ND Filters and "Vignetting"?

[RocketCowboy]

Hopefully not the wrong sub-forum, but looking for some input regarding graduated ND filters.

While getting some test shots with the 10-24mm over the weekend, the 77mm Polariod adjustable ND filter was providing some distortion of vignetting when I tried to use most of the darker settings. It seems more pronounced at the wider focal lengths, but still seemed noticeable even at 24mm. Could this be a bad ND filter, or just a side effect of mating this filter with a wide-angle lens?

Here's a couple shots of what I was seeing...





These are SOOC, just resized and saved from RAW to jpg for viewing.

Thoughts?

 

[BackdoorArts]

Almost all variable ND's will do this when you get past 5 or 6 stops. More expensive ones can go further, but you're essentially just seeing hot spots where 2 polarizers are shutting down the light unevenly. I've bought and returned 4 different Variable ND's for this reason and now just stick with fixed values and stacked filters. There are some who swear by these, but I just swear at them.

 

[RocketCowboy]

For the price of the 77mm filter, I was expecting better, but thanks for confirming that. It pretty well maps to what I was seeing ... things worked pretty well through the first 5 or so settings and only started to show when shutting down significant amounts of light.

 

[BackdoorArts]

It's unfortunate, because they're not cheap and they'd be convenient as all heck if they actually worked. If you hunt you can find some posts here where people tout how well theirs work, but I don't remember them being less than $200.

 

[hark]

Keep an eye out for sales. Earlier in the year, Jake mentioned that B&H had the Hoya 9-stop ND filter on sale for $49 (it came in 77mm). The price is no longer valid, but hopefully it will go on sale again.

Error

 

[RocketCowboy]

Thanks everyone!

Looks like I'll return the Polaroid 77mm ND filter and hold out for a better Hoya. So far, the Polaroid 58mm seems to be working out ok, so I might old on to that awhile longer.

 

[Blacktop]

Also for a UWA lens you really need thin filters. Your normal filters will vignette.

 

[PapaST]

Oh wow, I didn't even know variable NDs existed. Learn something knew everyday.

 

[RocketCowboy]

Also for a UWA lens you really need thin filters. Your normal filters will vignette.

The variable ND filter also precludes the use of the lens hood, so I was worried that flaring would be a bigger issue. My other 77mm filter is a Hoya HD2 CPL, which seems to be thin enough to not vignette on it's own, but was pretty bad if I tried to stack both the CPL and the variable ND.

 

[Blacktop]

I haven't even tried putting a filter on my Tokina yet. These lenses can be a PIA but once you figure them out they are worth it.

 

[hark]

Hoya does make some slim ND filters although they are more expensive. This is a 6-stop ND filter for my Sigma which is why it is 82mm.

Error

 

[RocketCowboy]

Thanks @hark ... that looks like the other advantage to going with a fixed-stop rather than variable-stop ND ... that Hoya looks like it would also work with the lens hood.