ND filter question, advice required please

Gary-360

Gary-360

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Gary
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I'm after a decent ND for use on my forthcoming holiday in the sun, it will be used for landscape and hopefully creating a silky beach/wave effect.

Can anyone suggest what type/strength would do, I haven't a clue about filters I'm afraid.

Thanks in advance, Gary
 
I'm also interested to hear about this. Sorry for the mini-hijack, but if someone could throw in some info about CPLs too, that would be nice.
 
I believe Cokin and Kood filters are measured as ND2, ND4, ND8 and so on.

ND2 would be a 1 stop reduction in light, ND4 a 2 stop, ND8 a 3 stop, and so on.
So, f/8 @ 1/200 of a second would become 1/100, 1/50, 1/25 etc.

Others are measured, I believe, at ND 0.3, 0.6, 0.9, and are worked out in much the same as Cokin and Kood.

For a silky water effect usually you want around 1/2, or even longer sometimes. I'd have a check at the beach, see what you require, and buy an ND filter from there.

Generally people use Cokin, it's around £20 for the filter holder and adaptor, and then around £10-£20 for the filters.
Kood fit in the Cokin filter holder system, and are about half the price and half the quality - perfect for a tight budget.

Lee filters or B&W are generally the dog's danglies as far as filters go, and they should be for the price. You'll find most people are more than happy with their Cokin filters, as am I. A brief review on the Kood filter can be found here: http://www.talkphotography.co.uk/forums/showthread.php?t=119524
 
Syx said:
I'm also interested to hear about this. Sorry for the mini-hijack, but if someone could throw in some info about CPLs too, that would be nice.
Click to expand...

Circular polarisers alter the light waves, basically making things slightly more saturated and reducing reflections.
Someone will no doubt be along shortly with some examples.
 
Where abouts in the sun and what sort of shutter speeds do you anticipate needing?

Essentially and ND filter just allows you to keep two of the settings (ISO/speed/aperture) the same and stop light in whole stop increments effectively allowing you to change the third setting without affecting the exposure value
 
Filters much the same as everything, you get what you pay for!

I'd advise buying into a system rather than buying screw in types as it will then expand with your kit and you can use them with other lenses etc. 85mm ones will suffice unless you have an ultrawide lens. then you will need the 100mm ones. You will also need a holder and an adaptor ring to fit your lens.

Cheap = Cokin and not colour neutral.

Good but cheap = Hitec/formatt, available from Teamwork Digital

Pricey but great = Lee filters

Best you can buy (import only) = Singh Ray
 
Aparently there is an issue with the HiTech (also sold as Formatt) filters. Some of them cast a magenta colour to images. There is a thread about this here, and the OP is supposed to be speaking to Formatt about this.

Cokin were known to also suffer from the same problem, but users seem to believe that this has been resolved by Cokin, and hence their new ND does not cast this colour effect.

If you really don't have that many lens, you may want to think about getting a screw-on ND instead of the filter & holder type. This will at least guarantee that you don't get any light-leaks.
 
Some good suggestions there, I've never really contemplated a system before but I could look into it; I'd prefer to get it right in camera as I'm pretty crap at Photo-shop :D

To answer one question, the beaches are in Fuerteventura where it's extremely bright with white sand, so exposure is critical on the beach and sky. I've been a few times and always managed some great shots with just a CPL, but I'm looking to move up a stage by using the correct filters for the job.

Gary
 
Has anyone got any experience of the Chinese Cokin "style" adapter/holders available on the bay? (eg. this one.

For £4 I'm tempted to give it a go, but if they're notoriously rubbish, I'll put the money towards a proper one instead.
 
A good CP would give you 2 ~ 3 stops and then add the CP effect. It may be worth just getting a good CP, unless you really want to get something special.

As for the creamy-water effect, you can achieve that with a CP, very low ISO and a big aperture number (small aperture).

Saves you the trouble of the ND and the hassle. Remember, the less you fiddle with, the more you can compose and catch that better shot.
 
Wail said:
A good CP would give you 2 ~ 3 stops and then add the CP effect. It may be worth just getting a good CP, unless you really want to get something special.
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Thanks Wail, that clears up exactly what I was wondering.
 
ND grads are more use than all over ND filters.

They are used to control the contrast in your picture - where you place the graduated section of the filter, the light is reduced. So, by covering the bright area you can reduce the contrast between that and the less bright parts of the picture.

eg - bright sky at sunset versus relatively darker arae of foreground land.
OR bright sand versus dark, volcanic cliffs.

ND grads used end to end can be used to lower overall tone too - as a full ND grad would.

I would suggest HARD grads too - you can generally see the line of contrast change, the horizon is one, get the line of the grad as close to the horizon line as you can (stop down and peek through the finder, you'll see the grad effect more.)

They don't have to be used flat/horizontal. They can be placed so as to follow the slope of a hill for instance, a mountain side.

I would say buy the better filters. They are not that much dearer £30 for Lee) and you only two, a 0.3 and a 0.6 which then also gives you a 0.9 (combine them).

You don't NEED a fliter holder. Blu tac does a wonderful job of holding mine against the front of the lens barrel. Just keep the blu tac off the centre of the filter - but it does no harm, just a bit of smear that washes off easily. That is the difference of cost of the Lee filters saved for you - so no excuse to buy cheap ones!
 
The biggest problem I have (as have others) is that I'll be using the 12-24 Nikkor a lot, which does not allow front mount filters or holders, so the blu-tac option me be viable here ;)
I do have 2 77mm CPL's for the 24-70 Nikkor, although vignetting may be an issue, it should cut down around 4/5 stops so this may be another option for me.

Gary
 
Lensflare said:
ND grads are more use than all over ND filters.
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Sorry Lensflare but that is utter tosh.

You can't do anything to reduce the total amount of light hitting the sensor in PP unless you overexpose and then pull it back which would result in a major loss of detail whereas you can expose for highlights and then a second exposure for lowlights and blend in PP.
 
Gary-360 said:
The biggest problem I have (as have others) is that I'll be using the 12-24 Nikkor a lot, which does not allow front mount filters or holders, so the blu-tac option me be viable here ;)
I do have 2 77mm CPL's for the 24-70 Nikkor, although vignetting may be an issue, it should cut down around 4/5 stops so this may be another option for me.

Gary
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Sorry, but doesn't the 12-24 take 77mm filters? At least so I thought :shrug:

I think it's the 14-24 that doesn't take filters!
 
Also, I don't ever recall the 24-70AF-S vignetting when using a CP on it, when it's mounted on DX bodies (your D300). On an FX body (your D3) it will vignet, unless you've got a SLIM CP like the one Heliopan or B+W make.
 
Could you use two CPL filters to make an infinitely adjustable ND filter?
 
I have no idea what that would be like .. sorry :shrug:
 
I agree with Rick that ND Grad effects are easy to produce in PS. This is down to personal preference. Some prefer to do it in camera with a grad filter and others take 2 exposures and blend them. Lensflare suggests hard grads and for the 2 examples he uses that's fine, but often, when shooting landscapes the entire horizon is uneven, in which case you would need a soft grad. Then you need the right strength as well, so to cover all eventualities, you would want 1 and 2 stop grads in both hard and soft graduations. This is where it can get expensive and fiddly, which is why I prefer the merge option. OK, before anyone says it, I'm lazy! :D For me, shooting 2 exposures is MUCH quicker and I have a better chance of catching the light I want.
In very bright light 2 stops is probably not going to be enough to blur the water. The CPL will give variable reduction in light up to around 2 stops, so perhaps a 3 stop standard ND would be an option? If its too slow, then you can always vary the ISO or aperture to achieve the speed you want.
 
In addition to the range by Cokin etc (up to a 3-stop reduction in one filter) you can get screw-in filters in 6 and 10 stop vareities made by B+W. If you want really long exposures in good light you should consider one of these.

It's as sunny a day as one could hope for in the UK in march, and I've just pointed the camera outside set to Aperture priority, iso100, f16. The metering system says that I should be shooting at 1/50th of a second. With a 3-stop filter in these conditions you're still only looking at 1/6th of a second. With a 6-stop, that's 1.3 seconds. With a 10-stop, that's 20 seconds. You can stack filters to get the same effect, but every piece of glass (or plastic in Cokin's case) you stick infront of the lens reduces the quality a bit more. Having tried stacking a couple of Cokin NDs, I wouldn't recommend it.
 
You could use two linear polarizers to produce an adjustable ND filter, I don't think you can with circular polarizers (I only use linear so can't test)
 
2 polarisers in tandem blocks all the light unless they are aligned.

You can use this effect to polarise th elight from a studio flash and have one over the lens...you can actually block all the flash light if you aren't careful.

Rick - agreed, but the original question asker was asking a basic question. I think your response is probably a bit advanced at this stage....whereas reducung the highlights with an ND grad is within bounds....if the original asker is more advanced, then apologies, but that was how I read it from the way the question was put.

IHaving grown up with having to do as much in camera.....I still do most of it the old fashioned way.

What is PP? Imean, what does it stand for?
 
Lensflare said:
IHaving grown up with having to do as much in camera.....I still do most of it the old fashioned way.

What is PP? Imean, what does it stand for?
Click to expand...

:thumbs: :clap:

yes very well said lensflare


i agree with that line of thinking .

as for PP some folks myself included hate this PP ing thing with a vengance ..

not to mention being useless at it
 
Lensflare said:
2 polarisers in tandem blocks all the light unless they are aligned.

You can use this effect to polarise th elight from a studio flash and have one over the lens...you can actually block all the flash light if you aren't careful.

Rick - agreed, but the original question asker was asking a basic question. I think your response is probably a bit advanced at this stage....whereas reducung the highlights with an ND grad is within bounds....if the original asker is more advanced, then apologies, but that was how I read it from the way the question was put.

IHaving grown up with having to do as much in camera.....I still do most of it the old fashioned way.

What is PP? Imean, what does it stand for?
Click to expand...

PP = Post Processing ;)

Thanks again for the info.

Gary
 
Lensflare said:
Rick - agreed, but the original question asker was asking a basic question. I think your response is probably a bit advanced at this stage....whereas reducung the highlights with an ND grad is within bounds....if the original asker is more advanced, then apologies, but that was how I read it from the way the question was put.

IHaving grown up with having to do as much in camera.....I still do most of it the old fashioned way.

What is PP? Imean, what does it stand for?
Click to expand...

PP is post processing, I'm not a fan either and prefer to get it right in camera but the bottom line I was trying to make was an ND grad can be replicated, an ND cannot.





daftbugga said:
:thumbs: :clap:

yes very well said lensflare


i agree with that line of thinking .

as for PP some folks myself included hate this PP ing thing with a vengance ..

not to mention being useless at it
Click to expand...

I dislike a lot of PP but its no different to dodging and burning - in fact it is a damn site easier to learn and correct any mistakes in, and there's a lot more advice available to improve your technique and make it more subtle
 
I took some photos last night with my linear polarizers.
These are often distinguished from a circular polarizer by the fact they have rotation rings (at least on screw-ins).

The picture on the left is with both polarizers on, F13, ISO 100, 15seconds.
The picture on the right is with both polarizers on, F13, ISO 100, 240 seconds (yes 4 minutes).
The difference is that in picture 1, I rotated the second polarizer so that it is aligned with the first. On the second picture I rotated the second polarizer so that it is perpendicular (90 degrees) to the first. I could have taken a shot at any point in between to vary the effect.
I have blown up on both halfs the same part of the photo. As you can see, I didn't quite get the light even over the photo, in the mirror you can see the reflection of the light fitting.
http://86.146.21.31/linpol.jpg

With a circular polarizer, I think all you are going to get is either black, or on a cheaper on, probably a de-moire effect (but as I don't have one to test, this is just guess work)
 
Hi, just to get techi for a bit.....Two linear polars will work as an adjustable ND filter, but beware that as you go towards extinction, you may get discolouration. The photo may start to go blue.
Two circular polars will also work, but the complication is that they must be facing each other, ie one must be used back to front. Difficult to assemble as the thread will be on the wrong side.
 
Can you explain the tech behind a circular polariser? I understand the theory behind linear ones, but circular, when doesn't really make sense to me. Does it mean that the 'angle' of light polarisation is basically rotating whilst you traverse a line across the polariser? (where as in a linear one, it would be constant of course).

Also, I guess that would make putting two circulars in line a non-starter for the original problem.
 
A circular polariser basically has two elements, one is a normal linear poleriser and the next turns that polarised light back into 'normal' mixed light.

This is necessary for cameras as the automatic focusing and exposure 'magic' polarises the incoming light, and so may block already polarised light.
 
A circular polarizer is in fact two filters put together, a linear polarizer with a quarter wave retarder. The linear polarizer acts as a linear polarizer should act whereas the quarter wave retarder is effectively a de-polarizer. The light coming from the subject, i.e. the sky is seen first by the polarizer, which acts upon the polarised light, reducing it, as desired by rotating the filter. This modified light then travels through the 2nd part of the filter, the quarter wave retarder, where it is now effectively depolarised. This is needed as, if the light then travels into the camera in which there is for example, a beam splitter, (often used for auto focusing or exposure calculating), which is sensitive to polarised light, you may see erroneous readings. (well you did ask...;))
 
instamatic said:
A circular polarizer is in fact two filters put together, a linear polarizer with a quarter wave retarder. The linear polarizer acts as a linear polarizer should act whereas the quarter wave retarder is effectively a de-polarizer. The light coming from the subject, i.e. the sky is seen first by the polarizer, which acts upon the polarised light, reducing it, as desired by rotating the filter. This modified light then travels through the 2nd part of the filter, the quarter wave retarder, where it is now effectively depolarised. This is needed as, if the light then travels into the camera in which there is for example, a beam splitter, (often used for auto focusing or exposure calculating), which is sensitive to polarised light, you may see erroneous readings. (well you did ask...;))
Click to expand...

I'm not sure how a polariser actually works, but if this explanation is as inaccurate as your post on another thread about polarising filters, then I'm sorry, but this is likely to be nonsense as well.
 
A circular polarizer is in fact two filters put together, a linear polarizer with a quarter wave retarder. The linear polarizer acts as a linear polarizer should act whereas the quarter wave retarder is effectively a de-polarizer. The light coming from the subject, i.e. the sky is seen first by the polarizer, which acts upon the polarised light, reducing it, as desired by rotating the filter. This modified light then travels through the 2nd part of the filter, the quarter wave retarder, where it is now effectively depolarised. This is needed as, if the light then travels into the camera in which there is for example, a beam splitter, (often used for auto focusing or exposure calculating), which is sensitive to polarised light, you may see erroneous readings.
 
jerry12953 said:
I'm not sure how a polariser actually works, but if this explanation is as inaccurate as your post on another thread about polarising filters, then I'm sorry, but this is likely to be nonsense as well.
Click to expand...

instamatic's post sounds good to me.
 
Ok, seems to make sense, but why when I have seen circular polarizers then, have they not had the rotation rings that you would see on a linear one (if they are a linear first)?
 
Penguin, circular/linear refers to the effective orientation of the polarising crystals in the glass, not the physical shape. All polarising filters have to be rotated for maximum effect, which varies in relation to the position/angle of the sun, and/or the polarising surface in the picture in the case of reflections.
 
jerry12953 said:
I didn't understand a word of it myself. That's not to say that it's wrong, but he posted another one about polarisers on a different thread which almost certainly is incorrect, so, I perhaps wrongly assumed ....
Click to expand...

I think instamatic knows what he's talking about. I've just read some of his recent posts and he's spot on.
 
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