Why such High ISO?

[Patriot]

Why are companies pushing for such high ISO numbers? At what point would someone really use ISO 25,600? It seem so pointless to go so high as IQ will drop because of it. Is it just bragging rights at who can produce the better sensor? It seems the same as shutter speed, I can't think of when someone would use a shutter speed of 1/8000th. If you taking pictures at night why not just use a tripod and slow the shutter to let in more light? Heck you could use ISO 100 if you leave the shutter open long enough right?

In my opinion they should focus that R&D funds to developing better optics(which can always get better) or focusing better in low light. How about making a hybrid split screen for better manual focusing and fast auto focusing. Those things are really good at manual focusing. I'm sure it could be done if they stop worrying about such ISO numbers and focus that energy else where.


I'm not saying that it's useless because I'm sure some people use it. Can someone explain this to me because I can't think of a good reason so far? Or could some show me a picture at which they had to push the ISO that high?

-Hunt

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[Judobreaker]

I'm guessing that with higher ISO capabilities the lower ISO numbers also improve, so the number might actually tell you something about general ISO performance.
I'm not sure, but it's what I'd guess.

[bratkinson]

Why such high ISO? Low light, plain and simple.

This past Sunday evening at an event at church, I wanted to keep my aperture in the 5.6-8 range for depth of field considerations, and shutter speeds faster than 125 due to shooting people with my 24-105 f4L and 16-35 f2.8L lenses, no flash. To get proper exposure out of that, it was ISO 5000 on my 5D3. But, when shooting wide open with the 135 f2L (for razor thin DOF), I simply lowered the ISO to 1600 and kept the shutter speed the same.

Bottom line, without the higher ISO, I would have been forced to shoot at shutter speeds 1/30-1/60 range, maybe lower, and 80-90% of the shots would be blurred due to subject and my movement.

[SCraig]

... Heck you could use ISO 100 if you leave the shutter open long enough right?

Yes, but noise would increase. Longer exposures mean electrical current flowing through the sensor for a longer period of time which means more heat is generated within the sensor, and that is one source of noise. Additionally, if you use High ISO Noise Reduction that amount of time is doubled since the camera records an image at the same exposure time but with the shutter closed as a noise reference image.

[480sparky]

I, for one, would love to see single-digit ISOs in a DSLR.

[Patriot]

I, for one, would love to see single-digit ISOs in a DSLR.

Could that even be possible? You could point that at the Sun and still be exposed right(probably). Sensor tech would have to come a long for that to happen right? I don't even know the lowest ISO right now. Is it 25 right?

[snowbear]

Marketing - ISO is the new megapixel!

[Garbz]

Yes, but noise would increase. Longer exposures mean ...

The trade off in sensitivity vs shutter speed ALWAYS favours shutterspeed. If you CAN shoot 10 seconds at ISO100 then do. You're taking a worse picture for 5seconds at ISO200, or 2.5 at ISO400 etc.

Why are companies pushing for such high ISO numbers?

Quality. Quantum efficiency is absolute key. It is the secret to high bit depth and great signal to noise ratio at any ISO. The better the numbers the better the image quality. The SIDE-EFFECT of my camera being able to pull incredible detail out of the shadows at ISO100 is that I get a usable picture at ISO25600. The better the efficiency and SNR of the sensor, the better the quality, and ultimately the higher the ISO will go before the picture becomes unacceptably poor.

At what point would someone really use ISO 25,600?

All the time for some people. I take it you don't shoot much indoors, or don't try and take photos of people in dim light without the flexibility to use a flash or the ability to use a tripod? This is something wedding photographers in churches have for a long time found really limiting.

It seem so pointless to go so high as IQ will drop because of it.

The image quality at ISO25600 is no worse on todays cameras than the image quality of ISO1600 of cameras 5 years ago. This also brings up the question of would you rather have a noisy picture or no picture at all?

It seems the same as shutter speed, I can't think of when someone would use a shutter speed of 1/8000th.

There is a whole field where 1/8000th of a second isn't fast enough. High speed photography. Actually this is a field where people find the minimum flash duration of 1/100000th second limiting too. And while we're talking about this to keep flash duration really short you need to shoot only small amounts of light which becomes much more useful if you have a camera capable of a high ISO

If you taking pictures at night why not just use a tripod and slow the shutter to let in more light? Heck you could use ISO 100 if you leave the shutter open long enough right?

If you have the ability you'd be mad not to. However the world won't stand still for 10 seconds. Sometimes it's appropriate to go for quality and motionblur can be damned, sometimes you're trying to catch some action and a long shutter speed / tripod isn't an option.

In my opinion they should focus that R&D funds to developing better optics(which can always get better) or focusing better in low light. How about making a hybrid split screen for better manual focusing and fast auto focusing. Those things are really good at manual focusing. I'm sure it could be done if they stop worrying about such ISO numbers and focus that energy else where.

Optics are very limited by the laws of physics. There's very little in the way of better optics these days. The only R&D that could be spent is making quality optics cheaper or making cheaper VR units. Nothing has changed in optics since the invention of aspherical elements some 40 years ago. As for better focusing, focusing is achieved through better sensitivity of the sensor at the bottom of the camera that does phase detection. This is directly linked to the research in higher ISOs for cameras. Autofocus already works better than human eyesight and split prisms so this is a dead end, actually using liveview with higher sensitivity to manually focus in really dark environments would be an idea in my opinion. Actually the only thing I really think has been a waste of time so far is the research in video on DSLRs.

I'm not saying that it's useless because I'm sure some people use it. Can someone explain this to me because I can't think of a good reason so far? Or could some show me a picture at which they had to push the ISO that high?

The following was taken on a D800 for 20seconds at ISO Hi+0.7 (Effectively ISO10000). 20 seconds was the maximum shutterspeed that didn't introduce startrails. ISO10000 was the lowest ISO that gave the required brightness. I have heaps of wedding photos from inside churches shot handheld at some stupid ISOs because there was no other option, but none online. I can post some if you want some example shots.

[Patriot]

Yes, but noise would increase. Longer exposures mean ...

The trade off in sensitivity vs shutter speed ALWAYS favours shutterspeed. If you CAN shoot 10 seconds at ISO100 then do. You're taking a worse picture for 5seconds at ISO200, or 2.5 at ISO400 etc.

Why are companies pushing for such high ISO numbers?

Quality. Quantum efficiency is absolute key. It is the secret to high bit depth and great signal to noise ratio at any ISO. The better the numbers the better the image quality. The SIDE-EFFECT of my camera being able to pull incredible detail out of the shadows at ISO100 is that I get a usable picture at ISO25600. The better the efficiency and SNR of the sensor, the better the quality, and ultimately the higher the ISO will go before the picture becomes unacceptably poor.



All the time for some people. I take it you don't shoot much indoors, or don't try and take photos of people in dim light without the flexibility to use a flash or the ability to use a tripod? This is something wedding photographers in churches have for a long time found really limiting.



The image quality at ISO25600 is no worse on todays cameras than the image quality of ISO1600 of cameras 5 years ago. This also brings up the question of would you rather have a noisy picture or no picture at all?



There is a whole field where 1/8000th of a second isn't fast enough. High speed photography. Actually this is a field where people find the minimum flash duration of 1/100000th second limiting too. And while we're talking about this to keep flash duration really short you need to shoot only small amounts of light which becomes much more useful if you have a camera capable of a high ISO



If you have the ability you'd be mad not to. However the world won't stand still for 10 seconds. Sometimes it's appropriate to go for quality and motionblur can be damned, sometimes you're trying to catch some action and a long shutter speed / tripod isn't an option.

In my opinion they should focus that R&D funds to developing better optics(which can always get better) or focusing better in low light. How about making a hybrid split screen for better manual focusing and fast auto focusing. Those things are really good at manual focusing. I'm sure it could be done if they stop worrying about such ISO numbers and focus that energy else where.

Optics are very limited by the laws of physics. There's very little in the way of better optics these days. The only R&D that could be spent is making quality optics cheaper or making cheaper VR units. Nothing has changed in optics since the invention of aspherical elements some 40 years ago. As for better focusing, focusing is achieved through better sensitivity of the sensor at the bottom of the camera that does phase detection. This is directly linked to the research in higher ISOs for cameras. Autofocus already works better than human eyesight and split prisms so this is a dead end, actually using liveview with higher sensitivity to manually focus in really dark environments would be an idea in my opinion. Actually the only thing I really think has been a waste of time so far is the research in video on DSLRs.

I'm not saying that it's useless because I'm sure some people use it. Can someone explain this to me because I can't think of a good reason so far? Or could some show me a picture at which they had to push the ISO that high?

The following was taken on a D800 for 20seconds at ISO Hi+0.7 (Effectively ISO10000). 20 seconds was the maximum shutterspeed that didn't introduce startrails. ISO10000 was the lowest ISO that gave the required brightness. I have heaps of wedding photos from inside churches shot handheld at some stupid ISOs because there was no other option, but none online. I can post some if you want some example shots.

You just destroyed me.

[SCraig]

Yes, but noise would increase. Longer exposures mean ...

The trade off in sensitivity vs shutter speed ALWAYS favours shutterspeed. If you CAN shoot 10 seconds at ISO100 then do. You're taking a worse picture for 5seconds at ISO200, or 2.5 at ISO400 etc.

Even with very long exposures? If there is a choice between, say, 30 minutes at ISO 6400 and 28 seconds at ISO 100 (radical example, I know) is the difference worth the extra exposure time? I would think that there would be a point at which ISO begins to take preference over shutter speed, but I don't really know where that point would be.

[MK3Brent]

Sometimes I shoot at 50,000 ISO.
Low light and action.

[KmH]

The numbers get bigger rather quickly.

Full stop steps of ISO:
ISO 100
ISO 200
ISO 400
ISO 800
ISO 1600
ISO 3200
ISO 6400
ISO 12,800
ISO 25,600
ISO 51,200
ISO 102,400
ISO 204,800

Recent advances in ISO are more about software than hardware.
DxOMark - ISO sensitivity
DxOMark - Pushed ISO: Let's make it clear

[480sparky]

......... I don't even know the lowest ISO right now. Is it 25 right?

0.8, AFAIK.

[Patriot]

... Heck you could use ISO 100 if you leave the shutter open long enough right?

Yes, but noise would increase. Longer exposures mean electrical current flowing through the sensor for a longer period of time which means more heat is generated within the sensor, and that is one source of noise. Additionally, if you use High ISO Noise Reduction that amount of time is doubled since the camera records an image at the same exposure time but with the shutter closed as a noise reference image.

That's understandable, but doesn't the sensor stay exposed for long periods while using the video feature? Does it matter if the ISO of LOW during the same period of time. I ask because I see a lot of star trail pictures that were taken over a matter of hours.

[BrianV]

Easy to answer the "why" of high-ISO. You need it to shoot in low-light with reasonable shutter-speed. No one asks why you need night-vision goggles.

As to the "how" the sensors do it, how ISO is measured, etc, Truesense Imaging is the old Kodak Sensor Division.

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They have always provided good technical references on digital imaging. They cater to the Scientific/Technical market and provide enough information for their detectors to be used in instrumentation.

ISO 2500, 50/1.4 Canon FL mount lens wide-open, 1/25th second shutter-speed. With one of the newer Truesense CCD's.



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