One of Jodi’s recent posts on the MCP Facebook page was a challenge to photographers on how to handle a tricky lighting situation. In Jodi’s post, see the thread here, she was at a gymnastic event for her daughter, and she was limited by her maximum lens aperture of f/2.8, and needed to shoot at 1/300-1/500 to freeze motion.
Having been in similar scenarios, I know firsthand what she was up against. As a wedding photographer I can tell you how tricky it can be shooting in a poorly lit church or reception hall!
Getting a correct exposure boils down to a combination of aperture, shutter speed, and ISO, and they all work together. Change one value by one stop, and you have to compensate by adjusting one of the remaining 2 values by one stop.
In Jodi’s case, she had her shutter speed set to 1/300 and 1/500 depending on the action taking place, and an aperture of f/2.8, and she needed 1 more stop of light. My comment on the post was “Bump your ISO to 12,800 or 25,600 and use Lightroom or Photoshop’s amazing noise reduction in post, and accept the grain as a “cost” of getting the shot.”
I know some of you just fainted at the mere thought of shooting at that high ISO, what with all that noise…but I’m going to show you how 5 sliders in Lightroom 3 when used correctly, will help reduce noise in your photo. There are trade-offs, and I’ll explain those as well. I’m purposely avoiding a discussion on whether grain is good or bad in a photo; it’s a widely debated topic, which to me boils down to artistic preference on the photographer’s (and client’s) part. Quite simply, I’m going to write on the basis that you have ISO noise in a photo that you want to reduce, and don’t know where to start.
Where does the noise come from?
When you shoot in low light, your camera’s sensor has to work hard to “see” the scene you are shooting. When you adjust ISO in a digital camera, you are adjusting the camera’s sensitivity to light by increasing or decreasing the amount of amplification the camera’s processor has to do with the light which was captured when the shutter was open. The more you have to amplify the “signal”, the more noise you introduce trying to make something from nothing. The snow you see on a television when you select a channel with no broadcast is the result of amplification of a weak or missing video signal.
Takeaway 1: A small amount of light which gets amplified = noise.
Takeaway 2: If you shoot at high ISO, with lots of light, you won’t see much noise. Try it!
Takeaway 3: We’re not trying to get rid of the grain, just the noise. Grain is a byproduct of high ISO, same as in film.
Lucky for us, the cool people at Adobe gave us noise reduction in Lightroom 3 (it’s the same engine as in the newer Camera Raw application for Photoshop CS5, so you can use the same method for Camera Raw).
Let’s check it out. Shoot a photo at the highest ISO setting your camera allows (you may have to enable ISO expansion in the menus…consult your manual or your favorite search engine).
Open the photo in Lightroom 3.
In the Lightroom 3 Develop Module, you’ll find the Detail section…
Expand the Detail section (click on the arrow) to reveal our new friends, the Noise Reduction sliders just under the Sharpening section.
Here’s an overview of the sliders’ functions as explained by Adobe:
Luminance: Reduces luminance noise
Detail: Luminance noise threshold
Contrast: Luminance contrast
Color: Reduces color noise
Detail: Color noise threshold
So let’s see them in “action”. (See what I just did there? Clever, yes?)
Keep in mind, when I mention sliders, I’m only working with the 5 sliders within the Noise Reduction section in Lightroom 3. Let’s look at the photo I’ll work with: (I have not made ANY color corrections to the photo, this is straight out of camera):
Hubba, hubba! (50mm, f/11, 1/60 sec) (yeah, sorry ladies, but I’m taken…)
I self shot this photo on a Canon 5D Mark II, at 25,600 ISO. I used this photo because it has:
1) Skin tones
3) Mid tones
5) Me (how can we go wrong?)
Look at the noise best visible on the black cabinet over my left shoulder. Oy gevalt:
A 1:1 zoom reveals some ugliness that we are going to remove (not me, the noise):
In the photo above, you can see the spackling of red, green, and blue pixels. That right there is high-ISO noise. It’s important to note that the main reason it looks so bad is because I may or may not have cheated (I did), by changing the Color slider value to 0 so you could see the noise better. Lightroom 3’s default for this slider is 25, which is a good starting point for not seeing color noise.
Press Z to toggle zoom to 1:1 on the photo, & choose a selection where you can see a good mix of lights and darks:
Start by slowly moving the Color slider until all the color noise is either gone, or at an acceptable level. In my photo, it looks like the Color slider works at about 20. Once you decide where the Color slider works best on your photo, move to the Detail slider.
The Detail slider (below the Color slider) is used to see if we can bring back any edge color detail. This is completely trial and error, & if you push this Detail slider too far, you’ll actually reintroduce noise in the form of artifacting back into the photo. Personally, I don’t go past 50 on this, but try the slider on your photo: starting at 0, move it slowly, and see if it makes any difference. If you can’t see any change, leave it at 0.
When you are happy with the reduction of color noise, jump up to the Luminance slider, and start moving this one to the right. Remember, slow is the key. This is where your eye comes in to play again. You have to decide the best balance between loss of noise/grain and loss of detail in your photo. Once you get to the happy medium, you can move onto the luminance Detail slider. For my photo, I’m happy with the Luminance slider set to 33. I pushed it until I just started to lose detail in my skin, and then backed it down a notch.
A word of caution (here’s that tradeoff I was telling you about before): if you push the Luminance slider too far, humans and pets will come out shinier then a certain shall-remain-nameless, plastic, perky, perfectly-proportioned girl’s toy who owns a Corvette, a private jet, & a camper (which really doesn’t fit with the private jet). I’m not sayin’, but I’m just sayin’.
“I like yer plastic face…” – Luminance gone wild!
Next, start sliding the Detail slider left and right (the default is 50, which is usually good), to see if you can get back more (edge) detail without re-introducing noise. Once again, there is no formula; it’s your photo, your artistic vision, your slider value. I’m leaving mine at 50.
Lastly, slide the Noise Reduction Contrast slider to the right to see if you can recover a little more detail. As its name implies, this slider puts detail back in your photo based on boosting luminance contrast. It can work really well to reveal details that were softened in the above steps, and in my photo, I’m not afraid to put this slider to 100 to bring back some of the texture to my face.
Voila! I now have one very usable photograph:
“Is it hot in here, or is it just me?”
Now that I’m happier with the photo, let me quickly recap my Noise Reduction workflow:
Open photo, and gasp (not really…)
Switch to Develop module.
Open Detail section.
Adjust Color slider to see if anything other than the default of 25 gives me better results
Adjust Detail slider (under color) to see if I can bring back any edge detail based on color
Adjust Luminance slider until the grain is acceptable or until the image starts smoothing, then back it off a tad
Adjust Detail slider (under Luminance) to see if I can bring back any edge detail based on luminance
Adjust Contrast slider to try and bring back some last bits of detail
To be perfectly honest, I rarely, if ever, use the bottom 2 sliders (Color and Detail). Lightroom 3’s default values are pretty close to what I would select.
Remember, there is NO magic formula, NO right, and NO wrong (well, there IS that creepy Luminance slider plastic-look). There is only what is pleasing to your client.
As photographers, we see our images differently than our clients do from a technical perspective. If you capture an emotion, or a moment, and you truly nail it, I’d bet my mortgage that your client won’t even see the noise.
If they do, you now know how to reduce it!