Filter problem

Julesgurr23 · 6 Apr 2012

I all, just been back from a trip to Cumbria, and whilst there had a really annoying problem with my graduated ND filter, which ruined a lot of potentially good shots.

Unfortunately I've deleted all pictures showing the problem in frustration, but am pretty sure it's the filter as without it I was taking pictures just fine.

The problem is that it seems do have darker patches, some pictures were still completely black in places, even on a 30 second exposure. I looked at the filter & it seemed clean to me, couldn't spot anything with my eye. Has anyone else come across this & know what is causing this? And what can do to fix it, or is a new filter needed?

Thanks in advance,

Julian

HoppyUK · 7 Apr 2012

It doesn't sound like a filter problem, but there's no way of telling without a picture.

tony09uk · 7 Apr 2012

i would recommend that you go out on a bright day with the nd grads and do little experimenting to try and work out what went wrong. Then post your results......remember your not after a great picture just some ideas and results for us to look at and try to help

AJQS · 8 Apr 2012

Julesgurr23 said:
The problem is that it seems do have darker patches, some pictures were still completely black in places, even on a 30 second exposure.

What the hell were you photographing? the whole point of a graduated filter is to darken part of the frame, but 30 seconds exposure in (I assume) daylight? you sure you havent bought a 10 stop ND filter by mistake? :thinking:

Mountaineye · 8 Apr 2012

Might be worth using some image recovery software to see if you can retrieve the deleted files. It would let you post an example here. There's plenty of free stuff around and of course the included software if you buy legit Lexar cards.

NikkiA · 8 Apr 2012

'black patches' sounds a lot like a variable ND filter rather than a graduated ND filter... a 30s exposure would sound like someone trying to use a vari-ND as a 10-stop too...

And if so, there's where the problem is, vari-ND isn't as good as plain NDs, because you're using 2 polarizers, and you get patches at wide angles.

HoppyUK · 8 Apr 2012

NikkiA said:
'black patches' sounds a lot like a variable ND filter rather than a graduated ND filter... a 30s exposure would sound like someone trying to use a vari-ND as a 10-stop too...

And if so, there's where the problem is, vari-ND isn't as good as plain NDs, because you're using 2 polarizers, and you get patches at wide angles.

Good call, if indeed the OP is confusing the two types of filter. Vari-NDs are useless IMHO and often sellers do not point out the problems at high densities with wide-angles.

posiview · 8 Apr 2012

Alan Clogwyn said:
What the hell were you photographing? the whole point of a graduated filter is to darken part of the frame, but 30 seconds exposure in (I assume) daylight? you sure you havent bought a 10 stop ND filter by mistake?

Mountaineye said:
Might be worth using some image recovery software to see if you can retrieve the deleted files. It would let you post an example here. There's plenty of free stuff around and of course the included software if you buy legit Lexar cards.

because I'd like to see what the problem was.

Cheers.

HoppyUK · 8 Apr 2012

posiview said:
because I'd like to see what the problem was.

Cheers.

I think we all would. But if it's an equipment problem, it should be easy enough to replicate.

Julesgurr23 · 9 Apr 2012

Ah apologies everyone, it is a variable not a graduated filter. Would it be recommended to try a fixed ND filter rather than a variable?