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Les Joined: 09 May 2001 Posts: 2682 |  Posted: Tue Jan 26, 2010 7:36 pm Post subject: backward tilt
Has anybody found a use for backward tilt by itself?
As in without using it in conjunction with dropping the bed (or rail) |
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1banjo Joined: 16 Nov 2008 Posts: 492 |  Posted: Tue Jan 26, 2010 9:00 pm
yes les
with your ground grass level & your looking at a tall building or tall Vertical lines
tilting back helps keep the Vertical lines from Converging
1banjo |
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Les Joined: 09 May 2001 Posts: 2682 |  Posted: Tue Jan 26, 2010 9:14 pm
I think your thinking of front rise. Front tilts and swings effect the plane of focus.
So with front forward tilt you can do the Scheimpflug dance where if you can tilt the lens forward so it bisects the intersection of the planes of both the tulips on the ground and the ground glass, all of the daisies from foreground to infinity (or darn close to it) with be sharp with the lens wide open. Now the flowers will be in focus but the dirt a foot below the flowers and the trees above will be fuzzy.
The same effect can be done with swings and the side of buildings.
and with Speeds and Crowns you can effect a fall by dropping the bed and then backward tilting the lens to bring it back to parallel. With view cameras you can tilt the rail down and back tilt both front and back to effect an extreme fall.
But I can't for the life of me think of of benefit of back tilt when everything else is level and perpendicular. |
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1banjo Joined: 16 Nov 2008 Posts: 492 |  Posted: Tue Jan 26, 2010 10:05 pm
well les
my text books it shows with your ground grass level & your looking at a tall building or tall Vertical lines tilting back helps keep the Vertical lines from Converging
But you do need front rise TOO
1banjo |
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brian d Joined: 15 Jan 2008 Posts: 44 |  Posted: Tue Jan 26, 2010 10:31 pm
I have used it to help bring out selective focus/depth of field for portraits |
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Les Joined: 09 May 2001 Posts: 2682 |  Posted: Tue Jan 26, 2010 10:38 pm
I'm curious what your book is.
Here's mine: Graphic Graflex Photography, ninth ed. 1952 page 170 in a chapter by John S. Carroll.
We can agree about the first pair of photos, tilting the whole camera back gives us a soft image and converging verticals.
The second pair of pictures are of interest, here. The camera has been tilted up and in relation to the building the lens is tilted back, but the rear of the camera has been tilted forward. The caption reads: "the camera back has been tilted to a vertical position by means of the spirit level on top."
The result: The vertical lines have been straightened by the use of the tilting rear standard. It is now, however, impossible to secure a sharp focus except at one point.
Last pair: The camera front board is tilted forward until it is parallel to both subject and camera back.
Result: The columns are now parallel, the building appears truly vertical, and the image is sharp all over, even before stopping down.
In the bottom picture, front and rear tilt are used but it's forward tilt not backward tilt. The same effect could have been done with an Crown with the bed level and the back straight, and done an extreme rise without any tilts |
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1banjo Joined: 16 Nov 2008 Posts: 492 |  Posted: Tue Jan 26, 2010 11:18 pm
hey les
yes that is one of the books that we use as a text book!!
and 5b is one of the ones that I was looking at
NOW look at it the film plane is level BUT not the rail or the lens
you can do the same thing by living the camera bed/rial flat so the
back of a press camera is level then rise the lens & tilt back
as in 5b the film plane is level but the lens is not level its back.
now also in Kodak's book PHOTOGRAPHY WITH LARGE-FORMAT CAMERAS
on page 24 bacely the same thing
VIEW CAMERA TECHNIQUE by Leslie Stroebel from Focal Press
we use all three as text book
1banjo |
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Dan Fromm Joined: 14 May 2001 Posts: 2165 |  Posted: Tue Jan 26, 2010 11:29 pm
Banjo, indirect rise requires front and rear tilt. Graphics have only front tilt. Think again. |
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Les Joined: 09 May 2001 Posts: 2682 |  Posted: Tue Jan 26, 2010 11:33 pm
Okay all the books show it, but notice the effect..."its impossible to focus on the entire building" in that position
this gets back to what I was saying before, front tilts effect the plane of focus, back tilts effect perspective. (Okay Les Stroebel said it first and often and eventually I got it right)
So unless the intent was to get a very selective focus I still don't see a reason for back tilt by itself. |
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glennfromwy Joined: 29 Nov 2001 Posts: 903 |  Posted: Tue Jan 26, 2010 11:36 pm
Les is correct. If you tilt the lens back, it will make it hard to get everything in focus and it may vignette. If you tilt the camea up and keep the front and rear vertical, what you are getting. in effect, is additional front rise. Everything will be in focus within the limits of the lens definition at the edges. The back must be parallel to the subject if you want it to look straight. You can also get backward tilt by turning the camera upside down, though I don't know why anyone would want to do that. |
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Les Joined: 09 May 2001 Posts: 2682 |  Posted: Tue Jan 26, 2010 11:38 pm
Dan,
While that's true, I'll even open it to view cameras as well.
Can anybody come up with a use for back tilt on it's own? |
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glennfromwy Joined: 29 Nov 2001 Posts: 903 |  Posted: Tue Jan 26, 2010 11:44 pm
Uh........... no. |
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1banjo Joined: 16 Nov 2008 Posts: 492 |  Posted: Tue Jan 26, 2010 11:45 pm
no les
that is the only use that I see in any of my books ( that like 5b)
1banjo |
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Dan Fromm Joined: 14 May 2001 Posts: 2165 |  Posted: Wed Jan 27, 2010 12:00 am
Les, how about using back tilt (and probably front rise too, to avoid running out of coverage) to focus on the surface of an undercut cliff?
x marks the photographer and \ marks the front of the cliff: x\
Not a common situation, architects usually make pyramids base down.
Oh, yeah, guys, if the camera's rail is tilted up (down at the back, up in front), then front tilt is needed to make lens board and film vertical. Indirect rise. If the rail is tilted down, then rear tilt is needed. Indirect fall. Just checked with my clunky old Calumet. |
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Les Joined: 09 May 2001 Posts: 2682 |  Posted: Wed Jan 27, 2010 12:30 am
Dan wins the non existent prize!
I figured if you do a back tilt you'd end up with a plane of focus parallel to the ground, but somewhere in the sky.
I live in a county that's 908 square miles in area and has a total elevation of 400 ft.
an outcropped cliff is something I would never have thought of. |
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