Mastering your exposures will give you consistently better results, especially if you shoot film. You will add fidelity to your images and get better control over your colours and contrast. There will also be less work for you to do in post-production to get the desired results.
This guide to perfecting your exposures covers advice for both manual and point-and-shoot film cameras.
What is a perfect exposure?
A perfect exposure captures the light in the exact way you’ve envisioned. An example of such an exposure is a photograph you find no reason to edit after scanning as it looks precisely the way you want it to. Personal preference is a factor.
Exposure, in this context, is limited to the amount of light your film receives — we are not talking about composition, blur, etc.
✪ Note: A normal exposure, which I define differently from perfect exposures, is discussed in detail below.
If your exposure isn’t perfect, you may still tune it to your needs after scanning your image with tools like Photoshop or Lightroom. The same goes for printing in a darkroom. However, the amount by which you can alter your exposures in post-production will depend on the film, the scanner, the printer, and the paper the image is being printed on.
In some cases, you may be able to change your image significantly without noticeably degrading its quality. But all images will lose some detail as you alter their brightness.
Now that we know what the objective is, let’s consider a few technical definitions and tools for measuring and understanding light.
18% middle grey.
Middle grey is the shade we identify as halfway between the darkest and the lightest colours in a scene.
A series of experiments determined that a point on a greyscale gradient strip that reflects 18% of the light is seen by most as middle grey. This finding has a significant implication for photography. It is foundational to the science of colour perception and is applied in image processing software, screen, print, film, and digital sensors.
Reflective light meters.
Your camera’s reflective light meter works by measuring the 18% middle grey point’s lux output. It finds the middle grey point by calculating the geometric mean of all the light reflecting off your scene within its range. Most of the time, that works. However, there are cases when a meter will falter.
The most common way reflective light meters fail is when they are pointed at a backlit subject. In this scenario, most of the scene is lit up by intense light while the (darker) subject of interest is relatively small. As a result, most meters will bias their readings to create optimal exposures over the largest (brightly lit) area, leaving the subject as a dark silhouette.
In fact, this happens so often that many film cameras with built-in light meters have a dedicated button meant to correct the exposure readings for this situation.
✪ Note: Another way to solve the backlit subject problem is via fill flash, which lights up the subject to match the bright background.
A spot meter is a reflective light meter that takes measurements from a small area of your frame. To get a light reading, you’d point it to a spot that you’d like to appear as middle grey in your image. Most of the time, it’d be something like a light-coloured leaf or an asphalt pavement, though a more precise reading would be from a grey card (a piece of paper or another material that reflects about 18% of light) placed next to your subject.
Some cameras will have a combination of both types of reflective light meters. Others will weigh several light sensors’ output and bias their measurements towards the middle of the frame. Some digital cameras will attempt to find faces and bias light measurements towards their tone.
Though the above and many other available technical solutions tend to improve the success rate of light measurements, there are still situations when a machine will fail to capture the photographer’s intent. For example, you may want to take a picture where your backlit subject appears as a black silhouette, but your “smart” light meter attempts to “correct” that, going against your wishes.
Incident light meters.
Another type of a light meter guarantees a correct middle grey reading as long as you place it next to your subject. It works by measuring the incoming light rather than reflected light.
However, you may not always have an opportunity to walk up to your subject and take a reading with your fancy light meter.
You can also estimate your exposure measurements without a light meter using the Sunny 16 rule:
Under full sun, correct exposure is set by dialling your shutter speed to approximately 1/ISO and aperture at 𝒇16.
For example, if you’re shooting ISO100 film in full sun, your aperture should be 𝒇16 and shutter speed — 1/125s.
Though the Sunny 16 rule works only under the full sun, with practice, you may be able to estimate your measurements under various light conditions. For example, you may remember that a light shade is about three stops darker than a sunlit scene and thus would call for 𝒇5.6 aperture (-3 stops) and 1/125s shutter with an ISO100 film.
➜📱 Sunny 16 Calculator — A free app I built to simplify exposure readings with the Sunny 16 rule. It has visual illustrations for 12 light conditions with an easy way to adjust your camera settings without altering the EV.
Metering for shadows.
Film negatives have more exposure latitude in highlights. This means that you are less likely to get harsh gradient transitions and loss of colour information in your images’ bright areas than in the shadows. You will also get better results fixing images that are too bright than those that are too dark.
Because of that, it is often advised to err on the side of overexposure while shooting with negative film.
As you may recall from the above sections about reflective light meters, those devices will look for a middle grey point by calculating the geometric mean of all the brightnesses in the scene. And so, when you point them towards the darker areas, their calculations produce readings conducive to brighter exposures.
This effect is more pronounced with spot light meters as it has fewer shades to average its reading over.
Essentially, pointing your light meter towards the darker areas of your scene increases your future photograph’s brightness and ensures that your shadows have more of their details preserved.
✪ Note: Slide or reversal film does not work that way; thus, you should avoid metering for shadows with these emulsions.
Exposure compensation techniques.
Exposure compensation means altering light meter readings for a particular purpose.
For example, your camera’s backlit subject mode is an exposure compensation tool. It works by adding +1.5 or +2 stops of exposure to the built-in meter readings.
Backlit subjects aren’t the only reason to use exposure compensation. Others include creative choices, sunset/sunrise photography, and nature photography.
You may also think of metering for shadows as an exposure compensation technique. However, while doing so, you are rarely sure how much you are compensating your readings by.
Though it may be easy to identify a backlight situation — when you are shooting your subject with the light behind them — you should spend some time with your light meter to understand what it tends to pick as middle grey in your scenes. As discussed above, there are different types of light meters that use various methods to determine their middle grey point. And so once you get familiar with yours, you’ll know better when to compensate, which way, and by how much.
A good way to understand your light meter (external or in-camera) is to use it and observe the results it produces. You may also bracket your exposures which should give you additional insights.
Film cameras with exposure compensation controls like Minolta TC-1 will make adjusting your exposures relatively easy. Others like Minox 35 will have just a backlight compensation button; Yashica Electro 35s don’t have that button, but you may use the ISO setting dial to “hack” your exposures.
Finally, cameras with fully automatic autoexposure, like Olympus Mju I, may only allow you to choose your middle grey with an exposure lock (i.e., you will be able to meter for shadows). Simple cameras like Diana Mini will have a few crude exposure settings. And manual cameras like the Voigtländer Vitessas or the Rollei 35s will give you full control over your exposures with a built-in uncoupled light meter serving as a guide only.
Identifying underexposure and overexposure.
I’ve noted above that a perfect exposure is the one that captures the shades and highlights in the way you’ve envisioned them. This could mean that your photograph ends up rendering the light darker or brighter than seen.
There are many ways to expose the same scene; however, it is also useful to consider an idea of a normal exposure — something that would produce scan/print results that closely approximate human vision most of the time.
A normal exposure is made with readings from a light meter without any changes. The concept of a normal exposure isn’t precise as different light meters will give you varying readings, and so will the photographers who use those meters. But for most scenes, the normal readings agree or approximately agree amongst most good light meters in capable hands.
Aside from appearing natural in your scans and prints, normal exposures tend to create negatives with a balanced pigment density and histograms that look centred.
✪ Note: You can bring up your film scan’s histogram using a tool like Photoshop by selecting Window > Histogram.
Underexposures deviate from normal exposures by allowing less light onto film. The result is thin negatives (light/mostly transparent film) and histograms that shift to the left. Underexposure is useful if you want to preserve more details in your highlights at the cost of your shadows.
Overexposures deviate from normal exposures by allowing more light onto film. The result is dense negatives (dark/mostly opaque film) and histograms that shift to the right. Overexposure is useful if you want to preserve more details in your shadows at the cost of your highlights.
In Figure 1, I placed under-, normally-, and overexposed versions of the same image along with their histograms next to each other. Out of those three versions, I prefer the underexposed one:
Underexposure and overexposure side-effects in film photography.
Film tends to produce technically optimal results with normal exposures in the scenes that match its dynamic range.
So a wide dynamic range film such as CineStill 800T would work best with high-contrast scenes such as bright daylight or artificial lighting, whereas a narrow dynamic range film such as Fujifilm Provia 100F is best suited for medium to low-contrast scenes such as the golden hour, a light shade, or fog.
Matching the scene’s contrast to your film’s dynamic range will improve your chances of capturing the most detail in shadows/highlights and give your extra leeway for adjusting your final image’s brightness in post-production.
✪ Note: You can find your film’s dynamic range information in most emulsion reviews on this website. You can also find it for all films with film characteristic curves published (as long as you know how to read them).
For your reference, human vision is estimated to have about 14 stops of dynamic range.
As discussed, negative films will usually be more forgiving when it comes to overexposure. However, black and white films tend to lose some contrast when overexposed and overexposed C-41 films often introduce colour casts along with some diminished contrast.
Bringing the contrast back to the overexposed black and white film frames isn’t difficult in post-production — whether printing or via Photoshop — however, not all films will react to those changes equally. Some will have no problem with your adjustments; others will begin to lose details when you adjust your contrast.
Colour correcting overexposed C-41 film may or may not be a daunting task — depending on the film and your end goal. Though some may say you can make any colour emulsion look like another in Photoshop, I disagree: extreme alterations to colour will noticeably degrade the quality of your picture.
However, some photographers overexpose their C-41 film with a specific goal of producing colour shifts. You will notice that some Kodak Portra film shooters will add one or two stops to their exposure to create “pastel” colour palettes.
Underexposures are typically less desirable with C-41 film as the colour shifts mix with diminished details, larger film grain, and dark/noisy high-contrast shadows.
Although, when it comes to black and white negative film, I prefer a slight underexposure to overexposure since I like my monochrome images to appear contrasty.
Slide or reversal film usually comes with significantly less dynamic range than negative film and is thus less tolerant to over/underexposures. Overexposure on reveresal film typically means that large portions of your image may appear completely white while underexposures may still be recoverable.
Steps for creating your perfect exposure.
Putting all of the above into practice:
1) Pick a film that matches your scene’s dynamic range. High contrast scenes will work best with a wide dynamic range emulsions and vice-versa. Wide dynamic range films will be more forgiving of exposure mistakes.
2) Meter your scene to determine a normal exposure. Know your meter and be mindful of the 18% grey point for best results.
3) Consider overexposing your film for more details in the shadows or underexposing if you want more details in your highlights. Remember that negative film is more forgiving of overexposure — the opposite is true for slide film.
4) You may alter the brightness of your image after you scan it or in print, but your film’s dynamic range, scan quality, and development may limit your ability to do so.
My final piece of advice would be for you to try measuring light using a mobile app, such as Lumu. They are reasonably accurate; better yet, they show how bright or dark your image may appear as a result of your exposure adjustments.
❤ By the way: Please consider signing up for your Adobe Creative Cloud membership (there’s a “photography” plan that comes with a Photoshop/Lightroom license) using this link so that this website may get a small percentage of that sale — at no extra charge for you — thanks!