A Simple Guide to Using Flash on Manual Film Cameras

✪ Note: In this guide, I refer to external on-camera flash devices as flashguns; this is what they used to be called, also flashcubes. Today they are referred to as speedlights. Mine are simple plastic black boxes with a bunch of numbers on them and no controls other than power and discharge buttons. This article only covers those features (power and discharge) and a few simple sync scenarios.

Getting a proper exposure of your subject in the dark could be challenging. Flash is a great help, although it too can ruin your perfectly framed shot if it isn’t tamed. Using a manual camera with an external flashgun gives you some additional control and flexibility to produce better images or enable shooting in light conditions previously unsuitable for your vintage camera.

Using external flash, especially with manual exposure cameras, may seem daunting at first, but it isn’t that hard.

Setting expectations.

Scenes lit by simple flashguns do not look natural. This is true, regardless of how modern your camera is. The latest devices may have greater control over the light volume and colour temperature, but it’s still quite easy to tell if the image was artificially illuminated.

Flash tends to create strong shadows, stark highlights, and blue tints, which may make the image seem “flat.” When shot in colour, the eyes can appear bloody red.

These artifacts are capable of disappointing photographers. Though uncommon and quirky experiments may stand out nicely in some contexts.

Mindfully choosing your scene, camera settings, and film type can reduce or emphasize those effects.

Of course, there are also hard limits to the effectiveness of a small flash. Typically good enough for a room, it won’t do much beyond a few feet/meters away from the camera. It’s practically impossible to see how the light will interact with the scene, and you are limited by one strong source with no advanced options like controlling the colour temperature, diffusing, etc.

When calculating exposure with flash, you may ignore shutter speed.

 ☝︎The altered function of a camera shutter is the key concept to understanding flash photography.

A flashgun is capable of flooding the scene with bright light for a very short period of time. Up to about 1/1000th of a second, depending on the device. During this moment, the camera has a chance to properly expose the film. But before and after the spark, it’s darkness — as far as your film is concerned.

Should the photo be taken in low enough light conditions, the flash will functionally replace the shutter.

In pitch-black, the shutter may be left open indefinitely, as the flashgun is to replace its function of exposing film for a short, controlled slice of time with its illumination. Once the light is gone, the darkness provides the same environment as the closed shutter — the absence of light.

Exposure = aperture~distance.

The timing of the flashbulb is consistent, but the amount of light that returns to your camera isn’t. Even though the bulb has constant luminescent power, the number of photons that get reflected depends on the distance from the illumination point (your flash) to your subject.

Just like with a flashlight, things close by are clearly visible, but the stuff that’s far away is dim.

Even though the flashbulb practically replaces the camera’s shutter, we still need to adjust our settings for correct exposure to compensate for lost light due to distance. With the shutter “out of the picture,” the only tool at our disposal is the aperture since the film’s ISO can not be changed mid-roll.

✪ Note: Older cameras and flash devices may mark film speed in DIN and ASA. DIN is rare to find on film canisters today, but ASA is just a different name for ISO. Use this app to convert DIN to ASA.

You may use a specialized exposure meter to calculate the aperture value you need but, most of the time, it’s not necessary. Flash manufacturers often provide an exposure chart mounted directly on the device. It gives you an aperture value based on the distance between the flashgun and the subject, plus film ISO.

If there’s no chart, please refer to the chapter below on how to make your calculations manually.

All you need to set your camera’s exposure is an estimate of the distance from your flashgun to your subject. Look up the aperture value for that distance and the film speed you’re using. Your shutter speed may remain unchanged.

For added precision, you can focus first and read the meter/ft value off your camera instead of trying to guess it. You may have to eyeball your distance, i.e., zone focus, if it’s too dark for a rangefinder.

Because shooting flash up close will require relatively small aperture values/high 𝒇-numbers, there’s less chance of blurring your subjects.

What to do if you can’t find an exposure chart for your flash.

You can make your own calculations using a guide number (GN), which the flash would either provide or you can look up online by searching its make and model. Here’s how the manufacturers calculate their guide numbers:

GN = aperture ✕ distance (measured with a film speed of ISO 100).

Note that there are separate guide numbers for measuring feet or meters. Flash units will typically list those as such, you may look them up, or you can assume that flashes made for the US or the UK (and maybe Canada) would be in feet, while the rest of the world would use meters.

Using the above formula, we can calculate the aperture that you need to set on your manual camera (remember, shutter speed doesn’t matter). Let’s say we’re shooting an ISO 100 film and the flash guide number is 10 (in meters) and we are standing 3 meters away from the subject. Plugging those numbers into the formula above, we get:

10 = aperture ✕ 3m

This gives us the aperture of (10 / 3 = 3.33) or 𝒇2.8 as the nearest aperture mark at the lens.

Let’s change things up with a guide number of 60, and a distance of 10m while shooting with ISO 400 film. At ISO 100, our guide number formula will look like this:

60 = aperture ✕ 10m

Which computes into (60 / 10 = 6) or 𝒇5.6 as the nearest aperture mark at the lens. However, we aren’t shooting with ISO 100 film, instead, we’re using ISO 400, which is faster than ISO 100 by 2 stops (ISO 200 is 1 stop faster than ISO 100, ISO 400 is 2 stops faster than ISO 100, ISO 800 is 3 stops faster than ISO 100, etc.) Because the film we’re shooting is 2 stops faster, we simply need to change our lens’ aperture number to be larger by 2 stops, which is 𝒇5.6 → 𝒇8 → 𝒇11.

You can also convert your guide numbers from meters to feet and back. There are about 3 feet (3⅜) in a metre thus we can multiply the above example’s 60 by 3 to get 180, which is an approximate guide number that can use feet for distance in the formula.

Or you can look online or in your device’s app store for “guide number calculators” to do all of this work on your behalf.

Synchronizing flash with the shutter.

The flashgun needs to fire in sync with the shutter release, precisely when the curtain or blades open and the light can reach the film. Analogue cameras come with a device that closes the contact and triggers precisely synchronized flash discharge.

The camera’s triggering mechanism may be connected to your flash via the hot shoe — a contact inside the accessory mount on relatively modern models. Older cameras could do the same with a PC (Prontor/Compur) -socket via a special cable (which can be found here).

Synchronizing flash is best done with leaf-shutter cameras, i.e: Vitessa, Electro 35, and Rollei 35. Focal-plane shutters (generally found on SLRs & some rangefinders) expose film gradually as the slit in the curtain travels. Because of this, at certain speeds, a part of your frame may be obstructed when the scene is lit by flash. Extra care may be needed with these shutters.

Leaf shutters expose the entire film plane at once, so all you need to do is make sure that this happens at the right time. Modern electronic bulbs are capable of lighting up the scene instantaneously; setting your camera on X “xenon” mode will do the trick. Plane shutters may also sync with your xenon flash but typically at a set speed of either 1/60th or 1/30th of a second (usually marked on cameras with red font or a flash ⚡ symbol) when the slit becomes as wide as the entire frame. This isn’t an issue unless you want to control the amount of ambient/non-flash light reaching your frame.

For plane shutters (on cameras like Leica, FED, Canon SLRs, and Prakticas), you may find special flash devices that can lift the limitation of a set shutter speed. They are FP (flat-peak) and HSS (high-speed sync) -type. The first delivers a longer, controlled burst of light. The latter creates multiple flashes throughout the exposure (you can find HSS flashes here). Both ensure that there’s ample illumination available, wherever the slit of the plane shutter may be relative to the film plane.

That’s not all. Older bulbs would not reach their peak brightness until a few milliseconds after triggering, which required timed synchronization. This is what S (slow), M (medium), and F (fast) modes on some cameras are made for. Each would delay releasing the shutter a certain amount of time after triggering the flash.

Finally, you may choose to get creative and set your camera into Bulb mode, holding the shutter open, and triggering the flash by hand before closing the shutter again.

Mixing light sources.

Flash isn’t just for pitch-black situations. It can be used in the daytime, most commonly to fill the backlit subjects’ shadows. For example, if you’re photographing a person against the sun, you can avoid a dark silhouette in your photo by lighting up their face artificially. This technique is called fill-flash.

Another case for flash in the daytime may be the need to use a higher shutter speed, i.e. if you’re trying to freeze the motion of a fast-moving object while shooting slow film.

When mixing light, you may want to ensure that your flash does not over-expose your shot by metering for the brightest light. For example, if you determine that your scene calls for 𝒇2.8 at 1/60th of a second while you’re 1.5 meters away, but your flash tells that at this distance, you should set your aperture to 𝒇8 — listen to the flash. Your ambient light will have a limited contribution to your shot, but it’s more likely to get an even exposure.

To increase ambient light’s influence on your image, using the above example, you could change your shutter speed to 1/7th of a second, which will provide an equal amount of ambient and flash’s light. It may be a good idea to use a tripod in this scenario if you don’t want any motion blur. This technique is called “dragging the shutter.”

 ☝︎Further reading: “Continuous light vs. Instantaneous Flash” — A Few Scanning Tips.

Getting cleaner shots with flash.

Depending on the aesthetic of your future photograph, you may want to attempt to correct some of the artifacts characteristic of flashing photography. Studio lights, umbrellas, bounce lights, diffusers, and other elaborate setups will do that and more, but for this simple guide, we can use a few tricks with just one basic flashgun.

Because colour rendering in artificial light is complex and prone to gaining an unnatural look, shoot black and white.

Control your shadows by holding the flash away from your camera. This could be achieved either with a PC sync cable or by opening your camera’s shutter with Bulb and triggering the flash with another hand when you want the exposure to happen. The latter technique will introduce some motion blur if you have enough light to expose your film without the flash. The direction of your shadows may alter the scene and portraits dramatically. This technique will also help you avoid the dreaded red-eye in your images.

Soften your shadows by lighting your scene from further distances. This is another great reason to hold the flashgun away from your camera if you could help it.

Feel free to experiment and do further research. There’s a lot to learn in the world of artificial lighting — this guide is just the basics. Thankfully, getting started with flash on manual cameras is as easy as measuring the distance and setting the appropriate aperture.

Buying a flash unit for your camera.

If you’re planning to shoot slower films, at narrower apertures (higher 𝒇-numbers for greater depth of field) or longer distances — look for flashes with larger guide numbers, for example:

☞ Minolta Auto 360PX (GN: 118 feet/36 metres).

☞ Minolta MAXXUM 4000 AF (GN 131 feet /40 meters).

☞ Minolta 3500xi (GN: 114 feet/35 meters)

If all you want is something that works for indoor portraits or non-specific photo projects, get something that isn’t too expensive, tested to work, and fits your camera well, for example:

☞ Rollei 121BC (GN: 27 feet/22 meters).

☞ Rollei E15B (GN: 65 feet/20 meters).

☞​ Konica HX-19 (GN: 59 feet/18 meters).

Before making the purchase, you should ensure that what you’re getting is tested — there is no excuse not to since all it takes is pressing a button (as long as the seller has the right battery for the unit). Most post offices and curriers forbid batteries in packages — make sure you have the right ones at home (most flashes just take AA).

❤ By the way: Please consider making your next flash-related purchase using the links above  so that this website may get a small percentage of that sale — at no extra charge for you — thanks!