Iso

[Shadowman]

Following this thread High iso usage and others I've started or participating in the discussion, I've posted a recent capture done at slightly high ISO.

f/2, ISO 3200, 1/100sec handheld


I'm not particularly happy with the quality, this is an experiment in capture and post-processing.

[Marie Hass]

Hi, John,

I guess I am not understanding your hypothesis? What were you trying to prove? What was your goal?

Did you have a prime you were working wih?

Marie

[MrB]

What aspects of its quality are you not happy with, John? My first thought was - is it supposed to have that mauve colour cast?

Cheers.
Philip

[Manfred M]

Okay - here are a couple of high ISO shots I took in India last year. We were watching five Hindu priests blessing the world at the well known ceremony in Varanasi. We were sitting on a boat in the Ganges River. It was so dark that what I was just barely able to get usable images by pushing the limits with the Panny GX7 and long focal lengths. In this case, I felt that noisy images were better than no images.


The mixed lighting created weird colours and in spite of the noise, especially in the sky, I found that the funky colours added to the strangeness of the event.




The lighting was even worse in this shot and by converting the B&W, the chromatic noise looked better, giving the image a gritty look.

[xpatUSA]

Just to keep a balance, here's how my Sigma SD1M handles ISO 3200 . .



. . which is why my camera setting never varies from ISO 100 . .

See image full-size and observe:

the infamous Foveon green/magenta blotching is well in evidence

weird discoloration on the front of the speaker

horizontal banding all over the place

de-saturated color (what there is of it)

that the pink lampshade is actually light tan . .

Definitely not a low-light action camera. Didn't buy it for that of course, Wife's DMC-LX7 works well enough for that king of thing.

[Shadowman]

Hi, John,

I guess I am not understanding your hypothesis? What were you trying to prove? What was your goal?

Did you have a prime you were working wih?

Marie

Hi Marie,

Yes, shot with a prime, the goal is to shoot lowlight action without flash, the outcome is that I have to either go high ISO and get lots of unwanted noise or shoot with moderate level of noise and shoot with slower shutter speed to get a decent exposure.

[Shadowman]

What aspects of its quality are you not happy with, John? My first thought was - is it supposed to have that mauve colour cast?

Cheers.
Philip

Hi Philip,

Not happy with the degree of sharpness or the amount of visible noise. I'm not getting a mauve color cast on my monitor.

[Shadowman]

Okay - here are a couple of high ISO shots I took in India last year. We were watching five Hindu priests blessing the world at the well known ceremony in Varanasi. We were sitting on a boat in the Ganges River. It was so dark that what I was just barely able to get usable images by pushing the limits with the Panny GX7 and long focal lengths. In this case, I felt that noisy images were better than no images.

Nice use of rim lighting to convey the scene.
The mixed lighting created weird colours and in spite of the noise, especially in the sky, I found that the funky colours added to the strangeness of the event.




The lighting was even worse in this shot and by converting the B&W, the chromatic noise looked better, giving the image a gritty look.

[Shadowman]

Just to keep a balance, here's how my Sigma SD1M handles ISO 3200 . .



. . which is why my camera setting never varies from ISO 100 . .

See image full-size and observe:

the infamous Foveon green/magenta blotching is well in evidence

weird discoloration on the front of the speaker

horizontal banding all over the place

de-saturated color (what there is of it)

that the pink lampshade is actually light tan . .

Definitely not a low-light action camera. Didn't buy it for that of course, Wife's DMC-LX7 works well enough for that king of thing.

How long of an exposure did you use?

[IzzieK]

If you had even attempted to remove those noise in the first shots, it would have degrade the image just a bit...??

Okay - here are a couple of high ISO shots I took in India last year. We were watching five Hindu priests blessing the world at the well known ceremony in Varanasi. We were sitting on a boat in the Ganges River. It was so dark that what I was just barely able to get usable images by pushing the limits with the Panny GX7 and long focal lengths. In this case, I felt that noisy images were better than no images.


The mixed lighting created weird colours and in spite of the noise, especially in the sky, I found that the funky colours added to the strangeness of the event.




The lighting was even worse in this shot and by converting the B&W, the chromatic noise looked better, giving the image a gritty look.

[Black Pearl]

An example from the 16mp Fuji X-Trans 1.5x crop sensor running at 6400. Chose this as it was next to me. Lighting is from a pair of wall lights dimmed down to (I'd guess) about half their output. Shot in raw and opened in ACR. There is NO noise reduction applied but I have output sharpened it.

If you view it at 100% there is grain though it has a film-like quality to it and certainly not mess of random colour interference though I'd say you could still print it at a decent size but once you've down-sampled the file for the web it is more than usable.

[IzzieK]

Good one at 3200, John...I agree about the purply colour hint that Philip mentioned.

Following this thread High iso usage and others I've started or participating in the discussion, I've posted a recent capture done at slightly high ISO.

f/2, ISO 3200, 1/100sec handheld


I'm not particularly happy with the quality, this is an experiment in capture and post-processing.

[rtbaum]

D750, ISO 6400, 420mm, f/5.6, 1/15 sec, handheld, as shot, just converted to jpeg

[Manfred M]

If you had even attempted to remove those noise in the first shots, it would have degrade the image just a bit...??

Both of these images had noise reduction applied to them and the final result is the trade off I made between noise reduction and sharpness.

[Shadowman]

An example from the 16mp Fuji X-Trans 1.5x crop sensor running at 6400. Chose this as it was next to me. Lighting is from a pair of wall lights dimmed down to (I'd guess) about half their output. Shot in raw and opened in ACR. There is NO noise reduction applied but I have output sharpened it.

If you view it at 100% there is grain though it has a film-like quality to it and certainly not mess of random colour interference though I'd say you could still print it at a decent size but once you've down-sampled the file for the web it is more than usable.

Has a nice, smooth transition from light to dark.

[Shadowman]

Good one at 3200, John...I agree about the purply colour hint that Philip mentioned.

Couldn't see it at first until I did a color cast adjustment, now to fix the change it applied to the skin tones and ice. Thanks for commenting.

[Shadowman]

D750, ISO 6400, 420mm, f/5.6, 1/15 sec, handheld, as shot, just converted to jpeg

Looks good, how many light sources?

[xpatUSA]

How long of an exposure did you use?

1/200 sec, John - but the picture was only posted to show how bad the Foveon is compared to most Bayer CFA sensor cameras at very high ISOs; to strike a balance with all the (to me) pretty good high-ISO shots in this thread. Not really looking for advice how to improve it, I only use ISO 100 with that camera, and generally no lower that -2EV on the spot metering, occasionally -3EV.

A lot of X3 Fill Light was used in post to bring out the noise; NR in post was set to minimum for the same reason. For Sigmas, the conversion matrices are necessarily severe because of the broad spectral response of each layer. Raw composite images aren't too bad from a noise POV but are not terribly colorful

[DanK]

Spurred by this, I just did some controlled tests with my Canon 5DIII (a fairly low-noise camera), shooting the exact same scene with ISOs from 100 to 6400. The results surprised me. That's one nice thing about empirical data.

I suggest looking at all of these in the lytebox.

One thing that is relevant is that the lighting was ideal, extending almost the full range, and with the majority of mass in the top half of the histogram:



I deliberately chose a scene with a flat surface, to show noise, and some detail, to show the impact of noise on sharpness. For the latter, look at the lettering on the red and white White Mountains guide, which was the point of focus.

I shot these at f/7.1 using a macro lens. I did no processing at all other than reading them into lightroom and allowing lightroom to apply its default capture sharpening and color noise reduction. I exported the jpegs at 92% quality with output sharpening turned off.

ISO 100:



ISO 800:



ISO 6400:



At 100%, the ISO 6400 image shows degradation, although less than I thought. You can see the full-size jpeg here:

https://dkoretz.smugmug.com/photos/i.../i-2V6mbxq.jpg

Some observations:

-- As expected, at this level of downsampling, they all look fine. The effects, when present, will be more apparent at larger sizes.

-- At 100%, the degradation of the image is considerably less than I had expected given past experience. For example, here is a 100% crop from an ISO 4000 image, with the ISO selected by the camera, after processing but without noise reduction other than LR's default:



This one looks fine when downsampled to a small online display, but the image degradation is substantial.

I think the reason is apparent from the histogram, which is very different from the first:



So, my take-aways:

1. Don't use small online displays to evaluate image quality, unless that is the only way you are going to present the image. They will obscure problems that may be apparent at larger sizes.

2. Modern lower-noise cameras can handle fairly high ISOs reasonable well, if the lighting is pretty good, meaning that the distribution of luminance has its mass fairly far toward the bright end.

3. If you have to use high ISOs with images that have a lot of the mass at the darker end, the results will not be as good.

Seem like reasonable conclusions?

Dan

[Shadowman]

1/200 sec, John - but the picture was only posted to show how bad the Foveon is compared to most Bayer CFA sensor cameras; to strike a balance with all the (to me) pretty good high-ISO shots in this thread. Not really looking for advice how to improve it, I only use ISO 100 with that camera, and generally no lower that -2EV on the spot metering, occasionally -3EV.

Hi Ted,

Understood about reason for posting, just wanted to get an idea of how much light was reaching the sensor.