When I chose the Sony camera system I knew I'd be climbing a mountain of compatibility and support issues. Some of those issues revolve around proprietary hardware interfaces (I'm looking at you hot shoe), but more often than not it's software support (and the previous lack of an available API) that cripples usability. Tethering (in the loosest definition) has been supported for some time with the Remote Camera Control (RCC) but native integration with popular photo editing/management software has been sparse if not completely absent.
So, how do Sony shooters Macgyver their way around this particular issue? Well you actually have a couple options, neither of which are perfect in my opinion. I've recently switched to Adobe Lightroom 4 from Aperture so I'll mostly focus my efforts there. In saying that you should also recognize that I'm a Mac user, so experiences may not be identical for Windows users.
Lightroom Auto Import and RCC
This could be considered the hybrid or passive approach and is the most cost effective solution available.
What you need
Adobe Lightroom, Sony Remote Camera Control (RCC) and a USB transfer cable. You can use the supplied USB transfer cable that came with your Sony A99 but I strongly recommend you invest in a longer and more robust cable. I'm using the TetherTools 15' A - B 5 pin cable. For the record I'm testing this process using a 2013 Macbook Pro w/ 16GB memory and a 2.3 GHz i7 CPU with Lightroom version 4.4 and Remote Camera Control version 3.2.
1) Connect your A99 to your computer using the USB cable. Power on your camera and then open Sony's Remote Camera Control software. If you've connected your camera properly you'll see a typical remote interface that registers your cameras current settings. This is really the point of the software, to control your camera and allow for remote setting adjustments. The only important step you need to worry about is the destination folder. In my example I've created a folder called "Tethered" on my desktop. This is where I'll dump all my RAW files for use with Lightroom.
2) Before you shoot any images you'll want to open Lightroom and make the following selections.
Click on the File > Auto Import > Auto Import Settings menu. You should now see the following window (see image below). The "Watched folder" should be connected to the same destination folder you created in RCC during step 1. The Destination can be any new (or existing) folder of your choice. Lightroom will automatically save the transferred files to this location. If you create a new Subfolder Name, Lightroom will create this during the first file transfer. You don't need to manually create this folder in your Lightroom Library. You also have the ability to rename and apply metadata to all of the incoming files. This is a pretty helpful option and will ultimately streamline your editing process. The last step is to ensure you've checked the "Enable Auto Import" box at the to of the window. This will command Lightroom to continually check the "Watched folder" for new files.
3) Now we're ready to make things happen. Without closing Lightroom pick up your camera and take a couple test shots. Assuming you still had RCC open you should see Lightroom begin to transfer images into your library.
In my experience it takes between 11 and 15 seconds to transfer a single RAW image (about 25MB in size). It's important to note that when shooting in burst mode the subsequent file transfers speed up a little. I'm not certain what Lightroom's interval is for checking watched folders but I would guess it's every few seconds based on my results. This is a fairly practical method for transferring images into Lightroom remotely but the speed is slightly undesirable. If you're shooting in a studio environment you likely don't want to sit and wait 15 seconds before you can preview a shot.
Lightroom and Third Party Plugins
In my endless pursuit of tethering options I came across a company called DNA Software (aka Aleshin Dmitry). They focus primarily on Sony Alpha camera applications and plugins. In particular he offers Lightroom (3, 4 and 5) tethering plugins that extend Lightroom's native capabilities to include select Sony cameras. This is really the core issue with Lightroom, it doesn't recognize the camera when you try to use the native tethering functionality. This plugin essentially eliminates the need to use Sony's RCC software and instead contains the tethering workflow within Lightroom. So, how does it stack up to the hybrid approach? Keep reading...
1) DNA Software offers a demo of the plugin so I recommend you test it out before committing to the purchase. I took the plunge and paid $39.99 USD for the commercial licence. Please follow the developer's instructions when attempting the installation as I'm not going to write them out here.
2) Once you've installed the plugin you can open Lightroom. Connect your camera via USB and turn it on. In Lightroom click on the File > Tethered Capture > Start Tethered Capture menu. If you've installed the plugin correctly you should see remote interface displayed and the A99 recognized as the connected device. That's it, start firing!! Your images will be displayed in your library similar to the last example.
On average I'm finding the transfer rates to be approximately 6 seconds per RAW file. I have read a few complaints about tethering sessions ending abruptly but I haven't encountered that problem myself. Considering this solution is approximately twice as fast as the hybrid method I think it's $40 well spent. As with all things though it's a matter of need versus want. If you're a casual shooter and aren't under any constraints you can definitely get away with the hybrid approach and save a few bucks. Patience is a virtue after all.
One thing I failed to mention earlier is the way Sony handles tethered (PC mode) sessions. Files WILL NOT be stored on your internal memory cards when utilizing either of these tethering options. I believe Canon allows for parallel file writing (to your PC and memory cards) but that definitely isn't the case with Sony. Hopefully they'll be able to address this with a firmware update in the future, but I'm not holding my breath.
Best of luck in your tethered adventures!