Help with ND stop explination

Robbo

Robbo

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How does this work, nd 10 is 10 stops, in F numbers? I can't get my head round it, does this mean you need your f. At 32 and the filter puts 10 extra on that?

I'm after long exposures during the day

Thanks
 
Not quite, but nearly.

A 10 stop ND filter will alter the exposure by 10 stops, sure, but not by altering the aperture. If you set the aperture to f8 and then put a 10 stop ND filter on, you are still shooting at f8. In other words, you are reducing the amount of light entering the camera by the equivelent of 10 stops by using the filter.

Alright, each step on the shutterspeed (say from 1/100 to 1/125) is ONE stop. As is each step on the aperture (so f8 to f9 is one stop) if you step up your shutterspeed by one, and also your aperture by one, you have altered the exposure by TWO stops, in total.

Alright, now. The level of ambient light is such that you need a fairly small aperture - lets stay with f8, also you don't want shallow depth of field. You need a slow shutterspeed too for artistic effect (milky water or whatever) but this slow shutterspeed will mean that your shot is going to be overexposed. How do you overcome this? Well you either forget the long shutterspeed or you fit an ND filter to limit the light entering the camera. The filters come in various strengths, 10 being very dark and therefore allowing a much longer shutterspeed. A 3 minute exposure at f8 might over expose the shot by 10 stops but you've corrected that by using the 10 stop filter.

Does this help? I'm not the worlds best teacher :shrug:
 
Ste Manns said:
Alright, each step on the shutterspeed (say from 1/100 to 1/125) is ONE stop. As is each step on the aperture (so f8 to f9 is one stop) if you step up your shutterspeed by one, and also your aperture by one, you have altered the exposure by TWO stops, in total.
Click to expand...

Sorry for the edit of the post but only wanted to highlight this bit, as far as I understand it each step on the shutter speed in not ONE stop, but 1/3 of a stop, the same as each step on the aperture ring is usually 1/3 of a stop.

So for aperture your FULL stops are; 2.8, 4, 5.6, 8, 11, 16, 22, and shutter speed FULL stops (for example) are 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8. 1/4, 1/2, 1, 2s etc
 
Ste Manns said:
Not quite, but nearly.


Alright, each step on the shutterspeed (say from 1/100 to 1/125) is ONE stop. As is each step on the aperture (so f8 to f9 is one stop) if you step up your shutterspeed by one, and also your aperture by one, you have altered the exposure by TWO stops, in total.
Click to expand...

1/100 > 1/200 is one stop.

F/8 > F/11 is one stop.
 
Hawker and Ali got it right with their corrections... 1/100 to 1/125 isn't anywhere near a stop. Each doubling or halving of the shutter speed is a stop equivalent to altering the aperture by one stop.

The ND filter reduces the amount of light reaching the sensor to allow long shutter speeds or small apertures (large DoF) while still correctly exposing the scene. Think of it like sunglasses for your camera!
 
Yes guys, you're right there. Sorry for the mistake, I have the choice on my camera to use either 1 stop or 1/3 stop increments and I'd completely forgotten I have it set to 1/3 increments, I tend to think of each increment as being one stop even though I know this is wrong! Just force of habit. I think my explanation is still valid though yes?
 
that helps!

So now the question is, say on an average light day, with 10stop filter and camera settings roughly what ranges could I get. Eg. From 1sec up to 10 seconds.

Hope that makes sense, I'm in deciding which one to get or if I will need two, one for short long exposures and one for long exposures
 
lol I hope you're not thinking of stacking two 10 stops! you'll be there all week, you can easily get shutter speeds over a minute in daylight with a 10 stopper :)

ps, shameless plug that's my flick link to my 10 stop photos (well 12 stop using welding glass)
 
Hawker said:
lol I hope you're not thinking of stacking two 10 stops! you'll be there all week, you can easily get shutter speeds over a minute in daylight with a 10 stopper :)
Click to expand...


No no lol I won't be going over 30 seconds

but I want to be able to range from 5 to 30, can I do it with this filter and mix of camera setting? Or will I need a lower filter or filters, eg 4 stop for 5 secs and 8 for 30
 
Not to complicate things but you are all slightly off in a sense that everyone is correct ;). The number of stops between each adjacent apertures or shutter speeds on each camera is depending on settings used by that camera (whether or not this can be changed). On pro grade Nikons for example this can be changed to be either in 1/3 of the stop, 1/2 of the stop or the whole stops.

More importantly is for OP to understand that moving each whole stop is basically doubling or halving the exposure itself (i.e. the amount of light sensor exposed to). If this is done by changing shutter speed then it also doubles or halves, but for aperture the change is not a doubling of the numbers.
 
To be honest I love my 10 stopper, but it's not that flexible as it's only aim in life is for long exposures. As you've said, go for a few lighter filters than stack them as required.
 
dalex_257 said:
Not to complicate things but you are all slightly off in a sense that everyone is correct ;). The number of stops between each adjacent apertures or shutter speeds on each camera is depending on settings used by that camera (whether or not this can be changed). On pro grade Nikons for example this can be changed to be either in 1/3 of the stop, 1/2 of the stop or the whole stops.

More importantly is for OP to understand that moving each whole stop is basically doubling or halving the exposure itself (i.e. the amount of light sensor exposed to). If this is done by changing shutter speed then it also doubles or halves, but for aperture the change is not a doubling of the numbers.
Click to expand...

You are right, it's the example of "1/100 to 1/125" being one stop that wasn't :)
 
Hawker said:
To be honest I love my 10 stopper, but it's not that flexible as it's only aim in life is for long exposures. As you've said, go for a few lighter filters than stack them as required.
Click to expand...

So what the shortest I could do withthe ten stop?

Would I be better getting two 4 stops that I could stack for longer exposures?

What length could a 4 get me?
 
Difficult to answer, as it depends on you unfiltered daylight shutter speed e.g. if you are getting 1/500 second then 10 stops from that would be about 2 seconds, but 4 stops would only be 1/30 of a second.

The best thing to do is get yourself a piece of welding glass (it will only cost you a couple of quid), that will give you 10 to maybe 13 stops depending on the piece of glass. Then play with that to give you a good feel of what that type of filter can do.
 
Hawker said:
You are right, it's the example of "1/100 to 1/125" being one stop that wasn't :)
Click to expand...


It's not what the OP was asking though. My mistake was I plucked the figures out of the air without thinking about it. As I work in 1/3rd increments on camera but think of them as 1 stop (incorrectly I know, but its how I visualize it in my head) I didn't notice I'd made that mistake. However, it isn't important here as the OP wants to know how the filter works. You're right for pointing out my mistake but please shut up about it now!!! I'm feeling daft enough about it as it is!!!

The sunglasses anology being superb btw :thumbs:
 
lol, don't get wound up about it, it's obviously a minor keyboard slip, the rest of your explanation was good. The 'sunglasses for you camera; is my favourite way of explaining what I'm doing when anyone walks up to me and asks about the lump of black glass on the front of my camera.
 
I'm not wound up, but as I don't post that often it is helping me get to that magic 100th post :D

Actually I'm more annoyed at myself as I know this and shouldn't have made the error. I don't actually think in stops when I am photographing, I found it hurt my feeble brain far too much, and got in the way of the artistic process too much. I now think in "notches", each click of the dial being one notch. Similar I suppose.

Whatever works for you eh?
 
I'm with you on that one, in fact if I'm using my 10 stopper I've got a little printed list of shutter speeds and f stops so I just have to get that out and count on that rather than working it out, +1 for the lazy :D

ps, come on only 8 more posts you can do it .....
 
Robbo said:
that helps!

So now the question is, say on an average light day, with 10stop filter and camera settings roughly what ranges could I get. Eg. From 1sec up to 10 seconds.

Hope that makes sense, I'm in deciding which one to get or if I will need two, one for short long exposures and one for long exposures
Click to expand...

Robbo, last months (photoanswers I think it was) has a table of exposure times for use with a 10 stop. According to the table, the shortest with a 10 stop (assuming a 1/4000 shutter speed in the first place) is 1/4s, although I'm not sure that combination would make a lot of sense.
 
I didn't want to make pointless posts though...:)

I try not to get bogged down by the science of stops and so on, I understand it and always have it there in the back of my mind, but I don't spend valuable shutter time working things out. I meter and use the "notch" system to get my exposure where I want it. If I decided I wanted ND filters, I wouldn't worry too much about which ones to go for, I'd buy a set of them and see how I got on with them. Afterall, if I'd bought a 2 stopper, it wouldn't be long before I decided to buy a 4 stopper. May as well buy them all in one go. As for learning how to use them, that would (and did) come through experience with them.
 
If you take an average well lit day which would allow you to take a correctly exposed photograph using f/8 and 1/125s at ISO 100, if you kept the ISO and aperture the same, a 10 stop ND would allow you to use a shutter speed of 8 secs in the same lighting conditions.

Is that what you wanted to know?
 
Scarecrow said:
If you take an average well lit day which would allow you to take a correctly exposed photograph using f/8 and 1/125s at ISO 100, if you kept the ISO and aperture the same, a 10 stop ND would allow you to use a shutter speed of 8 secs in the same lighting conditions.

Is that what you wanted to know?
Click to expand...

Yes :-) nice and simple for me
thanks
 
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