10 stop ND filter vs 8 stop Fader ND filter

I happen to come across a daytime long exposure video tutorial by Scott Kelby that I wanted to try.
My results following his instructions were nothing like his results.
If you Google "Scott Kelby long exposure", the first search result should be the YouTube video I'm refering to.

In the video, he used a 10 stop ND filter.
I don't have a 10 stop ND filter so, I used my fader ND filter which is capable of 8 stops.

I did a 2 minute bulb exposure like what was done in the video, rotated the filter to it's 8stop setting and, the image was completely blown out.
I used an F stop of F16 and he used F11.

After much trial and error, I was able to get a pretty good image along with the water effect similar to the water effect in the video.
But, my shutter speed was only 5 seconds at F16 vs his 2 minutes at F11. I think I also slightly decreased the stop factor on the filter as well.
I could just barley make out the scene when looking through the viewfinder.


I haven't used this filter very much up to now so, my question is, is there that much of a difference between 10 stops and 8 stops that it would produce that much of an extreme(nice exposure vs blown out) over the same 2 minute period of time?
Or could it have something to do with the optical quality of the Fader ND filter?

Yes. The 2 stop difference means that your 8 stop filter is letting in 4x the amount of light that the 10 stop filter is.

I just, recently, got my Big Stopper and it's amazing how dark that is compared to the 8 stops of my Vari-N-Duo.

If you are shooting at f/8, 1/100s and go down 8 stops on your shutter speed:
1 stop: 1/50
2 stops: 1/25
3 stops: 1/13
4 stops: 1/6
5 stops: .3s
6 stops: .6s
7 stops: 1.3s
8 stops: 2.5s

Now, add 2 more stops on top of that:
9 stops: 5s
10 stops: 10s

So, if a proper exposure is at 2.5s with 8 stops, you can see how moving your exposure time up to a full, 10s, without adjusting anything else would give you way too much light.

Snydremark wrote in post #14903140
Yes. The 2 stop difference means that your 8 stop filter is letting in 4x the amount of light that the 10 stop filter is.

I just, recently, got my Big Stopper and it's amazing how dark that is compared to the 8 stops of my Vari-N-Duo.

If you are shooting at f/8, 1/100s and go down 8 stops on your shutter speed:
1 stop: 1/50
2 stops: 1/25
3 stops: 1/13
4 stops: 1/6
5 stops: .3s
6 stops: .6s
7 stops: 1.3s
8 stops: 2.5s

Now, add 2 more stops on top of that:
9 stops: 5s
10 stops: 10s

So, if a proper exposure is at 2.5s with 8 stops, you can see how moving your exposure time up to a full, 10s, without adjusting anything else would give you way too much light.

This is going to be a stupid question but, if the 8 stop filter allows 4x the amount of light than the 10 stop filter and it only took 5 seconds in order for me to get a good exposure, wouldn't it then only take 20 seconds with a 10 stop filter to get the same exposure instead of 2 minutes?

Were you using EXACTLY Kelby's settings?

Paolo.Leviste wrote in post #14903357
Were you using EXACTLY Kelby's settings?

Indeed. Were you both shooting on a bright sunny day? Both shooting at the same ISO?

Paolo.Leviste wrote in post #14903357
Were you using EXACTLY Kelby's settings?

I used f16 not f11 and, I used ISO 200.
Other than that, things were the same.
I even covered the viewfinder with a dark cloth.
I use a Canon camera so maybe I should've used ISO 100.
He said to use the lowest ISO your camera can do.
He used ISO 200 but, he was using a Nikon camera and he said that's the lowest it could go.

Colorblinded wrote in post #14903372
Indeed. Were you both shooting on a bright sunny day? Both shooting at the same ISO?

There were a few passing puffy white clouds but other than that, it was a nice sunny summer day.

The scene itself matters too. Meter right from YOUR settings, because I'm sure the lighting is vastly different from when you took your shot in comparison to the Youtube video's. Even the time of day would make a big difference. Or location, or cloud cover...et al.

ISO 200 would make an entire stop's worth of difference. That's the difference between 1 second and a half second. But, you are also at f16, which lets in half as much light as f11.

So, that leads me (at least) to believe you went off Kelby's settings rather than what you needed to expose for in your particular situation.

canongear wrote in post #14903333
This is going to be a stupid question but, if the 8 stop filter allows 4x the amount of light than the 10 stop filter and it only took 5 seconds in order for me to get a good exposure, wouldn't it then only take 20 seconds with a 10 stop filter to get the same exposure instead of 2 minutes?

Generally speaking, yes, that's correct. There is one missing piece of info missing in all of this, though, which is what your ISO is and what his was.

[Adjusted for misreading settings the first time]
It would depend on the lighting conditions, also, though; if you weren't shooting along side of him, there's no way to say that you were in exactly the same light for your shot. If you were shooting in brighter conditions than he was, then you'd need less time and vice versa.

Also, you were using a different aperture, which throws it off, as well. If his exposure was 2min @ f/11 (assuming same light levels and ISO), then your exposure at 10 stops and f/16 would have been 4min. Which should have backed out to 1min @ f/16 for 8 stops.

However, with the 10 stop, you start getting into a "fudge factor" that doesn't really match up to the normal math, too; I found that I really needed to add about 1.5 to 2 stops worth of shutter speed to do a long exposure in mid-daylight with mine this last weekend. I don't have the ability to watch the video right now, but does he discuss how he arrived at those exposure settings?

What sort of a scene were you shooting compared to what he was shooting?

Paolo.Leviste wrote in post #14903413
The scene itself matters too. Meter right from YOUR settings, because I'm sure the lighting is vastly different from when you took your shot in comparison to the Youtube video's. Even the time of day would make a big difference. Or location, or cloud cover...et al.

ISO 200 would make an entire stop's worth of difference. That's the difference between 1 second and a half second. But, you are also at f16, which lets in half as much light as f11.

So, that leads me (at least) to believe you went off Kelby's settings rather than what you needed to expose for in your particular situation.

I just watched the video again and towards the end of it he says " we kind of have a cloudless sky tonight" so maybe he was doing this during the late afternoon or early evening and that's why he was able to do a 2 minute bulb exposure.
Although earlier in the video, he mentions "in the middle of the day" a couple of times.
I did my experiment around 3:00 p.m.
I guess there are just too many variables as you mention in doing something like this.
At least I've learned a couple of things by attempting it and, thanks to all for the responses to my question.

Snydremark wrote in post #14903478
Generally speaking, yes, that's correct. There is one missing piece of info missing in all of this, though, which is what your ISO is and what his was.

[Adjusted for misreading settings the first time]
It would depend on the lighting conditions, also, though; if you weren't shooting along side of him, there's no way to say that you were in exactly the same light for your shot. If you were shooting in brighter conditions than he was, then you'd need less time and vice versa.

Also, you were using a different aperture, which throws it off, as well. If his exposure was 2min @ f/11 (assuming same light levels and ISO), then your exposure at 10 stops and f/16 would have been 4min. Which should have backed out to 1min @ f/16 for 8 stops.

However, with the 10 stop, you start getting into a "fudge factor" that doesn't really match up to the normal math, too; I found that I really needed to add about 1.5 to 2 stops worth of shutter speed to do a long exposure in mid-daylight with mine this last weekend. I don't have the ability to watch the video right now, but does he discuss how he arrived at those exposure settings?

What sort of a scene were you shooting compared to what he was shooting?

It was of a suspension foot bridge over a river.
Other than water being part of the scene, nothing similar in subject or composition compared to what was done in the video.
It just hit me, in his image, there was no sky, in mine, there was some.
So, that would explain things!
Thanks for making me realize that.
I'll have to find a similar scene and try the experiment again.
P.S. He didn't explain why he chose a 2 minute exposure but, i'm guessing because he knew what f stop and ISO he was going to use along with the 10 stop ND filter, there's probably a formula that the pros use to figure that out.

canongear wrote in post #14903615
It was of a suspension foot bridge over a river.
Other than water being part of the scene, nothing similar in subject or composition compared to what was done in the video.
It just hit me, in his image, there was no sky, in mine, there was some.
So, that would explain things!
Thanks for making me realize that.
I'll have to find a similar scene and try the experiment again.

Glad to help

canongear wrote in post #14903615
P.S. He didn't explain why he chose a 2 minute exposure but, i'm guessing because he knew what f stop and ISO he was going to use along with the 10 stop ND filter, there's probably a formula that the pros use to figure that out.

Mostly, it's just the math of setting your exposure normally and then increasing it the number of stops that your filter decreases it; as above. However, you may find, even at 8 stops that you like the results better by increasing the exposure time another stop or so, in some cases.

Once you get to the point where the exposure is going to take minutes your camera's not going to give you the most useful metering information. Meter with the filter off, put it on and then adjust your exposure. That or trial and error it if you feel like it.

In the end as already mentioned it's hard to compare how one shot was set up compared to another. Different time of day, different light, etc.

Snydremark wrote in post #14903876
Glad to help

Mostly, it's just the math of setting your exposure normally and then increasing it the number of stops that your filter decreases it; as above. However, you may find, even at 8 stops that you like the results better by increasing the exposure time another stop or so, in some cases.

Colorblinded wrote in post #14904212
Once you get to the point where the exposure is going to take minutes your camera's not going to give you the most useful metering information. Meter with the filter off, put it on and then adjust your exposure. That or trial and error it if you feel like it.

In the end as already mentioned it's hard to compare how one shot was set up compared to another. Different time of day, different light, etc.

You both mention adjusting the exposure to compensate for the filter.
So, just to make sure I understand both your statements, I have a couple of questions.

Synderemark:
What you say, makes sense to me but, would I adjust the exposure to compensate for the filter only if i'm not using bulb mode?

Colorblind:
If it's known that the exposure is going to take minutes, what do you mean by adjust your exposure?
I think I might be reading more into what you are saying so, would just like some clarification.

In the video, Kelby doesn't mention anything about adjusting exposure.
He just makes sure the focus is set then, switches from auto to manual focus, puts the filter on and then starts the predetermined 2 minute exposure. The camera was already set to bulb mode.

I'd just use some math with some added guesstimating. So, take your exposure based off of what you see WITHOUT the filter. Let's say the scene is PROPERLY exposed at ISO 100, f11 at one second without the filter.

So, let's say you're at 1 second f11, correct? And you have that 8-stop ND filter, so add in the math. That means:

base: 1 second
1 stop: 2 seconds
2 stops: 4 seconds
3 stops: 8 seconds
4 stops: 16 seconds
5 stops: 32 seconds
6 stops: 64 seconds
7 stops: 128 seconds
8 stops: 256 seconds

For the sake of things, I'd think about adding 2-3 seconds to get shadows (if any) get more exposed if you think that won't blow your sky out. Also, you would basically have to be in bulb mode in my particular situation for anything over a 5-stop filter.

By the way, how are you triggering your camera?