Shutter Button in Digital Camera by mechanism varies. For entry level digital camera, it may be just a digital switch while DSLR cameras has complex mechanism. Please note that, in Digital Photography the word Shutter is used for two meanings, first is the light-proof, mechanically movable element back of the lens which controls the exposure time to make the image sensor exposed t light. This is just a part of the full Shutter Mechanism and we have discussed that part of Shutter before. Shutter Button controls the shutter of the camera through Shutter Mechanism. Shutter Button is the bigger usually oval button which has a good tactile feedback. In this article, our focus is on this Shutter Button.
Shutter Button and Digital Camera
Shutter Button is a bit perplexed topic in Digital Camera, since a mobile phone camera also might have a Shutter Button, which usually gives a tactile feedback, sometimes a specific clicking sound can be set to give a pseudo feeling of a real Shutter Button. Most of these Shutter Button works just as a digital switch.

On the other hand, the Shutter Button of a high end DSLR camera actually produces that specific clicking sound. Shutter Button is actually the short form of Shutter Release Button, this release came from the mechanical shutters those used a lever to reveal the aperture mechanism.
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More on Shutter Button
So, Shutter Button specially for DSLR cameras are not really very easy thing. Most Compact Digital Camera and Bridge Camera has only Auto Focus Mode with few manual override, the Shutter Button when pressed and hold to half way down, it usually locks the focus. This gives an opportunity to do some experimental photography. In DSLR cameras, it depends on the settings, mode, model and make.

Shutter Button for the advanced DSLR cameras might have manufacturer specific copyright and patents as there is a word – Shutter Lag – the time gap of actual Shutter Button Press Release and the action inside the camera.
Most DSLR camera stores the data, which can be retrieved with softwares, that how many clicks are actually made with the camera. Most DSLR Shutter gets a warranty of 50000 clicks. This is the reason why second hand high end DSLR costs lower – Shutter Button or rather the Shutter Mechanism as a whole is quite costly to get replaced.
