Luminous Landscape Forum
The Art of Photography => Landscape Showcase => Topic started by: Dave (Isle of Skye) on April 21, 2025, 04:27:09 pm
-
From last autumn as we toured around Ireland.
I can't remember the exact exposure time, but I am fairly sure it was something around 15 minutes, using a 10 stop and a 3 stop filter combined.
Dave
-
Nice.
-
Nice.
+1
P.S. How do you calculate a 15 min exposure? Cameras' meters typically max at 30 seconds. How do you do it in the field? Carry a spreadsheet? In your head? :)
P.P.S. In spite of the smiley at the end, this is a serious question
-
+1
P.S. How do you calculate a 15 min exposure? Cameras' meters typically max at 30 seconds. How do you do it in the field? Carry a spreadsheet? In your head? :)
P.P.S. In spite of the smiley at the end, this is a serious question
Well let me start by saying, I absolutely hate making exposures as long as this. As I just don't have the patience to stand around twiddling my thumbs, waiting for a 15 minute exposure to finish. But sometimes, it's the only way to get something worthwhile.
But to get back to your question Slobodan...
I just choose whatever f/stop I want and then throw on the 10 stop and set the camera to its 30 second limit and see what the internal meter reading says (Matrix/evaluative) and then bump up the ISO to 200 or 300 or 400 etc, until it is showing zero on the meter.
I then throw on the 3 stop and double that exposure time three times. So 30 seconds becomes 1 minute, then two, then 4 minutes. I then halve the ISO twice, so say it was at 200, I take it down to 50 so the 4 minutes becomes 8, then 16 minutes - but which I then expose for 15 minutes, just to make sure I don't overexpose the shot.
If I run out of ISO settings, because I am already down to 50 but it is still overexposing, then I increase the f/stop one or two stops.
I know there are apps you can install on your phone, that will quickly work out these calculations for you. But as I now appear to be the only human being left on the planet, who does not to own a mobile phone (and never will). I have to do it in my head instead.
Hope this helps.
Dave
-
Thanks, buddy!
-
Well let me start by saying, I absolutely hate making exposures as long as this.
It's a fine shot. I wonder if it really needed an exposure quite as long as 15 minutes. In my (admittedly not terribly extensive) experience, seascapes don't gain much after 3 or 4 minutes unless there are very slow-moving clouds you want to streak.
But I wasn't there.
Jeremy
-
It's a fine shot. I wonder if it really needed an exposure quite as long as 15 minutes. In my (admittedly not terribly extensive) experience, seascapes don't gain much after 3 or 4 minutes unless there are very slow-moving clouds you want to streak.
But I wasn't there.
Jeremy
I agree Jeremy, 15 minutes was a little on the excessive side. But I wanted to make absolutely sure, that the lighter coloured sea foam (spume), being generated by the waves, as they flowed around and then past the stack, had plenty of time to build up into a series of long, lighter coloured streaks, that stretched out right across the sea.
Thanks, buddy!
No probs ;)
Dave
-
Simply beautiful!
-
Simply beautiful!
Thank you ;)
+1
P.S. How do you calculate a 15 min exposure? Cameras' meters typically max at 30 seconds. How do you do it in the field? Carry a spreadsheet? In your head? :)
P.P.S. In spite of the smiley at the end, this is a serious question
Just found a better way to work out such ridiculously long exposures.
Put your 10 or 15 stop ND filter stop on - or what ever you are using or stacking together. Then set the ISO to 6400 and set your exposure time so the image looks well exposed on the back screen - which let's say it turns out to be 15 seconds. Then take a test shot of the scene and if it looks properly exposed, then go back down to ISO 100 and just turn each second into a minute. So a 15 second exposure at ISO 6400, is near enough equivalent to a 15 minute exposure at ISO 100.
...and of course you will have to use bulb mode on your camera and a remote you can lock open the shutter to do this - but most remotes for modern cameras have this function built in. Or if you are lucky enough to own a remote with an intervalometer built in, you can use that to set the exposure time.
Easy really ;D
Hope this helps.
Dave