Nd filter system

[woody25]

Hi,
Does anyone know if exposure compensation on the camera would do the same job as an nd filter? I'd love it if somebody could explain.

I suspect there is a good reason why these are very different things, so could anybody suggest a good nd filter system to mount on the front of different size lenses. I'd like to easily change the nd strengths depending on the brightness of the day, rather than say an nd 77mm size filter.

Many thanks in advance
Woody

 

[badboy1984]

the cheapest to start off would be Cokin P filters. Basically the cokin P is a 85mm square filter where the filter holder will be screw infront of your lens using a adapter ring (depend on size of lens to use different size). Then the filter will slot in the holder (hold up to 3).

 

[woody25]

the cheapest to start off would be Cokin P filters. Basically the cokin P is a 85mm square filter where the filter holder will be screw infront of your lens using a adapter ring (depend on size of lens to use different size). Then the filter will slot in the holder (hold up to 3).

Thanks that's perfect. Am I silly to think that exposure compensation would do the same thing? Any ideas

 

[dfawkes]

You would use an ND filter to give you a longer shutter speed than a non-filtered exposure would get you, e.g. if a normal exposure is 1/8 second then a 3 stop ND will give you 1 second for the same aperture/ISO combination.

Using EC just tells the camera you want the exposure to be darker or brighter than what the camera thinks (which is neutral grey). If you dial it down you'll get a shorter shutter speed (and a darker image) for the same aperture/ISO, if you dial it up you'll get a longer shutter speed (and a brighter image).

So you can't use it in the same way - using an ND filter doesn't change the overall exposure like EC would, it just gives you the longer shutter speed.

(as an aside if you want to eek out a little longer shutter speed and you have room in your exposure for another stop or two you can use e.g. EC+1 to give you 2" shutter instead of 1", and then reduce the exposure by 1 stop in post processing. But best not to worry about that for now!)

 

[woody25]

You would use an ND filter to give you a longer shutter speed than a non-filtered exposure would get you, e.g. if a normal exposure is 1/8 second then a 3 stop ND will give you 1 second for the same aperture/ISO combination.

Using EC just tells the camera you want the exposure to be darker or brighter than what the camera thinks (which is neutral grey). If you dial it down you'll get a shorter shutter speed (and a darker image) for the same aperture/ISO, if you dial it up you'll get a longer shutter speed (and a brighter image).

So you can't use it in the same way - using an ND filter doesn't change the overall exposure like EC would, it just gives you the longer shutter speed.

(as an aside if you want to eek out a little longer shutter speed and you have room in your exposure for another stop or two you can use e.g. EC+1 to give you 2" shutter instead of 1", and then reduce the exposure by 1 stop in post processing. But best not to worry about that for now!)

Really nicely explained - thanks v much

 

[HoppyUK]

Really nicely explained - thanks v much

In the OP, you're talking about a Graduated ND filter (darker at the top, fading to clear), which is quite different to a staight ND (dark all over) explained above.

 

[dfawkes]

I didn't read it as a ND grad, but you're right to point it out to avoid any confusion. Either way, EC doesn't fulfil the same purpose of either!

 

[HoppyUK]

I didn't read it as a ND grad, but you're right to point it out to avoid any confusion. Either way, EC doesn't fulfil the same purpose of either!

LOL you may be right!

I speed read it, and mis-read 'day' for 'sky' - it changes everything! Apologies.