Eliminate pixalation in low light photography

[davidmknoble]

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16 hours ago, SrMi said:

It depends. The amount of noise is defined by exposure, not by ISO. If you have lower exposure, you will have more noise, regardless of whether you "under" or "overexpose."

In your test, you probably had larger exposure when over-exposing and bringing the "exposure" down in the post.

Technically yes, but choosing a high ISO is drastically underexposing the sensor and having the camera boost the image.  My point is, don't boost it more, try to boost it less.  So, by over exposing a little at say, ISO 50,000, you might be exposing more like ISO 45,000 and then darking the image afterwards, which hides some of the noise.  Shooting at ISO 50,000 and making the image lighter accentuates the noise as much as the sensor and editing software can help.

There is only one base ISO per sensor.  Every other ISO is computer emulated by underexposing on purpose.  You could actually leave the camera on the base ISO and underexpse by 4-5 stops and just raise in editing software later.  It would introduce the same noise.

It is also experience, not just one test.

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[SrMi]

2 minutes ago, davidmknoble said:

Technically yes, but choosing a high ISO is drastically underexposing the sensor and having the camera boost the image.

A high ISO underexposes sensor only if you couple the exposure with ISO (automatic metering), but you are manipulating automatic metering anyway.

3 minutes ago, davidmknoble said:

My point is, don't boost it more, try to boost it less.  So, by over exposing a little at say, ISO 50,000, you might be exposing more like ISO 45,000 and then darking the image afterwards, which hides some of the noise.

Better is first to maximize the exposure (shutter speed and aperture) and "underexpose" by lowering the ISO below the metered value. If you keep the exposure fixed, changing ISO will have little influence on noise. Keeping ISO higher than necessary endangers highlights. I.e., it is better to increase "exposure" in the post than to decrease it as long as you have already maximized your exposure in the camera.

5 minutes ago, davidmknoble said:

There is only one base ISO per sensor.  Every other ISO is computer emulated by underexposing on purpose.  You could actually leave the camera on the base ISO and underexpse by 4-5 stops and just raise in editing software later.  It would introduce the same noise.

Most modern cameras have dual conversion gain (DCG), which is like two base ISOs. Very few cameras have computer-emulated ISO (metatag that determines the brightness). Most cameras become ISO invariant after the DCG point. In that range, ISO selection has little influence on noise but can cause clipping.

[marchyman]

On 1/21/2025 at 10:28 AM, charlesphoto99 said:

Funny, I was going to mention curves, but considering the very basic nature of the question, thought levels might be a better place to start. 

Lightroom doesn't have levels.  It is the one thing I miss from when I used Capture One. I've learned to adapt.

[davidmknoble]

@Neel, hoping you have had time to go and test more night photography around town.  Love to see your results!

You really have two options, and you may want to try both (without introducing more software).

1. (As @SrMi is correct, the M11 series has two ‘base’ ISO’s in the sensor whereas most of the older M’s did not) you can use either ISO 64 or ISO 200 (see photons to phots for the Leica M11 - https://www.photonstophotos.net/Charts/PDR.htm) and you will be at a base ISO. I would consider choosing 200.  Then you will want to underexposed the image by 3-5 stops which is equivalent to ISO 1600 and ISO 6400.  In LR or Capture 1, raise the exposure and edit (likely reducing the highlight slider).  Here there is less noise in the shadows as you raise them, and your shutter speed should likely be high enough.

2. You can use a higher ISO, whatever you are comfortable with, but whatever your exposure (tough metering with black sky and bright neon), overexpose about 1/2 stop and then when editing reduce the exposure slider and bring down the highlights.  If you started with a good exposure, you likely will not blow the highlights but you will bring down the shadows and reduce some of the noise.

Metering night shots is tricky.  You may want to find a building that is reflecting some ambient light and meter there, making that exposure manual.  One with a spotlight is too bright, like the neon signs.  Some handheld meters don’t register as well in that low a light.  So bracketing or simply experimenting can help.  Hold an incident light meter to meter the neon light by turning around 180 degrees with your back to the light.  That might help some if the meter is not too sensitive, but be sure to use the ISO your camera is set to and adjust from there.