Honestly, I had some issues with screw-ons on my 16-35mm... the vignetting was realy bad at 16mm. For PNW waterfalls, I totally suggest going with a square system instead. Here is what I recommend for ur budget:
* NiSi V7 100mm Filter System Kit with True Color NC CPL - basically the best way to handle glare without that weird yellow tint.
* NiSi 100x100mm Nano IR ND1000 10-Stop Filter - def need this for those silky water shots! I skip the GNDs now cuz the 5D IV sensor is actually pretty good at recovery, but a solid CPL is non-negotiable. 👍

Sooo, you've got the Canon EOS 5D Mark IV? That is literally one of my favorite bodies for landscape work! The dynamic range is fantastic, but I totally get why you want that in-camera polish. Getting it right at the source just saves so much headache later, right?? Before you drop $600 on a massive square setup, I gotta be the cautious one here. I've seen way too many people drop big bucks on square filters only to have them sit in a bag because they're a pain to set up in PNW rain. Since you're on a budget, honestly, just stick with high-end screw-ons for now! You'll get way more bang for your buck and save a ton of weight. For that Canon EF 16-35mm f/4L IS USM, you absolutely need a slim circular polarizer. I'd suggest the B+W 77mm HTC Kaesemann Multi-Resistant Coating Nano Circular Polarizer. It's about $110 and the build quality is AMAZING. It won't degrade your L-series glass at all! Since you're doing waterfalls, skip the GNDs for now and grab a solid ND. The Hoya 77mm ProND1000 Filter (10-stop) is a steal at around $80 and gives you those dreamy 30-second exposures even in daylight. If you want something for those moody forest streams, the Breakthrough Photography 77mm X4 6-Stop Fixed ND is incredibly neutral and high-quality for about $150. Basically, for under $350, you have a pro-level kit that fits in your pocket! You can always do a quick exposure bracket for the sky if the 5D IV's sensor isn't enough, but these filters are the REAL essentials. gl!

Respectfully, I'd consider another option before going full square kit. I spent years hauling big filter holders through the PNW forests, but honestly... physical GNDs are a trap there. The treelines are never straight, so you'll just end up with dark treetops!! Since the 5D IV has such a killer sensor, just bracket your shots for dynamic range. Spend that cash on a really high-quality screw-on CPL and a 6-stop ND instead. Simpler is better tho.

Sooo I’ve been looking into this a lot lately too since I also shoot with the 5D IV. Tbh the market is kinda overwhelming right now with so many brands! From what I’ve seen, u basically have the old-school premium names and then the newer players like Haida or Formatt-Hitech that are honestly catching up so fast. I’ve been reading that Haida is like the best value for money if youre worried about color cast, but then everyone still says the high-end boutique brands are the gold standard for a reason even if they're pricey lol. I’m still trying to figure out if the extra $200 for a "premium" logo actually makes a difference in real-world shots or if it's just marketing? Like, is the glass actually better or are we just paying for the brand at this point?? Honestly, if u want to stay in that $400-600 range, u can't go wrong with Haida or maybe even Benro. They basically do the same thing for way less. I’d just pick one and stick with their system so everything fits together. Does anyone else feel like the mid-range brands are basically just as good as the expensive ones now?

I spent a lot of time testing different glass on my own 5D IV before settling on a very specific setup for damp environments like the PNW. One thing I learned the hard way is that aluminum filter rings tend to bind in cold, wet weather, which can be a nightmare in the field. I eventually moved toward brass-mounted filters for the reliability factor alone. If you want a dependable DIY kit that stays within budget without sacrificing that L-series sharpness, here is what I would prioritize:

• B+W 77mm Master Circular Polarizer MRC Nano
• The brass construction is much safer for your lens threads than cheaper aluminum options.
• Marumi EXUS Solid Design ND64 6-Stop Filter
• This is usually the sweet spot for forest streams where a 10-stop filter is often too dark. I personally skipped the square systems because they are too cumbersome for hiking in the rain. Bracketing your exposures on that 30.4MP sensor is generally more reliable than messing with a physical GND in a forest where the canopy isnt a straight line anyway. Just make sure you carry a decent microfiber cloth since the PNW mist gets on everything instantly...

Interested in this too