10 stop ND filter vs 8 stop Fader ND filter

canongear wrote in post #14905055
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.

It's no different to regular photography, you have to balance the shutter speed, aperture and ISO to get the correct exposure. As you are using a specific ISO and aperture, that leaves shutter speed as the variable. It doesn't matter whether you are using an auto mode, manual mode, shutter button or bulb, you still need the shutter open for the correct length of time or you will over/underexpose your image. So, yes, you do have to still adjust for the correct exposure with bulb, as it is no different to using the shutter button in effect, both ways require the shutter open for the same length of time. The only reason for using bulb is if you can't set a long enough time on the camera.

The camera meter is designed to work with a certain amount of light, which means that it won't be accurate with a 10 stop ND on the lens. Take a meter reading first, modify it by 10 stops (or 8 in the case of your fader) and use that time for the shutter. Each stop requires you to double the length of time the shutter is open (see snydremarks post above).

They already answered but basically take your meter reading with the filter off. Since your filter is 8 stops you need to double the exposure 8 times when you put the filter back on. Your camera doesn't have a way to program that in unless you have the fancy Canon remote so put it in bulb mode and keep an eye on your watch.

Well, I learned a good lesson today regarding how to use a ND filter.
The lesson being that I didn't know how to properly use a ND filter.
Some of you might have already suspected that!

Decided to give things a try again today but this time, using the information from your replies to my questions.
The results were much better and there wasn't as much trial and error involved to achieve the look I was after.

I've also realized that I might need to get a better quality ND Filter.
I think the fader idea is a good one but, when I rotate the filter to it's maximum darkness, there is an overlapping effect on the image taken.
By that I mean where the filter transitions from complete darkness to the start of it's lightest.
I can't see it when looking through the viewfinder but, it appears in the image.
Also appears to be a bit of a blue colour cast in images taken with this filter.
Sunny and cloudy white balance were both used.
If there is no sky in any part of the image, these two things aren't that noticable.
Will practice a bit more with it though to see if it's actually the filter or me

Thanks to all of you for the information provided, I now have a starting point to work with that I didn't have or know of before.

canongear wrote in post #14907154
Well, I learned a good lesson today regarding how to use a ND filter.
The lesson being that I didn't know how to properly use a ND filter.
Some of you might have already suspected that!

Decided to give things a try again today but this time, using the information from your replies to my questions.
The results were much better and there wasn't as much trial and error involved to achieve the look I was after.

I've also realized that I might need to get a better quality ND Filter.
I think the fader idea is a good one but, when I rotate the filter to it's maximum darkness, there is an overlapping effect on the image taken.
By that I mean where the filter transitions from complete darkness to the start of it's lightest.
I can't see it when looking through the viewfinder but, it appears in the image.
Also appears to be a bit of a blue colour cast in images taken with this filter.
Sunny and cloudy white balance were both used.
If there is no sky in any part of the image, these two things aren't that noticable.
Will practice a bit more with it though to see if it's actually the filter or me

Thanks to all of you for the information provided, I now have a starting point to work with that I didn't have or know of before.

The V-NDs are known for causing issues at the extremes. Generally an "X" shape. It's the price you pay for the convenience of not having to buy/haul/change various strengths of filters (and convenience almost always has a price..look at superzooms).

Once you figure out how to properly use them, you can have a ton of fun, and create some awesome effects.

I generally have my cell phone with me, when i have my backpack, and this is when i use my ND filters. I use the built-in calculator to work out the proper shutter-speed(often using the 9-stop and a CPL or a 3-stop), and if it's dark.. i use the built-in stopwatch as my timer (i don't want to hit the light button on my camera, to see the timer.. vibrations).

Colorblinded wrote in post #14906307
They already answered but basically take your meter reading with the filter off. Since your filter is 8 stops you need to double the exposure 8 times when you put the filter back on.

This is one (among many) really bad things about Variable ND filters. You can't adjust it to 8-stops. You can adjust it until it's very dark - but you can't tell if that's 6, 8 or 10 stops. The only way to tell is to do a test exposure. You can't even use the camera's metering system as that is sensitive to IR - and VNDs tend to let in a lot of IR.

hollis_f wrote in post #14907798
This is one (among many) really bad things about Variable ND filters. You can't adjust it to 8-stops. You can adjust it until it's very dark - but you can't tell if that's 6, 8 or 10 stops. The only way to tell is to do a test exposure. You can't even use the camera's metering system as that is sensitive to IR - and VNDs tend to let in a lot of IR.

Understandable, but it's the best you can do I would suspect. Take a test and if it's off adjust accordingly. I haven't got a variable ND (just a 3 stop and 9 stop and a couple grad gels) but I have to admit I would have assumed they'd have markings on them to indicate minimum and maximum.

canongear wrote in post #14907154
Well, I learned a good lesson today regarding how to use a ND filter.
The lesson being that I didn't know how to properly use a ND filter.
Some of you might have already suspected that!

Decided to give things a try again today but this time, using the information from your replies to my questions.
The results were much better and there wasn't as much trial and error involved to achieve the look I was after.

I've also realized that I might need to get a better quality ND Filter.
I think the fader idea is a good one but, when I rotate the filter to it's maximum darkness, there is an overlapping effect on the image taken.
By that I mean where the filter transitions from complete darkness to the start of it's lightest.
I can't see it when looking through the viewfinder but, it appears in the image.
Also appears to be a bit of a blue colour cast in images taken with this filter.
Sunny and cloudy white balance were both used.
If there is no sky in any part of the image, these two things aren't that noticable.
Will practice a bit more with it though to see if it's actually the filter or me

Thanks to all of you for the information provided, I now have a starting point to work with that I didn't have or know of before.

Yes, this is one failing of the variable ones. They're built, basically, out of two, opposing CPLs; and this is the effect you get on wide/ultra-wide lenses with the CPL.

What focal length were you using?

Snydremark wrote in post #14911042
Yes, this is one failing of the variable ones. They're built, basically, out of two, opposing CPLs; and this is the effect you get on wide/ultra-wide lenses with the CPL.

Actually the common problem with CPLs on UWA lenses (a noticeable dark band in the sky) is unrelated to the common problem with VNDs on UWA lenses (a dark cross-pattern). You can easily check this out becuase the former depends on the angle between the camera and the sun while the latter is totally independant of the sun's direction (indeed, it will happen in artificial light).

Colorblinded wrote in post #14908424
Understandable, but it's the best you can do I would suspect. Take a test and if it's off adjust accordingly. I haven't got a variable ND (just a 3 stop and 9 stop and a couple grad gels) but I have to admit I would have assumed they'd have markings on them to indicate minimum and maximum.

On mine, there is an indicator mark on the part of the filter that doesn't rotate and on the part that does rotate, it has 18 individual white markings within a indicated min-max range. At the minimum range, the marks are small and, bigger at the maximum range.

Snydremark wrote in post #14911042
Yes, this is one failing of the variable ones. They're built, basically, out of two, opposing CPLs; and this is the effect you get on wide/ultra-wide lenses with the CPL.

What focal length were you using?

Was using 30mm end of my 28-135.
There wasn't a soul when I got to the spot where I was doing this, and no sooner than I had things all set up to take my first picture, three people on bikes appear out of no where and decide to stick around to watch what I was doing.
They didn't bother me or anything but, I didn't attempt any other focal lengths while they were watching.
I didn't want an audience watching me as I fumble to unscrew the filter, refocus and then screw the filter back on. Doing this multiple times due to any changed focal lengths.
That might've ruined the illusion for those three people that I knew what I was doing.

Why would focal length have any bearing on your exposure (unless you somehow manage to zoom directly into a dark/light area)? Set your mode to manual and focus ring to manual as well. That way, you can basically use hyperfocal distance to get roughly everything in focus.

Paolo.Leviste wrote in post #14920331
Why would focal length have any bearing on your exposure (unless you somehow manage to zoom directly into a dark/light area)? Set your mode to manual and focus ring to manual as well. That way, you can basically use hyperfocal distance to get roughly everything in focus.

Doesn't have any bearing on exposure; but it DOES have a direct bearing on whether the effect "distortion" occurs when using one of the variable NDs. What I find odd is that it was showing up at 30mm on, what I presume to be, a crop body.