It's easier to just jack up the ISO, get a meter reading, and compensate when you turn your ISO back down.
It's six stops from 100 to 6400. Simply increase the exposure by 6 stops. It's night time, so you'll likely need to make adjustments anyway. On Sun, Dec 9, 2012 at 12:35 PM, George Sinos <[email protected]> wrote: > I was listening to one of the many photography podcasts recently and > heard someone mention this estimating technique. > > He said he likes to make his night exposures at ISO 100 to minimize > noise, but zeroing in on the exposure time at that low ISO can take a > long time. > > So, he makes his initial exposures at ISO 6400. It turns out that the > exposures length in seconds at 6400 is pretty close to the length in > minutes at ISO 100. For example, a 10 second exposure at ISO 6400 > would work out to a 10 minute exposure at ISO 100. > > Making the initial estimated exposure time at 6400 reduces the number > of test exposures he needs to make at ISO 100. > > I had to make a little spreadsheet to convince myself. It's not exact, > but the error is relatively small. Probably less than is necessary to > give you a good starting point at the lower ISO. > > I don't do a lot of night or long exposure stuff and maybe this is > common knowledge to those that do. I've been around a long time and > heard a lot of "rules," but this one was new to me. > > gs > > George Sinos > -------------------- > [email protected] > www.georgesphotos.net > plus.georgesinos.com > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- David Parsons Photography http://www.davidparsonsphoto.com Aloha Photographer Photoblog http://alohaphotog.blogspot.com/ -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
