For photographers who need longer battery life with Speedlite flashes, the standard has been very expensive Quantum battery packs. Typically around $300+ dollars (seen here via B&H). There are a few cheap external solutions that use 6x AA batteries (seen here on eBay), but they are merely extended power sources and often don't help to improve recycle times.
Now a popular product making rounds in the last year as an alternative is the GoDox external flash battery packs. GoDox also have a variety of other lighting products including large studio strobes and continuous lights. I had a brief look at these products over at the PhotoPlus Expo in New York, and these battery packs look very good. The Godox external flash battery packs are available for Canon, Nikon, and popular Yongnuo flashes as well found via eBay (Click here).
GoDox External Battery Packs for Canon Nikon Yongnuo Flashes
YouTube member Wandomphoto performs a distance test with the Yongnuo RF603n (the n is for Nikon), and claims some pretty good results up to 1/4 mile away. These are very basic triggers and receivers that lack all the other high speed sync and communications that other high end triggers offer, but are fairly reliable. I am still using the RF602 triggers which included one remote trigger and one receiver. I haven't upgraded because they are not compatible with the RF603. The RF603 made a change in design that makes them 'Transceivers' which is both a transmitter and receiver. That's actually a much better design when you need to keep adding another remote or another receiver to the kit. A pair of these will run you about $30 bucks, and you can check them out via eBay (click here)
So you want to move your flash off camera? Sure you can use inexpensive wireless triggers, but the biggest drawback to moving a flash off camera, is losing ETTL communication and High Speed Sync. Unless of course you're shelling out some serious cash for a wireless remote system like Radio Poppers to supports this. YouTube member Matthewrichey created a video showing you how to take basic Cat5 cables and connectors to modify those short off camera flash cables giving them variable length.
Although he took the time to make a video showing you what the end result could look like, this is not his original idea. You'll find people were doing this several years ago, and there's some instructional step by step info over at DIYPhotography.net (here).
Some event Photographers run with a Flash on top of a Monopod, so they can bring it up high or move it around before snapping a picture. To keep communication between the camera so you can adjust flash compensation, this technique would require several feet of cable. If you're not the DIY type, you could just check out some of the existing 33ft (10 meter) long cords available for not much more than $30 bucks, saving you from buying an expensive set of Radio Poppers (and not having to worry about batteries for the triggers).
The Yongnuo YN-565EX ETTL Flash for Canon and Nikon is so far very nice. Yongnuo has really stepped up their game with this new YN565EX, providing a solid build that feels very similar to the Canon 580EX II which is the top notch in Canon gear. Many other features only available in Canon's top flashes are also included in the YN-565EX such as PC sync and External Power port option. For an on camera flash with Canon DSLRs, it works transparently for the average consumer. In ETTL mode, communication with the camera are recognized including Zoom Distance, Aperture, and Flash compensation. Note: This flash does not have an HSS option.
When used off camera, the flash can be set to Slave mode and triggered from a variety of Canon Master or Nikon Commander type triggers. Although you can fire the flash remotely, I need to do more testing to see if ETTL is still working wirelessly. I noticed the flash was not picking up my flash compensation, zoom, or aperture. It seems to have defaulted to a more manual mode but still fired as a slave. Maybe i'm missing something in the settings? Since this YN-565EX can be triggered through a Canon Master, this should (ideally) work to be triggered from the 'built in' wireless triggers from the Canon 7D and Canon 60D cameras (turn on Flash trigger in menu). I think the T3i may also have this option. In any case, the many features, build quality, and price makes this a perfect flash for on camera use, and for experienced flash photographers the manual modes 'off camera' work excellent too. You can find them online via eBay (click here).
Canon OEM flashes are no joke when it comes to pricing, but also no joke when it comes to features. Regardless, there's a handful of people who may never even cross those extra abilities and are just looking for a flash that works. You might have caught Aaron's review of the Yongnuo 560 at this article: http://cheesycam.com/yongnuo-560-flash-review/, but now we've got another one to add to the list. Vimeo member Rick Elrod shows a bit of the Yongnuo 468 which supports TTL communication from the Canon camera. In simple terms, the flash meters through the camera in a few different ways and makes decisions for you. This Auto Pilot feature works great and is more often what you need, and very seldom what you don't need. So for those who want to go the manual route in those rare incidents, the flash can be set all manually as well. Got questions? Send them over to Rick via the Vimeo page here. [Thanks Rick]
Aaron mentioned he received the Yongnuo 560 Flash for off camera use, and threw up a demo video. From the information in the video, i'm pretty impressed. This YN-560 version doesn't support TTL, but when using my Yongnuo RF-602 triggers, I'm using my flashes all manually anyways. I can see event photographers using these either on light stands or clamped around the ceiling to get some extra light into a dim lit event. Especially since they are fairly cheap, I wouldn't be as worried about damage or theft leaving them around. I'm totally paranoid just throwing my Canon 580 EX II's in places that seem 'untrustworthy'. I guess I found my backup solution. Thanks Aaron, for the demo on these inexpensive Yongnuo YN-560 flashes.