Any tips on what level of noise is/should be acceptable?

[TrekRover]

I have a tendency to fixate on pixel peeping and get really caught up in noise level.

I would prefer not to rely on Topaz's DeNoise software as there is always some loss of detail.

What is the max ISO I should shoot with if I want to display on 4K resolution screen and retain maximum detail? 

[LensBrew]

I believe that there is no accepted maximum. Each camera has a limit before the image falls apart. You need to know the limits of your sensor, the aperture, the ambient light, the need for artificial light, and final vision for the scene, shutter speed, tripod or handheld, etc.

For example, I shoot indoor sports and noise in a given and I go sometimes up to 16000 ISO. Sometimes I capture some street images at 100 ISO that would look nice with added grain and gives the vintage feel that I want in post. Try taking the same image in different settings and see which ones satisfies your vision. And don't worry too much about noise (personal opinion).

[tonygale]

It is such a subjective thing, it's impossible to say. In addition I think it really depends on the image. 

[MattK]

I would say that the medium in which you show it off should dictate how much. And don’t let the ISO level in camera dictated it because every shot is different. 6400 ISO in a dark shadowy photo will show up and look worse than a photo in brighter light where you maybe needed a higher shutter speed so the ISO crept higher. 

If I’m printing I don’t worry about it too much. Printing inherently smooths noise and viewing distances mean most people wouldn’t be able to see it anyway. 

If you’re posting a wider view on social media, you don’t need much noise reduction because people can’t zoom in (even though you can while editing). 

For me, I post a lot of wildlife photos where I like to crop in. While cropping doesn’t change the amount of noise in a photo, it has the appearance of pixel peeping because you’re showing a zoomed in version of the photo. In those cases, noise is an issue and I’ll use Topaz DeNoise on it (which I love by the way and find it actually enhances detail in most cases). 

Hope that helps!

[TrekRover]

I would say that the medium in which you show it off should dictate how much. And don’t let the ISO level in camera dictated it because every shot is different. 6400 ISO in a dark shadowy photo will show up and look worse than a photo in brighter light where you maybe needed a higher shutter speed so the ISO crept higher. 

If I’m printing I don’t worry about it too much. Printing inherently smooths noise and viewing distances mean most people wouldn’t be able to see it anyway. 

If you’re posting a wider view on social media, you don’t need much noise reduction because people can’t zoom in (even though you can while editing). 

For me, I post a lot of wildlife photos where I like to crop in. While cropping doesn’t change the amount of noise in a photo, it has the appearance of pixel peeping because you’re showing a zoomed in version of the photo. In those cases, noise is an issue and I’ll use Topaz DeNoise on it (which I love by the way and find it actually enhances detail in most cases). 

Hope that helps!

Thanks, Matt! This helps alot! I crop in alot for wildlife as well and sometimes I feel like there is too much noise. I had a bald eagle shot in overcast weather and I had to have a high ISO to capture feather details, but had too much noise. Unfortunately I felt that Topaz DeNoise didn't work too well. I may not be using it properly...I'll try not to get too paranoid about noise.