NDTimer

Fantastic app that allows me to focus on setting up my camera/filter, composition, etc -- instead of calculating exposure times manually. Contrary to the previous review I find the app to be very accurate regardless of what brand ND filter I use (Hoya or Lee) as it works off of stops not the particular brand type. Furthermore, you can easily adjust exposure in 1/2 stop increments by swiping the timer if you feel it is necessary either to compensate for your metering technique or for reciprocity failure when using film.

Had the same issue as others and notified developer. Fast professional response. Did a little troubleshooting and determined that the timer would not stop ONLY if you failed to acknowledge the notification to "close your shutter" if phone went to sleep while it was timing. Provided this feedback and this issue was fixed with an update promised in a couple of days. So until then make sure you acknowledge that notification popup and all will be fine. Very happy with the app AND the response of the developer.

Why you call an ND of 10 stops ND 1024? Are they Hoya numbers? An ND of 1 Stop ND 2? . I use Lee and most of the others I've seen use .3. .6 .9 3 for a full 10 stops..