What is shutter latency? The camera I'm using (medium format from Phase One) has the option to set the shutter latency to short or long — what's the difference between the two and when would I use which setting?
Phase One says the sensor is put to sleep to save battery, and is given a wake-up signal when you press the shutter release button. This wake-up process they call Shutter Latency and recommend to keep it set to "Normal".
The other setting is called "Zero" latency, and suggested to use it only when working with technical large format cameras, or certain manual cameras in special situations. No further explanation about "special situations" but it appears as consuming battery and looks like having the sensor powered up for long times. That would cause the sensor warming up with normal DSLR cameras, but Phase One is different.
I did not read the entire manual, so did not find reference to shutter latency settings Long and Short, but only the settings Normal and Zero.
I don't know medium format cameras, but in general shutter latency is the time that it takes from when you push the shutter to the time the shutter actually activates. The lower the latency, the more responsive the shutter, but the less time the camera has to make last minute adjustments or changes in hardware state. A higher shutter latency will allow the camera to make finer tuned adjustments and turn on hardware that was sleeping, but will not go as close to when you push the shutter.
Some other cameras express this as shutter priority vs focus priority. Lower latency should be used when you need the shot at the exact moment you push the shutter where as longer latency will generally let the camera do more work for you or leave stuff powered down and may generate a better quality image or increase battery life.
It may also do things like mirror lockup to reduce the latency so that the shutter can fire faster or keep hardware turned on.