[Excalibor]

May I ask why it wasn't able to take a longer exposure instead (was the area shaking somehow?) because after stacking, any moving object in the picture would either be noisy as hell or just ghostlike thin, not quite the same but similar to what you get with a longer exposure anyhow.

Edit: I guess it might makes sense if you had no tripod with you to get a stable camera position, too.

Indeed. If you think about it, it's a bit like Pixel Shift works: it takes 4 rapid pictures slightly moving the sensor and the composes the image with info from all of them... Handheld pictures will naturally shift a little bit around the main focus point: if you stack them all, you get more information per pixel and, thus, reduced noise... It's not perfect, but it might work in cases where a single high ISO picture or very long exposure won't do.

If you take hundreds of pictures of something (even with good light) but with a poor sensor or lens, and then stack them correctly, you'll get a picture with much higher IQ and less noise... High ISO allows to do this in low light.

Cheers!

[MatKus]

I've used iso 25k or 51k on my K50 few times, when after dark I've seen some bird and I couldn't recognize it. This type of image is way too bad to show to anyone, but might be enough to recognize species. If I had better quality at that or even higher ISO I'm sure I would find it useful more often.

[MJKoski]

It is useful in astro shooting to quickly check composition and presence of milkyway etc. stuff. Shame it is not used properly when using liveview in darkness. There should be possibility to really crank up the sensitivity to be able to compose AND accumulate frames which lowers FPS but gives good idea what is in the composition. Sony has "Bright Monitoring" feature to accomplish this.

[Alex645]

What are the benefits or drawbacks of having a sensor capable of such high ISO?

Does having a sensor with this capability increase/decrease the effectiveness of lower ISOs?

The technical foundation of photography starts with exposure which is the relationship between ISO, shutter speed, and aperture.

The main benefit of a greater range of ISO is that you can shoot with in lower ambient light, and thus greater depth of field and/or faster shutter speeds.
However there is a trade-off at higher ISOs with increased pixel noise. So on a practical basis, an older camera sensor that is max at ISO 6,400 may not suffer too much artifacts up to ISO 800, whereas a newer sensor that has ISO 819,200 may look similar to the older sensor but at a higher ISO like 6400.

So yes, the sensor quality at lower ISOs like 1600 will look better than a sensor that maxes at 6400 at ISO 1600.

The main drawbacks are indirect consequences such as having overconfidence in higher ISO. For example, hand holding the camera at a high ISO instead of using a tripod at ISO 100.

I've also known student photographers that were lazy and left Auto ISO on, and in bright daylight shot in P mode 1/8000" @ f/32, ISO 25,600 and it looks horrible when given the lighting and subject, they could have shot it at 1/500" @ f/8 at ISO 100.

[rogerstg]

Having recently found family pictures taken by my grandmother with a 110 Instamatic has reminded me that photography is not only about making art or technical excellence. It's often about preserving memories.

Those photo's are slightly blurry and composed poorly. The memories, however, are perfect.

[blues_hawk]

I use high iso when framing AP shots to save time. If I left the gain low I'd have to wait much longer (30-60seconds) per frame to check focus composition and rotation when using the k-50 on the tracking telescope mount or barn door tracker. Finding dark nebula like heart an soul is a good example. I'll use a 50mm lens @52,000 to find the double cluster and lock the angle then change to a longer lens to get shots with much longer exposure and lower gain(iso).

[photoptimist]

Too many people have an irrational fear of high-ISO noise/grain.

Sometimes motion blur from too long a shutter time detracts more from the image than noise does.

Sometimes out-of-focus blur from too wide an aperture detracts more from the image than noise does.

The world is dark 50% of the time and many indoor locations or deep forests are dark even in the daytime.

[08amczb]

I use ISO 102400-204800 on KP to preview long exposure compositions.

[othar]

Indeed. If you think about it, it's a bit like Pixel Shift works: it takes 4 rapid pictures slightly moving the sensor and the composes the image with info from all of them... Handheld pictures will naturally shift a little bit around the main focus point: if you stack them all, you get more information per pixel and, thus, reduced noise... It's not perfect, but it might work in cases where a single high ISO picture or very long exposure won't do.

If you take hundreds of pictures of something (even with good light) but with a poor sensor or lens, and then stack them correctly, you'll get a picture with much higher IQ and less noise... High ISO allows to do this in low light.

Cheers!

I am familiar with the concept, I just never encountered a shooting situation where I would have prefered many short high ISO pictures over low ISO and longer exposure ones, because the increase in IQ and reduction of noise only works for static objects and I can get those in a long exposure at ISO 100 too (multiple ISO 100 shots stacked on the other hand would make more sense to me)

Well I guess this method would make sense for astrophotography, assuming you photograph foreground and stars separately, or just stars.

[UncleVanya]

Gorgeous portrait!

I agree wholeheartedly with you: it's better a noisy picture than no picture at all! High ISO allows that and it's amazing how technology empowers us...

Cheers!

P.S.- again, amazing portrait! And the b&w treatment in post was the right idea, to work with the noise instead of fighting it... Thumbs up!

Edit: mobile keyboard made noise a moose xD

Thank you! I've printed a copy at 13x19 and it holds up really well. I am pretty happy with it.

[mikeSF]

May I ask you what was the subject of point 2)? I'm curious
From "extremely high ISO", as the title said it's gonna be a chore... let's say the starting image is shot at ISO 204'800... you'll need to stack 25 images just to get to a level of noise comparable with ISO 6400 (5 stops)...

i ran down to Big Sur to shoot bioluminescent algae on a beach under moonless conditions. At ISO 10,000, I was still at a 5 minute exposure to get a dim image. I learned on the shoot that I could even stack 10 images at 20,000 and get a much cleaner image than I had hoped for. I havent had another opportunity to do this since, but am ready for next time.

[Ropuchy]

I think it is useful when you absolutely want the shot and you'd rather sacrifice quality than miss it. Here's a shot of my dad made at ISO 25600 on a K-3. Given that the max ISO on the K-3 is 51200 and the K-1 is over 3 stops better than the K-1 this isn't much different than shooting a K-1 at ISO 204800 or higher.

That's a really fantastic photo! It almost looks like a super detailed painting or something.
But yeah, I agree, being able to capture those moments really quickly is great.

[victormeldrew]

So, you're walking down a dark alley at night with a slow lens and no flash.
You see Britney Spears and J-Lo having an all-out cat fight in the nude.

1) Put it in full auto and high speed continuous.
2) Shoot
3) ???
4) $$$

[UncleVanya]

So, you're walking down a dark alley at night with a slow lens and no flash.
You see Britney Spears and J-Lo having an all-out cat fight in the nude.

1) Put it in full auto and high speed continuous.
2) Shoot
3) ???
4) $$$

Lol. You nailed that.

[Ropuchy]

Alright. So the general idea is that the high ISO improves performance of lower ISOs, is useful for checking your shot in astrophotography without having to wait several minutes, helps to capture those one-chance sorts of shots, allows low light and high DOF shots to turn out better, and gives Pentax some bragging rights and makes their marketing department happy.

Did I miss much?

Thanks for all the replies!