Tethering: camera to computer or screen

Most DSLR and Compact System Cameras provide connections for a computer and/or a display screen, and some can do this wirelessly. Functionality may involve control and file transfer or merely display.

Models find feedback useful. In the studio this may extend from a mirror handily placed, through occasional looks at the back of the camera to a large screen placed where the whole crew can see it, showing the images in real time and replay, which can be effective.

In a large production there might be a creative director (or others) outside the studio, in the same building or far away, which may be connected by a network. They would find it useful to be able to flick through the collected images without interfering with the current one and import selected ones into editing software, etc.

A potential downside to use within the studio - or other location - is that both model and photographer may find themselves pausing and viewing the screen excessively. Discipline is necessary and should be sufficient to deal with this.

Wired connections

Wired connections, such as USB or HDMI cables, may fail by being pulled out by camera movement or tripped over, and might damage the cameras it departs. Mini-USB sockets are probably more at risk of this. The camera ports are delicate and expensive to repair. Strain relief - securing the cable very firmly to the camera so that a pull on the cable does not reach the port - is highly desirable. Clamping it to an Arca Swiss type plate or a cage works well.  The wires are also another piece of clutter to fall over.  If one is to have a USB cable, perhaps there might as well be a power lead, to the sort of mains power supply that ends with a dummy battery to plug into the camera.  For a permanent installation that might grow in use, arranging data and power along the mounting seems sensible.

There is a limit to the length of cable USB is reliable over.  Powered cables may contain an amplifier, and provide greater effective length.  3m should work, 5m is pushing things without power.

 

Wireless connections

Wireless connections are becoming mature. No additional software is required to simply plug a TV or other HDMI monitor in to the camera.

In order to control the camera, beyond stepping through the images on the card, some form of computer and software are needed  Modern software should operate however the connection is made, but not all may.

The manufacturers commonly provide a utility for operating the camera, with Canon's DPP Camera Utility and Camera Connect being examples. These are likely to work well and be effective, but may not run on all operating systems and devices. Various third party software, some of it open source, is available.

A useful effect of tethering is the immediate creation of a backup copy of files otherwise only held on the camera card(s). This is usually configurable.

The hardware choices are: a TV screen, a computer monitor, a tablet, or even a mobile phone. An interesting project is to provide a feed to an arbitrary number of devices of various sorts.

Software

For Canon the software provided with the camera at no extra cost - Canon Utility and DPP - works well.  Other brands have similar software. 

The Open Source programs DarkTable and Entangle are effective, are developing steadily, and in the case of DT do much besides.  Also at no extra cost.

Digicam Control is software licenced under the MIT licence - no cost - do what you like with it http://digicamcontrol.com/

Several other well-known programs can tether in addition to, or as their main function.  Some of them may be set to process the incoming image and show it as adjusted.

Using Tethering

Beyond the hardware, questions of whether to use tethering at all, or when, or how are more interesting, and neither are likely to enjoy consensus.

Being explicit about the risk of excess attention and time on the screen, doing the light-test and looking at it, then shooting a series of images, then looking again - each time with the model - seems to work.  Arranging the screen so nobody can see it normally, or so that it is visible only to the creative director or others, are options.

Marking cables with scraps of bright tape, adding them to the list of hazards to rehearse warnings on during a studio session (at least with new people) and being careful about the run of the wires are all desirable safety features.

Taking advantage of the backup afforded by having the computer download each image as it is made will slow the process. If that becomes visible then only downloading the JPEG while leaving the raw file as the copy on the camera card is a compromise.

Actually clearing the images off the camera card as they are downloaded, or setting the camera not to record to card, seems an unnecessary hostage to fortune in an era of large cards. 

Tethering over the Internet

Actually running the tethering program - DarkTable or Canon Utility or whatever it may be - over the Internet may be inefficient and fragile.  Remoting the desktop is possible, and routinely used in many situations.  An efficient remote desktop only moves the changes in the desktop, and the keystrokes and mouse movements, while the high bandwidth communication with the camera stays in the room it is in.  It also allows cross-platform working, if you choose wisely.  VNC - Virtual Network Computing - was the first and is still good, and operates between at least Linux, Windows and OS/X in any combination.  Moving the resulting files needs thinking about, but isn't hard**. 

Pointing the camera over the Internet would be more ambitious, needing a motorised tripod head or robot arm*.  A voice connection to ask someone to move it is probably this year's achievable aim. 

 

References, useful sources, and further reading

Useful (and fairly comprehensive) software list available athttps://www.tethertools.com/tethering-software/

See also more recent thread of discussion at https://purpleport.com/group/photography-chat/170563/shooting-tethered----who-does-it-with-what-and-why-/page/4/ 

* A pan and tilt remote head, from what looks like a serious video supplier is nearly £500. That's the cheap one, but seems to be ok for an SLR.
https://www.proav.co.uk/cameras-accessories/camera-supports-rigs/remote-pan-tilt-heads/ifootage-mini-2-axis-module

Amazon offers one carrying up to 260g which was currently sold out and clearly a less serious device, for a lot less.

Hooking those into a computer which also controls the camera, and which itself is remote controlled over the internet is a non-trivial exercise, but doable. It means all the setup trouble is at the camera end, not in multiple distant places, except the remote client software.
A pan and tilt head provides 2 degrees of freedom.***

Waldo is the SF story by Robert Heinlein which first describes remote arm manipulators with tactile feedback, around 1950. Teledildonics came along much more recently, and the name may not stick.  Haptics probably will.

The Canadarm and Dextre on the Space Station constitute a big Waldo.

When a Spacex Falcon, NASA or other rocket takes off many cameras are set up near it, some of which pan upward as it goes. Most of these usually survive the weather and launch.  (A grass fire destroyed one, which is perhaps a plausible shoot hazard)

** I'm a nerd so I expect to put them in a folder which the web server can deliver.  Options such as SFTP or SCP or rsync also don't need to involve any computers other than the one in the studio and the one at the photographer. Services such as Dropbox and WeTransfer will also eventually move the whole lot. 

 

*** Degrees of freedom: holding a camera we have yaw left-right and pitch up-down as 2 degrees of freedom or modes of movement.  We also have translate up and down, left and right, and roll to give Dutch tilt or go from portrait to landscape and vice versa.  And apart from zooming the lens we can walk forward and backward.  Two is a start.

 

Revised 2019 November.  Addition on remote tethering in the plague year, 2020 April, 2021 January with pan tilt and blastoff etc Slight further attention in 2022