Seeking detailed guides on noise reduction

[Overread]

Ok so I've decided that I really need to "hit the books" on noise reduction.

I've survived thus far on the odd forum post and feedback but I really need some recommendations now on either websites or books which you know of which really go into this subject in greater detail. It's my view that noise reduction and sharpening are two areas where I am finding myself spending the most time working with a few tools that I don't really fully understand nor utilize - especially if I want to get into something like individual channel noise reduction.

So I'd welcome any input you guys have. For reference I can and do use Lightroom, Photoshop and Neat-Image. Up till now Neat Image is my weapon of general choice as it tends to work well; though I must admit even there a lot of hte time I'm adjusting sliders without full comprehension as to what is going on or why or how it might better be done.

 

[dannylightning]

what i like to do in lightroom is use a brush first, i brush the whole frame, i turn down the exposure allot on the brush just so i can see what i am brushing and i turn up the noise slider on the brush to around 50-60, once i see i have everything brushed i set the exposure back to normal and usually leave the nose slider between 50-60.

i seem to loose less detail in the image using the brush to reduce noise instead of using the sliders in the detail section to reduce noise and the brush seems to do a great job at reducing noise.

after i do the brush if the image still has more noise than i want, ill go into the detail slider and turn up the luminace slider to around 20, if that does not do the trick ill go up to 30, anything over 20 seems like i start to loose detail in the image so i try not to use that slider unless i really need to

the first detail slider under noise reduction seems to bring some of the lost detail back into the image after you reduce noise with the luminace slider, the contrast slider does not seem to do anything that i can see. next under noise reduction you also have the color slider, second detail slider and smoothness slider, the color slider seems to take saturation out of the color on your image if you turn it up, i don't ever change that color slider. the second detail and smoothness sliders do much as far as i can see so i never use those. i am sure they do something but i cant see it.

not really what your are asking for but i would try the brush thing using the noise slider in the brush to try and reduce noise and see how you like it.

 

[tecboy]

I avoid using noise reduction. It doesn't improve my images. Based on my experience with sharpening, the amount slider gives harder edges, as well, little more noise. Radius gives halo and darken around the edges and adds little extra noise. Detail is more like fine tuning. It give little more extra hard and halo edges, and little more noise. Masking is blurring all the noises except the edges. I do that when I zoom in 1:1 ratio. After done tuning the sharpening, I zoom out and the image looks much crisp and sharp.

 

[The_Traveler]

Noise reduction and sharpening are sort of two sides of the same coin.
Both of them look for sharp changes in contrast and act on that information.
I find that, when there is good lighting that noise is minimal and doing noise reduction doesn't add much - except to reduce sharpness.

I use Noiseware by Imagenomics (Imagenomic Product Tutorials and Workflow Tips) specifically because the denoising window is large and I can actually see what the sliders are doing (or not) as they work.
I look in the shadows for color and luminance noise and do denoising on a duplicate layer so I can erase or mask away areas where denoising foes much.any damage.
I use Denoising to reduce sharpness in the backgrounds and that is a lot more subtle and softer than lens blur.

Fraser's book on Image sharpening talks a bit about denoising but I don't see the differences in his sample images - that's probably my shortcoming.

 

[jsecordphoto]

I have to do some pretty specific noise reduction while working on my astro images, so I've spent a lot of time playing around with different methods. If you're familiar working with layer masking in Photoshop it'll help you a lot. What I do is duplicate my background layer, then go into either Nik Define or use the camera raw filter to use enough NR to really clean up your shadow areas, where the noise is most apparent. Then I'll add a layer mask to the noise reduction layer, and either use apply image (with some tweaking) to only apply the NR to the dark areas where the noise is visible, or just brush in where it's needed. Depending on the image, sometimes I'll use color selection to apply it to certain areas.

Global noise reduction in Lightroom or just in general is too much of a blunt instrument.

 

[The_Traveler]

Global noise reduction in Lightroom or just in general is too much of a blunt instrument.

So true.
Noise reduction is a neat and useful tool to manage noise/sharpness.

 

[JerryPH]

Before offing advice, I need to know your camera and lenses. Do you shoot RAW and at what ISO you want to get good results at.

Example:

I shoot with a D4and can pretty much shoot all day at ISO 1600 without thought or concern, but can also shoot at ISI 102400 and give you an acceptable level of quality.

Probably the most evident thing is that this is a lot about the equipment, knowing it's traits and characteristics as much as it is a software issue.

 

[Overread]

Hey Jerry long long time no see!
I'm currently using a Canon 7D and as for the ISO values they range from anything at around 1600 all the way up to 25600 (or thereabouts - I forget the exact number). It varies as I'm working in darker conditions indoors whilst doing action shots where flash isn't an option so I have to take the ISO higher. Lens is a 70-200mm f2.8 and I'm often at f2.8. (1/620, f2.8 and ISO as high as it needs to be is the way I'm generally working)
At present most of my workflow mostly works well for digital display online; where hte crude global application of noise reduction tends to work most times; but I'd really like to improve the overall results so that prints and larger cropping can be possible without sacrificing image quality as much.

Global noise reduction in Lightroom or just in general is too much of a blunt instrument.

So true.
Noise reduction is a neat and useful tool to manage noise/sharpness.

Aye that it is. Thing is I can use layermasks and brushes, but I've found that it takes a fair while and I know there's a few ways to get photoshop to build layermasks which detect noise specks to isolate them from detail although I've never gotten them to quite work how I want - I think in part because the article are somewhat old so the software has changed, but also the nature of the camera sensor and how it renders noise also shifts through time.

 

[JerryPH]

Its been a long time since I visited here. Just came in for a look and got sucked in to the conversation.

Well, lets cover the basics. First off, the 7D is definitely no slouch, but being honest, high ISO is not it's strongest feature. In places where no flashes are permitted, one has no choice, so lets start off with a few hints and then see how it involves.

1. Shoot the highest quality RAW.
2. Some cameras give you less noise if you over expose by 1/3rd of a stop and lower exposure in post.
3. Leave all in camera noise reduction completely disabled, softward NR is proven superior.
4. Nail that exposure consistently (+1/3rd of a stop that is what you are doing). This one thing helped me the most. If I missed the exposure, raising it pretty much quadrupled my noise amount in the shot.

5. Keeping shutter speeds up is important, and your best friend there is quality fast glass. My fav aperture in very dark locations is between F/1.4 and F/2.0. If that means saving for that faster glass or at least renting it for a job, it will help you a lot. Just remember the shallower DOF and do what it takes to get the most important part if the shot in focus (ie: with living subjects, 99% of the time that means the nearest eye). Good hand holding technique is important too... no jittery hands.

All these things alone should get you half of the way. Unlike what people say, globally using Lightroom's NR or using it in specific sections on the shot is all that I ever needed. I can even pull a half decent ISO 204800 shot out of the camera on a consistent basis, but that is more likely due to my choice of camera, but that does not mean you cannot improve. Also unless it is absolutely mandated by the client, extreme pixel peeping should be used in moderation. Most clients want the photo that stirs their heart, not a 100% noise free shot.

 

[jsecordphoto]

Aye that it is. Thing is I can use layermasks and brushes, but I've found that it takes a fair while and I know there's a few ways to get photoshop to build layermasks which detect noise specks to isolate them from detail although I've never gotten them to quite work how I want - I think in part because the article are somewhat old so the software has changed, but also the nature of the camera sensor and how it renders noise also shifts through time.

Duplicating the background layer, doing NR on the new layer, adding a layer mask, then using apply image to only select the darker areas is fairly simple and much better than just using global NR on the entire image. Perhaps I'll make a video tutorial to post here on a few methods I use

 

[gsgary]

I'm surprised someone hasn't told you to buy a Nikon

 

[Overread]

Also unless it is absolutely mandated by the client, extreme pixel peeping should be used in moderation. Most clients want the photo that stirs their heart, not a 100% noise free shot.

Sadly without any clients I'm left to be my own worst enemy on that front
Much of what you say is certainly what I aim to achieve when shooting; histogram set to show RGB and I generally try to review it as often as I can so long as the action/event isn't ongoing. I have played around with auto ISO a bit so that I can just let the aperture and shutter speed do what they want for the most part in manual mode - but I can't (on the 7D) tell the camera to over-expose a little from it's meter reading on auto ISO (I think its a feature in some latter cameras but I'm not sure). So I tend to find myself in manual for the most part.

Being in RAW all the in-camera editing settings don't do anything and most of the fancy ones I have turned off too - its only for JPEG so no gain to me. About the only exotic is that I enabled the high-ISO setting to get the full range that the camera has - though at the top end the shots get very grainy (tends to be VERY grainy since by that point the light is failing and under exposure creeps in).

I can't really go wider than f2.8. Even if I did rent wider aperture primes the subjects I'm shooting (which I just realised I've not mentioned - showjumping) have just too much body and length of face. Even at f2.8 its a risky thing and that's without them charging around at the time as well.

In the end though subject and settings (barring ISO of course) are not as important to me at present. Whilst I can certainly continue to improve the accuracy of my exposures and keep working with the expose to the right theory when reviewing histograms I'm still going to get the noise that I've got to be able to work and deal with .

Duplicating the background layer, doing NR on the new layer, adding a layer mask, then using apply image to only select the darker areas is fairly simple and much better than just using global NR on the entire image. Perhaps I'll make a video tutorial to post here on a few methods I use

Ahh the blending applications is something I've not made heavy use of; though I've seen some examples of the power I've never really learned enough about their various effects to put them to good use. Part of why I'm hunting for articles/books on the subject to get a good well rounded view on things.

I'm surprised someone hasn't told you to buy a Nikon

That's because everyone is waiting for you to tell me to get a Leica and thus live in a noise-free grain-happy world

 

[gsgary]

Film shooters embrace grain this is another problem with digital

 

[jsecordphoto]

Film shooters embrace grain this is another problem with digital

What film shooters would those be? Never heard any landscape photographers shooting with film talk about all the great grain in their shots. Street photographers maybe

 

[Derrel]

I almost never worry about noise, so I am the last guy to talk to about NR techniques or software, but I thought that there was some advantage to doing at least "some" noise reduction at the raw conversion stage, instead of later in the process...seems like some high-tech geeky type wrote an article on that topic a few years ago, and his opinion was that at least some noise reduction could/should be done on the raw file at the conversion stage...