Sigma 10-20 filter confusion

[arej]

I am after some filters for my new Sigma 10-20mm - a polariser and a ND grad.
Looking at this filter holder at the moment:
http://www.warehouseexpress.com/buy-cokin-bp400a-p...
Is this OK on the 10-20 @ 10mm or will it vignette/crop the picture? I think I am right in saying this holder only takes 1 filter and so doesn't vignette?
Then this polariser looks OK:
http://www.warehouseexpress.com/buy-cokin-p160-lin...
ND grads I am more confused about - ND8 seems to be the most common/popular/useful? Looking on warehouse express I don't what the difference between all of them are. These are all different but I don't know how and not sure which I'd want:
http://www.warehouseexpress.com/buy-cokin-p121-gra...
http://www.warehouseexpress.com/buy-cokin-p121f-gr...
http://www.warehouseexpress.com/buy-cokin-p121s-gr...
What is the difference - not sure about the first one, seems normal, then the second is "full" and the third is "soft"?

Any help and experience would be much appreciated. What filters do you lot use?

Cheers

[ian in lancs]

I only used thin screw in filters an UV and a circular polariser. The latter I soon gave up on because with a wide angle lens the effect is patchy and doesn't look right.

As for the graduated The terms refer to the width of the transition. Hard usually refers to the ND / clear transition being quite narrow and thus abrupt but easier to place in the picture. Soft implies the transition is over a wider band and with landscapes will be difficult to get enough ND over the sky without darkening the land. I'd take your lens down to a dealer and try them (with different f stops too).

[Scott330ci]

I got mine from 7 day shop for £7.99

77mm ND grad - have had no problems with vignetting etc.

[rhubarb]

I'd steer clear of the CP one too - I had a low profile B+W one - no vignetting however really annoying bands of darkness - especially on blue skies at 10mm

[V12Les]

What i use on mine http://www.amazon.co.uk/Hoya-77mm-Digital-Circular...
Cant fault it.

[arej]

Thanks for the info so far.

I am not after a circular polariser, was going to get a square one as they are supposedly better at very wide angles e.g. 10mm, circular ones get banding etc.

Is the recommendation to get a hard grad for landscapes then? Would that be the one described as full in the options I posted before?

Is Cokin P the right system to go for (with the wide angle holder)? The Cokin Z etc are a lot more expensive.

Thanks

[Simpo Two]

arej said:

I am not after a circular polariser, was going to get a square one as they are supposedly better at very wide angles

There is a confusion over terminology here.

There are two kinds of polariser, circular and linear. This refers to the way in which the glass polarises light, not the physical shape of the filter.

Linear polarisers apparently interfere with AF systems, so most polarisers sold are of the circular type. Whether you then choose a square circular or a circular circular is up to you!

[SamHH]

arej said:

Thanks for the info so far.

I am not after a circular polariser, was going to get a square one as they are supposedly better at very wide angles e.g. 10mm, circular ones get banding etc.

Is the recommendation to get a hard grad for landscapes then? Would that be the one described as full in the options I posted before?

Is Cokin P the right system to go for (with the wide angle holder)? The Cokin Z etc are a lot more expensive.

Thanks

I think you might be getting a bit confused about polarisers. They come in two types: linear and circular. I don't know the technical difference between the two, but I do know that linear ones are a bit cheaper but aren't recommended for autofocus cameras because they can cause problems. So it's a circular polariser you want. Like most filters, you can get square ones that you slot into a holder, or round ones with a metal thread that you screw onto the lens. This latter type can also be called circular filters which is where the confusion with circular polarisers comes in.

With any type of polariser, linear or circular, square or screw-on, the effect varies depending on the angle of the sun. With a very wide-angle lens this means that the effect will vary across the photograph. This might be the banding that you referred to.

Regarding neutral density grads, both the hard and soft type have their uses. Personally I've found the soft ones to be useful more often, but ideally you would both sorts in a range of densities. However, if you use a tripod I've found that exposure bracketing and merging them on the computer is a far more versatile method than using filters.

[arej]

I understand now, I was confused about shape/effect. Thanks for the info. I will now look at circular polarisers - unfortunately these are more expensive!

Any opinions on filter systems (Cokin, Lee etc)? What do people use?

[SamHH]

I've got Cokin P ND grads. They're mostly fine but they do have a slight purple tint. I suspect that more expensive filters like the Cokin X or Zs or Lees would be better.

Here's an example of the polariser banding effect with wide focal length:

Edited by SamHH on Friday 30th October 12:06

[V12Les]

arej said:

I understand now, I was confused about shape/effect. Thanks for the info. I will now look at circular polarisers - unfortunately these are more expensive!

Any opinions on filter systems (Cokin, Lee etc)? What do people use?

Example of my previous post


Set at around 10mm IIRC

[arej]

Thanks for all of your responses.
One other question is which ND grad do people find more useful if I was just to get 1 to start off with - hard or soft?

Cheers

[arej]

Sorry to bring this thread back all!
Still haven't decided which ND grad to go for. For those that have them which ones do you use most regularly (ND4 or 8 etc and soft vs hard)?

Thanks

[TooLateForAName]

I was recommended to get the HiTech ND Grads. Set of 3 is £30 - in P size, people say that they dont have the colour cast problem that the cokins do.

I've not yet bought them so can't confirm. (available from www.formatt.co.uk or www.teamworkphoto.com)

[Rofly Lollers]

arej said:

and soft vs hard?

I'd go for hard. I have the Lee soft grads (and one cheapo screw-in hard grad). I think the hard grads would be more useful, especially with higher focal lengths.
I'm going to buy the hard grads today.

[GetCarter]

I use hard. They aren't that hard!

Edited by GetCarter on Wednesday 11th November 09:38