Lessons from Rozov: What’s a flash?. Part 1

A flash is a glass flask straight, spiral, horseshoe or even ring-shaped which has been evacuated, filled with a special xenon gas, fitted with two metal contacts anode and cathode and charged with high voltage from an electrolytic capacitor. A few coils of thin wire were wound on top of the bulb, to which a source of very high voltage several thousand volts was connected.

Photo 1. In the midst of a noisy ball.

Camera: Nikon F5

Lens: Nikkor 28-70/3.5

Film: Fujichrome Astia 100 ASA slide digitized and converted

Shutter Speed: 1/60th of a second

Aperture: f/5.6

In my photographic youth I could never have taken a picture like this without flash. But even with flash, it was a big challenge in those years. Flashes were as simple as a hammer. They can only charge for a long time and then completely discharge right away. There were no automatics yet. And yet photographers have contrived to shoot in dark rooms, relying almost entirely on their instincts and their automatic control skills.

In this case, the light is softened by a piece of white paper – a burlap put on a flash head raised from the ceiling.

An electric arc like an electric welder is created in the bulb when a pulse is sent to the outer wire, ionizing the xenon inside the discharge lamp. The charge of energy stored by the electrolytic capacitor pierces the thickness of the gas, releasing many photons particles of light into space. As soon as the charge in the capacitor runs out, the arc goes out. This is the basic construction of a flash.

Flashes were invented before World War II, because film sensitivity was very low at the time, and the need to take pictures in any lighting conditions was born with photography itself. Pulsed light sources revolutionized. You can now take pictures of moving objects indoors, at night, in railway stations and airports. It became difficult to hide from intrusive society photographers. The public got a glimpse into the details of big city nightlife. Sports reporters were able to capture the most dramatic moments of fast-paced sports such as boxing, wrestling, and soccer. Portraits can be taken more easily in the studio. Without automated pulsed light sources, a modern photographer would have a hard time photo 1 .

There are different kinds of flashes

You have to keep in mind that behind the word “flash” there is a trail of products, even superficially not much alike. What they have in common is that they all have the same purpose: to light up a space when you take a picture. There are two big groups of flashes: Reporter and studio flash.

Reporter flashes are divided into three groups by location: built-in, on-camera, and remote.

Built-in flashes are built into the camera body very close to the optical axis of the lens. These flash units are available on entry-level compacts and SLRs. It is because of their location they create a light and shade pattern that photographers call “pancake” disdainfully, because the light in such pictures is flat, devoid of shadows and looks like the light from millions of other compacts like them.

On-camera flashes can be mounted on the camera’s hot shoe. These flashes usually have a rotating head which can be aimed at the ceiling, walls or any other reflective surface to achieve a more natural and three-dimensional shadow pattern.

The remote ones shine on the object from anywhere. The control of such devices can be manual, but they can also be automated. Sometimes they are combined into a group of slave units which are automatically controlled by a master unit mounted on the camera’s hot shoe, or by the camera itself. These systems give you the flexibility to control the light in the field of view without relying on chance.

Camera flashes and remote flashes photographers are divided into two types according to consumer attributes: system and universal.

System flash units are manufactured by the same company as the camera you use. Canon, Nikon, Sony, Olympus and others make system flashes for their cameras.

Versatile flash units are available from third-party manufacturers. These flashes have adapters that allow them to use with cameras from different manufacturers.

System flashes are more expensive than general purpose flashes of the same power. But the desire to save money can get you into trouble. The fact that the flash ignition control is low voltage most modern cameras around 5 V and high voltage about 200 V . Using universal flashes on new digital cameras can cause them to malfunction. They burn very often, and repairs are more expensive than buying a new unit. So 200 V flashes are only good for use with mechanical film cameras or as off-camera flash units.

Circular flashes have a special place among compact camera flashes. They are designed for macro photography. Rear-facing designs which attach to the front of the lens. Light is emitted on all sides of the subject at the same time, so the image appears shadowless. There are actually shadows, but it’s as if they are dissolved, because each point that emits light has an antipode point on the opposite side of the ring, emitting exactly the same amount of light, which fills or rather dissolves the shadow formed by the first point.

Also, it should be understood that all shadows are directed toward the center of the image. The light of a ring flash is like a pencil drawing, with delicate tonal transitions from light to shadow. It meticulously renders the finest details of skin texture, draws the hair. Glamour magazines sometimes use ring flash light to produce unusual portraits of young beauties. But in this case retouchers and make-up artists have to work hard to hide skin defects typical for living people photo 2 .

This makes it easier to take pictures of non-glare subjects. For example, vintage coins photo 3 .

The use of ring flashes in macro photography is limited by proximity to the subject. When you shoot a small flower, for example, the lamp surface can be only five centimeters away from the flower, but twenty from the surface of the background, which leads to a significant drop in the background illumination, which not only gets darker, but also changes color photo 4 .

Studio flashes

Unlike their smaller brothers, who were born to be with the photographer wherever he or she happens to be, studio flashes are permanently prescribed in dark studios, where the time the arc in the flash lamp burns, the human eye does not have time to discern and appreciate the distribution of light in the frame. That’s why these devices can do more than just flash. They have built-in lead, or modeling, halogen lights that burn all the time. With these lamps the photographer first arranges the light and shade pattern of the future frame, and then shoots with a strong, but short pulse.

Studio flash units are more powerful and heavier than a reporter’s. Industry produces two types of flash units for the studio: monoblocs and generators.

Monoblocks are arranged according to the principle “all in one case”: power supply, electronic circuit, storage capacitors, pulse lamp, master lamp, loop of changeable reflectors. Each monoblock is quite a weighty box. You need a heavy stand to keep it firmly in place. The power of monoblocs ranges from 100 to 2000 joules.

Generator flashes are very powerful devices, their design provides spatial separation of several light heads and a single generator. Each generator flash light head consists of a reflector, pulse lamp, halogen and a long, thick wire. The generator incorporates everything else: the power supply, the battery of electrolytic capacitors, the circuit, the housing with the controls.

The light head weighs considerably less than a monoblock, but this advantage is offset by the fact that it has a thick and heavy wire. It can’t be thin, because there is a big current flowing through it every time it is triggered. Electrical resistance would cause the thin wire to overheat and risk a studio fire.

That’s why the length of such a wire is limited. In studios equipped with these flashes, the wires lie directly on the floor or hang from the ceiling. It’s not always convenient. There can be two or three heads in a generator set, the total power ranges from 1200 to 5000 joules.

Both generators and monoblocs have their devotees. Photographers who tend to move around in space prefer more mobile monoblocs. Homebrewers working only in studios are generators. But the industry also produces generators for on-location outdoor shootings. They are battery-powered.

All studio flashes are designed to create light in the studio that imitates some kind of natural phenomena or arbitrarily invented patterns. Thanks to the studio, the photographer can work at any time of day and in any weather. Generator flashes and monoblocs are equipped with a large set of devices that allow you to change the light head: to scatter it with umbrellas, soft boxes, light disks, or, conversely, to gather in a beam with spot heads, tubes or honeycomb filters, to color with light filters or polarizing, change its direction relative to the machine. In a word, the flash in the studio is something like a controlled sun in miniature photo 5 .

Flash sync terminal and shutter speed

Cameras have a “hot shoe” – a special socket with small slats – to connect their hot shoe flashes. The flash is inserted into these slats and locked securely with either a threaded nut or some other lock. The hot shoe is where the contacts for connecting the flash to the camera are located. Each company adheres to its own connection system, one company’s flashes will not work with competitors’ cameras.

That’s why the connection to the cameras studio flash or third-party flashes on the body of many DSLRs and mirrorless retains a special jack – sync terminal. The shape of the flash socket has been standardized since the film days. I wouldn’t call it a good camera, the connection is not very reliable. The wire going to the studio or any other flash is not fixed in any way. It’s easy to yank it out with an accidental movement at a crucial moment in the shot. You have to be careful or buy wireless infrared starters and radio control systems which are inserted in the same “hot shoe” slats and are fixed there securely photo 6 .

But no matter which shutter method you use you’ll have to go into your DSLR and choose a shutter speed. Mirror cameras and mirrorless cameras are usually equipped with a shutter. The shutter lets light into the sensor by means of a mechanism consisting of several horizontal lamellae. When closed, all slats build a fence in the light path from the lens to the sensor. The moment your finger presses the shutter release button, some of the slats drop down, opening the exposure window for the time set by the exposure meter. After the exposure time expires, the top stack of blades falls down, covering the sensor from the light.

I described a situation where the frame window opens fully for a brief moment. All would be great if it happened to all shutter speeds, but there is a technical limit after which the camera does not have time to fully open the frame window, and because shutter speeds shorter than 1/250 sec works subtly. He has to light the frame by opening only narrow slit between two lamellae and move this slit downwards until the whole frame area is exposed. If you shoot at, say, a shutter speed of 1/350 seconds, only part of the frame will be lit. The illuminated streak can be quite narrow if the shutter speed is set to, for example, 1/4000 s.

Pro and amateur DSLR manufacturers make sure to specify a shutter speed of sync in the menu. Thirty years ago all the great pro DSLRs had a sync speed of about 1/60th of a second. Today we’re up and down, and 1/250 seconds is the norm. Up just two exposure steps in the lifetime of the generation of technical geniuses who invented computers, cell phones, and digital photography! But most likely the engineers have already squeezed everything they could out of the mechanical lamella shutter. Further development will take some new, electronic path.

Note to the more curious: Most camera phones and cameras are equipped with central shutters that synchronize with flashes at any shutter speed without restriction, because the flash only triggers when the shutter is fully open, and the shutter itself is designed so that it is fully open at any shutter speed.

Is the sync shutter speed that important to the practicing photographer? I remember well how in my youth shot with “Zenit”, which had a synchronization occurred at 1/30 seconds, that is, when you turn on a flash camera shutter worked one-third of a second. This shutter speed is considered dangerous when shooting handheld with a Poltinoc or any TV set, even a portrait one. You can avoid blurring and lubrication only if you take care of that. But the flash is fleeting. The average flash duration for a studio flash is 1/500 sec. Consequently, you can get a blur for the time it takes to fire the flash only when the subject is moving quickly in the frame. But the frame window was fully open precisely at 1/30 second, and during that time the picture drawn by the master halogen and all the other light sources that were around had time to overlay the sharp image drawn by the flash. When synchronizing at 1/250 sec the situation changes dramatically. The flash still provides 1/500 s, but the halogen only affects 1/250th of a second. Halogen light is no longer enough to paint your own picture in such a short amount of time. In practice, if you shoot at minimum sensitivity in the studio, the warm light from the halogen will not affect either the sharpness of the picture or its color temperature photo 7 .

Photo 2. Portrait.

Camera: Nikon D2X

Lens: AF-S Nikkor 17-55/2.8 ED

Sensitivity: 100 ISO

Shutter speed: 1/250 s

Aperture: f/7.1

85 mm focal length on film standard

Circle flash

An example of using the ring flash for a portrait of a woman. Despite the lack of deep shadows, the image did not lose the feeling of three-dimensionality.

Photo 3. Commemorative medal for the marriage of Tsar Nicholas II and Princess Alice of Hesse.

Camera: Nikon D3

Lens: AF Mikro Nikkor 105/2.8

Sensitivity: 100 ISO

Photo 4. Vanka wet.

Camera: Nikon D2X

Lens: Micro-Nikkor 55/2.8

Sensitivity: 100 ISO

Sync shutter speed: 1/250 s

Aperture: f/11

Circle flash

A flower from the balsam family has been living on our windowsill for years. When I got the ring flash in my hands I immediately tested its charms on this humid plant. The flower is only two centimeters in diameter. Distance from the front lens of the macro lens – about 5 cm, to the background – 20 cm. You can clearly see the change in the color of the greens when the amount of light goes down.

Photo 5. Red Fetus from the “Fruits of Love” series .

Camera: Fujifilm FinePix S2 Pro

Lens: AF-S Nikkor 17-55/2.8 ED

Sensitivity: 100 ISO

Shutter speed: 1/160 s

Aperture: f/11.3

Focal length: 70mm film standard

Studio portrait photography. Only one monoblock was used. The “sun” had a power of 400 Joules and it was directed at the ceiling and the upper part of the wall on the left side of the characters. Filling in the shadows was due to light reflection from the white walls of the room.

Photo 6. About the lanternman and the polar day in Petrozavodsk.

Camera: Nikon D2X

Lens: AF-S Nikkor 17-55/2.8 ED

Sensitivity: 100 ISO

Shutter speed: 1/50 sec

Aperture: f/7.1

Focal length: 28mm film standard

In Petrozavodsk, I took this photo for the American Utility Systems photo bank. The plan of shooting included a section on keeping the street lights in order. But there’s one problem: they turn off all the city lights in the summer. The sun is shining almost all day long, because it’s polar day. At night the sun goes below the horizon, but it shines from there as well. What’s a poor photographer to do?? I wouldn’t come to Petrozavodsk in the fall just for this one piece. I had to use a Nikon radio-controlled system flash. To make it produce the warm glow of an incandescent bulb, I put a teal-colored filter on the head of the flash.

Photo 7. Spring tan.

Camera: Nikon D3

Lens: AF-S Nikkor 24-70/2.8 ED

Sensitivity: 200 ISO

Shutter speed: 1/250 seconds

Aperture: f/11

Focal length: 48 mm

I set up a studio in a semi-darkened marquee in Kharkov. The spring sun that paints the hero’s body so beautifully never peeked through there. On the left side of the high stand I mounted just a mono-block with a small soft-box, on the right side I mounted a big white light disk for shadow illumination. While waiting for the trainer, we took a formal portrait of her assistant. Note: neither the halogens nor the diffused light that penetrated through the chapeau slits affected the color reproduction. The flash power at maximum synchronization shutter speed eliminated the influence of the stray light.

Continued.