Metering with Grad ND Filters

TelePaul

Just making sure I understand this right. With a Grad ND filter I meter for the foreground and slap the filter on, right?

Slav

I would say you spot-meter the scene and choose the appropriate density/edge gradient filter for it.

AnCatDubh

TelePaul wrote: »

Just making sure I understand this right. With a Grad ND filter I meter for the foreground and slap the filter on, right?

I'm thinking (but don't know) it would depend on what you wanted to do. If purely to do the "candyfloss water at mid day" type of thing then if you meter with the filter off you won't get the long shutter exposure.

If you are are just toning down a sky with a ND Grad filter then presumably you want normal shutter speeds so you would meter normally off the foreground or whatever accepting that the ND grad will do its thing and keep a proper exposure on the sky.

Does that logic sound reasonable? I've haven't used one (on the to-do list) so i'm interested in your question but i'd be thinking along those lines (which could be completely wrong btw)

Eirebear

While on the subject of filters, i bought an ND filter the other week...somewhere along the line they mxed up the order and sent me a red filter instead.

Ive decided to keep a hold of it, but im unsure of its uses.

I know its designed for BW photography, but will it work the same if i shoot colour and then convert?

TelePaul

AnCatDubh wrote: »

If you are are just toning down a sky with a ND Grad filter then presumably you want normal shutter speeds so you would meter normally off the foreground or whatever accepting that the ND grad will do its thing and keep a proper exposure on the sky.

Yeah that's what i figured.

Slav

Eirebear wrote: »

I know its designed for BW photography, but will it work the same if i shoot colour and then convert?

It won't be of much benefit if your are talking about converting a digital image. You will get the same result if you use mainly the red channel when you convert to B/W.

CabanSail

The way i have had ND Grad Filters explained to me was that you Spot Metered the landscape & decide on an exposure. This will normally be to vary the Shutter Speed as you will want the Aperture shut down for the DOF. Then you Spot Meter the sky to work out how many stops brighter it is, so you can then select the correct ND Grad to use. This is all meant mainly for film as you can do this stuff in PP with Digital if you shoot RAW. It may help if you bracket too.

The Red Filter is used for B&W Film to make Blue (Sky) and Greens (Foliage) much darker. It makes the clouds pop out. An Orange Filter will be similar but not as strong. There is no need to do this in Digital as you are shooting Red Green & Blue Channels, so if doing a B&W Conversion it's like shooting with every filter on at the same time. If you put a Red Filter of a Digital Camera it's the same as turning off the Green & Blue Channels.

Eirebear

Slav wrote: »

It won't be of much benefit if your are talking about converting a digital image. You will get the same result if you use mainly the red channel when you convert to B/W.

CabanSail wrote: »

The Red Filter is used for B&W Film to make Blue (Sky) and Greens (Foliage) much darker. It makes the clouds pop out. An Orange Filter will be similar but not as strong. There is no need to do this in Digital as you are shooting Red Green & Blue Channels, so if doing a B&W Conversion it's like shooting with every filter on at the same time. If you put a Red Filter of a Digital Camera it's the same as turning off the Green & Blue Channels.

Cheers, i still think ill go out and experiment with it.

Sometimes its more fun getting the effect off camera instead of relying on photoshop all the time.

Slav

CabanSail wrote: »

The Red Filter is used for B&W Film to make Blue (Sky) and Greens (Foliage) much darker.

Darkening foliage might be tricky with the red filter. Leafs usually reflects a good bit of red and infrared so with a deep red filter the effect can be quite the opposite: some foliage renders much lighter then it would without the filter.

Eirebear wrote: »

Sometimes its more fun getting the effect off camera instead of relying on photoshop all the time.

It is fun alright but B/W film photographers would love to have this ability to apply a filter after the shoot. Sometimes it's difficult or even impossible to predict how the things would look on the negative being exposed behind a filter. A classic example is to separate a red flower from green leafs. It's hard to predict how this particular foliage will look with a red filter because we cannot see the reflection spectrum curve with our eyes. The flower will be lighter but so might be the leafs as well even if they look pure green for us.

Eirebear

Slav wrote: »

It is fun alright but B/W film photographers would love to have this ability to apply a filter after the shoot. Sometimes it's difficult or even impossible to predict how the things would look on the negative being exposed behind a filter. A classic example is to separate a red flower from green leafs. It's hard to predict how this particular foliage will look with a red filter because we cannot see the reflection spectrum curve with our eyes. The flower will be lighter but so might be the leafs as well even if they look pure green for us.

Im not a film photographer though, so fun it is, you can keep your thinking!