Alt-Scheimpflug

[Sharktooth]

 

[Donald Qualls]

This gets the same result as the geometric method and looks easier, but I generally set up tilts and swings by eye -- "bottom of scene is out of focus, need to tilt the front foward (and, since getting a centered-movements camera, not need to tilt-refocus-repeat).

 

[otto.f]

This gets the same result as the geometric method and looks easier, but I generally set up tilts and swings by eye -- "bottom of scene is out of focus, need to tilt the front foward (and, since getting a centered-movements camera, not need to tilt-refocus-repeat).

 

[Sharktooth]

It's just an alternative technique. It might be useful in some situations, and with some cameras. I haven't seen this method described anywhere else.

 

[brbo]

It's just an alternative technique. It might be useful in some situations, and with some cameras. I haven't seen this method described anywhere else.

I might be missing something... but what do you mean?! That you haven't yet heard that back tilt will change the plane of focus?

 

[Sharktooth]

It's the math, man.

 

[abruzzi]

I might be missing something... but what do you mean?! That you haven't yet heard that back tilt will change the plane of focus?

thats well known as is the process of determining angle on the rear and moving the angle adjustment to the front. I think whats clever here is using two measurements--the distinace of the rear displacement for focus along with the distance between the objects on the ground glass, and from that determining the angle. Its not well explained in the graphic but i think that what hes doing.

EDIT: also to say that it requires that you have standards where swing/tilt are marked in degrees.

 

[Donald Qualls]

it requires that you have standards where swing/tilt are marked in degrees.

Or else two standards that are the same height, so you don't have to mess with "similar triangles" and proportions to get the right offset on the front.

Much easier, IMO, to do the front tilt by eye on the ground glass.

 

[brbo]

I think whats clever here is using two measurements--the distinace of the rear displacement for focus along with the distance between the objects on the ground glass, and from that determining the angle.

Thanks! I did need that explanation.

 

[Sharktooth]

Yes, it's the math to calculate the tilt angle (or swing angle). The unique feature is that you don't need to actually tilt or swing anything to determine the angle.

It's not meant to replace the traditional methods. It's just an alternative approach that may be useful in some situations. As abruzzi noted, you will need some type of tilt angle scale on the front standard. Most of the wooden field cameras, and metal technical cameras. don't have tilt scales, so they wouldn't be useful for this technique.

It's a fun novelty for the mathematically minded. I go into more detail in this link over at the Large Format Photography Forum. Just be forewarned that it's very "wordy" Easy-Bake Scheimpflug

 

[tih]

This is closely related to the canonical (and documented) way of finding the correct front tilt with Sinar P cameras. They have angle scales on the standards, and the standards tilt around axes that are offset from center and marked on the ground glass. The idea is that you first focus on something close to the tilt axis, and then tilt the rear standard (around that line) until you get the focus plane you need. Read the angle, zero the rear tilt, and tilt the front standard the other way to the same angle. If you need a combination of tilt and swing, you start by finding focus on something at or near the intersection of the tilt and swing axis lines on the ground glass, as that point will be unaffected by either movement.

 

[abruzzi]

Yes, it's the math to calculate the tilt angle (or swing angle).

trig to the rescue!

EDIT: I'll add that what I like about this it it lines up with how I've long visualized lenses and cameras--specifically that a lens creates an upside-down miniature version of what is in front of it. and the key to focus is that to focus on an object or objects the film/sensor has to intersect those objects.

 

[Sharktooth]

trig to the rescue!

EDIT: I'll add that what I like about this it it lines up with how I've long visualized lenses and cameras--specifically that a lens creates an upside-down miniature version of what is in front of it. and the key to focus is that to focus on an object or objects the film/sensor has to intersect those objects.

Be careful with that "t" word, abruzzi! It causes many people to run away in terror.

I find it quite beautiful, and that's what attracts me to this approach. It's the magic that was given to use by ancient mathematicians a few millennia ago, and is fundamental to the modern world we live in today.