tbh I was in the exact same boat with my 90D a few months back. I looked at the Canon 600EX II-RT but honestly I couldnt justify spending nearly 500 dollars when there are cheaper options that do basically the same thing. I ended up going with the Godox V860III-C Ving TTL Li-ion Flash for Canon and it has been a total game changer for my birding setup. The main reason I recommend this over the Canon or even the cheaper Godox AA models is that Li-ion battery pack. It recycles so fast that I can actually use it with the 90D burst mode without getting a bunch of black frames halfway through a sequence. Plus, you save a ton of money over time not buying massive packs of AA batteries for every outing. It handles HSS perfectly for those bright skies peeking through the canopy and the TTL is surprisingly reliable even in tricky wooded lighting. I use mine with the Better Beam Flash Extender FX-3 which fits the flash head perfectly. If you are worried about reliability, just make sure you update the firmware when you get it. Its way more budget friendly than the native Canon gear and leaves you extra cash for a better tripod or maybe a lens upgrade later on. Just my two cents tho!

How far away are those birds usually? Ngl if you want to save some cash, the Yongnuo YN600EX-RT II Wireless Speedlite for Canon is a solid alternative that handles HSS perfectly.

@Reply #6 - good point! I have seen way too many loose hot shoes over the years because people get way too aggressive with those heavy extenders. In my experience, if you are really trying to push the 90D to its limits with birding, you have to prioritize heat management and build quality over just saving a few bucks. I have been shooting with the Canon Speedlite 600EX II-RT for about four years now and honestly, it is the only thing I trust for long days in the woods. I tried a few cheaper clones early on but they always seemed to thermal out just when the action got good. There is nothing worse than watching a rare owl fly off while your flash is stuck in a cooling cycle. The weather sealing also matches up perfectly with the 90D body, which is huge if you are dealing with morning dew or a surprise drizzle. To really nail those high burst rates tho, you gotta look at the Canon CP-E4N Battery Pack. It basically forces the flash to keep up with the cameras shutter and provides way more consistent voltage than internal AAs. It adds some weight to your belt, yeah, but it keeps the flash head from melting down during a long sequence. Just be careful with that mounting foot like the others said... I always check the tightness before I head out.

Bump - same question here

Quick reply while I have a sec because I went through this exact struggle with my own birding setup. If youre trying to save some cash but still need that HSS for filling in shadows on the 90D, you should definitely check out the Godox TT685II-C TTL Flash for Canon. Its basically the same internals as the more expensive V-series but it runs on AA batteries instead of a proprietary lithium pack. Honestly, if you grab a set of Panasonic Eneloop Pro AA High Capacity Rechargeable Batteries, the recycle times are surprisingly snappy. You can get two of these flashes for the price of one Canon 600EX II-RT and still have money left for your extender. The TTL is super reliable on the 90D and it handles high-speed sync perfectly when youre shooting in those bright patches of the canopy. Another solid budget pick is the Yongnuo YN600EX-RT II TTL Speedlite for Canon. It mimics the Canon menu system almost exactly and works with the Canon RT radio system if you ever decide to go that route. Just a heads up tho, if you're doing heavy burst shooting at high power, any flash without an external battery pack is gonna struggle to keep up with the 10fps on the 90D. If you find yourself missing shots because of the recycle time, look into a cheap external pack like the Godox PB960 Propac Power Pack later on to really juice it up.

Great info, saved!

Been thinking about this thread for a few hours. People here have made some good points about going with Godox or Yongnuo over the pricey Canon stuff. I would suggest being a bit cautious tho when you start rigging things up.

• Be careful with your hot shoe. Using a heavy flash plus an extender puts a ton of stress on that mount. I would suggest a DIY bracket to keep the weight off the 90D body so you dont end up with a broken camera in the woods.
• Make sure to watch the heat. HSS is a total power hog and it makes things hot fast. If you are firing off bursts, be careful not to melt your flash head lens.
• If you try a DIY extender, just be careful with the alignment. You can actually scorch your gear if it is not set up perfectly. Gotta stay mindful of the gear while chasing those owls.