I could be wrong but I don't think that there is another Canon lens that has both front filter thread and rear gel filters. Curious implementation as front filters are much easier than rear gel and you get grad ND and rotating CP filter options as well where there isn't a bulbous front element. For bulbous front elements, front filtering is big and expensive.I wonder if that is the reason for putting in support for rear filters -- two thick front filters results mechanical vignetting?
In general, there is mechanical vignetting in all focal lengths depending on the protruding filter distance leading to slim filters to avoid this.
To avoid vignetting, most filter systems for 16-35mm (ie wide but not ultra wide) have a bigger stepup thread and then you can stack 100x100 or 100x150mm front filters + inbuilt CPL without vignetting. I use the Nisi V7 system https://nisiopticsusa.com/shop/nisi-100mm-square-filter-system/
They also have 75mm system for small front filter threads.
Their 150mm systems and 180mm system are for specific lenses without a front filter thread.
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