P.C. based solutions:
4. Capture One
1. Control My Nikon
A great application, allowing you up to 3 simultaneous uses per a license, for 34 dollars it would be difficult to beat that on value alone. The interface may not be polished unlike some of the big name commercial applications out there, but it's all business and it works well and is very easy to use. This company also publishes an identical application for Canon users should you be so inclined to use it.
Hiding behind this very simple interface, is a very complex and powerful scripting module for automating the various in camera functions that this application can control through wires or WiFi from the comfort of a PC.
It is a stand alone product and not packaged with any of the required physical trappings to tether your devices, however they do offer suggestions on where to find them. This should work with a wide variety of D.I.Y and commercially made WiFi hardware, the wired option is a self explanatory.
C.M.N also supports remote control of tripod platforms that implement robotics for controlling the pan and tilt of the camera.
Astrophotographers will love this application!
This will enable your camera to bypass the built in restrictions for exposure time limits using M.U.P and Bulb Mode. Canon may not have this issue, I don't have one so I don't know.
There is the added bonus of being able to control all this from a distance (including a live view) without having to freeze your assets off while you are taking those amazing shots through your telescope powered camera.
C.M.N allows triggering of the shutter & flash via acoustic (voice commands or clapping) and optical triggering (stuff moves in front of the camera or camera see's the strobe).
This application is free to try for 30-60 days.
2. Remote DSLR Control:
I am not familiar with this application but it is completely free to use however it appears active development ceased around November of 2012.
0.8.6.2 Beta was the last known update in late 2012.
By all appearances it is very similar to Control My Nikon in it's capabilities but perhaps missing some of the automation's that C.M.N provides.
(Screen shot courtesy of R-DSLR website)
I do not have any hands on time with this software either but it seems very similar to C.M.N (#1) and R-DSLR (#2).
It is totally free to use, unlike #2 it is actively under development. The latest developer release is dated January of 2014. It is a Google code supported project. The interface is not very polished but it appears to work with decent support for Nikon and Canon.
4. Capture One:
A product made by Phase One, this will work with a wide variety of cameras, it is primarily intended as a interface for digital backs (Mamiya, Leica, HasselBlad) but it does work for other cameras as well. It is free to try for about 30-60 days, the software costs 90 dollars and does not include any hardware for tethering, I don't know if this has any WiFi tether capabilities or not. It is basically pairing Adobe's Photoshop Elements capabilities with Capture One's tethering utilities, the elements capabilities can be turned off if all you need is the tethering portion.
This application is normally packaged as a bundled option for some of the higher end camera bundles from Mamiya (owned by Phase One).
I can't really add much to this since I've not had any experience with it, it is on my list commercially developed tethering tools that i'd like to buy.
It is a bundled package with all the necessary things to connect through WiFi or through wired means to a large number of Nikon and Canon cameras (Pentax support unknown) as well as the software. The company also produces an application for controlling your camera through portable devices such as iOS and Android platforms. Cam Ranger offers as much if not more control than Nikon's tethering packages for a fraction of the price with all the needed hardware to accomplish the task of hooking up your camera and shooting pictures. Cam Ranger makes other fun extra's that can be controlled with this software, such as a robotic tilt pan head but that's beyond the scope of this article.
I've tested this software, I would never pay for this or recommend that anyone give Nikon money for this..
It's an embarrassing piece of crap with the Nikon name on it, it won't even recognize my D800E, according to Nikon it is compatible with this software but does not work at all according to my own hands experiences with it.
For any who wish to give Nikon money for this, it's 180 dollars.
I will be updating this list as I discover more, if you know of any tethering packages or related stuff I did not cover feel free to chime in, I will review and add it later.
Disclaimers: I receive no remuneration for mentioning products here, all products and their respective trademarks are property of the aforementioned companies in this article.
(I am not a web developer or an english major, I will not spend a lot of time obsessing over formatting and diction so if I make mistakes.. just deal with it!)