GND filter questions

Hi all.

I'm thinking about getting some fairly cheapish graduated ND filters mainly as a learning experience. I shoot landscapes and currently rely on manual exposure blending to get the dynamic range I require. I like the idea of achieving this 'in-camera', plus manual blending doesn't work that well with moving subjects (clouds, water etc)
Has anybody got any experience with the Cokin filters? I hear colour casts are a problem? Which combinations are most useful, hard/soft/density? Also what size system do I need to go for? Currently I use a Pentax K10d and 18-55mm, I'm also looking to buy a Sigma 10-20mm sometime soon, so obviously I'd like to get a system that works with all my lenses.
Thanks for any help.

Toby

Toby,
Cokin P-size will be ok. They will work with the 10-20 if you use the special "slim" filter holder.
Hitech do P-size equivalents for a little less money.
www.speedgraphic.co.uk used to have deals on a set of ND grads - which make it very competitive.
There's also www.srbfilm.co.uk who stock the Cokin and Hitech as well as all kinds of adapters.

The Cokin and Hitech do have a touch of magenta colour cast - but nothing too obtrusive. If you stack two of three NDs together you really begin to see it then!
I moved onto the Lee Foundation holder + Cokin Z-Pro size ND grads. They are better quality than the P-size, but have the tiniest tinge of magenta. Lee filters are pretty neutral but don't render blue skies as well as the Cokin (or so I'm told). The Lees are great for really moody skies... but no many can afford them


That said, if you use a tripod and shoot RAW then you may get more mileage from taking two or three shots (the K10D can easily take 3 shots that are 2Ev apart - which is what I'd recommend) and then blend with layer masks in Photoshop. That'll cost you nothing and will work with all lenses

Matt

Thanks for the info Matt. I'll look into those options. Also I'm interested to hear what actual filters you'd recommended to get me going. 2 stop? 3 stop? soft? hard?

As I initially mentioned, I'm currently using bracketed exposures and manually blending them. I'm happy with this technique, but I want to try using filters, really as a matter of interest. I understand both techniques have limitations, being able to do both is something that'll be beneficial to my shooting.

Cheers
Toby

As far as I know there are only one kind of Cokin ND grad - and they're pretty "soft" (ie the change between clear and ND is fairly gradual). Unless you are doing sea-scapes all the time, the soft are probably best. The Lee filters are available in Hard and Soft - but a set of 100mm Lees will cost you £52 each (plus the holder and adapters).

I have a set of three - P121L, P121M and P121S. The "M" (medium, 2 stop, 0.6) is used the most, followed by the "L" (light, 1 stop, 0.3), and finally the "S" (severe, 3 stop, 0.9). If you had to choose one, I would go for the 2 stop.

However, as I mentioned, Speed Graphic normally have the three + holder for £33.
You can get P-sized adapters from SRB Film

Hope that helps!
Matt

Matt - what do you use to protect your Z size filters when taking them along... They look a little too flexible to just put in the caers bag in the fabric case they come with... I have a nick on the edge of one of mine already (fortunately not in the FOV)...

Jamie

Jamie,
I bought a nice Lee 3 filter holder
Only trouble was... one day I was in a hurry and slipped two filters in the same slot. Ouch - they both got some scratches Still annoyed about that one
...if anyone knows how you can polish a filter...

Matt

carefully!

Toby,

I have a cokin P filter holder and a cokin soft grad 2 stop filter. I use it for a lot of landscapes. You need an adapter to fit the lens thread and the filter holder slides onto it, if you have different sized lens threads you either need different adaptors or several lens converter thingies (cant remember what they're called!), though these can cause more vignetting.

here are some images using my nd grad filter: