ND Grad filters

[Rob]

I've got this idea for a shot. It's going to be taken during the day and I need a three to five second exposure. Anyone have any idea what kind of ND Grad I'd need to pull this off, given murky UK weather?

Rob

 

[PlasticSpanner]

Each filter is 1 stop so you should be able to calculate it from there!

So it's 1/60 @ F11

So you'll need up to 8 ND to get 4 secs @ F11 i.e 2 X 4 ND

 

[PlasticSpanner]

It would probably be more economical to buy the at 4, 3, 2 and 1 & use all of them.

That way you'll have a good selection to use in the future! :thumbup:

 

[PlasticSpanner]

Back again!

BTW do you mean to use ND Gradient filters or just ND filters?

 

[Rob]

Just flat ones, maybe one grad for the sky balance.

Rob

 

[MyCameraEye]

Not sure what your idea is but I use a ND 8X on a Sunny day along with a polarizer to make waterfalls look like milky. Not sure if this runs along the same line with your idea but this might help.

 

[duelinthedeep]

what does an ND filter do anyway?
whats the diff between ND and ND gradient filters?

 

[PlasticSpanner]

An ND Filter is a Neutral Density filter that simply reduces the light entering the lens/camera without adding or removing any colour.

A normal ND filter is the same density all the way across it and an ND Gradient filter will increase in density from one side to the other e.g to darken a sky without darkening the landscape.

Gradient filters can also be coloured to turn overcast skies blue or pale sunsets red for example.

 

[duelinthedeep]

ohhhh..thats great information thanks!

 

[Insomniac]

Just flat ones, maybe one grad for the sky balance.

Rob

Rob, if you're looking to balance the exposure of the sky to a darker foreground use a graduated ND filter, you can darken the sky bringing it closer to the foreground exposure.

For anyone that is unfamiliar, this is an example of a ND filter produced shot. I believe this was mid morning with a 4x ND filter.

 

[JonathanM]

Can using a polariser prodeuce a similar eduction in light, but to a lesser extent? Maybe only 1 stop? Or does a polariser alter the colour entering the camera?

 

[PlasticSpanner]

A polarizer will alter the colours through the lens and will only reduce the exposure by 1/2 - 1 stop.

 

[Rob]

I will be trying the shot on Wednesday. It's gonna be interesting if I can pull it off!

Thanks Chris!

Rob