Will the Canon EF 17-40mm f/4 Lens Hood accommodate a 77mm to 82mm filter adapter?
The two lenses I use the most take 77mm and 82mm filters. If the Canon EF 17-40mm f/4 (77mm) would allow me to use a 77mm to 82mm adapter—and still let me use the lens hood—I'd go that route, and buy the larger filter to share across the two lenses.
"Will the Canon EF 17-40mm f/4 Lens Hood accommodate a 77mm to 82mm filter adapter?"
I would seriously doubt it. Most Canon hoods are a custom fit to the lens barrel. Threads have nothing to do with it.
It is likely you could install the adapter after you install the lens hood. Just measure the inside diameter of the lens hood.
I use the Xume magnetic filter holders on my lenses to allow easy swapping of filters when I want different filters for creative reasons.
I used to have the ef 17-400mm f4L, actually I had two of them. The Canon hood is very wide and open so it would not surprise me if you could mount the filter size adapter ring. Although I don't think it will fit but it might. You might have another problem in that the filter and the adapter ring cause the lens to vignette. This is a problem with any UWA and WA lens and why the hood is so wide and open. Unless you buy a thin filter of the correct size it can vignette the lens at the wide end all by itself. This is probably a case where you need the correct tool for the job.
I agree with Ernie that you could run into an issue with vignetting.
But the adapter will probably fit HOWEVER you won't be able to take the hood on or off with the adapter in place because it just barely clears the regular clear protective "filter" I use. The construction of the 17-40 won't let you slide the hood on/off from the camera mount side so once the adapter is in place your hood will either be on or off unless you remove the adapter.
But it should fit with the hood in place unless the adapter for some reason protrudes rearward from the normal thread depth because the base of the filter should sit just proud of the ring for the hood mount.
I bought my 17-40 back in 2005 with my 1D Mark II and still use it often with my newer Canon bodies. IQ is quite good and I have never felt the need for a 2.8 in a ultra wide angle even though almost all of my other glass is f2.8 or faster.
The cheapest experiment would be to buy a 77-82 filter ring off ebay for about $5. I do not have one of these adapters but I have an EF 24-105mm f/3.5-5.6 lens with it's correct hood (it uses a 77mm filter) and an 82mm filter. The filter will lay flush with the inside of the hood but with virtually no room to finger lighten the filter except on the top edge. The odds are pretty good the 82mm filter with adapter will work but you would have to put it on after attaching the hood which would be a nuisance if you like to reverse the hood for traveling. If you ever cross thread a filter, I wish you luck.
It turns out that the 77mm to 82mm adaptor fits. But there's not enough space to use one's fingers to turn the filter in order to seat the threads. I used two thin strips of wood (so as to not scratch the metal), and it went on and off very nicely.
The problem, though, as some here estutely predicted, is vignetting—in the form of extreme shadows on three of the four corners (nearly black vignetting) when shooting at 17mm (a mm at which I do ninety-nine percent of my work for this job).
I have since ordered a 77mm filter for this lens. The 82mm can live on my 82mm lens.
Of note, if I zoom in to 18mm, all signs of vignetting go vanish. This has allowed me to temporarily continue to shoot with this excellent polarizer filter. Indeed, Breakthrough Photography's X4 CPL filter is so clear, that when I first fired up the camera, and looked at the LCD back, I gasped. I never imagined I'd be able to see the difference from the LCD back! On the 32-inch monitor, the effects are more dramatic.
The color shift on the X4 CPL is less than the previous filter I've been using (Hoya HD), but I still need adjustment to tone down the oranges for my HDR shots with certain shades of wooden floors and kitchen cabinetry—I just need less adjustment.
Lastly, the X4 CPL is faster than the Hoya HD, but not by much. I informally judge the Hoya as needing one and a quarter to one and the third stops more light. Whereas I informally judge the X4 to be closer to needing one stop (or, perhaps just a smidge more than one stop). For my work, I'll take every second I can save between setups. I typically need to make 40 to 60 setups per shoot—on tripod. I use a different camera for the exteriors. (I don't use a CPL on my exteriors, as I don't enjoy the uneven polarization CPL filters often exhibit in the sky portions of my images.)
Thank you all for your enthusicastic feedback! Now, get out there and shoot something! 😄