ISO performance on SL2-s vs SL2

[jaapv]

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11 hours ago, kobra said:

Also, on the other thread, there was talk of "middle grey" which I think is not used in stills photography?)

Actually it was codified for stills photography by Ansel Adams. It is zone V in the Zone System. 

[BernardC]

13 hours ago, kobra said:

Also, on the other thread, there was talk of "middle grey" which I think is not used in stills photography?

"Middle grey" is what reflective meters look for. This includes any meter viewing through your lens, or a hand-held spot/reflective meter.

In other words, a reflective meter looks at a scene and tells you the correct exposure so that it averages-out to middle grey. The scene could be fresh snow or black velvet, but the meter doesn't know that, so it assumes that it's looking at middle grey.

Most modern camera meters use multi-zone metering: logic is applied to help it "find the middle" in high-contrast scenes, but the principle is the same.

The other type of light meter is called "incident". Some hand-held meters can work in incident and reflective modes (and sometimes "spot" which is a type of reflective metering).

An incident meter is pointed at the light, not at the scene. These are popular on many film sets because they aren't influenced by the reflexivity of the subject. For instance, a white shirt and a black tux will read the same, because the meter is measuring the amount of light falling on the subject, not the subject itself.

Incident meters can also provide an additional bit of important information: the lighting ratio. To do this, you point the meter at the "key" light (the main light falling on the subject), get a reading, and then meter the fill light (you may need to block the key light to do this), and sometimes also the back-light. You then calculate the difference in f-stops between the readings. Lighting ratios tell you a lot about the mood of a shot (high-contrast, low-contrast), and therefore help with storytelling (you might want one scene to be flat/grey and another to be more contrasty/saturated).

 

Back to our topic: the technique of exposing digital at "base ISO," and then applying exposure compensation to "protect the highlights" means that you are taking a reflective meter reading at the camera's lowest EI, and then metering the highlights separately in order to calculate how far they are from middle grey (your reflective reading). For instance, if you know that your camera can hold details up-to 5 stops above middle grey, and the brightest part of your image is 6 stops above middle grey, you need to apply "-1 stop" of compensation. The rationale is that you will always maximize dynamic range because you are recording the brightest part of your image at the maximum level that your sensor can handle.

Film/video shooters (and many stills shooters) tend to use a different approach. They place middle-grey around the middle of the sensor's dynamic range (which means that their "base" EI is around 500-800 instead of 100). This has a few advantages: you can set several cameras to the same exposure, even if they don't all see the same highlights, and they will all match in editing. You can also set an exposure for a shot where the lighting and/or composition changes (camera move, someone opens a curtain or turn-on a light, etc.). The main advantage is that you won't have to correct every one of thousands of shots in a long-form project. That's a huge cost saving if you are paying a colourist thousands of dollars per day. Their job is to lift a film's visuals from "good" to "great," not to fiddle with the brightness knob for days on end.

 

In the end it really doesn't make much difference for still photography. Pick a technique based on your preferred worklflow and results.

Unsurprisingly, landscape photographers often use the "lowest feasible ISO" method. Their images can require the highest possible dynamic range, they spend a lot of time doing image correction anyway, and they print large enough that people will look closely at shadow detail. It doesn't hurt, of course, that this was Ansel Adam's preferred method. Note: other versions of the Zone System use reflective metering, so it's not the only landscape workflow.

Photographers who produce larger sets of images (event photographers, but also long-term art projects) will benefit from choosing a "base ISO" with more slack. You can work a lot faster that way, and your output will be more consistent from shot to shot.

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[kobra]

5 hours ago, jaapv said:

Actually it was codified for stills photography by Ansel Adams. It is zone V in the Zone System. 

Thanks @jaapv ! I've read a brief overview of Adams zone system but it's on my to do list to dig deeper into it. 

Brad

[kobra]

1 hour ago, BernardC said:

"Middle grey" is what reflective meters look for. This includes any meter viewing through your lens, or a hand-held spot/reflective meter.

In other words, a reflective meter looks at a scene and tells you the correct exposure so that it averages-out to middle grey. The scene could be fresh snow or black velvet, but the meter doesn't know that, so it assumes that it's looking at middle grey.

Most modern camera meters use multi-zone metering: logic is applied to help it "find the middle" in high-contrast scenes, but the principle is the same.

The other type of light meter is called "incident". Some hand-held meters can work in incident and reflective modes (and sometimes "spot" which is a type of reflective metering).

An incident meter is pointed at the light, not at the scene. These are popular on many film sets because they aren't influenced by the reflexivity of the subject. For instance, a white shirt and a black tux will read the same, because the meter is measuring the amount of light falling on the subject, not the subject itself.

Incident meters can also provide an additional bit of important information: the lighting ratio. To do this, you point the meter at the "key" light (the main light falling on the subject), get a reading, and then meter the fill light (you may need to block the key light to do this), and sometimes also the back-light. You then calculate the difference in f-stops between the readings. Lighting ratios tell you a lot about the mood of a shot (high-contrast, low-contrast), and therefore help with storytelling (you might want one scene to be flat/grey and another to be more contrasty/saturated).

 

Back to our topic: the technique of exposing digital at "base ISO," and then applying exposure compensation to "protect the highlights" means that you are taking a reflective meter reading at the camera's lowest EI, and then metering the highlights separately in order to calculate how far they are from middle grey (your reflective reading). For instance, if you know that your camera can hold details up-to 5 stops above middle grey, and the brightest part of your image is 6 stops above middle grey, you need to apply "-1 stop" of compensation. The rationale is that you will always maximize dynamic range because you are recording the brightest part of your image at the maximum level that your sensor can handle.

Film/video shooters (and many stills shooters) tend to use a different approach. They place middle-grey around the middle of the sensor's dynamic range (which means that their "base" EI is around 500-800 instead of 100). This has a few advantages: you can set several cameras to the same exposure, even if they don't all see the same highlights, and they will all match in editing. You can also set an exposure for a shot where the lighting and/or composition changes (camera move, someone opens a curtain or turn-on a light, etc.). The main advantage is that you won't have to correct every one of thousands of shots in a long-form project. That's a huge cost saving if you are paying a colourist thousands of dollars per day. Their job is to lift a film's visuals from "good" to "great," not to fiddle with the brightness knob for days on end.

 

In the end it really doesn't make much difference for still photography. Pick a technique based on your preferred worklflow and results.

Unsurprisingly, landscape photographers often use the "lowest feasible ISO" method. Their images can require the highest possible dynamic range, they spend a lot of time doing image correction anyway, and they print large enough that people will look closely at shadow detail. It doesn't hurt, of course, that this was Ansel Adam's preferred method. Note: other versions of the Zone System use reflective metering, so it's not the only landscape workflow.

Photographers who produce larger sets of images (event photographers, but also long-term art projects) will benefit from choosing a "base ISO" with more slack. You can work a lot faster that way, and your output will be more consistent from shot to shot.

@BernardC - this is the best explanation I've seen on why a middle ISO is valuable - thank you!!! 

I'm not yet understanding how to apply it in my own shooting situations, but your comments are bookmarked so that I can review and experiment to make practical application. 

And, now @hansvons comments make a lot more sense to me. I knew I was missing something, but just could not quite get there on my own. Thanks to both of you for patiently helping me understand! 

Next up, the SL2-S was already delivered, I am in AZ and tonight is an ideal night to see the Milky Way; so I'm going to experiment with both cameras tonight to see how their differences will apply in night sky photography. 

Again, many thanks,

Brad

[SrMi]

Just now, kobra said:

Thanks @jaapv ! I've read a brief overview of Adams zone system but it's on my to do list to dig deeper into it. 

Brad

I believe the zone system belongs to the fundamental knowledge of every photographer who takes his hobby or profession seriously. However,  I believe there are better and simpler ways to determine exposure with digital cameras.

Instead of the zone system, I suggest using the histogram combined with your experience with the camera's metering and exposure so that you do not clip relevant highlights. If time permits, use exposures as large as possible. Avoiding clipping relevant highlights is the most important part of proper exposure (aka getting a usable image). 

I believe the best way is to pick a technique and get lots of experience. The best way to evaluate the quality of your exposure is to use a tool like RawDigger, where you can see whether you have clipped the highlights and how far you are from maximal usable exposure.

Even more important is not to be afraid of getting suboptimal exposure. Photography should be fun. Some people, like me, think getting the most out of their equipment is fun .

 

[kobra]

5 hours ago, SrMi said:

I believe the zone system belongs to the fundamental knowledge of every photographer who takes his hobby or profession seriously. However,  I believe there are better and simpler ways to determine exposure with digital cameras.

Instead of the zone system, I suggest using the histogram combined with your experience with the camera's metering and exposure so that you do not clip relevant highlights. If time permits, use exposures as large as possible. Avoiding clipping relevant highlights is the most important part of proper exposure (aka getting a usable image). 

I believe the best way is to pick a technique and get lots of experience. The best way to evaluate the quality of your exposure is to use a tool like RawDigger, where you can see whether you have clipped the highlights and how far you are from maximal usable exposure.

Even more important is not to be afraid of getting suboptimal exposure. Photography should be fun. Some people, like me, think getting the most out of their equipment is fun .

 

Thanks @SrMi - good advice. 

I have long been using the histogram and the highlight blinkies in several of my camera systems. I do understand they are not perfect, as they are based on an in camera jpg and I am shooting RAW to get more DR in post. I am still learning the SL2, so feel like this is a good time to push things a bit to see what results I get. And, I am a fan of RawDigger although I will not pretend to be expert. I have found that helpful, but I think if I get more intentional while making specific changes that the data could become more meaningful. 

Your advice is "pushing" me to "push" it more   thanks again! 

Brad

[Chaemono]

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Am 6.4.2023 um 19:34 schrieb SrMi:

How much more? At import, you could just batch NR all your images.

I am willing to spend hours on images that I care about, I have no qualms about spending less than a minute on AI NR.

LR Denoise AI now incorporated right into LR. Would be interesting to see how it performs with M11 ISO 1600 and above files.

[SrMi]

2 minutes ago, Chaemono said:

LR Denoise AI now incorporated right into LR. Would be interesting to see how it performs with M11 ISO 1600 and above files.

I am happy with the M11 results. I think it is on par with DxO, but Adobe is more convenient and has simpler settings. On my computer (Mac Studio), Adobe runs faster than DxO (2x). Others have reported that DxO runs faster than Adobe.