Which filter and when

mxfun

mxfun

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Sean Logie
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As title says, i know how a CPL works in different light and so on. What i can't seem to grasp so easily ,is the use of ND filters .Can anybody on here give me some examples when they would use .... say a ND2 or a ND8 ,probably simple enough to some ,am curious enough to listen and learn if anyone could spare the time to explain ,or indeed show examples in the difference between the two ,also the best conditions to use the ND2 or ND8 . :)
 
Looks like everybody's in the same boat as me then .... eh :shrug:
 
The bottom line is you use them when you need less light.

You might want a longer exposure at a certain aperture value, or you might want to use a wide aperture without using a faster shutter speed. The filter you use depends on the strength you want. the most common ones are nd 2, 4 and 8 which block out 1, 2 and 3 stops of light respectively. For each stop of light you block out you can double your shutter speed once or widen the aperture by one stop.

Hope this clears things up a bit.
 
The Matt said:
The bottom line is you use them when you need less light.

You might want a longer exposure at a certain aperture value, or you might want to use a wide aperture without using a faster shutter speed. The filter you use depends on the strength you want. the most common ones are nd 2, 4 and 8 which block out 1, 2 and 3 stops of light respectively. For each stop of light you block out you can double your shutter speed once or widen the aperture by one stop.

Hope this clears things up a bit.
Click to expand...

Cheers Matt(y)
 
The light ND filters like x2/4/8 are for when you want to use a wide lens aperture for shallow depth of field, when the light is bright.

The heavier ones like x64 (six stops) or x1024 (ten stops) are for extending the shutter speed down into full seconds or minutes, to give long exposure effects like blurry waterfalls, milky seascapes and streaky clouds etc.
 
HoppyUK said:
The light ND filters like x2/4/8 are for when you want to use a wide lens aperture for shallow depth of field, when the light is bright.

The heavier ones like x64 (six stops) or x1024 (ten stops) are for extending the shutter speed down into full seconds or minutes, to give long exposure effects like blurry waterfalls, milky seascapes and streaky clouds etc.
Click to expand...

Ah right , didn't realise there were heavier NDs .Right , so if i was thinking of shooting a really bright sunset or sunrise I'd be using the lighter ND and for that silky look from say a seascape late at night when it's dusk I'd want to use the heavier NDs ,is that the gist of it ,obvisously be more to it than slapping on a ND and away i go ,at least now I'll have the basic idea of what to get .Cheers Hoppy :)
 
almost there (unless I am misunderstanding your post)

mxfun said:
and for that silky look from say a seascape late at night when it's dusk I'd want to use the heavier NDs ,
Click to expand...
the less ambient light, the lighter (lower ND number) the ND you would require to create the effect.

If you had a waterfall, that you could get a nice crisp water image at f/4, and t 1/125, and you knew at around t 1/6 you would get a blurred sheet of water, you could either
1) wait for dusk, and shoot f/4, t 1/6
2) shoot f/32 t 1/6
3) add an nd 8 filter, and shoot f/4 t 1/6
The numbers are kinda about right I think


mxfun said:
so if i was thinking of shooting a really bright sunset or sunrise I'd be using the lighter ND
Click to expand...
Well, to add a little more confusion to the pot.....
There are filters called ND Grads as well. Usually, half of the plate is clear. The other half of the plate is gradually getting darker, to a level of ND stated on the filter (ND2 for example). For shooting things like a sunset, where the sky is bright, but the ground is dark, you want to reduce the amount of light coming in from the sky, but not the ground.
To mix it up a bit more, the description I gave above is called a Soft ND grad, there is also a hard ND grad, which has more dark on the dark side. I.e. the boundary between light and dark is in the same place, but it gets to the dark amount quicker.
 
Thanks for the informative replies ,my next question is... which filter system . I've sorta been eyeing up the coking P system's ,ND grad ,NDx2,NDx4,NDx8 ,and a circular polarizer ,good or indifferent :shrug:
 
Personally I use screw-ins. Advantage of a 'filter system' is that if you have a grad, you can move it up and down in the frame.

The cokin do get good reviews.

If you are going to be doing long exposures using large ND numbers, there is an argument that screw-in are better, as there is less chance of light leaking in from the sides.
 
coldpenguin said:
Personally I use screw-ins. Advantage of a 'filter system' is that if you have a grad, you can move it up and down in the frame.

The cokin do get good reviews.

If you are going to be doing long exposures using large ND numbers, there is an argument that screw-in are better, as there is less chance of light leaking in from the sides.
Click to expand...

That was i concern of mine ,the light sneaking in , so do you stack your screw filters. If i were to go the screw filter route ,would i get vignetting using my Tamron 17-50 f2.8 if i stacked the filters
 
Yes. I bought a set of cheapo filters, 2, 4, 8, because WEX delayed by a couple of months an ND10 from B&W which they quoted as being in stock.

I played with them on a Canon 10-22, which supposedly you cannot use more than 1 filter on. If you don't mind loosing the corners, you can get away with quite a few filters, which is good. I wanted a 'panoramic' effect, so I didn't care about the corners. It was so bright where I was, I ended up stacking all three (2,4,8) and a polariser. Still at f/16 I had some quick exposures. One I am looking at at the moment, was 1/15s, with I think the polariser, ND2, ND4 at 10mm
 
Just seen the second part. No, I do not think you will see vignetting. I believe that it is only a major effect when you are using wider angle lenses and stacking filters. If it is of major concern, and you have a little extra money, then you can get a larger filter (I think your lens is 67mm?) say 77mm, and then us a step-up ring. By doing this you move the filters' edge away from the field of view. But the filters are more expensive.

I think this had 4 filters (UV as it was a hired lens, and near the beach I am not going to risk it, polariser, ND2, + ND4 at 10mm)
 
coldpenguin said:
Just seen the second part. No, I do not think you will see vignetting. I believe that it is only a major effect when you are using wider angle lenses and stacking filters. If it is of major concern, and you have a little extra money, then you can get a larger filter (I think your lens is 67mm?) say 77mm, and then us a step-up ring. By doing this you move the filters' edge away from the field of view. But the filters are more expensive.

I think this had 4 filters (UV as it was a hired lens, and near the beach I am not going to risk it, polariser, ND2, + ND4 at 10mm)
Click to expand...

I have thought about the stepping ring theory ,all food for thought ,thanks for your help coldpenguin(y)
 
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