Hi, I have a set of NDs and ND / polarizers for my drone, but haven’t thought about using the NDs for photography. Is there a reason why you would want to slow the shutter speed down when taking photos?
Love the Gasometer (?) top down shot!
Better colour saturation.
Polarizing filters will help saturate colours but ND filters don’t do anything except limit the amount of light reaching the sensor, nothing else. The only time I use ND filters is for video (so I can slow my shutter speed down), not for photography.
Neutral density filters do as you suggest, Christopher.
They reduce the amount of light hitting the sensor and, to achieve the same exposure as would be the case without the filter the length of time the shutter is opened needs to be extended and/or the physical aperture in the lens needs to be made larger - confusingly the larger the f number the smaller the physical aperture.
Neutral Density filters are neutral in colour, ideally they introduce no colour distortion in the photo, just act a “sunglasses for the camera.”
Why use them?
In video photography a high shutter speed will give a succession of pin-sharp images. When seen at the normal 24 / 25 or 30 frames per second the transition from one picture to another is noticeable. There is sufficient motion blur in subjects filmed at 1/50 or 1/60 second shutter speed to make transitions far less noticeable.
However - a slow shutter speed may require a correspondingly small aperture to give the correct exposure. A small aperture gives a greater depth of field, not always required in either video or still photography. Or perhaps the aperture is fixed. That is where ND filters come into play - to adjust the amount of light entering the camera to allow a specific shutter speed or aperture. As the strength of the light varies so does the density of the filter need to vary. Hence such filters are often sold in a set of densities. They may be called ND4, ND8, ND16 or the equivalent - 2 Stop, 3 Stop or 4 stop Density.
ND filters do not affect the colour or (unless darker at the top than the bottom) do not affect the relationship between sky and ground in a photo.
In stills photography if you want motion blur - water flowing for instance - use a neutral density filter. If yo want limited depth of field and don’t want a high shutter speed - use a neutral density filter. If you want to protect an expensive lens against front element damage from gentle knocks use a UV filter. As @Drumsagard says polarising filters may saturate colours - though I would recommend shooting in RAW and adding colour during processing - may also help with reducing reflections.
Here is a well-known GADC member explaining what I’ve tried to say - well worth subscribing to his channel for a lot more useful advice!
I explained very poor what i use them for and how. I forgot to add my filters are nd polarising ones so do both.
One thing that I don’t think has been mentioned is the polarising filters work best when the light source, i.e. the sun, is at 90º to where you are pointing the camera. The don’t work when the sun is in front of or behind you.