Jumping in here because the 16-35mm is a beast with filters. Quick question before you pull the trigger on anything: are you shooting with the version II or the version III of that lens? It makes a massive difference because the III has an 82mm thread and is even more prone to vignetting at 16mm if the filter ring is even slightly thick. I would suggest being very careful with the circular polarizer and ND combo. If you stack two circular filters, you are almost guaranteed to see dark corners at 16mm on a full frame like the 5D Mark III. It basically ruins the shot. For your 300 dollar budget, you might want to consider looking at the NiSi V7 100mm Filter System Starter Kit. It usually sits right around that price point and includes a built-in circular polarizer that sits closer to the lens glass to prevent that vignetting you are worried about. If thats too pricey, make sure to check out the Haida M10 Filter Holder Kit which is a solid alternative. Square systems are way better for rivers because you can slide a graduated ND to handle the sky, which a circular filter just cant do properly. Honestly, cheap glass has terrible color cast like magenta or blue shifts that are a nightmare to fix later. Definitely let us know which lens version you have though, because the clearance varies quite a bit.

Late to the party but I love the energy here! @Reply #2 - good point! Figuring out those thread sizes is huge for your budget. To summarize: square systems provide the best modularity but cost a fortune, whereas circulars are budget-friendly but prone to vignetting at 16mm. If you want a square setup that fits your $300 limit, the K&F Concept Z-Series Square Filter System Kit is a fantastic alternative! Its amazing how good the glass is for the price. For those Olympic rivers, the NiSi Explorer Collection 100x100mm Nano IR Neutral Density Filter ND1000 is perfect for long exposures. If you prefer circulars, the Breakthrough Photography X4 CPL 82mm is basically the gold standard and super slim so it wont vignette. Just dont stack filters or youll definitely see black corners. Stick to one high-quality filter at a time and youll be golden.

Ngl, 300 bucks is super tight for a full square setup. Be really careful with stacking circulars on that 16-35mm tho because the vignetting is brutal at the wide end. If you buy thick ones, you're basically throwing money away when your shots have black corners. Honestly, just grab one high-quality slim circular polarizer for now. Better to have one good piece of glass than a kit of junk.

> Should I just stick with a couple high-end circulars or is there a square system that actually fits a 5D setup without breaking the bank? In my experience, jumping into a budget square system for a trip like Olympic is usually a recipe for frustration. Over the years, Ive seen way too many photographers deal with light leaks on those cheaper holders during long exposures. It basically ruins the shot. Reliability is king when youre hiking in the PNW. Ive tried many setups and honestly, square systems under 300 bucks usually compromise on the foam seals or the glass coating quality. Before you commit tho, are you planning on doing super long exposures like 2 plus minutes or just quick 1/2 second water blurs? Also, do you find yourself shooting at 16mm most of the time or do you tend to zoom in closer to 24mm? Knowing those specifics helps figure out if the vignetting will actually be a dealbreaker for your workflow.