ND grad filter magenta colour cast issues

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Hi all..

Just wondering if anybody has this issue and can offer any advice?

Im starting to get into using filters and having a few magenta colour cast issues with my ND grads and ND's. I have cokin and SRB, the cokin has more cast than the SRB. I have borrowed a Lee filter and same problem so I can blame my 'cheap' filters.

I dont want to have to colour corect in PS as defeats my aim of using filters to get it right in camera!

Shooting canon 40D. And the darker the clouds the darker the cast, blue skyes have a faint cast but I can still see it! I was shooting with somebody else swapping filters and they had no problems and lovley netural images,they did have a current camear so it may be 'clever'? Is it a filter, camera or user error?

Many thanks
Bob :)
 
Have you got a shot you can show to demonstrate, especially the one where the Lee shot casts?

I have never had colour cast issues with Lee, but had them all the time with Cokin which is why I got shot of them pronto.
 
Hi Stu

Many thanks for your reply. I have now questioned my self, I have asked the person I was with if it was a lee filter - they are a pro so maybe I just assume it was a lee but it was a reverse grad and im only aware of Lee and HiTech who make them.

Thinking about this after I posted, the only common is the use of a CPL in all images. When I get chance will try without the CPL but on its own with no grad filters it causes no cast.

1. The shot I believe was with a Lee filter [TBC!], We both used the same filter and there was no cast on the other camera. I have reduced the cast quite a bit!
Higger Tor Sunset by Rob Haines Photography, on Flickr

2. Shot with no clouds and minimal cast. this is a SRB and Cokin filter stacked. when the coking is placed there is more cast obvious, the filter or effect of 2 filters holding more light back?
Les Allues Church by Rob Haines Photography, on Flickr

3. Again 2 filter stack with cast in clouds and sun halo
Low Meribel Valley Sun by Rob Haines Photography, on Flickr

Many thanks

Bob
 
I was wrong then! :) Assumption is dangerous!! But thanks for the link, a very interesting article and just learnt a new technique to try!

But the same filter [brand irrelevant] on different camera one with cast, one without cast - leads me to think its a camera setting?

Cheers

bob
 
Perhaps your CPL is causing some issues in conjunction with the Cokin filters (not sure how or why mind) but I do know stacking with Cokin filters makes the cast even worse.

Interesting to hear the reverse grad caused you casting, as I have a hitech filter which doesn't cause any cast - not a reverse grad admittedly.

I know they are expensive but Lee grads are the only thing worth buying really for this sort of work.
 
I know you have a lot less control with jpegs, but shooting raw, I've never understood the need for any type of graduated filter, since most of my landscapes rarely have a straight line division between the upper and lower parts, and any filtration is often applied to part of the scene where I do not want it.
Most of the time I find applying the Graduated Filter in LightRoom takes care of things, and where it covers an area I do not want it, lifting the brightness back up with the Shadows slider takes care of things.
If I have a shot I think I may need to do work on I'll sometimes bracket my exposures to make sure I have a range of images to work with, although I avoid using an HDR effect, usually just a bit of exposure blending.

As for "getting it right in camera," unless you have a whole range of different density ND grads, it's going to be a bit of a "hit or miss" process.

I don't understand this reluctance to do things with software, since these days it's an inherent part of the photographic process.
The Graduated Filter in LightRoom offers far more control than using a graduated filter at the taking stage, and it doesn't suffer from colour casts either (- unless you tell it to!)
 
Stu - cheers for your thoughts and time. just tried with no CPL and still a cast shown. Maybe I just need to bite the bullet and buy better filters!

Brian, I have nothing against PS, I just prefer the satisfaction of trying to master camera technique and capturing what I see. I don't really have a use for my images [don't sell them etc] so hit and miss is fine as its a nice feeling when its a hit, doesn't happen often but im cool with that!

Cheers

Bob
 
The one thing I'd say is crop and full frame. This is something I've heard about, but not actually seen first hand. Something to do with the resin process for HiTech definitely, although not sure about Cokin and then the additional filter on the sensor or something. (Can anyone else add or debunk this?)

I still find the grads are needed even if bracketing and doing any PP as it minimises how much you need to do, but for the enthusiast who can't afford Lee filters I think it's to be expected.
 
I know you have a lot less control with jpegs, but shooting raw, I've never understood the need for any type of graduated filter, since most of my landscapes rarely have a straight line division between the upper and lower parts, and any filtration is often applied to part of the scene where I do not want it.
Most of the time I find applying the Graduated Filter in LightRoom takes care of things, and where it covers an area I do not want it, lifting the brightness back up with the Shadows slider takes care of things.
If I have a shot I think I may need to do work on I'll sometimes bracket my exposures to make sure I have a range of images to work with, although I avoid using an HDR effect, usually just a bit of exposure blending.

As for "getting it right in camera," unless you have a whole range of different density ND grads, it's going to be a bit of a "hit or miss" process.

I don't understand this reluctance to do things with software, since these days it's an inherent part of the photographic process.
The Graduated Filter in LightRoom offers far more control than using a graduated filter at the taking stage, and it doesn't suffer from colour casts either (- unless you tell it to!)

One word, dynamic range and noise from pulling back shadows. You can use soft edged filters which won't show the filter line

Lee 0.9SE and 0.6SE grads used to allow exposure of the foreground without losing detail in the sky or mountain. Lee little stopper also used

_DSC0190 by SFTPhotography, on Flickr
 
One word, dynamic range and noise from pulling back shadows. You can use soft edged filters which won't show the filter line

Lee 0.9SE and 0.6SE grads used to allow exposure of the foreground without losing detail in the sky or mountain. Lee little stopper also used

_DSC0190 by SFTPhotography, on Flickr
Can agree with the dynamic range and noise it's def affected, but that can depend on the level of pull back etc. If you play with luminosity for the blues and bump the contrast up too, then yes it gets noisy and can be considerable dependent on the original lighting.
 
Can agree with the dynamic range and noise it's def affected, but that can depend on the level of pull back etc. If you play with luminosity for the blues and bump the contrast up too, then yes it gets noisy and can be considerable dependent on the original lighting.

The newer sensors are a lot better than the older ones for shadow recovery etc, but with soft edges it's easy to balance exposure and not get obvious signs of filter use.

Again, spot the filter line

_DSC2908 by SFTPhotography, on Flickr
 
I've tried using Hi-Tech 7 stopper and grads.

When I bought these the advice I was given was to go for Hi Tech because they were supposedly cast'less.

I get casts with both the ND and the grads.

But it's not entirely consistent. The strength of the cast varies. Sometimes it's quite minor - other times it's like using cross processed film. I notice there are suggestions that this can be down down to long wavelength red / IR affecting the sensor. That's plausible IMO.

I'm only inclined to use the grads if I get completely stuck in terms of dynamic range - but even then I'm beginning to think of experimenting with post processing to mask and merge multiple exposures as an alternative to using them.
 
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Cheers for all your advice :) ST4 - love the photos especially the mountain range.

Think I will have to accept limitations in a 7yr old camera and 'cheaper' filters. Out of interest, the other camera I was swapping filters with and they has no cast was an Olympus so 2x crop so no FF!

I am experiencing inconsistent results which doesn't help pinpoint issues! I am going to try the same filter set up with my girlfriends Lumix G5 and see what that does!

Cheers for your time and help :)

bob
 
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The newer sensors are a lot better than the older ones for shadow recovery etc, but with soft edges it's easy to balance exposure and not get obvious signs of filter use.

Again, spot the filter line

_DSC2908 by SFTPhotography, on Flickr
Perfectly illustrates my point that grads only work with a straight line transition between the two parts of the image.

Introduce some hills, trees or buildings that overlap the transition and you are applying the filter where it's not needed.
 
Perfectly illustrates my point that grads only work with a straight line transition between the two parts of the image.

Introduce some hills, trees or buildings that overlap the transition and you are applying the filter where it's not needed.

So illlustrate where the filter line(s) are on the image. I used IIRC two soft egded grads
 
So illlustrate where the filter line(s) are on the image. I used IIRC two soft egded grads
I'm confused too??? It's a soft grad and not a hard grad. Hills...trees...use a soft grad. Sea...flat horizon....use a hard grad. And in terms of using a digital one in place of a physical grad then what's wrong with the recover in PP to correct a minimum part of an exposure?
 
Perfectly illustrates my point that grads only work with a straight line transition between the two parts of the image.

Introduce some hills, trees or buildings that overlap the transition and you are applying the filter where it's not needed.

Brian, check Steve's first image in this thread which perfectly demonstrates his point. I suppose it depends on the conditions and the strength of the grads youre using.
 
Noise in a word, the detail might not all be recoverable. Easier imho to do it in camera or exposure blend
You've got me wrong, I meant from his point of view. I'm all for proper exposure on camera but the argument put forward doesn't hold up if you are going to layer digital grads, as surely you can use them properly in camera, gaining a proper exposure and minimal brush PP for slight tweaks afterwards will be better then just digital grads. Only exception i can think of would be the use of properly exposed being darkened for dramatic/artistic purposes, as there would be little noise introduced.
 
You've got me wrong, I meant from his point of view. I'm all for proper exposure on camera but the argument put forward doesn't hold up if you are going to layer digital grads, as surely you can use them properly in camera, gaining a proper exposure and minimal brush PP for slight tweaks afterwards will be better then just digital grads. Only exception i can think of would be the use of properly exposed being darkened for dramatic/artistic purposes, as there would be little noise introduced.

Yes, if you can get the entire scene exposed within the histogram without clipping or blocking then ND grads aren't strictly needed, unless you wish to expose longer to brighten up the FG and move the scene to the right of the histogram.

If it's for artisitic effect only, you can do it digitally and I have done this many times.

I did this all digitally from shadow recovery and then beefed the sky up

DSC_0301 by SFTPhotography, on Flickr

The full res shows more noise but didn't have grads with me
 
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So illlustrate where the filter line(s) are on the image. I used IIRC two soft egded grads
As I said, it perfectly illustrates my point - if you have a straight boundary it's impossible to see where the transition is.

However, a lot of my landscape shots don't have that defined boundary, so if I applied a graduated filter it would affect an area that I wouldn't want it to.
On a static shot it's simple to take a set of bracketed exposures and blend them, but most of time you can do it using the graduated filter in Lightroom.

I don't have time to search for a definitive example but here are a couple of before and after shots that illustrate what I'm talking about.

A really flat (single) exposure on an overcast morning.
View attachment 26257

With a few minutes work in Lightroom.
View attachment 26258
I simply cannot see how using a hardware graduated filter would work on a shot like this.
Although it would pull some detail out of the sky, a hardware filter would also darken the upper part of the building.
 
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As I said, it perfectly illustrates my point - if you have a straight boundary it's impossible to see where the transition is.

However, a lot of my landscape shots don't have that defined boundary, so if I applied a graduated filter it would affect an area that I wouldn't want it to.
On a static shot it's simple to take a set of bracketed exposures and blend them, but most of time you can do it using the graduated filter in Lightroom.

I don't have time to search for a definitive example but here are a couple of before and after shots that illustrate what I'm talking about.

A really flat (single) exposure on an overcast morning.
View attachment 26257

With a few minutes work in Lightroom.
View attachment 26258
I simply cannot see how using a hardware graduated filter would work on a shot like this.
Although it would pull some detail out of the sky, a hardware filter would also darken the upper part of the building.

The same way that a Lightroom filter works. A lightroom filter will also cover your building and darken it. Sure you can brush in some exposure, but you can do that anyway even if you have used a filter.

Each to their own, but reducing exposure in post can introduce noise depending on the image, so I prefer filters
 
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