Magenta tint with ND filters

[parish]

Been thinking about getting an ND grad filter or two, but two threads here show that Cokin NDs produce a magenta tint (in one thread it looks more like dayglo pink ) so I'm looking for advice.

Why does this happen? I thought Cokin were a good make, so why do their filters have this problem? Is it because they were designed for film and digital sensors react differently?

Does this affect all NDs or just Cokin?

 

[reddeathdrinker]

The whole colour cast issue is one of these things that seems to be a bit overblown. Lots of people have "heard" of the problem, but how many have actually had it? Not a great percentage methinks... I certainly never have, and I've used both Cokin and Kood ND/ND grads. A bad batch of filters, or poor post-processing/white balance issues could also be to blame...

Personally, I reckon it was a myth started by someone at Lee to boost their sales

 

[parish]

These are the two threads I was referring to

Tintern Abbey

101 seconds on Skye

 

[reddeathdrinker]

One bad batch of filters isn't the end of the world. My Cokin's are fine - no tint, even at long exposures. If you have your doubts, try Hi-Tech or Kood filters instead

Here's one from recently - both ND grads on the sky, straight jpeg conversion in Lightroom, no presets, straight from camera...

 

[Steve 7]

If you are using Lightroom or Photoshop, is this not easily dialled out with the 'Tint' slider??

 

[mattyh]

I've had it plenty.. it seems to be on longer exposures to me...

 

[Jimmy_Lemon]

I always scoffed at these pink tint complaints, as I had never had any problems with my ND grads, but used them for the first time at the Newcastle Meet on my new L glass and it really shows up, white clouds became pink! This is the same grad I had used before on my kit lens, 10-20 and 70-300.....so it seems to suggest to me that it happens in a combination with some lenses

Mattyh I think that above might have just been the light pollution to be honest, I have some that look the same from that night without any filters.

 

[mattyh]

OK maybe that was a bad example, but I do have loads from daytime & stuff that can't be light pollution, I generally delete them though

 

[fracster]

I have only ever had the problem when using 2 or more stacked.

And yes, I did clean the sensor after this one.............

 

[OneTen]

IIRC this problem was common years ago with the Cokin graduated grey filter, before they added ND grads to the range. I use Cromatek ND grads that fit the Cokin P holder.

 

[Jimmy_Lemon]

Example of how mine behaves now.

Without:

With:

Excuse the bad quality they are screen grabs.

 

[Jimmy_Lemon]

hmm just occurred to me looking at them building in the background that that might have been taken with the 10-20 which would mess up my theory :|

/me toddles off to check

EDIT - Balls, those are with the 10-20, so theory about it not liking some lenses is shot as I have got fine shots from the 10-20 plus the same filter before maybe it is certain conditions that causes it?

 

[Jimmy_Lemon]

10-20 with same filter on, but in wales = this:

no sign of pink! I am confused

 

[mattyh]

It'll be something to do with refraction or some other light bending thingy-ma-jig, but I don't know what

 

[reddeathdrinker]

It'll be something to do with refraction or some other light bending thingy-ma-jig, but I don't know what

It's something to do with science!! Sounds plausible enough to me

Looks like the jury has returned a verdict of "buy them anyway, try them. If they're right, they're right, and if they're wrong, return them"

 

[CraigDouglas]

I'm switching over to lee filters for this exact reason. Sometimes they are fine, sometimes they are really bad - depending on scene and conditions. I've got some recent examples from my holiday of shots they have ruined, but here's one were it made a lucky benefit on a long exposure:

 

[CraigDouglas]

Here is a recent one from the lakes last week. Probably why I'm slightly biased against them now because I was really looking forward to this shot and they ruined it (Although without the filters at all it wouldn't have been possible to balance the light anyway)

and here is another...

Having said that though, I took around 200 other shots with them that holiday and they show little or no sign of the colour cast.


EDIT: In reply to the OP (got down off my rant now ) cokin are a good make, but true Neutral density grads are difficult to make. Compare the price of the cokin filter to the LEE filters and you'll see why they are a good alternative. For me though, I don't fancy climbing up a load of hills, snap away, and then get home only to find i've got a pink sky in some of them. Admittedly it only happened in a couple of percent of my shots, but I often stack filters in certain conditions which emphasizes it.