I have been searching everywhere but I can't find a clear answer. I have a few older Yongnuo flashes, specifically the 560, 560ii, and 565ex. I am trying to find a transceiver trigger that will allow me to remote control flash power from on top my camera. Is this even possible with the older flashes? Or is it just time to upgrade and get some new flash units?
There is no transceiver/trigger that will have remote power control over the YN-560 or YN-560II. They don't have built-in RF with power control, and the single pin on the foot means the only signal that can be communicated over external radio triggers is sync.
You can remotely control the power on the YN-565EX if you use TTL-capable triggers, such as the YN-622s.
You basically have two choices, if you want to stay with Yongnuo:
Dump all your units, and go with the YN-560-TX triggering system. This is manual-only triggering (no TTL or HSS), but you will have remote power control if you use a YN-560-TX or a YN-560IV or YN-660 on the camera hotshoe. As slaves, you can use the YN-560III, YN-560IV, or YN-660. You cannot add Yongnuo TTL gear into this setup without losing TTL capabilities to make it compatible with the triggering system. Any non-Yongnuo speedlights cannot be power-controlled through RF-603II or RF-605 transceivers. Yongnuo's YN-622 and RF-60x systems are incompatible.
Dump the -560 units, and get TTL-capable speedlights and add YN-622 transceivers, or get the YN-685EX (which has a built in 622 receiver). You can use a 622 or 622-TX unit as your on-camera transmitter. But any flashes you want to add into this setup must be TTL-capable (and if you're a Canon shooter, menu-commandable) if you want to set manual power levels (vs. TTL ratios).
There's also a third option that may make more sense for future growth (well at least this month; low-end Chinese flash gear churns at an alarming rate. The FlashHavoc blog is a good way to keep up with what's current):
- Dump all your units and go with the Godox X system. The UI/UX isn't quite as nice for Canon (especially if you're shooting with a pre-2012 body), but you can easily mix TTL and manual-only speedlights, and, unlike the RF-60x/YN-560 system, you will have HSS with either (assuming you're shooting with a body that can do FP/HSS--Nikon 3x00 and 5x00 bodies can't). The TT600--the Godox equivalent of the YN-560III/IV/-660 plays nicely in the same system with the TT685 (the Godox equivalent of the YN-685--only it has a transceiver built in, not just a receiver). And the same radio system is built into Godox's other lights: the Li-Ion powered speedlights (V850II/V860II), the bare bulb flashes (AD200, AD360II), and the monolights (SKII series, QSII series, QT600II, and AD600). If you ever want to go bigger than speedlights, Godox gives you a lot of choices; Yongnuo not so much.
Or is it just time to upgrade and get some new flash units?
Yes, it is time.
The manual power only YN560 and YN560 II have no provision for power control beyond the controls on the flash units themselves. With no connectors for any external unit to communicate with the flash's internal controls, there is no way for any current or future triggering system to set power externally.
Your YN565 EX is externally controllable by radio in either manual or TTL modes via a YN622 set of triggers. You need a YN622 transmitter attached to both the camera's hot shoe and on the foot of the off camera flash. The YN622-TX is a transmitter only unit that includes an LCD screen showing various menus and settings. The YN-622 is a transceiver that can be used as either a transmitter on the camera or as a receiver attached to the flash. It has no LCD screen and displays selected settings via an LED light next to each switch or via the switch position itself. It is a bit more difficult to use as the on camera unit unless your camera has menu based external flash control (pretty much a post 2008 Canon EOS model). Both the YN622-TX and YN-622 come in Canon and Nikon flavors. The YN-622 transceivers were updated in 2015 to the YN-622 II.
If you decide to stay in the Yongnuo system you can use a YN622-TX controller/transmitter on your camera and a YN-622 II set to receive mode attached to your YN-565EX. For the other two flashes (to replace your YN-560 and YN560 III) you can either use a YN685 that has a built in YN-622 radio receiver, a YN568 EX II combined with a YN-622 II attached, or a YN-565EX II with a YN-622 II attached.