Long Exposure Day Time Photography

While planning for a Long Exposure Daylight Photography workshop I found remote triggering to be artificially difficult.

Using "WiFi remote" app on your phone, completely takes over the phone, preventing the use of a timer, and disabled ISO64 on my D850.

As a result, I decided to use Exposure stacking.

The setup to take the photo is super easy:

Set camera on a tripod, in aperture mode with appropriate depth of focus.  Use ISO for fine adjustment of Exposure time.

Camera must have long exposure NR turned off

Long exposure target exposure time between 1 and 8 seconds.  

If your target is 5 min, that's 300 photos at 1 second.

Target between 4 and 8 seconds per photo.  

Its best to use a N1000 (i.e. 3 stop ND filter) alone.  (multiple filters cause vignetting).

8 seconds Exposure time should be:

1/125 for ND1000

1/1000 for ND1000+ND8

Camera should be on tripod, AF on, VS off

Take the photo and check histogram.

Put the ND filter(s) on, turn off AF

Take another shot and check histogram and vignetting.

Start interval intervalometer.

Nikon 850d has minimum time for internal intervalometer delay of .5 seconds. (750d is 1 sec).

With a remote shutter you can just leave it down, and it will take photo after photo.

For Processing:

download imagemagick

https://imagemagick.org/index.php

put each series in a directory, pay attention to only include 8sec shots.

run imagemagick on the command line

"C:\Program Files\ImageMagick-7.1.0-Q16-HDRI/magick.exe" *.NEF -evaluate-sequence mean OUT_mean.TIF

"C:\Program Files\ImageMagick-7.1.0-Q16-HDRI/magick.exe" *.NEF -evaluate-sequence median OUT_median.TIF

"C:\Program Files\ImageMagick-7.1.0-Q16-HDRI/magick.exe" -resize 25% -delay 20 -loop 0 *.JPG OUT_gif.gif