NDTimer: Long-Exposure Calc

NDTimer is a long exposure calculator for neutral density filters. Enter the shutter speed your camera metered without the filter, tell NDTimer how strong the ND filter is, and it gives you the exposure the shot actually needs. The result updates as you type. Every ND filter is labelled differently. One is marked 10 stops, another ND1000, a third OD 3.0. They are the same filter. NDTimer accepts all three notations and shows the other two beside your answer, so there is no conversion chart to find on a windy beach. HOW IT WORKS Required shutter = base shutter x 2 to the power of stops. That one line is the whole of long exposure arithmetic: six stops doubles your exposure six times. NDTimer runs it and prints the time in a form you can dial in: 1/15s, 8s, 2m 13s, 1h 30m. WHAT YOU CAN DO - Enter filter strength as stops, as an ND number (ND8, ND64, ND1000) or as optical density (OD 1.8, OD 3.0) - Read the required shutter in plain time, from a fraction of a second up to hours - See stops, ND factor and optical density together under every result - Tap any of 19 shutter presets, 1/8000 through 30 seconds - Tap any of 12 ND presets, ND2 through ND1000 and on to ND32000 at 15 stops - Work in fractional stops, so an ND400 rated at 8.65 stops is calculated as 8.65, not rounded to 8 or 9 - Stack filters by adding their stops: a 6 stop plus a 10 stop is 16 stops - Open the reference screen for the exposure law and the ND to stops to density conversions - Read the screen in a light or dark theme that follows your phone WHO IT IS FOR - Landscape and seascape photographers smoothing water, cloud and grass - Architecture and street photographers clearing moving people out of a frame - Anyone shooting daytime long exposure behind a ten stop filter, or stacking two of them - Photographers who want the number before the light changes, not after FAQ What is an ND filter? A neutral density filter is dark glass that cuts the light reaching your sensor, so you can hold the shutter open in daylight. Why do I need a long exposure calculator? The filter multiplies exposure time by 2 to the power of its stops. A 10 stop filter turns a metered 1/60s into roughly 17 seconds, and that is not a sum you want to do in your head on location. What do I enter as the base shutter? The shutter speed your camera meters before you fit the filter. Tap a preset when it is a fraction of a second. Does it work offline? Yes. NDTimer makes no network calls at all. There is no account, no sign in, no ads and no tracking, and nothing you enter leaves your device. Does it handle stacked filters? Add the stops together and enter the total. A 6 stop on top of a 10 stop is 16 stops. NDTimer is a long exposure and ND filter calculator, and nothing else. Fit the filter, read the time, open the shutter.