Thoughts on filters

[RockArea]

I’m talking here about the square or rectangular filters NDs, ND grads etc that are frequently used for landscapes on DSLRs with adapter rings, holders and all that paraphernalia. I know many landscapers swear by their Lee filters which I’m sure must be the best but they are so expensive that I can’t persuade myself to spend the amount of money that it costs to buy into that system.

For a few years now I’ve been using neutral density grads in the Cokin P (ND2, ND4 & ND8) system and have found them to be good although they can introduce a magenta cast particularly if you use two or more at the same time. I also have a Hitech 10 stop filter to produce that very slow, smokey water look. The lenses that I mostly use for landscapes are my Nikkor 18-200 VR with a 72mm filter ring and my Sigma 10-20 which has a 77mm filter ring. No problems with the Nikkor lens but the filter holder will cause a vignette with the Sigma wide angle. I have adapted my holder to prevent that happening.

My Cokin grads have become a bit scarred over the years, mostly through misuse, I’m afraid, and I’m now planning to replace them.

It seems to me that I have 3 choices (although there may be others):

1)   another set of Cokins and look after them a bit better. This has the advantage of being relatively cheap and I have all the necessary holders and adapters

2)   a set of Hitech grads. They’ll fit my Cokin holders and are only a little more expensive but I’m not sure they’re necessarily better than the Cokins

3)   a set of Lee grads with the necessary holder and adapters (all different from the Cokin). Much more expensive and optically much better)

I’d be interested in hearing your views, particularly if you have any experience of the different systems.

[branny]

I tend not to use filters as I am lazy. Photoshop is so good now that we can do almost anything in raw.
Danny

[BigAl]

I tend not to use filters as I am lazy. Photoshop is so good now that we can do almost anything in raw.
Danny

When you've got high contrast between sky and land you cannot always get the full range back from raw. An ND grad filter could help keep the image in the range that retains the full colours of raw.

[branny]

Of course it would Al but as I say I am Lazy and If I am doing landscapes or record photography I would tend to do HDR. I am not very technical and if my images don't come out correctly...so what I just move onto worry about something else.

[RockArea]

I tend not to use filters as I am lazy. Photoshop is so good now that we can do almost anything in raw.
Danny

That's interesting to hear, Danny, as you often take those 'shooting straight into the sun'  shots that are the ones that I tend to think about using filters for. That shows what can be done without and ... they are a faff!

[Hatter]

I also prefer to do "graduated" type stuff by combining multiple exposures nowadays - either HDR or a graduated layer mask.

What you can't do in software, is reproduce the effect of an ND filter to get long exposures in bright light.

[scoundrel1728]

What you can't do in software, is reproduce the effect of an ND filter to get long exposures in bright light.

I don't know of any theoretical reason why a filter couldn't be created to simulate the effect of one long exposure from a series of shorter ones.  Mathematically, it would similar to an interpolation algorithm similar to what is done to heal the breaks in digital star trail shots.

[Hatter]

I don't know of any theoretical reason why a filter couldn't be created to simulate the effect of one long exposure from a series of shorter ones.  Mathematically, it would similar to an interpolation algorithm similar to what is done to heal the breaks in digital star trail shots.

Really?  I was thinking along the lines of something like this:
http://www.flickr.com/photos/tomsdigital/7039208629/in/photostream
(Photo by Tom Salmond who is a member of my local camera club)

[Chocky]

I have a conic  Minolta Z6 and it has an APO lens and built in filters s if I want to create a night time scene with a day time shot I can
I did it by accident and was so upset
Here are to shots taken with in minutes of each other. I changed to day time when I realised . It also has a sunset filter which brings the photos out sot of golend

 

[Seven_Wishes]

Lee filters are very fragile and a lot more costly to replace ... but will perhaps give better results if they are kept in mint condition.
The magenta cast I think is because of IR light and because the ND filter is only neutral across the visible spectrum ... the more ND filters used and the longer the exposure the more IR light hitting the sensor ... one advantage of film here in that most film stock is not susceptible to IR light.

[Plossl]

I was talking to  a pro early one morning on the beach at Southwold He told me he had changed his filters to Hi-Tech because of the expense of the Lee's He said his results were just as good and the Hi-Tech's didn't fog up as much as the Lee's or Cokin's

[RockArea]

That's interesting to hear, Steve and it also links in with Ed's comment above. I bought a Hitech 10 stopper because it was a lot cheaper (and it was available). After using it I was a bit disappointed at the magenta cast it produced and wondered if I should have held out for a Lee. I later read that the Lee Big Stopper also gives a magenta cast. Of course, if that cast is due to exposure time with IR light and not to optical purity, that's bound to be the case.

Thanks for that info guys, it certainly puts points on the Hitech option.

[busybee]

David, I thought you would be interested to know what Graham says. He has a set of Lee NDs which he uses rarely, but they are excellent quality. More recently he has gone for the Heliopan variable ND (0.3 - 1. filter. This has the advantage of there is only one thing to carry, you can set the exposure and aperture that you want and then turn the filter until the exposure is correct. Not sure where he got it from, but I expect you can google it.

I use the Cokin filter holder with my Sigma 10-20, but I don't get any vignetting - just have to be very careful that it is correctly aligned. Maybe your Nikon frame size is fractionally larger than my Canon 7D's.

Re: the Magenta cast, presumably this can be corrected in post processing?

Chocky I guess the inbuilt filters can be fun to play with, but if it can be done in camera then you could almost as easily do the same thing afterwards, without risking unwittingly spoiling all your other shots.

[Jenny]

Ive not read everyone's comments, (due to being on Ella time ) but my late step Dad used to use filters often, and got some really good effects with them, not as OTT as HDR of course thats a science in its own right.

I dont use my DSLR anymore just because its so big and the point n shoot I have is probably alike technology wise, but when I did I always had a UV/Daylight filter on it to protect the lens, maybe you could use the replacement filters in conjunction with those?

hugs moi

[Chocky]

Yes . I think my inbuilt filters are very  diffeent to what you are all talking about . But yes it's fun  to learn with I guess

[Jenny]

Yes . I think my inbuilt filters are very  diffeent to what you are all talking about . But yes it's fun  to learn with I guess

I wasnt talking about inbuilt ones i was talking about the ones you screw on to the lens on a proper DSL

[Chocky]

Iknow. I was just sayng I have acamera with in built ones

[Jenny]

Oh I see you have one, I miss understood Beryl.
Yeah Im not using them either, I guess you can do quite a bit once you have it on your computer in editing.

[RockArea]

David, I thought you would be interested to know what Graham says. He has a set of Lee NDs which he uses rarely, but they are excellent quality. More recently he has gone for the Heliopan variable ND (0.3 - 1. filter. This has the advantage of there is only one thing to carry, you can set the exposure and aperture that you want and then turn the filter until the exposure is correct. Not sure where he got it from, but I expect you can google it.

I use the Cokin filter holder with my Sigma 10-20, but I don't get any vignetting - just have to be very careful that it is correctly aligned. Maybe your Nikon frame size is fractionally larger than my Canon 7D's.

Re: the Magenta cast, presumably this can be corrected in post processing? ...

Thanks for that, Belinda.

The Cokin holder is available in a wide angle format and maybe you were wise enough to get this version. I have just googled the Heliopan and it seems a very fine unit. It's a circular filter (a double polariser, I think) and it is used as a variable Neutral Density filter so will increase the length of exposure by 1 to 6 stops (so might come close to the effect shown in Gareth's picture). It comes at a price though (£267 for a 77mm to fit the 10-20). Of course it changes the whole image from top to bottom and that's different from the graduated ND filters which give a darker tint to the sky at the top of the image in order to equalize the exposure. So I guess Graham would still get out the Lees if he needed to do that.

Lots of good thoughts and info coming out here, thanks folks!

David

[scoundrel1728]

The magenta cast I think is because of IR light and because the ND filter is only neutral across the visible spectrum ... the more ND filters used and the longer the exposure the more IR light hitting the sensor ... one advantage of film here in that most film stock is not susceptible to IR light.

This should be easy enough to check/correct, simply by checking up on the transmission spectrum of that model filter.  If there is excess infrared transmission, adding a visible pass/infrared cut filter to the mix should correct the problem.  Any additional color cast can be corrected by doing a manual white balance with the filter in place.  (If you are using one of these filters, you can't be in that much of a hurry.)  Or you can correct in post, as Belinda has suggested.