Sunsets, Saturation, and Noise

[graphite]

I have been trying to figure out how to reduce noise on low light, high-contrast, photos - particularly sunsets. It seems that all of my photos have to be very saturated to get rid of the noise. Here are a couple of examples. Any C&C is welcome.

1. Nikon D5200, Tamron 10-24, f/4.5, 1/80 sec, ISO-200, spot metering. HDR Filter in Lightroom 5


grazing_sunset by graphite_subaru, on Flickr

2. Nikon D5200, f/16. 1/8 sec., ISO 100, Center Weighted Metering. Exposure adjustment in Lightroom 5.


sunset_fin by graphite_subaru, on Flickr

 

[ceeboy14]

HDR filter is probably the culprit but it's hard to tell. Try backing off the sat sliders and use the noise reduction feature in RAW and in PS.

 

[Derrel]

I went to FLickr and looked at both of these at full size. First off...are you sure you are exposing enough? I mean, I looked at the goat sunset shot and thought that at ISO 200, a shutter speed of 1/80 second at f/4.5 is just...way too fast a shutter speed for the darker areas. I see a little bit of what looks like very slight camera shake, and yes, I can see some noise. But, my instinct tells me that the shot is basivally under-exposed for the earth part, and fine for the much brighter sky tones.

Still, the amount of noise you have is not objectionable to me by what I'll call historical standards; back in 2003, we would have been jumping up and down to have been able to make full-sized images with noise that low. We're pretty spoiled these days.

My thought is that the noise in the shadows is due to under-exposure, which is sort of a result of exposing more for the brighter parts of the scene. And on shots like the above, the total scene dynamic range between the shadows and the sun-lighted parts of the sky is quite wide; you're going to have to bias the exposure one way or another in the field, and then in post processing, are going to need to "adjust" the entire scene so it looks right. I think maybe you've been erring slightly too much toward getting the highlights right in the field, and working on "lifting" the shadows, and then all you get is noise. I think maybe shooting in RAW mode and biasing the exposures to "too much" exposure, then recovering the highlights in software, is what you might want to try.

Your original premise of reducing noise on low-light, high-contrast scenes (using single-frame exposure methods) is not exactly as simple as boosting the sharpening in post. THis is one area where newer software has made it easier, by far, to handle these tough situations.

 

[graphite]

Thanks a ton Darrel!!! That is a huge amount of information and it is very helpful. That's exactly what I was hoping to get.

 

[Derrel]

You are welcome graphite. One practical tip for field use is this: turn on the histogram and the "blinkies" when shooting, and when the blinkies show up, know that with a MODERN Nikon d-slr sensor in RAW mode, there is at least a full f/stop of recoverable highlight detail that can be "pulled back down" in software, and that you can often add more exposure than the blinkies and or histogram indicate. I will explain why.

So for example, on the nifty shot of the net-wire fence and the goats with the beautiful sunset sky, with the camera tripod mounted and set to ISO 200, with the lens at f/4.5, you could have lowered the shutter speed say 1.3 to maybe even 2.0 Exposure Values ( slower on the shutter wheel) and the "blinkies" might flash on the sky-tones, indicating overexposure on the embedded .JPG file that is inside of every RAW file. But those "blinkies" are based on the JPEG data, and the way the camera's settings are affecting the JPEG file.

If say the Tone Curve were set to "Normal", and the Saturation were set to +3 notches, the embedded JPEG would most likely tend to have too much contrast, and the red channel would start to saturate, and the "blinkies" would come on, in large part due to the way the camera was processing the embedded JPEG file. BUT the best operating procedure would be to ignore the blinkies, and ADD MORE exposure in the field, and then, when the RAW file was opened, you could "pull back" the exposure, and gt a great sky and eliminate a lot of the noise in the shadows. This is the old "exposing to the right" advice, but with some explanation as to how the blinkies, and the histogram are not always an exact, set-in-stone indicator of what is possible.

The thing is, the in-camera JPEG's histogram, and the blinkies it displays, are an indicator of what the CAMERA and its software do to a .JPG image file; WHat post-processing software can do LATER, is another thing, so in the field, you almost want to ignore the blinkies, and once they first light up, you can often add MORE light, and come away with a better result.

 

[Stevepwns]

Im going to throw a thank you in for those explanations, I have been having this same issue and I am hoping I can use this to better my sunsets and sunrises. Thank you Derrel. :hail:

 

[hirejn]

At ISO 100, 1/8 second there should be no noise. I don't think NR will kick in at 1/8. With overprocessing in post, such as adding a lot of filters, saturation or exposure, you can easily introduce noise, so be careful. If you're shooting RAW, you need to process the noise out in post using noise reduction. You can also use Nik Dfine to reduce noise in any image. Photoshop also works but I prefer the tools of LR and Nik. An unedited JPEG at ISO 100 should be virtually noise free.

 

[Trblmkr]

All very good information... however looking at your sunset picture, I noticed you have some water spots in the middle of your clouds. I don't know if this is part of your noise issue, or just a dirty lens.