Because a lit room is several stops darker than an overcast afternoon, and the aperture of a kit zoom at its long end takes several more away. The two figures together explain almost every blurred indoor frame.
The eye adapts and the sensor does not. That is why a room that looks bright is dim in exposure terms.
The ambient level and the aperture
The ambient level, which indoors is several stops below daylight even under good lamps.
The maximum aperture at your focal length. A kit zoom quoted f/3.5-6.3 gives its second figure at full extension — two and a half stops darker than at the wide end, and that is before the room is taken into account.
The three ways out, in order of cost
- Open the aperture: zoom wider, or fit a lens with a single wide figure. This catalogue’s primes print f/1.8 and f/1.4, which is three or more stops beyond a kit zoom’s long end.
- Add light: a flash or a continuous panel. Eight titles here publish a colour temperature, and matching it to the room is what keeps the result from looking green or orange.
- Raise sensitivity, accepting noise.
What will not help
Stabilisation, which addresses camera movement and not subject movement — a moving child at a slow shutter speed stays blurred whatever the published stop count. And pixel count, which changes sampling and gathers no extra light.
Where this page and the maker’s own manual disagree, the manual decides. Every focal length, aperture, guide number, stop of stabilisation, load rating and sealing claim on this page is reported from the manufacturer’s own documentation, with its unit written as published, and named as such — none of it is measured here. An engraved figure is reported as the maker engraves it, and is never restated in another convention, because the two are not the same number. And the second statement repeated rather than assumed: a zoom quoted f/3.5-6.3 has two maximum apertures, not one. The first belongs to the short end of the range and the second to the long end, and the value moves between them as the barrel extends. Both ends are written here every time, because the second is the one that decides what the lens can still do as the light goes.
What people ask before they commit
Can I just raise the sensitivity?
Up to a point, and the cost is noise, which grows as the signal shrinks. Raising sensitivity is the correct move when the alternative is a blurred frame — a noisy sharp picture is usable and a clean blurred one is not. It is a trade rather than a solution.
Would a flash be better than a faster lens?
It adds light rather than gathering it, which is a different kind of answer and often the more effective one. The constraint to know is the sync speed the body publishes: above it a single burst lights only part of the frame, which is why flash and bright ambient light need a filter or a smaller aperture rather than a faster shutter.
Last reviewed 12 September 2026