Schleimpflug in architecture

[Neil Grant]

Of course rising front is the most common movement I architectural, but which of you members are also using Schleimpflug to place the plane of sharp focus optimally? The situation I’m thinking of is where the camera viewpoint is oblique to the facade, with a near point at say 15m and far point at 45m. Without movements, lens and film planes parallel and focus pitched 1/4 in, sharpness can be seen falling away to towards the far point. Likely the schleimpflug correction would require a sub-degree rotation of one of the standards. Are members doing this or relying on stopping the lens down to say f/22 to get good focus throughout? THanks.

 

[P Sanders]

If I'm understanding correctly the oblique facade will require swing - perhaps thinking of it as a horizontal tilt (front to back but sideways?). Keeping it reasonably sharp at far/infinity and about 1/3 of the way in at the near. This also depends upon the lens, the wider the angle the more apparent 'in focus' everything will look. You may find f/32 better for coverage than f/22, again depending upon the lens and coverage.

 

[Besk]

I stop the lens down ONLY after making the movements.

 

[Doremus Scudder]

First of all, it's "Scheimpflug," no "L."

On to your question: the way I think about it is, anytime that repositioning the plane of sharp focus (PoSF) results in a shallower necessary depth of field, and as a result, a more optimum aperture, it is worth using.

For architectural work, if you are striving for parallel vertical lines, you need to keep the back oriented plumb and level. If you want horizontal lines parallel as well, you need to position the back so it is parallel to the plane those horizontal lines are in (e.g., a facade).

Still, if there are both near and far elements in the scene that require stopping down a lot (past f/32 for 4x5 for me), it's worth exploring if tilts and/or swings can more optimally position the PoSF.

An example: say you are photographing a tall building and want to include a lot of foreground in the image. As long as there are not any tall things close to the camera position (trees, etc.), you can often apply a bit of tilt, using the vertical center of a foreground object and the mid-point of the building as reference points, to get everything within the DoF without stopping down so far.

If photographing a receding wall at an oblique angle to the camera, swing is your friend. There are lots of possibilities for image control here in addition to getting things in focus and within the DoF. The position of the back relative to the oblique wall will determine how the parallel lines in the wall move to the vanishing point. More oblique (swinging or positioning one side of the back away from the nearest part of the oblique wall) will enhance the keystone effect. Moving the back closer to parallel to the oblique wall will lessen the effect. Then, when you have your image composed, use the front swing to get the entire wall in sharp focus. There are some limits to this due to lens coverage, but compromise is a possibility too.

Hope that helps,

Doremus

 

[abruzzi]

I never really done architecture with an LF camera but I would absolutely use swing in a case like that. I do it all the time in rural New Mexico to keep a fence line in focus, or sometimes a cliff face in focus. Just remember that when you swing the portion of plane of focus that is closer to you has shallower depth of field than the portion further from you. So area of apparent focus becoes more wedge shaped.