Mountaintop photographygreenspun.com : LUSENET : Large format photography : One Thread
I frequently like to take my View camera to high places. When focusing my camera on the distant mountains, I find the foreground rocks are slightly out of focus but I am afraid to use lens tilt because then the valleys at sea level will become out of focus because of the inherent geometry of the focal plane which travels in a horizontal direction. The valley floors are below the focal plane, aren't they? So the question is should I or shouldn't I use lens tilt? Will 3 to 5mm be the best aperture to avoid diffraction and still get maximum depth of field?
-- John Dorio (firstname.lastname@example.org), August 24, 1999
When confronted with this situation I tend to "shield" the valley with my foreground, that is I get as low to the ground as my composition will allow and hopefully block the midground from view. Then I use tilts to bring the foreground into sharp focus.
An out-of-focus foreground is very distracting IMO. I suppose if I were to choose between the rocks and the valley floor I would go for the sharp foreground.
-- Mark Windom (email@example.com), August 24, 1999.
There is a technique I use in just such a situation that has never failed me. When establishing the adjusted subject plane, I use a far target point a third of the way down below the top of the mountain and a near target point of one third down from the top of the foreground rock. These two points form the new subject plane. The most distant point in the scene is now the base of the mountain. The closest is the very top of the foreground rock. By alternately focusing on these two extremes and carefully noting that range on my focus scale. I can then do two things. 1. Park the lens halfway between the two points on my scale. 2. By knowing the amount of shift, determine the aperture needed to bring everything into focus. I taped a precision millemeter scale on my focus bed and scratched a witness mark on the rail that moves. I copied some pre-calculated shift ranges on the back of my camera bag's ID tag so I always have handy. By physically placing the lens exactly in between the near and far focus points, you are focusing one third into the scene. The rules governing depth of field now make it possible to bring everything into focus provided you use an appropriate aperture. Every object above the subject plane should lie in the "1/3 in front" and every object below that plane should lie in the "2/3 in back". This is a heck of a lot easier to draw than write about, so feel free to e-mail me with any questions.
-- Robert A. Zeichner (firstname.lastname@example.org), August 24, 1999.
It sounds like you are using too much tilt to begin with. I also shoot in very high places and have valleys below me with a very close foreground. I use a very small amount of front tilt and everything is in focus after I stop down to take up the slack. And I have found that things that are a long way off tend to respond to the half way rule better than the 1/3-2/3 that is used with relatively close objects. You want your plane of focus to run from the farthest mountain top to your valley bottom if I'm seeing your scene correctly. Then tilt so that your forground is in focus and your mountain top is in focus and use the aperture to take up the slack. The focus may be off at first but by focussing as you tilt you can split the difference and achieve a good focus on the near and far points. See if that helps. James
-- lumberjack (email@example.com), August 25, 1999.
The depth of field when using tilt is measured (if that's the appropriate word) perpendicular to the plane of focus when you use tilt. For a given aperture, the width of that zone increases with distance from the camera. Because of this, you would normally expect to have the greatest difficulty keeping vertically separated objects that are close to the camera in focus. The further from the camera they are, the greater the vertical separation you can have between two objects and still have them appear to be in focus.
In mountain photography, or any case where there is a lot of vertical relief, the biggest difficulties occur on the slopes near you or among the flowers at your feet, not on the other side of the valley. If the near slopes are hidden behind the foreground and if there isn't much relief in the foreground itself, achieving focus with tilt is easy. Unless a rather wide aperture is used, the valley floor up to the ridge crest should be in focus.
Note that the question of where to aim the camera on the opposite side of the valley is really determined by how the plane of focus passes through the relief near to you. If the slope at your feet is visible, and if you aim at the ridge crest, you'll need a rather small aperture to keep the slope in focus. Even assuming that the are clouds that need to be in focus at the very top of your image, I would aim no higher than 1/3 of the way up the ridge as a starter in this example. Be sure to check the focus as you stop down to verify that all of the topography in the foreground and middle region comes into focus.
You should look at The View Camera. I think they had an article a year or so ago that illustrated in a studio what I've prooly recounted in words.
The bottom line is to use tilt, and be more concerned about vertical relief nearer the camera than that further away.
Best wishes, Bruce
-- Bruce M. Herman (firstname.lastname@example.org), August 26, 1999.