Tethering

Learning goal

You will be able to check every frame that comes out of the camera on a large screen as soon as it is transferred to the computer. You will explain why the camera's small screen can be misleading about sharpness, color and brightness, and on the computer check sharpness by enlarging the frame to actual size, exposure with the histogram, and color with a gray reference. You will know when running the shoot from the computer is useful, set the shooting pace by taking transfer delay into account, and name files within a capture session and save them redundantly to both card and disk. You will make the selection during the shoot by looking at the same screen as the client, and keep the safety of the cable and the setup in mind. In a portrait shoot you will pay attention to whom the screen faces and whether the model is ready to see their own face on a large screen, and know how an uncalibrated screen can distort different skin tones.

The question

The silversmith on the market street wants a catalog for the pieces in their window; the older club member has taken on the job, and your friend is assisting. On the test day, after every frame they look at the screen on the back of the camera: the stones are gleaming, the silver clean, everything sharp. In the evening, when they open the files on the computer, they notice that the stone of one ring is soft, a silver necklace has shifted slightly toward yellow, and dust is visible in a close-up. Half of it needs to be shot again. On top of that, the silversmith wanted to decide which frames would go in the catalog while the shoot was going on, but three people couldn't fit around the camera's screen.

The next morning they connect the camera to a laptop with a cable. Each frame appears on the large screen within a few seconds; the stone's sharpness is checked at actual size, and the shop owner marks the frame they like right there. Why would you want to see the photo on a computer while you shoot? How can a frame that looks flawless on the camera's screen give away its problems on a large screen?

Context

In the color profiles lesson we defined screen calibration as bringing a screen's color and brightness to a known standard with a measuring device (Lesson 11.9). In the culling lesson, too, you saw how to go through a shoot's frames and set aside the ones to be used (Lesson 17.3). Tethering carries these two jobs into the shoot itself: you see the frame at once on a calibrated screen, and make the selection while still in the scene.

The screen on the back of the camera is small, its brightness changes with the ambient light, and the image it shows is usually not the raw file itself but a small preview the camera produces from it. That is why a frame looking sharp and correctly colored on the small screen doesn't guarantee it will be so in a large print or on a catalog page too. In the studio, in product shooting and when working with a client, this difference turns directly into lost time and money.

Simple explanation

What does tethering change?

Tethering is connecting the camera to a computer with a cable or over a wireless network, and every frame shot being transferred to the computer instantly and displayed on a large screen. A few seconds after the frame is shot it appears on the large screen and can be enlarged there to actual size. Whether a stone's edge is sharp, whether there is dust or a fingerprint on a necklace's ring, every detail missed on the small screen shows in this enlargement.

The large screen makes it easier to check not just sharpness but exposure and color too. The histogram is large and readable; a clipped area on bright silver is noticed at once. If at the start of the shoot a gray card or color card is placed in the frame and a reference frame is shot, the white balance is corrected at once on the computer by clicking on that card, and the same setting is applied to the following frames. This way the silver's shift toward yellow is caught before the shoot ends.

But the large screen has a condition: if the screen isn't calibrated, the colors it shows are misleading too. On an uncalibrated screen a correct frame can look too warm or too cool, and the photographer corrects it in the wrong direction. Tethering makes sense together with a calibrated screen.

How do you run the shoot from the computer?

Remote capture is managing the camera's settings, such as shutter speed, aperture, ISO and focus, and its shutter through a program on the computer. Many tethering programs support this. If the camera is very close to a product, on a ceiling arm or at a hard-to-reach angle, changing settings from the computer instead of reaching for the camera for each one both speeds things up and keeps the camera from moving. Showing live view on the large screen also makes it easier to place focus exactly on a stone's edge.

Transfer delay is the time that passes between a frame being shot and appearing on the computer screen. Large raw files take a second or two to transfer even by cable; over a wireless connection this time is usually longer. That is why tethering isn't suited to fast burst shooting: frames shot one after another enter a queue and the screen falls behind the real moment. At a calm pace, such as product and studio portraits, the delay is no problem; with a fast-moving subject, on the other hand, the cable is dropped and the frames are examined afterward.

The cable is a risk too. A taut cable hanging from the camera can pull the camera off the tripod and drop it if a foot catches on it, or strain the camera's port. Securing the cable to the tripod with a clamp or a loose loop makes sure that if it is pulled, the load falls not on the camera but on the attachment point.

How are files and the client managed?

A capture session is gathering the frames of a tethered shoot in a single folder, with a shared naming scheme and settings applied together. At the start of the session a folder is opened for the client's name, the date and the job; frames are named accordingly. If there are hundreds of products in the catalog, each product's code can be added to the file name. This order means not having to search after the shoot for which frame belongs to which product.

Backup recording is each frame being written at the same time both to the camera's card and to the computer's disk. During tethering, in some setups the frames go only to the computer; if the computer freezes or the cable comes out, the last frames can be lost. Setting the camera to write the frame to the card too saves the job in a mishap.

Looking at the same screen as the client moves the selection from the end of the shoot into the shoot. The shop owner marks the frame they like right there, and says at once how they want the light or the placement to change; the photographer continues the shoot in that direction. This both saves time and reduces disagreements that might come up later. But the client seeing every frame means they also see the photographer's attempts; some photographers turn the screen to the client only at certain moments.

Whom does the screen face in a portrait?

In a portrait shoot, tethering means the model and those running the shoot seeing the face at actual size on a large screen. This is valuable for assessing an expression or a lighting setup together, but not everyone is ready to see their own face on a large screen, with every pore and every line. Asking before turning the screen to the model, building comments on light and expression rather than on the face, and keeping the client from making comments about the model's skin in front of the model, make sure the shoot takes place in a safe environment.

An uncalibrated screen distorts different skin tones in different ways. On a blue-heavy screen dark skin slips to gray, a muddy brown; on a red-heavy screen light skin looks too pink. If the photographer trusts the screen and tries to correct this, they spoil the real file. A calibrated screen and a reference frame taken with a gray card at the start of the shoot tie different skin tones to the same reliable measure.

Visual evidence

The next morning you set up the camera on the tripod, very close to a ring. You secure the cable to the tripod leg with a loose loop and connect it to the laptop. You open a capture session with the shop owner's name, and set the camera to write the frames to the card too. The first frame is a gray card beside the ring; when you click on the card on the computer the silver's yellowness disappears, and this setting is applied to the following frames too.

A few seconds later each frame appears on the large screen. Enlarging to actual size, you see that the stone's front edge is soft; you move the focus forward a little from the computer and shoot again. You remove a small speck of dust on the ring's band with a brush. At the screen, the shop owner marks the frames they like and asks for the light to come a little more from the side for a necklace.

In the afternoon, the shop's craftsperson poses holding a ring in their hand. You ask before turning the screen to them; they agree. On the calibrated screen the warm brown of their dark skin is correct, and the lines on their fingers natural. The comments stay on the light and the ring's angle.

Common mistakes

Summary

Tethering connects the camera to a computer and lets you check each frame the moment it is shot on a large, calibrated screen for sharpness, exposure and color, run the shoot from the computer, and make the selection together with the client inside the shoot. Because of transfer delay it suits calm-paced jobs; frames are organized in a capture session, written redundantly to both card and disk, and the cable is secured safely. In a portrait the screen is turned to the model after asking, and comments are built on light and expression; a calibrated screen and a reference frame with a gray card make sure different skin tones look correct.

Mini assignment

In this assignment you will do two things: a tethering test and the module's project.

1. Connect your camera to a computer with a cable; if you don't have a connection, imitate the same flow by transferring each frame to the computer right after shooting. Shoot a small product and examine one frame on the camera's screen and one frame at actual size on the large screen; note which flaws show only on the large screen.
2. At the start of the shoot take a reference frame with a gray card, set the white balance from it and apply it to the following frames; open a capture session folder and name the frames consistently.
3. Module project: Choose three of the techniques you saw in this module, from among long exposure, light painting, HDR, panorama, focus stacking, timelapse, high speed, multiple exposure, intentional camera movement, infrared or tethering; produce at least one strong frame with each.
4. For each frame, write in a few sentences which technique you chose and why, what you planned in the shoot, and what came out differently than you expected. If there is a person in one of the frames, add how the skin looks and how you checked it.

Check yourself

• Can you explain why the camera's small screen can be misleading and what you check on the large screen?
• Can you justify that you chose each of the three techniques in your project according to the scene's needs?
• If you photographed a person, did you check on a calibrated screen or with a reference that the skin looks correct?

Glossary

Mini quiz

1. Why can a frame that looks sharp on the camera's screen come out soft on the computer?

• A) Because the computer blurs the frame
• B) Because the small screen shows a small preview produced from the raw file
• C) Because the cable distorts the image
• D) Because the histogram is wrong

2. Which kind of shoot is tethering least suited to?

• A) A product catalog
• B) A studio portrait
• C) Food photography
• D) A sports moment that needs fast burst shooting

3. On an uncalibrated screen, dark skin looks as if it is slipping toward gray. Which is the most correct step?

• A) Making the skin warmer in the file
• B) Raising the screen's brightness
• C) Calibrating the screen and assessing by the reference frame with a gray card
• D) Leaving the camera on automatic white balance

4. What is done so that the last frames aren't lost if the computer freezes during tethering?

• A) The camera is set to write the frames to the card too
• B) A switch is made to a wireless connection
• C) The frames are shot as small JPEGs
• D) The capture session is closed

Answers

1. B — The camera's screen shows a small preview; soft focus shows up at actual size.
2. D — Because of transfer delay, frames shot fast one after another enter a queue and the screen falls behind the moment.
3. C — An uncalibrated screen shows color wrongly; trusting it and correcting spoils the real file.
4. A — Backup recording makes sure the frames are also on the card in a mishap.

Summary card

• Check the frame at actual size on a large, calibrated screen.
• At the start of the shoot, take a reference frame with a gray card.
• Tethering is for calm-paced jobs; take transfer delay into account.
• Open a session, write the frames to the card too, secure the cable.
• In a portrait, turn the screen after asking; build comments on light and expression.

Bridge to the next lesson

As the catalog shoot was ending, your friend looked into the workshop in the shop's back room. The craftsperson was heating a silver bar in the fire, hammering it, turning it into a ring, then setting a small stone in place. A single ring frame in the catalog showed the finished product, but it didn't show the fire, the hammer, the craftsperson's hands or the hours of labor. Your friend wondered whether a single frame would be enough to tell all this. What is the difference between a single photo and a series? The next lesson deals with how a series of photos tells time and context, and how it shows what a single frame can't.