for a Nikon D3100.  I'm looking for one with a lockup of some kind so I don't have to hold the button the whole time.  This doesn't seem to be specified on any I've seen on Amazon yet, Nikon's site doesn't seem to have any listed, but I'll look again.



Figured I may as well hit up Arfcom too.  Thanks in advance.

I'm not sure what you think lockup mode does, but it isn't that.

What you're thinking of is the bulb setting on many nikon cameras. I don't know if your camera supports it or not, google should answer that.

Anyways, what it does is when you trigger the shutter, it stays open until you trigger it again.

The regular nikon remote is more than capable of doing this, as well as numerous third party aftermarket ones. Hell, I trigger my camera with the IR blaster on my phone

Ah, I guess I misunderstood how they work.  I had it in my head that the button needed to be held down until for the duration of the shot.  I haven't tried a bulb mode shot yet with this camera, nor have I read up on that part of the operation yet in the manual.  



My old Canon SLR used a cable release with a small ring that had to be twisted to 'hold' the button in, so I was kind of assuming the button on the camera or remote was the same way.



Sadly I don't have a phone that does those new-fangled things.



Looking for camera accessories on the Nikon site only brought me to a couple microphones.

Not sure if your camera is compatible, but this is what you seek.

http://www.bhphotovideo.com/c/product/207373-USA/Nikon_4730.html


there are also wired releases for some camera models.

I just got the Amazon Basics version of the ML-L3. I think they're around $8.

The ML-L3 is probably what you want. It's just a shutter release. If you're thinking for something like the lock screw on a cable release, the ML-L3 doesn't do that. You push the button on the remote and the camera does the rest based on how you've set up the shot.



Make sure you shop around. Camera shops want about double what you can find one on the web for.

I bought this cheapie on Amazon for $20.  Probably won't last, but works great for me.  All kinds of features; timers, intervals, bulb, single and CS, etc.