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Actually, the D3100 cannot use the ML-L3 remote. The ML-L3 remote is a wireless remote, and the D3000 and D3200 can use this wireless remote, but the D3100 is wired remote only. However, in my view, you have the better solution. First and foremost, a wired remote is faster than an IR remote. I have direct knowledge of this as I have engineered camera trigger and intervalometer systems for both wired and IR triggers. And a wired remote typically has a 2-level switch. Like the shutter, you can press a wired remote half-way down for focusing, and all the way down for the photo (however, I am not sure if it will trigger video on the D3100 or not). IR remotes do not have this capability, which is one reason they have a delay, as cameras typically internally have a focus - delay - trigger action when you use a IR remote. This means when the camera is triggered with a IR remote, it will first focus, then after a pre-determined delay, fire the trigger. This delay is part of the reason IR is slower, but also, the IR system sends out a specific encoded sequence via IR transmitter, which does take time. And if you want a wireless remote, you can buy an inexpensive trigger, such as a Yongnuo RF-603, which is a RF, not IR trigger, and with a 100~200ft range. And finally, there are virtually NO IR remote intervalometers - at least commercially made. They are all wired only. I have designed and built IR versions, but they are not available commercially. The wired remote you need is a Nikon MC-DC2 or compatible 3rd party remote. However, the easy solution is to simply pre-focus the lens in manual focus mode to where you will be standing. And you can stop the lens down a bit to add a bit of DoF so that if you do move around a bit, you will still be in focus. This will work unless you are walking all around the place, which in that case, you will want an assistant to handle the camera.