Anyone using a Lee foundation kit with 24L/35L? Vignetting?

Ok so here's the deal. I still own one zoom (well, that I use) - the 17-40L. I only have it in my bag because I can't live without my GND filters, which I mount onto the Lee foundation kit. It vignettes horribly at 17mm (black corners), but zoom into 19mm, and all is well. That's why it stays in my bag - I never use the zoom otherwise.

I would love to replace the zoom with a prime or two, since I am a ginormous prime whore (I lose weathersealing with the 1DMKIIN now though...hmmm), but I can't because of the vignetting issue (that...and the weathersealing). The lens is great for landscapes but f/4 is just too slow for every other time I use it, so most of the time it collects dust, unless I'm landscaping.

So if any of you use the Lee foundation kit - do you use it with a 24L? 35L? If so, do you get horrible black corner vignetting? If the answer is yes, I'm keeping my 17-40L. If the answer is no (samples please ), then I'm selling the zoom tomorrow unless for some reason you convince me that I really need a weathersealed lens that I rarely use.

If its any help I get no vignetting on my 16-35L II using the Lee FK. But I do use the wide-angle adaptors.

Anke wrote in post #7017496
If its any help I get no vignetting on my 16-35L II using the Lee FK. But I do use the wide-angle adaptors.

Thanks Anke, but I get the same with my 17-40L, and if I wanna go faster, f/2.8 ain't gonna cut it .

I use the lee setup with the wide angle adaptor on my 10-22 (and 17-40) on a 50D but i have only fitted 2 of the slots rather than all three supplied. How many do you have fitted? Some people report some lenses need just one fitted to avoid vignetting.

NinetyEight wrote in post #7017789
I use the lee setup with the wide angle adaptor on my 10-22 (and 17-40) on a 50D but i have only fitted 2 of the slots rather than all three supplied. How many do you have fitted? Some people report some lenses need just one fitted to avoid vignetting.

Again, it's not a problem on the zoom - I wanna know if you get vignetting on a prime!

If you get no vignetting at 19mm on the zoom, I can't see why it would cause vignetting on a 24 or 35 prime at all.

Dorman wrote in post #7017814
If you get no vignetting at 19mm on the zoom, I can't see why it would cause vignetting on a 24 or 35 prime at all.

Depends if it's the holder or the adapter that causes the vignetting, I just don't know for sure.

It's the holder that causes the vignetting, and in many cases it's the slots that are causing it. For example, 10-22 on a crop cam will vignette when using the 3 filter holder, but if you cut one off using only 2, or the single slot wide angle holder, you'll be fine. I'd assume the same principle would apply to your 17-40, and therefore to the primes.

perryge wrote in post #7017793
Again, it's not a problem on the zoom - I wanna know if you get vignetting on a prime!

Appreciate that, and maybe I'm not being that helpful, but how many slots do you have or need on your holder as this will affect the results and is another variable.