Ok, time has come to buy external shutter release. I have Nikon D5100, and I looked at nikon official page, they offer wireless shutter release, and cable release.
Unfortunately, wireless release is working with IR technology, and I think that is a little bit of problem for me, because I'm very interested in long exposure pictures (100s). So I looked for another wireless devices, and on Amazon I found this one.
In the description I read that range of this device is 30m. So therefore it can't be IR technology?! It has 2 parts, first one is a classic cable release (it can work without a second device), in which is embedded wireless receiver which can be paired with second device (wireless transmitter).
So, when buying this device you get wireless remote and cable release in one.
Has someone else bought this device? Does this device have a lock mode for taking pictures in bulb mode? Especially when using wireless receiver? In amazon comments, I didn't see that someone had used it with a Nikon D5100?