What you need to know about every facet of image quality – from camera gear to color spaces and exposing to the right
In the past, I’ve written about camera settings in terms of optimization – pushing your gear to the limits in order to maximize image quality. Today, I’ll revisit those advanced techniques and explain how to combine them to capture the highest quality images you possibly can.
First, a simple premise: There is an optimal way to set your camera for a given photo. Not only that, but there is also an optimal way to set your post-processing software and export settings based on your output medium.
Sometimes, of course, you’ll need to sacrifice a bit of image quality in order to use the right camera settings. If you need to take a photo at f/1.4 for the shallow depth of field, go for it. Don’t stop down to f/5.6 just because it’s the lens’s sweet spot.
But often, there’s some significant leeway in the settings you choose, and it can be tricky to know exactly which ones will give you maximum image quality.
That’s what this article is for. I like to think that it’s one of the more important endeavors I’ve attempted recently on Photography Life; it’s my way of distilling many previous concepts we’ve written about into an overarching explanation of maximizing image quality. And it’s pretty long, and it’s occasionally complicated, but it works. This is the process I aim to follow for every photo, though I certainly don’t always succeed.
The only big thing I omitted was flash photography. Flash is complex enough to merit its own article, and this one is already bursting at the seams.
Other than that, the information below should apply regardless of the subject or genre you are photographing. Let’s start with camera equipment:
1. Camera Gear and Image Quality
I can’t avoid pointing out that your choice of camera system has an impact on image quality. Some cameras simply have more resolution or better high ISO performance than others. Certain lenses are sharper, too.
But my goal today is not to recommend that you buy new camera gear if you want better image quality. It’s to explain how to maximize your image quality from any equipment.
If your current gear cannot produce the images you need, even with perfect technique, I’d be pretty surprised. I’d also recommend a different camera system. But if you’re reading this, I’m assuming that you already have workable equipment for the job at hand.
So, the only point I’ll make here is simple: Use a tripod!
Certainly, there are cases where tripods don’t work – most street photography, aerial photography, underwater photography, and a few others – but right now, we’re talking about maximizing image quality. Unless a tripod simply won’t work for your shot, use one. It’ll do more good than anything else discussed below.
With that said, let’s move on to exposure.
2. Best-Case Scenario Exposure Settings
I’m going to start with the optimal settings for best-case scenario photos.
By “best-case scenario,” I mean that you don’t have any restrictions on what shutter speed you can use. You’re shooting from a tripod, and nothing in the scene is moving (or anything moving is meant to be a blur, like a waterfall).
I’ll cover the exceptions afterward, but they’re all just variations on the process below.
2.1. Aperture and Focusing
Before setting anything, note your lens’s “target” aperture – where it has the sharpest performance on a flat, test-chart-like scene.
For most modern lenses, this occurs somewhere from f/4 to f/8. But you should test your own lenses to be sure, or at least compare reviews online that analyze things like sharpness.
Here’s the key: This aperture (call it f/5.6) might be the target in terms of sharpness, but that doesn’t make it optimal for your photo. Quite often, you’ll need less or more depth of field than f/5.6 offers.
The first case is if you want a shallow depth of field – then, your job is super easy, and you can skip to the next section of this article. Just set whatever aperture gives you the depth of field you need. Don’t worry that you’re not at the lens’s “target” aperture. First and foremost, you need your photo to look right.
But shallow depth of field isn’t always going to be your goal. If you want the whole photo to be sharp from front to back, you’ll need to put in a bit more effort. Specifically, you’re going to balance depth of field and diffraction. That’s a big task, though not as hard as you might think.
I’ve covered the optimal method a few times in the past; it’s optimal because it leads to equally and maximally sharp foreground and background regions in your photo . That won’t always be your goal – sometimes, you’ll be prioritizing foreground or background sharpness over the other – but it’s a pretty excellent default.
Essentially, you focus using the double the distance method, followed by consulting charts to determine which aperture is mathematically ideal for maximum image quality. It goes like this:
- Frame the shot.
- Identify the closest object in your photo that you want to be sharp.
- Focus on something that is double the distance away from that object. So – if the closest object in your photo is a patch of grass a meter away, focus on something that’s two meters away.
- Use a chart derived from our sharpest aperture article to figure out which aperture best balances depth of field and diffraction.
- Set that aperture.
Creating the chart is where most people have hangups, but it’s not especially difficult. It takes perhaps 10 minutes of effort to whittle down the charts I already made into something useful for your gear. The whole process is explained in our earlier article.
For example, the chart (in feet) for the Nikon 20mm f/1.8 AF-S is below. Note that this lens has a “target” aperture of f/8, and it can’t stop down more than f/16:
If you don’t want to consult charts in the field, I don’t blame you. One alternative – which I hope doesn’t sound too crazy – is just to memorize the chart for your typical gear. It’s easier with a prime lens than a zoom, but doable regardless. And, again, this article is about maximizing image quality in every possible way. If that’s not your goal, just don’t follow these steps. An experienced photographer can guess a good focusing distance and aperture in most cases, no need to follow the technique above. Do whatever works best for you.
Set base ISO, and you’re done.
Many aspects of image quality are about gathering as much light as possible. With the lowest possible ISO value, you can use a longer shutter speed to gather more light while avoiding overexposure.
You’ve probably heard that some cameras have special “LO” ISO values that are lower than base ISO. Don’t use those; they’ll harm your dynamic range. Stick to your camera’s base ISO value instead.
2.3. Shutter Speed and ETTR
Next – set a shutter speed that exposes to the right (ETTR). I’ll explain the two different methods to do so in a moment.
ETTR is all about gathering as much light as possible, without gathering too much and overexposing important parts of your photo.
Somewhere along the way, photographers invented a myth that ETTR means capturing bright, overexposed photos. Frankly, in many cases (high-contrast scenes especially), the proper ETTR image is significantly darker than what the camera’s matrix meter recommends by default.
ETTR has nothing to do with capturing a photo that looks bright. It’s all about retaining 100% of your important highlight detail. Here’s how you do it:
Method One: Histogram
The easiest way to check if you’ve exposed to the right is to consult your camera’s histogram and see if any color channels are overexposed.
It’s not a flawless method, in part because the histogram on your camera is based on the JPEG preview. This means that you’ll get a very different histogram in “Vivid” versus “Portrait” picture control.
If you rely heavily on this technique, you’ll want to use the most neutral picture control, since it most approximates a RAW file.
Ah, forgot my usual disclaimer – shoot in RAW, not JPEG. Especially if you’re the type of photographer who reads articles like this, with the goal of maximizing image quality.
Method Two: Spot Metering
A more advanced way to figure out the optimal exposure is by spot metering on the brightest part of your photo. Then, dial in positive exposure compensation to place that part of your photo as a bright highlight – to be specific, as bright as possible so that you can still recover it 100% in post-processing.
It might take a moment in the field to figure out what the brightest part of your photo is, and the consequences for picking the wrong spot are almost certain to be overexposure. But at the end of the day, this isn’t too terribly difficult to do in the field, especially for something slower-moving like landscape photography.
However, the exact “100% recoverable point” is something you need to test ahead of time for your specific camera. With my Z7, it’s +2.7 EC (though I’ll often set +2.3 EC instead, to build in a bit of a safety net). Picture Control doesn’t matter here, since it is independent of your camera’s metering.
As an aside, this method – spot metering to expose the brightest tone of your scene optimally – reminds me a lot of Ansel Adams’s zone system, just a bit more digital. Kind of exciting if you ask me.
If you use the histogram method, the optimal way to set your white balance and tint to optimize histogram accuracy is to set “unitary white balance” or UniWB.
In short – use the flattest possible picture control settings. Then, turn “tint” as green as possible, and set the white balance on your camera so that the red and green color channel multipliers are as close to each other (and to 1) as possible.
You can figure out the white balance at which this occurs by examining your photos in EXIF viewing software. (For MacOS, I use ApolloOne because it’s free, although there are plenty of similar programs.) It’s labeled as “Blue Balance” and “Red Balance” in most EXIF viewers. With the Nikon Z7, for example, the UniWB is 4945 K, although you can’t set that exact value and need to use 4940 or 4950 instead.
To take this to the extreme, you can use a color filter on your camera to balance out the fact that the green channel generally clips before the others in sunlight. I recommend a 30% magenta filter (specified as cc30m or cc30p by most filter companies) or a 40% magenta filter (cc40m or cc40p).