To what extent it can be harmful for a camera and lens to take shots when being on the beach? I mean the influence of beach sand on the gear. What precautions should be taken to prevent any bad effects of it?
The combination of sand and wind that is common on a beach can be harmful.
The sand can get into the camera and damage the lenses and sensors.
There are quite a few different approaches:
- Don't take a camera to the beach I think this is far too extreme, without risk there is no reward
- Don't take an expensive camera to the beach plausible, but still a little much for me
- Take your camera but take good care of it
- make sure to keep it covered as much as possible (gallon sized zip-locks are your friend) and clean it as good as you can when leaving. When cleaning, try to blow any sand/dust off before you wipe it off (think about sandpaper).
- avoid changing lenses while on the beach, if you need to change lenses, go inside a car/building/somewhere secluded to avoid letting grit inside the body.
- use a uv filter to protect the lens (some will argue with this, but a damaged filter is much cheaper than a damaged lens)
- Do Not place your camera in the sand (also avoid touching it with sandy hands)
- Avoid putting a camera bag down in the sand, because once the sand is in the bag, it will be hard to get it out.
- Don't worry about it, just go ahead and take some good pictures. This is the photojournalist approach... if you get good enough shots, you can pay to repair/buy new equipment.
I think option 3 is the best, do what you can to take care of the equipment, use a single lens if possible, and take some good pictures.
Sand is not the only issue, there is also saltwater is the air. Even if you keep your camera dry, the environment at the beach is more corrosive than some distance inland. (Cars owned by those who live near the beach show more corrosion than those not near the beach.) This isn't as big an issue as sand, and is far less an issue the more plastic the camera body.
I would always give the externals of the camera a good wipe-down when returning from beach shooting.
Well, a lot of it depends on the camera and lens(es) involved. A lot of point and shoots designed for rugged use are perfectly fine there. For dSLR cameras, it will depend. For most brands (if not all of them), the top end of their gear is often dust and weather sealed and so the camera, itself, is probably well defended. However, if the lens is not dust and weather sealed, you can run into some issues with that. Net effect, if both camera and lens has weather sealing, knock yourself out! If they aren't, then chills42's option #3 is a prudent way to go.
Take the risk seriously. Beaches not only have sand, they tend to be windy. Within just a minute of getting your camera out you can have sand on your lens or somewhere else. This is a good time to have a UV filter on your lens.