Help needed on ND Graduated filters and correct metering

[GaryMarsh]

Can anyone tell me how to meter correctly when using nd graduated filters in high contrast scenes. I have read in various photo mags how to take a spot meter for the sky and one for the foreground and then work out the difference in stops and this will define what nd grad needs to be used. What is most confusing is ok, I have worked out which grad filter to use but when I come to compose my shot do I reset my metering system to matrix and leave the camera to work out the rest or do I take a reading in matrix mode before applying the grad and revert to this setting when taking the shot to compensate for any changes made by the grad.

Any help appreciated!!
Regards
Gary

[knifebox]

Hi Gary. Im no expert but what I usually do is to meter for the foreground to have the correct exposure for it, take a test shot not minding the blown highlights yet and then snap on the GND and adjust accordingly.

If the picture is side lighted, you wouldn't have too much to worry about because the graduation of brightness from the sky to the foreground is very subtle. For most cases, you wouldn't even need a GND in the field for these as you can add a GND in Adobe Camera Raw before going to Photoshop (but it helps to cut down your process time if you do, so it will depend entirely on your patience with post processing).

You'll have a big leap in this difference, however, if you're taking pictures of sunrises or sunsets where you almost always shoot towards the sun. In this case, I just use matrix metering, slap on the GND and adjust after every test shot.

cheers!

[rob marshall]

What is most confusing is ok, I have worked out which grad filter to use but when I come to compose my shot do I reset my metering system to matrix and leave the camera to work out the rest or do I take a reading in matrix mode before applying the grad and revert to this setting when taking the shot to compensate for any changes made by the grad.

Use manual mode. Meter for the foreground bottom half, then the top half. Work out the difference and use appropriate ND grad. Set manual mode to the bottom half metering, because there will be no filter on that half so exposure will be correct. The top half will have the exposure reduced by the filter.

Try to get it right in camera, but you can make some adjustment in RAW.

[GaryMarsh]

Hi James,
Thank you for your reply it is all becoming clearer now! much appreciated.
Regards
Gary

[GaryMarsh]

Hello Rob,
Your help is much appreciated on this subject I will try this method next time I get chance to get out there with my camera.
Thanks
Gary

[Colin Southern]

All good theory - but in practice, you can just let the camera have a crack at it in Evaluative / Matrix Mode - check the histogram & check for blinkies - and adjust the exposure accordingly. If you're shooting RAW then you have a pretty good safety margin so long as you're not blowing the highlights.

The "problem" with metering the foreground zone and then the background zone (and working out the difference) is (a) they can be different areas of reflectivity (and thus would meter differently anyway), and (b) you need to be careful that you don't "violate the rules of local contrast", where the eye expects to see certain levels in relation to other areas.

Having just said all that, 9 times out of 10, a 3-Stop GND is pretty close; and if you're shooting RAW, you can easily tweak that in post-processing.