Can Someone Clarify the Scheimpflug Rule for me?

[bobwysiwyg]

I've been working at learning to use my 4x5 (I' fairly new to large format). I thought I understood the gist of this until I came to page 47 of "Using the View Camera."

There are four illustrations. The upper-left and lower-left illustrations are for entirely different movements, yet the text associated with them seems to suggest both movements bring things into focus even if they are along an angular plane.??

I "thought" that generally speaking using front tilt was for one thing and rear tilt for another. I'm not sure now which is associated more with focus vs. perspective correction. Any help would be very much appreciated. :confused:

[darr]

Try reading this for more clarification. (http://www.trenholm.org/hmmerk/VuCamTxt.pdf)

[Mark Stahlke]

OK, I just looked at page 47. The two diagrams on the left show that you can achieve Scheimpflug using either front tilt or rear tilt (or both as indicated by the top right diagram). This part is about focusing and doesn't consider perspective at all. That's in the next chapter. The common meeting point is what Scheimpflug is all about.

Using rear tilt to focus may result in perspective correction or distortion, as the case may be.

Does that help?

Cheers,
Mark

[bobwysiwyg]

Darlene,

Thanks, I will study this.

[bobwysiwyg]

OK, I just looked at page 47. The two diagrams on the left show that you can achieve Scheimpflug using either front tilt or rear tilt (or both as indicated by the top right diagram). This part is about focusing and doesn't consider perspective at all. That's in the next chapter. The common meeting point is what Scheimpflug is all about.

Using rear tilt to focus may result in perspective correction or distortion, as the case may be.

Does that help?

Cheers,
Mark

Um, not sure. Maybe I should just get the cam out and try some things with the next nearby.

[rugenius]

Any ideas where the movie files are?

Thx.

[Mark Barendt]

http://www.largeformatphotography.info/how-to-focus.html

[Mark Stahlke]

Maybe I should just get the cam out and try some things with the next nearby.
Yes!
Just look at the ground glass. If it looks good shoot it. Sometimes I think we make this stuff way harder than it needs to be.

Cheers,
Mark

[rugenius]

Got all the files from the website, THANKS!:) :) :)

[percepts]

Any ideas where the movie files are?

Thx.

http://www.trenholm.org/hmmerk/
http://www.trenholm.org/hmmerk/HMbook18.html

[rdenney]

Here's all you need to remember:

Scheimpflug's rule states that the focus plane, the lens board plane, and the film plane all intersect. When the lens and film planes are parallel, they intersect the focus plane at infinity--they are all three parallel.

So, the trick is to either imagine or observe directly the plane of sharp focus where it passes by the camera. Then, aim the film back, the lens board, or a little of both to some common line along that focus plane.

Sometimes it's hard to visualize while looking through the ground glass. I was photographing some Japanese maple branches the other day, and couldn't seem to find the right tilt. So, I stood to one side of the camera, and in my mind's eye extended the plane that passed through the points I wanted in focus underneath the camera. When I did that, I realized that I had not tilted the lens nearly enough for the lens board and the film back to point to a common line along that plane.

Start with the floor of your living room, using your camera. Focus on a spot about 8 feet away to get the basic separation between the lens and film. Viewing it from one side, tilt the front lens down until the lens board and film back point to the same spot on the floor and refocus, and observe how the floor is now in focus along its whole length. You may have to go back and forth between focusing and moving to one side and looking at where the lens board and film back are aiming at. Then, straighten the lens and tilt the film back rearward (or up) until it points to the same spot on the floor that the lens is pointing to, and after refocusing you'll see that the floor is again focused along its length. We all had to do this before the concept really became clear to us.

Rick "oh, and start with your longest lens to exaggerate the angles" Denney

[Greg Lockrey]

...what Denney said.

[Nathan Potter]

Ricks' exercise with the floor will be most instructive. I used a level roadway extending into the distance to do the same thing. Essentially a line extending the tilt of the front and rear standards needs to meet at the road surface no matter what the tilt angles of the standards are. Note that as the camera is moved closer to the roadway surface the degree of tilt becomes extreme in order to have the extension lines still meet at the roadway surface. If the extension lines meet above or below the roadway surface then the plane of critical focus is above or below the roadway surface but still parallel to it. If the camera is tilted off horizontal then the plane of critical focus is at an angle to the roadway.

Properly speaking it is the rear nodal principal plane that when extended needs to meet the film extended plane to satisfy the Scheimpflug condition. Note that any subjects that project out of the Scheimpflug plane with not be in critical focus.

Nate Potter, Austin TX.

[Clement Apffel]

some nice comments and exercises so far.

I'll just add a youtube demo about getting the plane of focus along the side of a box :

http://www.youtube.com/watch?v=gR4m70xr9mE

A very practical way to get scheimpflug working.
It could help you both to understand it and to make it happen.

regards,
CA

[jwaddison]

A very instructive thread, thank you all! I've never seen it explained so well by so many. Thanks to the OP as well for asking.

[Bob Salomon]

If you do the movements on the back you will change the subjects shape. For instance, if you tilt the camera up to capture a large building the vertical lines will converge (keystone) By tilting the back so it is parallel to the building you will correct the convergence. Tilting or swinging the front does not change the shape of the subject.

Scheimpflug can be done on either the back or the front standard, or both standards.

[Thom Bennett]

Once you understand Scheimpflug there is an quick, easy way to use it:

Determine the nearest and farthest points you want in focus.
Focus on the farthest point you want in focus.
Tilt, in the direction of the plane you want in focus, until the farthest point and the nearest point are both EQUALLY OUT OF FOCUS. (Sounds counterintuitive until you see it on the ground glass.)
Refocus until both pop into focus.
Once you do it a few times it becomes a very quick and visual way of establishing Scheimpflug.
Try it and let us know what you think.
Practice it on something like a newspaper laying on a table. That will give you easily discernible points to work with.

[Clement Apffel]

Once you understand Scheimpflug there is an quick, easy way to use it:

Determine the nearest and farthest points you want in focus.
Focus on the farthest point you want in focus.
Tilt, in the direction of the plane you want in focus, until the farthest point and the nearest point are both EQUALLY OUT OF FOCUS. (Sounds counterintuitive until you see it on the ground glass.)
Refocus until both pop into focus.
Once you do it a few times it becomes a very quick and visual way of establishing Scheimpflug.
Try it and let us know what you think.
Practice it on something like a newspaper laying on a table. That will give you easily discernible points to work with.

Never heard of that technique before.
sounds like a quick & easy one.
thanks for sharing.

I'll try it at my next outing.

[Alan Davenport]

I'll add another recommendation to look over Harold Merklinger's web pages.
http://www.trenholm.org/hmmerk/HMbook18.html has several movie links that demonstrate what happens when you use the various tilts available. Merklinger's explanations were what led me to the "Aha!" moment when I got the view camera bug.

[Chris Strobel]

Yes!
Just look at the ground glass. If it looks good shoot it. Sometimes I think we make this stuff way harder than it needs to be.

Cheers,
Mark

Lol!Yeah I never have understood the formula with all that math looking stuff.Guess my IQ just ain't high enough :confused: .I personally just move things around till they are in focus :o

http://farm4.static.flickr.com/3305/3484272473_1b2f1fbfd6_o.jpg

[Ron Marshall]

The only person ever able to clarify the Scheimpflug Rule was Scheimpflug.

[Drew Bedo]

"The ground glass is truth"

[ki6mf]

Read the suggested posts. Keep in mind that tall fore ground objects often are out of focus because the plane/angle of focus nearest the camera is tilted. This tilt means the focus moves off of vertical and a tall object that sticks up through this plane of focus will be out of focus. Its best to use Scheimpflug with tall objects in the background and lots of open space in the immediate fore ground.

[Mark Stahlke]

Lol!Yeah I never have understood the formula with all that math looking stuff.Guess my IQ just ain't high enough :confused: .I personally just move things around till they are in focus :o

http://farm4.static.flickr.com/3305/3484272473_1b2f1fbfd6_o.jpg

WOW! That's a beauty Chris. Keep doing what you're doing. It works.

Cheers,
Mark

[bobwysiwyg]

some nice comments and exercises so far.

I'll just add a youtube demo about getting the plane of focus along the side of a box :

http://www.youtube.com/watch?v=gR4m70xr9mE

A very practical way to get scheimpflug working.
It could help you both to understand it and to make it happen.

regards,
CA

I'm going back through all these explanations and examples, thank all. Just finished this one and it makes more sense to me now.