Gradual Neutral Density filters

Hi,

after seeing some great photos that have only been made possible with neutral density filters, I would like to purchase one. As they come in many different colours, which would be the best to go for? blue would be good for emphasizing the midday sky but not so good for sunsets - so I'm looking for the most versatile - would this be grey?

I'm really glad I found this forum - thanks to all the people who have helped me out so far.

Neutral Density (ND) filters usually come in various shades of grey depending on how dark the effect is that you want. Graduated ND filters as their name suggests are graduated from grey through to no filtering at all to give adjustable results.

I'm not sure ND filters come in other colours but I could be totally wrong.

Mr ist,
I think your confusing graduated filters and ND graduated filters, graduated filters come in allsorts of combinations from various graduated colours to graduated "effects"

Nuetral Density or ND filters are simply used to reduce the light reaching the film/ccd and do not colour the image, the graduated type of ND filter is ideal for retaining detail in over bright skies while maintaining correct exposure of the forground.

Dont confuse a "Grey Grad" with a "Graduated ND" they may appear similar but will definately not give the same effect.

Thanks v. much for pointing that out - I didnt realise there was a difference, although I think I need the difference explained as I'd have thought a filter with grey fading to clear would give the same effect as an ND grad.

The important word is 'Neutral', as opposed to 'grey'. A neutral filter should not introduce any colour cast, whereas a grey one is not necessarily neutral in it's colour, so skies may take on a green or magenta tint, for instance.

Basically, if a manufacturer doesn't want to have the trouble of making sure their neutral density grads neutral, they'll call the grey grads so they don't have to.

Dan

A bit more clarification.

Using a grey grad will make your sky look "stormy" or "overcast" whereas using an ND grad will simply balance the exposure between the sky and the forground without affecting the "appearance" of the sky.


if your intent on trying filters, (any kind) then check out cokins website for some ideas




http://www.cokin.co.uk/pages/main.htm

Hi IS,

As far as I'm aware, the look of the sky would be purely dependent on the strength of the filter - a 3 stop ND would darken a sky more than a 1 stop ND, and could thus make it look stormier if this darkening was more than was needed to balance the exposure.

The Cokin website intrigued me a bit - they describe their filters as being made of "CR-39 Organic Glass", whereas CR-39 is actually a monomer plastic, and is usually refered to by manufacturers as Optical Resin. Have Cokin misinterpreted it from french to english, or are they misrepresenting their goods?

Dan

Gents - a word of advice here... if you are looking into using grads for the sole purpose of balancing the sky/foreground exposure on your landscape images - there really is very little choice... I kicked off years ago using Cokin A series filters, then onto the bigger P series as I wanted more wide-angle coverage. The Cokin filters are very good to start with and as I moved to using very wide angle lenses 17mm on film (and bigger filter threads 77/82mm on fast lenses) I had to go up to the Cokin X-pro range to avoid vignetting. To be fair I didn't notice the colour casts (slight magenta) from the cokin grey grads until I'd tried out Lee filters ND grads from which there is NO colour cast - neutral means neutral... My previous choices have proved to be expensive, a full set of Cokin X-Pro filters plus holders etc was very expensive indeed. If you take a look at what photography you are doing and have a look at where you want to be in the future, filters (if you use them a lot) is one area where it pays to get it right first time round. I do a lot of landscape work and my Lee filters have transformed the way I approach my photography and it now doesn't matter what kit I'm using, SLR either digital or film, Med format (645nII) or Fuji Panoramic I am able to rely on consistent, vignetting free results from the very widest lenses in my collection. Yes, Lee is initially expensive to set up with holders and rings for each lens but you can slowly, as funds allow, build up a collection of filters from either their resin range (expensive) or gel (relatively inexpensive) range of filters.

As has been said in previous posts; why stick sub-standard plastic/resin/glass in front of your excellent Pentax lenses...

Before investing in any filters it's worthwhile doing some research - a very good place to start is Lee Frosts book - "A Photographers Guide to Filters"... reading this will help to avoid the making the same, potentially expensive, mistakes as I did...

Will

Fair point Daniel, but I didnt want to confuse the OP so kept it simple, even so, using ND grads in that context is going a bit beyond there "intended"? use.

I must also confess here that I have never actually used ND filters so my knowledge is not exactly from experience but more from general knowledge of them. I have of course used coloured grads on several occasions (yes I was bitten by the Cokin bug and have several near useless filters laying around somewhere)
A bit of EXPERIENCED advice here, anyone wanting to dabble with this sort of filter would be well advised to visit a camera fair where "A" series Cokin filters can be picked up for around a £1-2 each.