6 ms·

Exposure Simulator

139 points by sneela 7mo ago

ChrisMarshallNY 7mo ago
That does a fairly good job. I'm sure that image nerds would poke holes in it, but it seems to work pretty much exactly the way it does IRL. The noise at high ISO is where it can get specific. Some manufacturers make cameras that actually do really well, at high ISO, and high shutter speed. This seems to reproduce a consumer DSLR.
- arghwhat 7mo ago
  With the disclaimer that I am comparing to the memory of some entry-level cameras, I would still say that it's way too noisy. Even on old, entry-level APS-C cameras, ISO1600 is normally very usable. What is rendered here at ISO1600 feels more like the "get the picture at any cost" levels of ISO, which on those limited cameras would be something like ISO6400+. Heck, the original pictures (there is one for each aperture setting) are taken at ISO640 (Canon EOS 5D MarkII at 67mm)! (Granted, many are too allergic to noise and end up missing a picture instead of just taking the noisy one which is a shame, but that's another story entirely.)
  - einr 7mo ago
    Noise depends a lot on the actual amount of light hitting the sensor per unit of time, which is not really a part of the simulation here. ISO 1600 has been quite usable in daylight for a very long time; at night it's a somewhat different story. The amount and appearance of noise also heavily depends on whether you're looking at a RAW image before noise processing or a cooked JPEG. Noise reduction is really good these days but you might be surprised by what files from even a modern camera look like before any processing. That said, I do think the simulation here exaggerates the effect of noise for clarity. (It also appears to be about six years old.)
    - kqr 7mo ago
      The kind of noise also makes a huge difference. Chroma noise looks like ugly splotches of colour, whereas luma noise can add positively to the character of the image. Fortunately humans are less sensitive to chroma resolution so denoising can be done more aggressively in the ab channels of Lab space. Yes, this simulation exaggerates a lot. Either that, or contains a tiny crop of a larger image.
  - ChrisMarshallNY 7mo ago
    Yeah, I don't think that it's easy to reproduce noise (if it was, noise reduction would be even better). Also, bokeh/depth of field. That's not so easy to reproduce (although AI may change that).
- 1e1a 7mo ago
  Video showcasing ISO noise behavior of a few different cameras: https://youtu.be/iiMfAmWbWSg?t=94s https://youtu.be/iiMfAmWbWSg?t=94s
  - ChrisMarshallNY 7mo ago
    That's a pretty good demo! Very limited camera choices, though.
    - 1e1a 7mo ago
      Yeah, it would be interesting and useful to see this across many more cameras.
      - ChrisMarshallNY 7mo ago
        Some of the new Nikon cameras have excellent high-ISO performance. Also, they now own RED, so we should see some interesting stuff, down the road.
      - asdff 7mo ago
        dpreview is good for that. They shoot a test image of every camera on the market, and you can compare specific iso values on the same subject side by side.
  - nayuki 7mo ago
    Excellent presentation and explanation. I agree with ~90% of it except the small part at 4m54s where he tries to give an answer about the existence of noise. Yes, sensor readout noise and A/D quantization noise exist, but he forgot the big elephant in the room: photon shot noise ( https://en.wikipedia.org/wiki/Shot_noise https://en.wikipedia.org/wiki/Shot_noise ). Light is inherently quantum mechanical, and the lower the brightness of a scene, the more that the discrete nature of light shows up in captured images. Lately I've been researching cameras for astronomy, especially for deep-sky objects (DSOs) like nebulae that require hours of exposure time. The marketing material for these cameras go into a lot of detail: quantum efficiency (the percent chance that a photon converts into an electron), dark noise at different temperatures (fractions of electrons per second), readout noise (usually around 1 electron), and well depth (usually around 10k electrons). Compared to general photography, the astro community much more motivated to explain and keep track of all the sources of noise. Random product example: https://www.zwoastro.com/product/asi585mc-mm-pro/ https://www.zwoastro.com/product/asi585mc-mm-pro/
- sneela 7mo ago
  I recently bought a film camera (Minolta X-700) and I wasted a whole roll because I inverted the aperture (i.e, 2 = sharp, 32 = blur)... I'm interested to see how the roll turns out - gave it for development the other day, had a good laugh with the employees though. I now have a mnemonic for it: Blor - a (somewhat) portmanteau of Blur and low. So low aperture = blur. Edit for clarification: I mean low number (2 vs 32) = blur
  - 4gotunameagain 7mo ago
    The larger the entrance pupil is, the narrower the depth of field is. The smaller, i.e. the closest to an ideal pinhole camera, the wider the depth of field is. A an ideal pinhole camera has infinite depth of field. Unfortunately the aperture f numbers are the wrong way round; larger numbers correspond to smaller diameters.
  - tiagod 7mo ago
    High aperture = Blur Unfortunately the lower number actually means bigger aperture.
    - sneela 7mo ago
      And that's what exactly confused me :) With my mnemonic, I say low *number = blur I should have been more specific
      - Filligree 7mo ago
        The aperture size is usually described as e.g. f/32, where f is a camera-specific constant. Denominator, not numerator. That's why larger number = smaller aperture.
        armadsen 7mo ago
        To be a little more precise, f is not a camera-specific constant. It's the focal length of the lens. It's a formula that tells you the diameter of the entrance pupil. So at a focal length of 50mm, an aperture value of f/2 means an entrance pupil diameter of 25mm. But photographers generally just say "f2", meaning an aperture value of two set on the dial of the camera/lens. It's one stop faster (twice as much light) as f/2.8. It'll give you a relatively shallow depth of field, but not as shallow as e.g. f/1.4.
- JKCalhoun 7mo ago
  I think it is excellent as well—that it also demonstrates aperture and shutter priority is a bonus. I do feel (image nerding now) that its shutter/ISO visual for showing the image over/under-exposed is not quite correct. It appears they show incorrect exposure by taking the "correct" image and blend (multiply) with either white or blend with black (on the other end of the exposure spectrum) to produce the resulting image. I suppose I am expecting something more like "levels" that pushes all the pixels to white (or black) until they are forced to clip. (But maybe I am too trained in photo-editing tools and expect the film to behave in the same way.)
  - kqr 7mo ago
    No, you're correct. I would have expected the highlights to blow out much sooner (for digital) and the shadows to block up much sooner (for analogue). The simulation doesn't portray this accurately, but it gives the general idea!
- turnsout 7mo ago
  It needs to be updated to do its calculations in linear light, but it's probably useful for getting an intuitive sense of what the different levers of photography do to an image.
- zokier 7mo ago
  Camera ISO and noise can be really complicated and even contentious topic. One complication is that some cameras are "ISO invariant" and on those cameras afaik it is beneficial to stick to the one or two native ISO values. There is also the whole discussion around ETTR etc
1e1a 7mo ago
Changing the ISO appears to scale the noise differently from the rest of the image.
- dahart 7mo ago
  Yep, just like a real camera.
ggambetta 7mo ago
Nice, but I'm going to need some ND filters :)
pimlottc 7mo ago
It seems to be impossible to grab the sliders on mobile Safari
- dahart 7mo ago
  Try tapping on the target value
trimaster 7mo ago
Not sure why value on the exposure compensation scale changes in manual mode when ISO is fixed. Shouldn't it be static in that case, unless ISO was in auto?
- czpl 7mo ago
  That's a light meter, not exposure compensation.
cratermoon 7mo ago
This is missing a setting for the kind of light falling on the subject. Is it full open sunlight? Open shade? Overcast? Sidelight? Backlight? It all matters.
PetitPrince 7mo ago
For me it's missing something to illustrate the relationship between shutter speed and motion blur. If the subject was a running fan instead of of lightbulb that would have been ideal.
- moon2 7mo ago
  From the website: If I ever find a good moving prop like a small fan, maybe I'll also re-shoot new previews to demonstrate how shutter speed affects moving objects. Now, I'm just not sure how would one simulate a running fan with a picture. While for a static image you can have separated foreground and background and then apply effects for simulation (I know iPhone HEIC images have this property), for moving images you have to simulate the blur and the stillness, which is probably more difficult in terms of coding.
  - andyfilms1 7mo ago
    I love the idea that this guy was easily able to scrounge up a florescent bulb in a beer coozie, but a desk fan is somehow unobtainable.
  - nomel 7mo ago
    Why simulate? Most modern cameras can be controlled through USB. Just actually take each one (except for ISO, which you can easily fake), encode the frames in a reasonable bitrate MP4, then have a lookup for the frame in the video. :D
    - internetter 7mo ago
      This would require 18000 frames
      - moon2 7mo ago
        If you consider how long lower speed shutters will take and the aperture combinations, it would take a long time to take all the pictures and would stop being feasible.
erghjunk 7mo ago
that's an insane amount of noise at 200 ISO.
- 10729287 7mo ago
  Probably Foveon sensor.
semiquaver 7mo ago
I know that modern systems like aperture priority or full auto make things easier, but I maintain that the many photos I took with a fully manual film camera (Canon AE-1) were simply better than those taken with any subsequent DSLR. The simple act of calibrating the shutter speed, aperture size, and manual focus before and during shooting helps you slow down and think about composition and framing, making the end result more valuable. Same goes for the limited number of shots on a roll of film. Nowadays it’s easier to just take lots of shots and fiddle with the setting and do bracketing and such. But I maintain something important was lost by the move to automatic cameras.
- mmh0000 7mo ago
  Don't worry! We're moving away from automatic cameras, too. Soon, you'll just use ChatGPT to generate your vacation images on demand. I'm being a little hyperbolic, but it really seems like, for a non-insignificant portion of the population, that will be true.
  - blacklion 7mo ago
    Friend of mine suggested "vacation camera" concept when Panoramio was established (around 2006): box with compass, GPS and Internet connection. You point it to the sight, press button, it downloads photos of this sight. If you have premium subscription, it downloads professional photos with professional post-processing. Inserting user's mates was a problem in 2006.
  - sixothree 7mo ago
    The rate at which people are currently posting AI enhanced or modified images of themselves is a bit surprising to me. Apparently people very much like wearing different outfits or travelling to new places without actually having to put them on or actually leave the house.
- moon2 7mo ago
  That's why I love fiddling with analog cameras for a bit, or even experimenting with old lens on newer DSLRs. I have a Canon Rebel from 2011 and sometimes love to use my soviet Zenit Helios 44M lens in it. I do have the Zenit which came with this lens, but I have yet to develop its film.
moon2 7mo ago
This is honestly the best and most simple way to learn photography, at least something basic that is still very hard to grasp sometimes. I know photography is not just about the photometer, and about depth of field, but this simple simulator helps to learn about these relationships between aperture size, shutter speed and ISO which always bugged me (sometimes my shots were bad and sometimes great).
agos 7mo ago
this is a cool idea, but not very well executed. it appears it just overlays white on top of anything? exposure does not work this way
Toutouxc 7mo ago
> image "noise" or "grain" that is introduced into a picture as you increase the ISO Not this absolute shit again. This is not how photography works or how physics actually work. Image noise does NOT come from high ISO, it comes from low exposure (not enough light hitting the sensor). ISO is just a multiplier between a number of photons and the brigthness of a pixel in your photo. The implementation of the multiplier is (usually) half-analog and half-digital, but it's still just a multiplier. If you keep the exposure the same, then changing the ISO on a digital camera will NOT introduce any more noise (except for at the extremes of the range, where, for example, analog readout noise may play a role). This "simulator" artificially adds noise based on the ISO value, as you can easily discover: Set your shutter to 1/500 and your aperture to F8, then switch between ISO 50 and ISO 1600 and look at the letters on the bulb. ISO 50, dark but perfectly readable. ISO 1600, garbled mess. Since the amount of light hitting the simulated sensor stays the same, you should be seeing slightly LESS noise at ISO 1600 (better signal to noise ratio than at low ISO), not more. edit: To add something genuinely useful: Use whatever mode suits you (manual, Av, Tv) and just use Auto ISO. Expose for the artistic intent and get as much light in as possible (i.e. use a slower shutter speed unless you need to go faster, use a wider aperture unless you need a narrower one). That’s the light that you have, period. Let the camera choose a multiplier (ISO) that will result in a sane brightness range in your JPEG or RAW (you’ll tweak that anyway in post). If the photo ends up too noisy, sorry but there was not enough light. ISO is an almost useless concept carried over from film cameras where you had to choose, buy and load your brightness multiplier into the camera. Digital cameras can do that on the fly and there’s usually no reason not to let them. (If you can come up with a reason, you probably don’t need this explanation)
- shakow 7mo ago
  > If you keep the exposure the same, then changing the ISO on a digital camera will NOT introduce any more noise So does this mean that changin the ISO directly on my camera, or in DarkTable/whatever at post-proc time is virtually the same?
  - nayuki 7mo ago
    If you have an ISO-invariant camera, then yes - the final image would look the same whether you shot at low ISO and raised it in post versus shooting at a high ISO and doing no further editing. You can try it yourself. Or you can read the numerous reviewers who have already done that in the past decade, such as DPReview.
thot_experiment 7mo ago
kinda lame to use "brightness" as an analog for exposure, they're really not the same thing, at the very least do the transformation in a deeper color space before displaying it to the screen, the source images almost certainly have more than the 8 bits being used here
xp84 7mo ago
> Note! The exposure portion of this simulator currently does NOT work with Internet Explorer! Don't tell me what to do!
Bimos 7mo ago
I like the fact that the photos seem to be real rather than simulated.
sirto 7mo ago
I would like to add to the discussion my mod of Tim's work (with the author's permission) for astrophotography: https://paolo.sirtoli.it/astrophoto.html https://paolo.sirtoli.it/astrophoto.html Every photographer knows very well the exposure triangle: shutter speed, aperture and ISO, but in astronomy usually only aperture and focal ratio are considered. So I added a third dimension to illustrate the basic triad of astrophotography: telescope aperture, focal ratio and image resolution.
bibimsz 7mo ago
hdr cinema setting: shutter: one click right of 1/60 fstop: one click right of f11 iso: one click left of 100
- bibimsz 7mo ago
  or maybe: ss: one right of 1/550, fs: f/4, iso: 100
bibimsz 7mo ago
I found this quite fun! Thanks for going through the effort!

139 points by sneela 7mo ago

That does a fairly good job. I'm sure that image nerds would poke holes in it, but it seems to work pretty much exactly the way it does IRL. The noise at high ISO is where it can get specific. Some manufacturers make cameras that actually do really well, at high ISO, and high shutter speed. This seems to reproduce a consumer DSLR.

arghwhat 7mo ago
With the disclaimer that I am comparing to the memory of some entry-level cameras, I would still say that it's way too noisy. Even on old, entry-level APS-C cameras, ISO1600 is normally very usable. What is rendered here at ISO1600 feels more like the "get the picture at any cost" levels of ISO, which on those limited cameras would be something like ISO6400+. Heck, the original pictures (there is one for each aperture setting) are taken at ISO640 (Canon EOS 5D MarkII at 67mm)! (Granted, many are too allergic to noise and end up missing a picture instead of just taking the noisy one which is a shame, but that's another story entirely.)
- einr 7mo ago
  Noise depends a lot on the actual amount of light hitting the sensor per unit of time, which is not really a part of the simulation here. ISO 1600 has been quite usable in daylight for a very long time; at night it's a somewhat different story. The amount and appearance of noise also heavily depends on whether you're looking at a RAW image before noise processing or a cooked JPEG. Noise reduction is really good these days but you might be surprised by what files from even a modern camera look like before any processing. That said, I do think the simulation here exaggerates the effect of noise for clarity. (It also appears to be about six years old.)
  - kqr 7mo ago
    The kind of noise also makes a huge difference. Chroma noise looks like ugly splotches of colour, whereas luma noise can add positively to the character of the image. Fortunately humans are less sensitive to chroma resolution so denoising can be done more aggressively in the ab channels of Lab space. Yes, this simulation exaggerates a lot. Either that, or contains a tiny crop of a larger image.
- ChrisMarshallNY 7mo ago
  Yeah, I don't think that it's easy to reproduce noise (if it was, noise reduction would be even better). Also, bokeh/depth of field. That's not so easy to reproduce (although AI may change that).
1e1a 7mo ago
Video showcasing ISO noise behavior of a few different cameras: https://youtu.be/iiMfAmWbWSg?t=94s https://youtu.be/iiMfAmWbWSg?t=94s
- ChrisMarshallNY 7mo ago
  That's a pretty good demo! Very limited camera choices, though.
  - 1e1a 7mo ago
    Yeah, it would be interesting and useful to see this across many more cameras.
    - ChrisMarshallNY 7mo ago
      Some of the new Nikon cameras have excellent high-ISO performance. Also, they now own RED, so we should see some interesting stuff, down the road.
    - asdff 7mo ago
      dpreview is good for that. They shoot a test image of every camera on the market, and you can compare specific iso values on the same subject side by side.
- nayuki 7mo ago
  Excellent presentation and explanation. I agree with ~90% of it except the small part at 4m54s where he tries to give an answer about the existence of noise. Yes, sensor readout noise and A/D quantization noise exist, but he forgot the big elephant in the room: photon shot noise ( https://en.wikipedia.org/wiki/Shot_noise https://en.wikipedia.org/wiki/Shot_noise ). Light is inherently quantum mechanical, and the lower the brightness of a scene, the more that the discrete nature of light shows up in captured images. Lately I've been researching cameras for astronomy, especially for deep-sky objects (DSOs) like nebulae that require hours of exposure time. The marketing material for these cameras go into a lot of detail: quantum efficiency (the percent chance that a photon converts into an electron), dark noise at different temperatures (fractions of electrons per second), readout noise (usually around 1 electron), and well depth (usually around 10k electrons). Compared to general photography, the astro community much more motivated to explain and keep track of all the sources of noise. Random product example: https://www.zwoastro.com/product/asi585mc-mm-pro/ https://www.zwoastro.com/product/asi585mc-mm-pro/
sneela 7mo ago
I recently bought a film camera (Minolta X-700) and I wasted a whole roll because I inverted the aperture (i.e, 2 = sharp, 32 = blur)... I'm interested to see how the roll turns out - gave it for development the other day, had a good laugh with the employees though. I now have a mnemonic for it: Blor - a (somewhat) portmanteau of Blur and low. So low aperture = blur. Edit for clarification: I mean low number (2 vs 32) = blur
- 4gotunameagain 7mo ago
  The larger the entrance pupil is, the narrower the depth of field is. The smaller, i.e. the closest to an ideal pinhole camera, the wider the depth of field is. A an ideal pinhole camera has infinite depth of field. Unfortunately the aperture f numbers are the wrong way round; larger numbers correspond to smaller diameters.
- tiagod 7mo ago
  High aperture = Blur Unfortunately the lower number actually means bigger aperture.
  - sneela 7mo ago
    And that's what exactly confused me :) With my mnemonic, I say low *number = blur I should have been more specific
    - Filligree 7mo ago
      The aperture size is usually described as e.g. f/32, where f is a camera-specific constant. Denominator, not numerator. That's why larger number = smaller aperture.
      - armadsen 7mo ago
        To be a little more precise, f is not a camera-specific constant. It's the focal length of the lens. It's a formula that tells you the diameter of the entrance pupil. So at a focal length of 50mm, an aperture value of f/2 means an entrance pupil diameter of 25mm. But photographers generally just say "f2", meaning an aperture value of two set on the dial of the camera/lens. It's one stop faster (twice as much light) as f/2.8. It'll give you a relatively shallow depth of field, but not as shallow as e.g. f/1.4.
JKCalhoun 7mo ago
I think it is excellent as well—that it also demonstrates aperture and shutter priority is a bonus. I do feel (image nerding now) that its shutter/ISO visual for showing the image over/under-exposed is not quite correct. It appears they show incorrect exposure by taking the "correct" image and blend (multiply) with either white or blend with black (on the other end of the exposure spectrum) to produce the resulting image. I suppose I am expecting something more like "levels" that pushes all the pixels to white (or black) until they are forced to clip. (But maybe I am too trained in photo-editing tools and expect the film to behave in the same way.)
- kqr 7mo ago
  No, you're correct. I would have expected the highlights to blow out much sooner (for digital) and the shadows to block up much sooner (for analogue). The simulation doesn't portray this accurately, but it gives the general idea!
turnsout 7mo ago
It needs to be updated to do its calculations in linear light, but it's probably useful for getting an intuitive sense of what the different levers of photography do to an image.
zokier 7mo ago
Camera ISO and noise can be really complicated and even contentious topic. One complication is that some cameras are "ISO invariant" and on those cameras afaik it is beneficial to stick to the one or two native ISO values. There is also the whole discussion around ETTR etc

1e1a 7mo ago

Changing the ISO appears to scale the noise differently from the rest of the image.

dahart 7mo ago
Yep, just like a real camera.

ggambetta 7mo ago

Nice, but I'm going to need some ND filters :)

pimlottc 7mo ago

It seems to be impossible to grab the sliders on mobile Safari

dahart 7mo ago
Try tapping on the target value

trimaster 7mo ago

Not sure why value on the exposure compensation scale changes in manual mode when ISO is fixed. Shouldn't it be static in that case, unless ISO was in auto?

czpl 7mo ago
That's a light meter, not exposure compensation.

cratermoon 7mo ago

This is missing a setting for the kind of light falling on the subject. Is it full open sunlight? Open shade? Overcast? Sidelight? Backlight? It all matters.

PetitPrince 7mo ago

For me it's missing something to illustrate the relationship between shutter speed and motion blur. If the subject was a running fan instead of of lightbulb that would have been ideal.

moon2 7mo ago
From the website: If I ever find a good moving prop like a small fan, maybe I'll also re-shoot new previews to demonstrate how shutter speed affects moving objects. Now, I'm just not sure how would one simulate a running fan with a picture. While for a static image you can have separated foreground and background and then apply effects for simulation (I know iPhone HEIC images have this property), for moving images you have to simulate the blur and the stillness, which is probably more difficult in terms of coding.
- andyfilms1 7mo ago
  I love the idea that this guy was easily able to scrounge up a florescent bulb in a beer coozie, but a desk fan is somehow unobtainable.
- nomel 7mo ago
  Why simulate? Most modern cameras can be controlled through USB. Just actually take each one (except for ISO, which you can easily fake), encode the frames in a reasonable bitrate MP4, then have a lookup for the frame in the video. :D
  - internetter 7mo ago
    This would require 18000 frames
    - moon2 7mo ago
      If you consider how long lower speed shutters will take and the aperture combinations, it would take a long time to take all the pictures and would stop being feasible.

erghjunk 7mo ago

that's an insane amount of noise at 200 ISO.

10729287 7mo ago
Probably Foveon sensor.

semiquaver 7mo ago

I know that modern systems like aperture priority or full auto make things easier, but I maintain that the many photos I took with a fully manual film camera (Canon AE-1) were simply better than those taken with any subsequent DSLR. The simple act of calibrating the shutter speed, aperture size, and manual focus before and during shooting helps you slow down and think about composition and framing, making the end result more valuable. Same goes for the limited number of shots on a roll of film. Nowadays it’s easier to just take lots of shots and fiddle with the setting and do bracketing and such. But I maintain something important was lost by the move to automatic cameras.

mmh0000 7mo ago
Don't worry! We're moving away from automatic cameras, too. Soon, you'll just use ChatGPT to generate your vacation images on demand. I'm being a little hyperbolic, but it really seems like, for a non-insignificant portion of the population, that will be true.
- blacklion 7mo ago
  Friend of mine suggested "vacation camera" concept when Panoramio was established (around 2006): box with compass, GPS and Internet connection. You point it to the sight, press button, it downloads photos of this sight. If you have premium subscription, it downloads professional photos with professional post-processing. Inserting user's mates was a problem in 2006.
- sixothree 7mo ago
  The rate at which people are currently posting AI enhanced or modified images of themselves is a bit surprising to me. Apparently people very much like wearing different outfits or travelling to new places without actually having to put them on or actually leave the house.
moon2 7mo ago
That's why I love fiddling with analog cameras for a bit, or even experimenting with old lens on newer DSLRs. I have a Canon Rebel from 2011 and sometimes love to use my soviet Zenit Helios 44M lens in it. I do have the Zenit which came with this lens, but I have yet to develop its film.

moon2 7mo ago

This is honestly the best and most simple way to learn photography, at least something basic that is still very hard to grasp sometimes. I know photography is not just about the photometer, and about depth of field, but this simple simulator helps to learn about these relationships between aperture size, shutter speed and ISO which always bugged me (sometimes my shots were bad and sometimes great).

agos 7mo ago

this is a cool idea, but not very well executed. it appears it just overlays white on top of anything? exposure does not work this way

Toutouxc 7mo ago

> image "noise" or "grain" that is introduced into a picture as you increase the ISO Not this absolute shit again. This is not how photography works or how physics actually work. Image noise does NOT come from high ISO, it comes from low exposure (not enough light hitting the sensor). ISO is just a multiplier between a number of photons and the brigthness of a pixel in your photo. The implementation of the multiplier is (usually) half-analog and half-digital, but it's still just a multiplier. If you keep the exposure the same, then changing the ISO on a digital camera will NOT introduce any more noise (except for at the extremes of the range, where, for example, analog readout noise may play a role). This "simulator" artificially adds noise based on the ISO value, as you can easily discover: Set your shutter to 1/500 and your aperture to F8, then switch between ISO 50 and ISO 1600 and look at the letters on the bulb. ISO 50, dark but perfectly readable. ISO 1600, garbled mess. Since the amount of light hitting the simulated sensor stays the same, you should be seeing slightly LESS noise at ISO 1600 (better signal to noise ratio than at low ISO), not more. edit: To add something genuinely useful: Use whatever mode suits you (manual, Av, Tv) and just use Auto ISO. Expose for the artistic intent and get as much light in as possible (i.e. use a slower shutter speed unless you need to go faster, use a wider aperture unless you need a narrower one). That’s the light that you have, period. Let the camera choose a multiplier (ISO) that will result in a sane brightness range in your JPEG or RAW (you’ll tweak that anyway in post). If the photo ends up too noisy, sorry but there was not enough light. ISO is an almost useless concept carried over from film cameras where you had to choose, buy and load your brightness multiplier into the camera. Digital cameras can do that on the fly and there’s usually no reason not to let them. (If you can come up with a reason, you probably don’t need this explanation)

shakow 7mo ago
> If you keep the exposure the same, then changing the ISO on a digital camera will NOT introduce any more noise So does this mean that changin the ISO directly on my camera, or in DarkTable/whatever at post-proc time is virtually the same?
- nayuki 7mo ago
  If you have an ISO-invariant camera, then yes - the final image would look the same whether you shot at low ISO and raised it in post versus shooting at a high ISO and doing no further editing. You can try it yourself. Or you can read the numerous reviewers who have already done that in the past decade, such as DPReview.

thot_experiment 7mo ago

kinda lame to use "brightness" as an analog for exposure, they're really not the same thing, at the very least do the transformation in a deeper color space before displaying it to the screen, the source images almost certainly have more than the 8 bits being used here

xp84 7mo ago

> Note! The exposure portion of this simulator currently does NOT work with Internet Explorer! Don't tell me what to do!

Bimos 7mo ago

I like the fact that the photos seem to be real rather than simulated.

sirto 7mo ago

I would like to add to the discussion my mod of Tim's work (with the author's permission) for astrophotography: https://paolo.sirtoli.it/astrophoto.html https://paolo.sirtoli.it/astrophoto.html Every photographer knows very well the exposure triangle: shutter speed, aperture and ISO, but in astronomy usually only aperture and focal ratio are considered. So I added a third dimension to illustrate the basic triad of astrophotography: telescope aperture, focal ratio and image resolution.

bibimsz 7mo ago

hdr cinema setting: shutter: one click right of 1/60 fstop: one click right of f11 iso: one click left of 100

bibimsz 7mo ago
or maybe: ss: one right of 1/550, fs: f/4, iso: 100

bibimsz 7mo ago

I found this quite fun! Thanks for going through the effort!