Long Exposure (Slow Shutter) ND and IR Filter Factor Table

When you use Neutral Density or Infrared filters, the challenge is to get the right exposure, because you cannot see anything from viewfinder. Camera meter reading would be misleading. Solutions: Camera must be on Tripod with Cable Release

  1. Choose Quality (should be Raw), the ISO and White Balance
  2. Compose / focus / take meter reading / note the exposure (f-stop and shutter speed) / take the picture without filter
  3. Check in histogram (or by other means) to see that the picture in terms of composition and exposure are as desired
  4. If satisfied / put camera and lens on Manual / place the filter on the lens / have the same aperture (f-stop) as in (2) / only you have to play with shutter speed
  5. The shutter speed will depend on how many stops to add with filter. This is a matter of trial and error / Follow the filter factor / e.g. ND 1000 will need an increase in shutter timing by 10-stops
  6. Now you check the following Table and depending on what your original shutter speed was without filter in (2) / also the f-stop being same as in (2) / by how many stops you want to increase the shutter / choose seconds, minutes or hrs. from the Table / shutter timing has to be increased (put on BULB if it is more than 30 seconds) / shoot

Suppose, according to my exposure reading in (2), without filter, shutter was 1/60 at f/8. Now I want a 10-stop increase in shutter with filter. / Following the Table, I will need 16 seconds of timing to shoot. If not correct, I have to increase or decrease the shutter stop and accordingly, the shooting time.

© Mahmood Iqbal: May, 2015

ND and IR Filter Compensation © Mahmood Iqbal: May, 2015


About Mahmood Iqbal

An Economist (PhD) and a Professor (Part-time) at the Carleton University, Canada. The author of "No PhDs Please: This is Canada." Besides doing research on serious economic and policy issues for the last 25 years, like to write journalistic pieces on subjects of interest. An amateur Photographer. ... Blog appears to be appropriate venue to post my wondering thoughts without any peer pressure and academic review process.
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