Enough to cover the gap between the published shot count and what you actually do, which is usually a factor rather than a margin. The figure on the box is measured to a standard procedure that resembles nobody’s day.
The published number is a measurement under a procedure. The useful number is a multiple of it, and the multiple depends on what you do.
What the figure assumes
A defined interval between frames, a stated share of flash firings, and the screen used in a prescribed way. Anything continuous — video, live view, long exposures — falls outside those assumptions, and cold weather reduces available capacity in a way no shot count describes.
A practical reading
For stills in fair weather, one spare covers most of a day. For video or for cold, the cells are consumed at a rate the shot count does not describe at all, and two or three is not excessive. What no maker publishes is a runtime for video in minutes, which is the figure that would actually answer the question.
Spare cells and grips, counted apart
Camera batteries are a family here, and so are grips, which hold additional cells rather than extending the life of one. That separation is the useful distinction: a spare is capacity you swap, a grip is capacity you carry.
The habit worth more than the arithmetic
Charge everything the night before and keep the spares in one named place. Neither is a specification, and this site does not dress habits as figures — but the failure being avoided is the one no published number prevents.
What people ask before they commit
Why is the published shot count so optimistic?
Because it is measured to a defined procedure — a set interval between frames, a stated proportion of flash use, the screen used in a stated way. Video, image review, long exposures and cold all sit outside it. The figure is honest about what it measured; it was never a description of a working day.
Does a battery grip change the arithmetic?
It holds more cells rather than making them last longer, so it doubles capacity and adds weight and bulk. This catalogue keeps grips as their own family — thirteen products — precisely because they are a separate purchase with a separate trade-off, not an accessory to a battery.
Last reviewed 12 September 2026