to vary the setting just because the background varies in tonality from light to dark because that makes all the tonal values in the scene no longer correct.

Ericbowles offered another situation where the light is constant, "I meter for the face of a subject. I don't want clothing or background lighting to change my exposure - or force me into using exposure compensation to offset those changes. Just give me a fixed ISO if light is constant." I've run into the same situation taking pictures of speakers at conferences. All the speakers give their presentations from the same podium. The light never changes, but one speaker has dark skin and another has light skin; one wears a white suit while another wears navy blue. Differences in skin and clothing can make the meter choose a different ISO setting if I were using manual exposure with auto ISO, giving me inconsistent tonal values from shot to shot. My preference in such situations is to meter from a gray card or use an incident light meter, manually adjust shutter speed, aperture, and ISO to suit the lighting, then leave those settings alone and just shoot.

The Sekonic article I referenced explains why:

"A better alternative to reading the light in many scenes is to use an “incident” meter. Handheld incident meters read the intensity of light falling on the subject and are usually taken from the subject position. Because they are not affected by variances in subject color or reflectance, incident meters accurately record the amount of light falling on the subject. In the majority of situations, an incident reading is extremely accurate and records tones, colors, and values correctly."

 

[jrtrent]

• Bob A L wrote:

Just to modern hi tech photographers maybe. To a lot of us old guys, for 40 years or so I and any of my friends would have called a photo that was too dark underexposed and a photo that was too light overexposed and some of us still do. Things used to be so much simpler.

Before joining DPR forums I used to think like you until I had it drummed into me what exposure actually is and that ISO is not an exposure control.

Suddenly things became much clearer in terms of the roles aperture, shutter speed and ISO play.

Using incorrect terminology, although yes it is common, does not make it correct and should not be thrust upon newbies to photography.

I just wish that the "old guys" you refer to updated their knowledge on what exposure actually is in reality otherwise they leave themselves wide open to justifiably being corrected, at least for the sake of correctly educating newbies.

I posted the definition of exposure I accept and I see you are still unable to answer my question to you regarding what definition of exposure you accept.

Maybe you don't have one?

Maybe he didn't define exposure, but I like his definitions of underexposed and overexposed. Below is a way of thinking about exposure that I like. Perhaps you used to like something similar:

"A photograph's exposure determines how light or dark an image will appear when it's been captured by your camera. Believe it or not, this is determined by just three camera settings: aperture, ISO and shutter speed . . ." https://www.cambridgeincolour.com/tutorials/camera-exposure.htm

If my brother asks what exposure I gave that picture I sent him of a gnome our aunt sent decades ago, I can say the exposure was 1/15 second, f/1.8, and ISO 100.

 

[Pocket Lint]

Is there any reason why others use manual iso in manual mode instead of auto ?

When your camera meter isn’t exposing the scene how you want it and you are blowing out details in highlights or losing details in shadows... n/t

That's what the EC control is for.

Lol I don’t get why this thread has to be this complicated. No need to delve in to EC in this thread OP didn’t even mention it, probably deserves its own thread.

 

[BrentSchumer]

It seems to me to make sense set the control that actually controls what it is you want to control. You set the EC directly, to something other than 0, when you know that you want the image lightness to be different from what it would be with the default metering solution, and you set the EC to 0 when the default solution is what you want.

Why do you care what exact ISO you have? What reason do you have for wanting to control the ISO setting?

An exact ISO, unlike an exact f-number or an exact shutter speed or an exact EC setting, doesn't correspond directly to any visible aspect of a photo.

I'd have thought you'd care about how light or dark the image was, relative to the typical metering solution.

If I rely on auto-ISO, I have to carefully monitor the shutter speed when out-and-about. E.g. I have the shutter set at 1/150s to capture routine action and then stop and take a picture of a shady statue. If I'm on manual ISO it will be obvious that the image is under-exposed and I can dial back the shutter speed. If I'm on auto-ISO I might forget about my high shutter speed and shoot at a higher ISO, degrading image quality. That's an artificial example, but I find that it's more effort to "police" auto ISO than to quickly manually set the property with a flick of my wrist. a bright rock to a dark bush. In both situations the bird

Even in situations where my manual ISO is off I'm almost always under-exposing (fixable with ISO-invariant sensors) whereas the auto-ISO general over-exposes (tougher to correct). Especially with my compact camera I really want to minimize ISO to maximize quality, and controlling exposure trade-offs with a 1" sensor requires more finesse than the metering mode can handle.

 

[Bob A L]

But you miss the point - I don't shoot raw - have absolutely no need for it. As explained I have absolutely no intention to process any photo I take in my computer, My camera does that. I admit to messing up on occasion, and either have to throw something away or break down and fix it in the computer, but don't need raw to do that. And my exposure (lightness) does change if I take two photos under the same lighting using the same aperture and shutter speed but with different ISO settings unless I fix them in the computer later. As to cameras I use Nikon, Panasonic, Olympus, Sony, and Canon and they all work the same.