Cokin Z-PRO ND filters

[pauld]

I have just recently bought 3 neutral density Cokin Z PRO filters. Am currently using them on waterfall shoot and have to say the outcomes are awful especially when you stack them - which given the colour of the water is a must. Most of the images are magenta, there seems to be nothing neutral about them. The problem can be solved in PS with adjust colour but at £30+ each I should not have to be doing this. They will be going back when I get home. A pro who I am with cannot believe the poor quality.

How does Cokin get away with this

Anyone had similar experiences??? :annoyed:

Paul

[cowasaki]

Where did you buy them from? Are they genuine?

[pauld]

Got them from FOTOsense and they are the real thing

Here is an example, which actually does not look as bad as it does in PS

http://www.talkphotography.co.uk/gallery/data/500/Cokin1.jpg[/IMG]

[pauld]

And here is what it should look like after PS....

http://www.talkphotography.co.uk/gallery/data/500/Cokin2.jpg

[cowasaki]

That is poor! I bought a filter for £3 from ebay that creates less of a caste than that!

[pauld]

Exactly my thoughts - these are Cokin's so called PRO range - the ND grads are not much better as they leave a pink cast on grey/white clouds which is much harer to get rid of...

[GAELICSTORM7]

I have used the Cokin Z-pro nd filters with out any issues on both skies and water ? having said that if I'm working an image I've taken it goes through photoshop anyway so it wouldn't be an issue anyway I guess ?

Alan

[pauld]

Alan

I hear what you are saying and I do the same but these are not ND in my view...and for the price they are not good enough. I may have got a bad set but do not see why..when you look at the filters edge on you can see the colour cast.

[cowasaki]

I think the point is that these are the PRO filters, there shouldn't be bad batches!

[Davec223]

I had heard that Cokin had sorted the cast issue out and the latest ones didn't cause a cast. Is it possible you got earlier ones?

[GAELICSTORM7]

I'm sure I once read that the Cokin N/D filters were not actually N.D. filters but grey or grad grey, I never really understood what this meant and as I had always been happy with Cokin filters in the past, I decided to buy them again.

Your image does seem to have a heavy colour cast to it (rather than just grey), will check some of mine tomorrow and see if they are the same.

Are yours the grad ones or full type ?

Cheers,

Alan.

[pauld]

Only just got them but that is not to say the retailer has not had them a while...

[RichardtheSane]

i'd send them back and get some new stock!

I tried cokin a while ago and was never happy. Now i have Lee

[pauld]

That's what I plan to do with a couple of pics as well to make the point...

[Gandhi]

This is from the Singh Ray website:

"I'm getting a color cast with my Neutral Density filter. What's the problem?

A: When using a Neutral Density filter (graduated or solid) you are generally causing your camera to make a longer exposure than normal, sometimes much longer. The software in some digital cameras uses response curves that adjust the RGB sensors sensitivity based on the exposure time, which may introduce more red into the image. Sort of a digital form of reciprocity failure. In other instances, blocking visible light and a longer exposure allows infrared light to "build up" on the red sensors leading to a red or purple-ish cast. If your filter looks neutral but you see the cast in your images, try taking some test shots using the filter with a different brand of camera, or with a film camera. If you still see the cast, and you're within the warranty period, contact Singh-Ray to have your filter evaluated and possibly repaired/replaced. "

[pauld]

It was mentoned that I could play around with the colour channels re colour temp especially red but I really have not got the time when in the field...does anyone do this??

[HoppyUK]

This is from the Singh Ray website:

"I'm getting a color cast with my Neutral Density filter. What's the problem?

A: When using a Neutral Density filter (graduated or solid) you are generally causing your camera to make a longer exposure than normal, sometimes much longer. The software in some digital cameras uses response curves that adjust the RGB sensors sensitivity based on the exposure time, which may introduce more red into the image. Sort of a digital form of reciprocity failure. In other instances, blocking visible light and a longer exposure allows infrared light to "build up" on the red sensors leading to a red or purple-ish cast. If your filter looks neutral but you see the cast in your images, try taking some test shots using the filter with a different brand of camera, or with a film camera. If you still see the cast, and you're within the warranty period, contact Singh-Ray to have your filter evaluated and possibly repaired/replaced. "


That explanation seems like a rubbish excuse for poor quality filters. I've never heard of cameras adjusting colour balance for long exposures, and that would only ever apply to Scene Modes even if it was true, not Av, Tv, P, M etc. And all digital cameras have strong IR and UV filters over their sensors, to restrict sensitivity to purely visible light.

The problem is that it's hard to make filters that are truly neutral, especially strong ones. The only credible claim to neutrality that I've read is on www.kenrockwell.com in reference to the new range of Tiffen HT filters, grads and ND. I would also guess that the Hoya X400 filter (nine stops) is pretty good but that is special order only in the UK, and Tiffen are very hard to get. The famous American store B&H sells both. http://www.bhphotovideo.com/c/product/155264-REG/Hoya_A67ND400_67_mm_Neutral_Density.html

[Gandhi]

Hmmm,

Strange. I used to get an awful colour cast with my Lee filters on the d70 but strangely I've had no such problems withe the d200, 300 or now, slide film. The D70 is well known for it's sensitivity to IR over other more modern cameras so that would seem to support the theory somewhat. Well, in my case anyway.

Digital cameras do also apply processing to the data off of the sensor prior to it being available as a RAW image. This is why there are subtle but noticeable differences to RAW files from different camera manufacturers using the same sensors, nikon and sony for instance.

Singh Ray are far from being poor quality filters btw.

[jerry12953]

Singh Ray are far from being poor quality filters btw.

Indeed. Shockingly expensive in fact.

I've got 2 Singh-ray ND grads which I bought when the exchange rate was better, and they ARE excellent.

I had a problem a few years ago with Lee ND grads and my Contax/Zeiss lenses. I got weird warmish colour casts with both of them, hence the Singh-rays.

[jerry12953]

It was mentoned that I could play around with the colour channels re colour temp especially red but I really have not got the time when in the field...does anyone do this??

Wouldn't you do this in post-processing? You wouldn't want to, but you could....

[coldpenguin]

I may be completely mis-understanding the severity of the problem, but couldn't the problem be solved by performing a custom white-balance within the camera with the NDs on? Then there should be almost zero post processing required (to get rid of the cast anyway)

[pauld]

The problem though with custom wb is there is often not the time to do this when shooting landscape as you are waiting for the moment with neverything set up... they guy with me this week shot 5 stop ND grads with Lee at the same time as shot with Cokin - no colour cast...