Irrational views on SLT part duex

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Shield3
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Irrational views on SLT part duex
8 months ago

This is for Nord/Troj:

You are both saying a "properly exposed" shot at ISO 6400 will look the same as one properly exposed at ISO 100.

I disagree, due to the increased noise, lowered dynamic range, banding, etc introduced at higher ISO's.

I just took 2 shots handheld. These are heavy, heavy crops. In both shots the camera was set to Auto ISO and I adjusted the shutter speed until shot 1 hit 6400. Shot 2 was at ISO 100. Both are at F/8. Neither shot was focused very well so please ignore that.

Shot 1: 1/8000, ISO 6400, F/8. Camera metering was dead center for exposure.

Shot 2: 1/100, ISO 100, F/8. Camera metering was dead center for exposure.

Does anyone think these shots look identical?

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Shield3
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Re: Irrational views on SLT part duex
In reply to Shield3, 8 months ago

EinsteinsGhost wrote: "A difference of four stops that you arrived at is huge, and extremely unlikely."

How do you then explain the ISO 6400 with the shot and histogram I posted?  Are you willing to concede it was probably at least 3 stops worse than your NBA game lighting?

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MediaArchivist
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Better test
In reply to Shield3, 8 months ago

Take the ISO 6400 shot first, note the metering values (f/stop and shutter speed). Now do another shot at ISO 100, with the same speed and f/stop (this shot will be very dark).

Now, pump the exposure of the second shot up in your favorite PP software. The two resulting images should be very close if you are using an "ISO-less" sensor.

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EinsteinsGhost
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Re: Irrational views on SLT part duex
In reply to Shield3, 8 months ago

EinsteinsGhost wrote: "A difference of four stops that you arrived at is huge, and extremely unlikely."

How do you then explain the ISO 6400 with the shot and histogram I posted?  Are you willing to concede it was probably at least 3 stops worse than your NBA game lighting?

I cannot assume the difference is three stops in the lighting. It could be that some of it is at least due to how your camera meters a particular scene and how it applies ISO selection. We have seen this argument with how Olympus is promoting high ISO capabilities in its newer cameras.

The other part is your reluctance to using anything but high shutter speed even though the situation does not warrant it. You are doing so at the expense of DR which is central to your argument. Why not use a lower ISO for better DR if that is a key factor?

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Re: Better test
In reply to MediaArchivist, 8 months ago

MediaArchivist wrote:

Take the ISO 6400 shot first, note the metering values (f/stop and shutter speed). Now do another shot at ISO 100, with the same speed and f/stop (this shot will be very dark).

Now, pump the exposure of the second shot up in your favorite PP software. The two resulting images should be very close if you are using an "ISO-less" sensor.

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But if I have to "pump up the exposure" then it wasn't a properly exposed shot.  I'm comparing 2 shots done with the same camera, same focal length, same F/stop, one right after the other.  Only alternating shutter speeds, and both shots have plenty of shutter to freeze action especially at such a short focal length and F/8.

The camera's metering was pegged in the middle for both shots - i.e. "properly" exposed.  Why does the ISO 6400 shot look so much worse if Troj/Nord are correct?

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Re: Irrational views on SLT part duex
In reply to EinsteinsGhost, 8 months ago

EinsteinsGhost wrote:

EinsteinsGhost wrote: "A difference of four stops that you arrived at is huge, and extremely unlikely."

How do you then explain the ISO 6400 with the shot and histogram I posted? Are you willing to concede it was probably at least 3 stops worse than your NBA game lighting?

I cannot assume the difference is three stops in the lighting. It could be that some of it is at least due to how your camera meters a particular scene and how it applies ISO selection. We have seen this argument with how Olympus is promoting high ISO capabilities in its newer cameras.

The other part is your reluctance to using anything but high shutter speed even though the situation does not warrant it. You are doing so at the expense of DR which is central to your argument. Why not use a lower ISO for better DR if that is a key factor?

I like the ball being frozen. Why does that mean the situation doesn't warrant it?  How else are you going to freeze it? The lighting is just pretty bad in there - a buddy of mine shoots indoor soccer with a 6d and has trouble as well.

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EinsteinsGhost
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Re: Irrational views on SLT part duex
In reply to Shield3, 8 months ago

EinsteinsGhost wrote:

EinsteinsGhost wrote: "A difference of four stops that you arrived at is huge, and extremely unlikely."

How do you then explain the ISO 6400 with the shot and histogram I posted? Are you willing to concede it was probably at least 3 stops worse than your NBA game lighting?

I cannot assume the difference is three stops in the lighting. It could be that some of it is at least due to how your camera meters a particular scene and how it applies ISO selection. We have seen this argument with how Olympus is promoting high ISO capabilities in its newer cameras.

The other part is your reluctance to using anything but high shutter speed even though the situation does not warrant it. You are doing so at the expense of DR which is central to your argument. Why not use a lower ISO for better DR if that is a key factor?

I like the ball being frozen. Why does that mean the situation doesn't warrant it?  How else are you going to freeze it? The lighting is just pretty bad in there - a buddy of mine shoots indoor soccer with a 6d and has trouble as well.

The most challenging condition for action that I have encountered is at an indoor rodeo show. I failed to get tickets last night to a big one but may go for one over the weekend or next. I may have to look around for a Canon shooter to see how the camera meters to either of mine (a55 or NEX-6 w/SLT). The arena is quite limited in light. My only experience so far (and couple of years ago) suggests 1600, f/2.8, 1/250s in decently lit sections (lighting can be uneven and usually darker). With this motion blur is often guaranteed.

Basketball movement is far slower IMO and more often than not, the ball may not be the focal point and will drop a shade outside the DOF (blur vs motion blur). The player movement is usually much greater key.

With night baseball, I have used 1/1250s to almost freeze a fast ball but not quite (ISO 1600, f/2.8 in that case). Will try 1/2000s next time.

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Nordstjernen
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Re: Irrational views on SLT part duex
In reply to Shield3, 8 months ago

Shield3 wrote:

This is for Nord/Troj:

You are both saying a "properly exposed" shot at ISO 6400 will look the same as one properly exposed at ISO 100.

Shot 1: 1/8000, ISO 6400, F/8. Camera metering was dead center for exposure.

Shot 2: 1/100, ISO 100, F/8. Camera metering was dead center for exposure.

Does anyone think these shots look identical?

You did not get the point at all!

What I say is that using the same exposure (that is: the same amount of light hitting the sensor) the end result will be almost identical!

1/8000 sec and 1/100 sec at f:8 is NOT the same exposure!

If you use 1/8000 sec and the same aperture setting for both pictures, you will get the same result after processing the raw files. Sure, the very dark ISO 100 shot must be brightened very much at post processing. Still, both pictures will show the same amount of shadow detail and noise.

This is what fixed sensor sensitivity and ISO free raw files is about.

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Re: Better test
In reply to Shield3, 8 months ago

Shield3 wrote:

But if I have to "pump up the exposure" then it wasn't a properly exposed shot.

None of us (Nord/Troj) have said that the low ISO exposure should look good straight from the camera.

I'm comparing 2 shots done with the same camera, same focal length, same F/stop, one right after the other. Only alternating shutter speeds, and both shots have plenty of shutter to freeze action especially at such a short focal length and F/8.

We are talking about identical amount of light hitting the sensor! Then you need to use the same exposure settings (shutter speed/aperture). ISO does not have anything to do with exposure - adjusting the ISO value doesn't alter the amount of light falling on the sensor.

The camera's metering was pegged in the middle for both shots - i.e. "properly" exposed. Why does the ISO 6400 shot look so much worse if Troj/Nord are correct?

Because you are doing someting entirely different from what we are talking about! You are using different exposure for the two frames!

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Shield3
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Re: Irrational views on SLT part duex
In reply to Nordstjernen, 8 months ago

Nordstjernen wrote:

Shield3 wrote:

This is for Nord/Troj:

You are both saying a "properly exposed" shot at ISO 6400 will look the same as one properly exposed at ISO 100.

Shot 1: 1/8000, ISO 6400, F/8. Camera metering was dead center for exposure.

Shot 2: 1/100, ISO 100, F/8. Camera metering was dead center for exposure.

Does anyone think these shots look identical?

You did not get the point at all!

What I say is that using the same exposure (that is: the same amount of light hitting the sensor) the end result will be almost identical!

1/8000 sec and 1/100 sec at f:8 is NOT the same exposure!

If you use 1/8000 sec and the same aperture setting for both pictures, you will get the same result after processing the raw files. Sure, the very dark ISO 100 shot must be brightened very much at post processing. Still, both pictures will show the same amount of shadow detail and noise.

This is what fixed sensor sensitivity and ISO free raw files is about.

I thought you said "if both shots were exposed properly". Not "same amount of light hitting the sensor". Big difference.

Went back and read it. You said "If you first shoot a well exposed frame at ISO 6400 and then shoot at ISO 100 with exactly the same exposure settings, the processed pictures will look almost identical - same amount of shadow detail and same amount of noise!"

In my above shots the exact or very near the same amount of light was hitting the sensor.  The exposure time was shorter in one than the other, but all other things were equal.  If the sensor was truly "ISO-less" then my above shots, metered the same from the camera, would be near identical.  They're not even close.  Sorry but ISO matters.  Besides, if an ISO 6400 shot was truly "properly exposed" then it stands to reason the ISO 100 shot would be enormously blown out.

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TrojMacReady
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I wish you would read first.
In reply to Shield3, 8 months ago

Shield3 wrote:

This is for Nord/Troj:

You are both saying a "properly exposed" shot at ISO 6400 will look the same as one properly exposed at ISO 100.

You omitted the important part in Nord's statement, one that I even repeated and highlighted: using the samy physical exposure (and obviously same light).

And neither of us claimed it would be exactly the same, noise will be similar, but the low ISO shot will have far more highlight headroom, which (depending on scene and DR of the scene), may or may not be a visible benefit.

I disagree, due to the increased noise, lowered dynamic range, banding, etc introduced at higher ISO's.

I just took 2 shots handheld. These are heavy, heavy crops. In both shots the camera was set to Auto ISO and I adjusted the shutter speed until shot 1 hit 6400. Shot 2 was at ISO 100. Both are at F/8. Neither shot was focused very well so please ignore that.

Shot 1: 1/8000, ISO 6400, F/8. Camera metering was dead center for exposure.

Shot 2: 1/100, ISO 100, F/8. Camera metering was dead center for exposure.

Does anyone think these shots look identical?

I'll repeat my last post, since for unknown reasons, you failed to read it.

My first first post on the matter, which is basically quoting Nord:

He wrote:

"If you first shoot a well exposed frame at ISO 6400 and then shoot at ISO 100 with exactly the same exposure settings,"

That answers that.

Then my second post after you ignored the important bit the first time

Not sure if serious or just trolling, but how does comparing differnt light scenes and thus different exposure settings (see his comment about that) make any sense here?

Note that we're talking about exposure settings, not metering settings.

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Shield3
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Re: I wish you would read first.
In reply to TrojMacReady, 8 months ago

If it were truly "ISO-less" then the results shouldn't change based on exposure time. It's not. That's why on all cameras you see the dynamic range and shadow noise go to pot at high ISO's.

You'll never get me to think otherwise. I do appreciate you continuing to say "not sure if you're trolling" to somehow add credibility to your claim though. Bonus points.

A properly exposed ISO6400 shot then shot at ISO 100 would certainly mean the 100 shot is going to get blown out.

But, again, if they were truly ISO-less one should be able to do what I've done in this thread and the shots be very similar.  Why aren't they?

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William Curtindale
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Re: Irrational views on SLT part duex
In reply to Shield3, 8 months ago

Wow, I am really enjoying this thread.  LOL

We all have things to learn and this is good.

Thanks

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Re: I wish you would read first.
In reply to Shield3, 8 months ago

You seem to be stuck on the term ISO.  ISO really doesn't exist on digital cameras but was carried over as a way for film photographers to have a better understanding of what the sensor is really doing, and that is adding gain.

When you think about what the sensor is really doing and ignore the poor ISO term,  Nord's and Troj's explanation makes perfect sense.  But you are trying to apply a film mentality to a digital world.  The words may have been transposed from tech to the other, but the way it actually works is different.  This is where you seem to be failing to understand.

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Paul

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Shield3
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Re: I wish you would read first.
In reply to VirtualMirage, 8 months ago

If cameras were truly "ISO-less" then the inverse would be true - a "properly exposed" ISO 100 shot could be re-shot after setting the camera to ISO 6400 (with nothing else changing) and the images could be recovered to look identical in post.

If anyone truly believes that, I have nothing else to say in this thread.

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Shield3
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Re: I wish you would read first.
In reply to VirtualMirage, 8 months ago

VirtualMirage wrote:

You seem to be stuck on the term ISO. ISO really doesn't exist on digital cameras but was carried over as a way for film photographers to have a better understanding of what the sensor is really doing, and that is adding gain.

When you think about what the sensor is really doing and ignore the poor ISO term, Nord's and Troj's explanation makes perfect sense. But you are trying to apply a film mentality to a digital world. The words may have been transposed from tech to the other, but the way it actually works is different. This is where you seem to be failing to understand.

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Paul

So replace "ISO" with GAIN.  Same difference.

Is an amplifier's total harmonic distortion higher or lower as the amp's gain is turned up all the way?

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William Curtindale
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Had To Join This Great Discussion (my samples)
In reply to Shield3, 8 months ago

I had not tried this in the past (have read post on this but am amazed). Never too old to learn and this is really interesting. I did this the lazy way (sitting in my easy chair - just about laying down).

Both shots were RAW and taken at 1/50sec. and f/2.8. My first shot was at ISO 6400 and the second shot (dark original) was at ISO 100. Post processed in PS CS6.

Original RAW file saved to jpg (unaltered except for minor cropping):

ISO 6400 (1)

ISO 100 (2)

Compare RAW files with adjustments:

ISO 6400 (no exposure adjustment in ACR) (1a)

ISO 100 (exposure taken to the top in ACR) (2a)

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Ta da!
In reply to William Curtindale, 8 months ago

Pretty much exactly what I would expect.

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William Curtindale
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MediaArchivist / Nordstjernen : Ta da!
In reply to MediaArchivist, 8 months ago

MediaArchivist wrote:

Pretty much exactly what I would expect.

It's always is good to learn from others.

I have to admit I was surprised.

Thanks

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Re:your samples
In reply to William Curtindale, 8 months ago

This is amazing. I suspect this is gonna help me a lot in finding better solutions for my low-light shooting.

Thanks Bill, and Nord & Troj

Bart

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