10

I would like to take long exposure shots in the day, but I just can't imagine how to do it because even fireworks (night shot) exposed for more than five seconds are too bright.

I did some research, and I guess it's because I have no filter. What do you recommend to me for night and for day for long exposure shots?

mattdm
  • 143,140
  • 52
  • 417
  • 741
Patrick Desjardins
  • 459
  • 1
  • 3
  • 8

2 Answers2

15

You're looking for ND (as in Neutral Density) filter. They're usually marked as ND2, ND4, ND8, ..., each step indicating 1-stop change in your exposure settings. For example if you were shooting at f/2,8, 1/100, ISO100 then adding ND2 filter will give you options to shoot either at f/2,0, 1/100, ISO100 or f/2,8, 1/50, ISO100.

Most of recognized filter manufacturers have ND filters in their lineup, including Hoya, B+W, Singh Ray, Lee, Cokin.

Should you already own a polarizing filter you might use it to get rid of 1-2 steps of light or even combine it with the second polarizer to create a variable density ND filter.

Karel
  • 10,729
  • 6
  • 48
  • 78
  • +1: for referencing that article. Random story: I posted a comment on that blog post on Feb 29th, 2008. – Alan Aug 18 '10 at 21:05
  • 1
    A word of caution - in theory you should be able to combine ND filters to get even longer exposures, but when you do this with Cokin filters the photos take on a pink cast. I've no idea why this is, but it is a common problem, so if you've not already bought into the Cokin system I'd go for Lee instead. –  Aug 19 '10 at 10:48
6

In addition to the ND filters Karel mentions, a circular polarizer will also reduce the light by 2 stops and, as an added bonus, cut down certain types of glare and reflection from things like glass, water, and other bright surfaces.

Joanne C
  • 33,138
  • 4
  • 72
  • 132
  • +1 Useful additional tip that might not require any extra purchases (I tend to use CPLs as lens protectors, as they're so useful outdoors anyway) – Rowland Shaw Aug 18 '10 at 15:47
  • Interesting choice, though there are times I'd prefer not to have the light loss, but I can see the benefit for certain types of outdoor photography. Mind you, I use the Cokin system, so my lenses aren't normally filtered until I need it anyways. – Joanne C Aug 18 '10 at 15:57
  • I've read that you can use two (Non circular IIRC) Polarizers stacked on top of each other to create a variable ND filter. As you might be aware, two polarizering filters that are set to filter light perpendicular to each other will completely block light (try it with a couple of sunglasses!). I thought this was a unique solution. The obvious downsides are needing two non-cpls, vignetting, and possible ghosting. – Alan Aug 18 '10 at 17:24
  • I've heard of that technique as well, which I always thought was interesting though I've never tried it since I actually only have one linear polarizer. I would think the other downside would probably be effect on autofocus, linear polarizers can mess that up. – Joanne C Aug 18 '10 at 17:42
  • 1
    @Alan @John - only one linear polariser, the one in the front. CPLs are just linear polarisers with a quarter-wave plate on the back. Typically, though, this setup takes you pretty far from "neutral" in terms of colour. – ex-ms Aug 18 '10 at 18:41
  • @matt Thanks, I checked out Karel's link after and realized that it was a mix, but a little late. :) Anyways, interesting concept. – Joanne C Aug 18 '10 at 20:00