How can I get multi-minute daytime long exposures when a 9-stop ND filter isn’t enough?
Asked 5/6/2011
2 views
2 answers
0
I’m shooting very bright beach scenes and want much longer daytime exposures for smoothing wave motion. With a 9-stop Hoya ND filter, ISO 50, and f/22, I’m still only getting about 5–30 second exposures in full sun. I’d like to reach at least 1 minute, ideally several minutes. I tried adding crossed polarizers, but that caused heavy vignetting and was awkward to use. What are the practical ways to achieve multi-minute long exposures in these conditions?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
15y ago
2 Answers
25
I see two options:
You can stack ND filters. Sounds like you just need to eke out another stop or four, so your second filter doesn't have to be quite as extreme as the 9-stop filter you already have. By only having two filters, rather than 3, you should be able to reduce the vignetting a bit. It would help if your filters were the slim kind designed for wide-angle lenses. You might also consider getting a bigger-diameter filter and a step-up ring, or a square gel-type kit.
The other option, which doesn't require buying any more hardware, is to take multiple long exposures and average them in post-processing. Just take several shots at the exposure level you can achieve, then blend them together. This is a pretty common technique when creating star trails, and you can achieve different looks by using different blending modes (e.g. star trails will appear brighter than they "should" if you use a Maximum blending mode instead of the average.)
Originally by user378. Source · Licensed CC BY-SA 4.0
user378
15y ago
0
Generated from our catalog & community — verify before relying on it.
The practical options are:
-
Stack additional ND filters. Adding another ND filter is the most direct way to gain the extra stops you need. To reduce vignetting, use slim filters, a larger filter with a step-up ring, or a square filter system.
-
Blend multiple exposures in post. If your current setup gives 5–30 second shots, take a series of frames and average/stack them in post-processing. This can simulate a much longer exposure and is a common technique for effects like star trails and smoothing motion.
A solar filter is another very dense option, but it’s primarily intended for photographing the sun and may introduce odd color or other image-quality issues, so it’s not usually the best general solution for scenic long exposures.
Also note that stopping down to f/22 helps with exposure time, but very small apertures can soften the image due to diffraction. In practice, adding more ND is usually preferable to relying on the smallest aperture alone.
Recommended products
UniqueBot
AI15y ago
Your Answer
Related Questions
Can I simulate a 2-minute long exposure by stacking shorter exposures in Photoshop?
Should I buy a 9-stop or 10-stop ND filter for long-exposure water shots?
Which ND filters are useful for beginner long-exposure photography?
Why does a long-exposure photo with blurred trees look like a miniature scene?
What ND filter strength do I need for daytime lightning long exposures?