Posted by Tom Nevesely on January 16, 2007 at 4:34 PM
I've always wondered this...
For example, when shooting mountains with a reflection in a lake at sunrise what is the best way to position a ND grad filter? You have a bright sky, then some darker shadow areas and then the brighter reflection. I've always metered the sky and the reflection and chose my filter strength according to that but the mid-ground with no light on it is usually rather dark. Is it better to use 2 filters - one for the sky and one for the reflection or can it somehow be done with one soft edge and have it go lower over the part of the reflection to blend the light better. I remember hearing the latter once but I don't understand how that would work.
Thanks!
Posted by Mark Windom on January 16, 2007 at 8:30 PM
With the type of scene you are describing I typically use a soft grad and position it so it begins somewhere in the darker shadowed midground area. The transition with Singh-Rays is so gradual that there is minimal further darkening of this area. I don't allow the filter to affect the reflection at all. I choose a grad that will allow the mtn reflection to remain about 1 stop darker than the mtn itself.
Posted by Steve Konrad on January 17, 2007 at 1:02 AM
You may have already seen this, but Singh-Ray makes a couple of filters that might help out in your situation. They have a reverse graduated ND, or a graduated strip ND. I have not used either, so I'm just going by the documentation on their website.
Posted by Kah Kit Yoong on January 17, 2007 at 7:57 AM
It depends. Firstly if you have a dark area in between 2 light areas, stacking will make the shadow area go to black so don't do it. I think you have options you can position a hard grad at the line between the sky & shadows. Sometimes this can result in the reflection being lighter than the actual image which I don't usually like as this does not happen in reality. In this case it may be necessary to use a soft grad pulled down to cover the reflection.
The reflection is actually darker than the sky. In this situation I would take spot readings of the sky, the mountains, and the reflection and first determine if I can fit it all within my film/sensor exposure latitude. Ideally you'll want to keep the reflection about 1 stop darker than the sky and still have some detail in the mountains so a carefully placed grad on the ridge line is probably your best bet. The strength and gradation should be determined by the value differences at the scene and the shape of the ridge.
With a digital camera you can analyze the histogram to know if you have clipped highlights or shadows and adjust in the field. You may need to correct some things in post-processing but you will know if you captured good shadow and highlight detail.
Guy
Posted by Chris Ross on January 17, 2007 at 7:32 PM
Depends on the scene you're shooting. I found a 1 stop grad quite useful for a reflected mountain as long as the lighting is reasonably soft. Any stronger and the reflection can be brighter than the mountain. In this case I place it on the sunlight/shadow line. If you're in the shade an incident reading for the shadowed area, then spot readings for the sky and other areas covered by the fliter to make sure they're in range. If not adjust the filter strength. Alternately for digital you could shoot and check the histogram for blown highlights.
Posted by Paul Skoczylas on January 18, 2007 at 12:12 PM
If the sun isn't in the frame, take three shots, one at the meter reading for the overall scene and one each at +/- 2 stops from that reading (adjusting the shutter speed). Best if you can shoot using the camera's AEB setting and a remote release, so you don't touch the camera between frames.
Then when you get back to the computer, load them all into Photoshop and blend accordingly. Or even easier, use something like Photomatix to do it for you!
See the image on the front page of my website: http://www3.telus.net/avrsvr/ for an example. (IIRC, that one was done with two only frames.) Or a shot that no GND could help on: http://www3.telus.net/avrsvr/D20060930_HR4.html (3 or 4 frames). Note the direct sunlight on the white concrete, and the dark shadows below, both of which retain detail. Or this one: http://www3.telus.net/avrsvr/D20061219_H11.html (5 frames, at a spacing of 2 stops--the extra frames were needed because of the bright sun in the frame.) Or: http://www3.telus.net/avrsvr/D20061218_H01.html (3 frames).
Etcetera. I still carry a couple of GNDs in my bag, but I haven't used them much lately!
Discussion
6 repliesFor example, when shooting mountains with a reflection in a lake at sunrise what is the best way to position a ND grad filter? You have a bright sky, then some darker shadow areas and then the brighter reflection. I've always metered the sky and the reflection and chose my filter strength according to that but the mid-ground with no light on it is usually rather dark. Is it better to use 2 filters - one for the sky and one for the reflection or can it somehow be done with one soft edge and have it go lower over the part of the reflection to blend the light better. I remember hearing the latter once but I don't understand how that would work.
Thanks!
With a digital camera you can analyze the histogram to know if you have clipped highlights or shadows and adjust in the field. You may need to correct some things in post-processing but you will know if you captured good shadow and highlight detail.
Guy
Then when you get back to the computer, load them all into Photoshop and blend accordingly. Or even easier, use something like Photomatix to do it for you!
See the image on the front page of my website: http://www3.telus.net/avrsvr/ for an example. (IIRC, that one was done with two only frames.) Or a shot that no GND could help on: http://www3.telus.net/avrsvr/D20060930_HR4.html (3 or 4 frames). Note the direct sunlight on the white concrete, and the dark shadows below, both of which retain detail. Or this one: http://www3.telus.net/avrsvr/D20061219_H11.html (5 frames, at a spacing of 2 stops--the extra frames were needed because of the bright sun in the frame.) Or: http://www3.telus.net/avrsvr/D20061218_H01.html (3 frames).
Etcetera. I still carry a couple of GNDs in my bag, but I haven't used them much lately!
-Paul