help plse!!light metering issue with lee nd filters

[mickeyt]

ok..im trying to grasp landcape photography with my 5d mark 2 ..i set to manual ..125 shutter speed ..f11 iso 100.to start...i take a foreground reading of say 125...i then compose my shot and introduce the filter ..but which one?..thats an issue..0.3 nd..0.6 nd or 0.9 nd?... i put on the grad and then divide the exposure time by the number of stops of the filter ..so say its originally metering 125..on a 0.6 nd id have to slow the exposure time by two stops..ie 30th second...if i then add a polariser it uses say 2 more stops so id change the exposure time to 1/8 seconds.. id then use remote trigger..cover the camera ..important no light getting into the view finder and take the shot.. question ...what am i doing wrong??!!. this part of photography is what i wish to master imparticular the use of lee neutral hard grad filters as the shots look so much better..can u she some advice plse? thhks mike

 

[EdBray]

What you need to do is meter for the foreground (lets say 1/125 @f8) now meter from the sky (say 1/000 @ f8) this would give a difference of 3 stops so you would shoot at 1/125 @ f8 but use the 0.9ND grad to balance the exposure between the sky and the foreground.

You should always use the exposure for the foreground (using the same example as above) but you may want to change the balance of the sky by perhaps using a 1.2 ND grad or a 0.6 ND grad to darken or lighten the sky.

 

[mickeyt]

thanks ed..so me being dumb...do i then have to change the exposure time once I've put the say 0.9 nd filter on while I'm staying in manual.say f11..iso 100.....so if the original meter reading had to be slowed down with 0.9 grad,id then have to slow the shutter speed down fro 1/125 by three stops to 1/8 second to compensate?...this is where it get tricky..i can do that up to 30 secs with the 5d..then have to switch to bulb if i want the exposure time to be far greater..ie I've used the big stopper plus say polariser when i ned to expose for over a few minutes? getting thru this mist I'm sure I'm on the right track but its tricky!

mike

 

[EdBray]

No! You meter for the subject (usually the foreground) and that is your exposure setting, you are only metering from the sky to give you your ratio of the difference between the bright sky and the landscape.

How you choose to balance the sky with the landscape is your choice, you can go for no grad filter which will usually leave you with burnt out highlights in the sky, you can use a grad filter with different densities to acheive the effect you want (GRAD FILTERS HAVE NO EXPOSURE FACTOR) they are only used to balance the exposure of different areas of the image.

If you use a polorising filter that may well have an exposure factor and can be as much as 2 stops, in this instance I would meter the foreground with the poloriser in situ to give the effect required and set that exposure, then I would add an ND grad to further balance the sky with the subject if it's required, there would be no exposure factor added for the ND Grad.

The only other filters that would normally require an exposure factor are contrast filters for Black and White Film and ND filters (full filters not grads) which can have any exposure factor from x0.1 up to the 3x (Le Big Stopper) and even further up to 4x (welding glass).

 

[mickeyt]

thanks..still confused but will fathom it out..i want the milkiness of the sea /rivers with the filter used for the sky as well...ill keep reading!..seems to me the exposure time needs to be set somewhere in all that when on manual...cheers...

 

[EdBray]

thanks..still confused but will fathom it out..i want the milkiness of the sea /rivers with the filter used for the sky as well...ill keep reading!..seems to me the exposure time needs to be set somewhere in all that when on manual...cheers...

Okay, if you want milky water type shots you need to use long exposures, Full ND filters (not grads) and a poloriser will help with this by forcing you to use a slow shutter speed to get a correct exposure, unfortunately this usually means that the water gets blown out in the highlights.

Balancing the sky with the foreground is done by using ND grads to reduce the large variation of light between that coming from the sky and that reflected from the landscape.

If you have a camera that can do multiple exposures a good technique to try is after mounting your camera on a sturdy tripod, take 4 exposures all at 2 stops less exposure (than that metered) on the same frame. Or better still, take 8 exposures all at 3 stops less exposure (than that metered) on the same frame. This builds up the exposure over time but gives a feeling of movement in the water/clouds.

 

[mickeyt]

cool,,will do ..many many thanks for ur patience.

 

[J.D.]

thanks..still confused but will fathom it out..i want the milkiness of the sea /rivers with the filter used for the sky as well...ill keep reading!..seems to me the exposure time needs to be set somewhere in all that when on manual...cheers...

You're confusing ND grads with full ND filters. They are 2 types of filters with different functions. The confusion may come from the neutral density (ND) part - all this means is that the filters block light of all wavelengths equally so the image doesn't have a colour cast.

As Ed says, no need to change exposure settings when using ND grads - the function of them is to reduce the exposure of bright parts of a scene (e.g. sky). By altering your exposure settings with these you will end up overexposing the darker parts of the scene (e.g. foreground subject), and losing detail in the sky, which is what you are trying to maintain by using these.

For milky water you will need to use a full ND, and can use it with an ND grad for balancing the foreground with the sky if necessary (filter holders have more than 1 slot so you can use multiple filters)

 

[mickeyt]

hi james..yes ur right..i went on a trip with some other photographers and have def got all muddled..i used the nd grad for the clouds and a big stopper behind it..hence why i get so confused.!...but i do think I'm on the right lines in the metering side so will now take the difference between the shot of close land/sand etc to the camera then take the reading from the sky to work out which nd grad to use..thats the sky sorted ..no need to change exposure time ..however if i then use the big stopper or any other full filter ,I've got to go back to the metering difference and work out my exposure times so the shot can get the correct exposure time for the shot i want..i think I'm getting there..now I've just gotta work out night time metering and I'm on my way!...gulp..

 

[mickeyt]

hi james..yes ur right..i went on a trip with some other photographers and have def got all muddled..i used the nd grad for the clouds and a big stopper behind it..hence why i get so confused.!...but i do think I'm on the right lines in the metering side so will now take the difference between the shot of close land/sand etc to the camera then take the reading from the sky to work out which nd grad to use..thats the sky sorted ..no need to change exposure time ..however if i then use the big stopper or any other full filter ,I've got to go back to the metering difference and work out my exposure times so the shot can get the correct exposure time for the shot i want..i think I'm getting there..now I've just gotta work out night time metering and I'm on my way!...gulp..