“Thames Sunset” shot with a 10 stop ND filter allowing to exposure for 40 seconds with the Sun within the frame.
Using Neutral Density filters can make a dramatic change to your photos. The photo above is a 40-second exposure, which only is possible with something to stop down the light. The Sun is within the frame and had I shot without the filter, the shutter speed would have been 1/25 seconds. I shot this at ISO 100 and f/8. I could have gone to ISO 50 and to F/22, and changed the shutter speed to maybe around a 1/4 or 1/2 seconds, but not 40 seconds.
ND filters are pretty expensive stuff, and I have ended up spending a fortune on them, not only because I have a fairly complete set, but also because I have made some mistakes. Expensive mistakes, that is. In this buying guide, I will try guide you not to make the same mistakes.