OK, to answer all your questions, the ML-L3 is an infra-red remote with an effective range of about 15 feet, more or less. It is not using rf (radio frequency) but a DIY electronics circuit can be done. Just like light, you can set the remote to bounce the signal but be aware, it must hit the in sensor (which happened to be very sensitive over a wide range). And because light cannot pass through five floors and a comforter, it si not possible to use the remote this way, unless you either make your own rf (radio frequency) to ir (infra-red) circuit or you drill a hole through five floors (and the comforter) and then insert a fibre optic cable and point it to the Nikon D50. Oh, not only that, practically, this remote works on most Nikon cameras. For the list, you'd have to Google it. Some places are selling compatible remotes that work with more than one brand of camera too. You can search for this on eBay.com or lelong.com.my
Depending on your camera setting, you could either take a delayed shot, fast shot or just bulb. This is very important when I want to get a nice shot at low ISO while using a tripod. My normal procedure would be to set everything and then use the countdown timer which, sometimes, tend to make me lose interest.
So, if you want to use this, in my case, I would set the camera on auto-focus to get the clearest shot, then switch it to manual before I activate the remote feature. Otherwise, the camera would auto-focus or try to auto-focus everytime you press the button on the remote. Which is not a good thing if your subject is fast moving or hard to focus, etc.
Depending on your camera setting, you could either take a delayed shot, fast shot or just bulb. This is very important when I want to get a nice shot at low ISO while using a tripod. My normal procedure would be to set everything and then use the countdown timer which, sometimes, tend to make me lose interest.
So, if you want to use this, in my case, I would set the camera on auto-focus to get the clearest shot, then switch it to manual before I activate the remote feature. Otherwise, the camera would auto-focus or try to auto-focus everytime you press the button on the remote. Which is not a good thing if your subject is fast moving or hard to focus, etc.
Here I am, testing
the ML-L3 remote