Do ND filters affect image quality...?

[neoDSLR]

... I guess there is another layer of glass/plastic for the light to pass through, but I used a Cokin ND4 and ND8 full grad for the first time recently and noticed that the image quality was much reduced and that there was a reddish/warmer colour cast as a result. Is this normal?

 

[Robbo]

bit confused about say full grad filters?

 

[grum]

Definitely a reddish cast to my B+W 10 stop - don't think it reduced quality much if at all though.

 

[gembobs]

My old cokin A series ND8 and gradual grey filters ('A' series) did give a magenta cast to my shots. When I upgraded to digital from film, I went to hitech 85mm filters, and haven't noticed any cast, but haven't yet stacked my filters.

I can't comment on image quality, as my shots were on film and only printed at 6x4 or the next size up (print size escapes me at this moment)

 

[The Matt]

It's to be expected, particularly when you stack them

 

[Robbo]

If you shoot raw you should be able to get rid of that tone, is it really bad?

 

[chewyuk]

How still was the camera when you took the shot, it'll probably be a tad softer unless absolutely still due to a little camera shake, unless you used a tripod and shutter release cable. I've not noticed a deterioration in IQ using filters.
Adding a colour cast is an entirely different question, Yes they do in some cases.
The 10 Stop does add a reddish pink cast (magenta) also the old Cokin filters tended to do the same.

 

[smalls]

cokin filters are know to give magenta cast when stacked, mine gave a cast when used on there own, can be corrected in PP, but the idea of filters is to get it right in camera so kind off defeats the point, look into hitech or lee filters

 

[savyo]

is the tint not something that could be solved with using custom WB rather than dealing with it in PP?

 

[Nod]

One of the reasons may be that the ND filters are designed to cut the visible light but may be letting a higher proportion of IR through which could be introducing a colour cast. Older Cokins (which IIRC they called Grey rather than ND) were a bit notorious for the magenta cast they gave but the newer ones (now called ND) aren't quite as bad, although it seems there is still a problem. As mentioned, a custom WB should help, or the cast can be corrected fairly easily in PP, especially if shot in raw.