It is surely the simplest of operations — instructing the camera when to take a photo. Surprisingly, for such a straight forward task, there are a myriad of ways to actuate the shutter. What are they and what is the best?
In many ways camera UI design hasn't changed very much since the early 1900s with small, handheld devices that loaded film. When it comes to actually releasing the shutter, a button has always been the preferred option because it provides a simple mechanical linkage. However the rise of microelectronics and digital has changed the camera landscape forever so that there are now a myriad of options when it actually comes to taking a photo. So what different ways are there?
Pretty much every camera manufactured has a button on the top-right corner of the body that actuates the interior shutter. In mechanical cameras it performs a single task: to release the shutter. In fact, in purely manual cameras the photographer is entirely in charge of focus and exposure: this is achieved using aperture, shutter speed, and the focus ring. Only when these are correctly set do you expose the film (or sensor).
That covers basic camera operation which manufacturers have been keen to automate through exposure metering, autofocus, and program modes. A key aspect of these three innovations has been that they operate at the point of exposure, all of which means that the shutter button is in control of a surprisingly complex series of operations.
Coupling the shutter release to AE makes sense (and is near-instantaneous) and also closely tied to the program mode selected (e.g. for the selected aperture, at the given exposure, set the shutter speed). However it makes less sense for AF (other than for novice photographers) as it is one of the most critical aspects to get correct (and can't really be fixed in post production). It is also the slowest of automations and so the decoupling of focusing and shutter release (a.k.a back button focus) has become increasingly common for many, simply because it is significantly more flexible, yet (in most cases) achieves similar ease of operation.
2. Cable Release
For the landscape photographer, cable release is perhaps just as common and is used for the simple reason that you don't want to introduce vibration, which obviously means the camera is tripod mounted. Cables can be mechanical or electrical (such as Nikon's MC-DC2) and need to be able to hold the shutter open in Bulb. They can be useful in a surprising range of situations, so always leave one in your bag!
I always feel that the self-timer (or more accurately the delay timer) is unloved by the professional photographer because they are usually behind the camera, but can be surprisingly useful. Introduced in the mists of camera design, it was the stalwart of the family group shot, where the camera was precariously balanced on a convenient table or chair.
However it is the poor man's alternative to the cable release (or just because you've forgotten it!) allowing you to release the shutter without touching the camera. The biggest caveat is that it doesn't work in bulb mode, so — usually — any exposure longer than 30 seconds is a no-go. This can be a frustrating limitation: why can't you pre-program a set time? It might take a little experimentation to get the right setting, but it's better than not getting the shot. Drop a comment if you know any firmware that allows this.
Beyond this, you'd obviously use the self-timer to take a selfie (I'm currently doing a long term daily selfie) but it can be quite useful (with DSLRs) to introduce a delay on short-ish exposures to allow any mirrorbox vibration to settle prior to exposure.
4. Wireless Remote Control
The modern alternative to the cable release is full wireless remote control. The simplest option is the standard infrared remote (often supplied with older models), followed by a hot shoe add-on that is radio controlled (such as Nikon's WR-1). However most camera systems now offer integrated WiFi and Bluetooth alternatives; WiFi is the earlier technology but is high power and high bandwidth. You only need it for transferring photos, so Bluetooth is generally preferable to conserve power although dual-systems are available. Obviously you need a device to control the camera: this can be a simple remote control, through to a full smartphone app. The latter offer the greatest flexibility, not only releasing the shutter, but also altering a range of other settings such as aperture, ISO, and shutter speed. So why use a cable release? Because it's simple and so more reliable. Smartphones run out of power and usually aren't waterproof, both problematic for landscape photographers. Given how flexible apps are, I'm surprised I don't use them other than for transferring photos.
Tethered camera control has been used by studio photographers pretty much since PCs could edit photos and cameras had electrical systems. Wired tethered systems offer the simplest, most reliable, and fastest connections, but WiFi (to PC) is also an option. The biggest benefit of being tethered for camera control is bypassing the intermediate storage of the memory card. The raw file goes straight to your editing environment — the PC — which saves on workflow and allows you to check for errors immediately, so that you can re-shoot if necessary. When working with a full studio team it can be important to have full sign-off and that may only be possible with careful checking. For live or near live shooting you can fully automate the editing and upload of imagery to a bureau.
Smartphones have tended not to have physical buttons and manufacturers seem keen to remove them at every opportunity; it's almost in the definition of a smartphone, a result of having a large interactive screen. Camera apps have tended to ape the shutter button, placing a large control on screen. It's simple and intuitive. As smartphones gained AF systems, it made sense to add focusing by tapping the point of interest.
Cameras have been slow to catch up. Canon introduced its first touchscreen with the PowerShot SD980 IS in 2009, yet it wasn't until the EOS 650D in 2012 that they arrived on DSLRs. Even then they tended to be used to navigate menu systems rather than control the camera. Does it matter? It's more of case of using the right tool for the job. Navigating menus makes sense, as does choosing the focus spot. Just remember that different brands have considerably different support for touch operation.
7. Custom Button
Custom buttons are about changing the ergonomics of a camera to better suit your needs. Mid and top end cameras usually sport many buttons and allow you to assign a range of functions to them. As far as I'm aware you can't reassign the shutter release on a camera to another button — drop a note in the comments if there are any cameras that allow you to do this.
Using a custom button makes a lot of sense for smartphone users though. Dabbing the screen whilst trying to hold the edge of your thinly bezeled device, as well as keeping your hand out of shot, can be tricky! How about just holding the edge of the phone and pressing the volume button?
8. Voice Activated
With the advent of Siri, Google Now, and Alexa, smartphones have gained voice control and a number of camera apps (such as Open Camera) sport voice activation with the simple utterance of "cheese." It's an obvious method to release the shutter and surprisingly useful. Whilst you won't see this coming to the firmware of a camera near you anytime soon, the obvious integration is via remote control apps. For example, Camera Remote Control offers this via the IR port, whilst ControlMyNikon operates for tethered cameras. Do any manufacturers support voice control? Drop a comment below if they do.
Taking a picture is a simple task — you release the shutter. OK, you do need to determine the exposure, then set aperture, shutter speed, and focusing, however the fact that rudimentary cameras were doing this over 150 years ago is testament to the process. The complexity has been introduced through attempts to automate the process to the point that releasing the shutter is a complex task with a multitude of ways of achieving it. Whatever you choose just remember the underlying principles of what is happening: it could well be the cause of any problems you are having. And my own use? I primarily utilize the shutter release button, but use back-button focusing, along with a liberal smattering of self-timer and wired release modes. What do you use?