Excel help with Scheimpflug
Does anybody know of a excel application (or has written) to help calculate the Scheimpflug rule? I don't know enough about excel, however I guess it could be done. Enter the required information and the angle and focus distance would be given. Any nerds who can help??? We could then run it on our PALM with BTZS software and have almost everything.
Large format Pat
The Scheimpflug principle is far easier to use in practice than it is to read & write about, and you can set a camera up quickly in about 30 seconds with very little practice & experience.
Harold Merklinger's book "focussing the view camera" does not make exactly an easy read, but was immensely helpful to me. It specifies in addition to the Scheimpflug rule the "hinge rule" which broadly states that, film standart vertical, at a given focal lens the tilt angle of the lens determines at which distance the plane of sharp focuss passes under the camera (or over it, if you tilt upwards), and the focus determines the angle of the focal plane.
There are tables included, but I found that, after some practice, just knowing the principle itself carries you a long way, the Scheimpflug rule itself alone being very inexact.
Rule # 1: start slowly, about 2 degrees
Rule # 2: apply in small steps
Rule # 3: repeat if nescesary
Rule # 4: don't start at 15 degrees
Rule # 5: every lens reacts diferetly
Rule # 6: wide angles need less
Rule # 7: long lenses need more
Rule # 5: start practising
Sorry, I am no wizzard in Exel, but hopefully it helps
Originally Posted by largeformat pat
Large format Pat;
The "hinge rule" is easy to understand and use in practice. With a monorail view camera a simple rule is: "focus on the near and tilt toward the far", but I can also do that in reverse. The rear standard movements are normally used for correcting distortion. The rule is the same for vertical and horizontal swings - the 3 plains should converge at some imaginary point (plain of sharp focus; front standard; rear standard) - and should be performed as separate operations, one before the other, or you'll get lost in the process and end up staring over. Lens center-line pivots, or tilts (monorail design), and base pivots (flatbed design) give you slightly different results.
There will always be some tweaking of the movements as you work, especially the final focusing. Thats how I do it. Methods can vary. I can do the operations faster and easier than I can explain them. You must practice with the camera - it's easier to learned by doing it - reading rules and doing calculations is for the nerds (your word) who like being technical about how it should be done.
I just had my coffee and felt like babbling about something. You probably know all this already, so I didn't really answer your specific question. Sorry!
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I made a spreadsheet many years ago based on Harold Merklinger´s articles. It is long time ago and I have forgotten much of the mathematics behind. It is located over at the LF-forum and is still there for you to download:
Originally Posted by largeformat pat
Get a Sinar P (or P2), and it is much quicker. Doesn't even require practising.
Originally Posted by archphoto
Step 1 focus the bottom marker-line on the screen
Step 2 tilt until the top marker line is in focus too.
It would probably be interesting to have this in a spreadsheet of some kind but, to me, the best Scheimpflug lesson I ever learned was Steve Simmons' method. Once the scene is composed, focus on the farthest point you want in focus. Then tilt (or swing) in the direction of the close focus point until both the far and the near points are EQUALLY out of focus. (It sounds like such an oddball thing until you actually see it on the ground glass). Lock that tilt/swing down and, as you refocus, both points pop into tight focus. It is so quick to do once you practice it a few times that all of the hocus-pocus about focus goes away. I use this all the time with center tilt/swing. Not sure about using it with base tilt. Also, you will be surprised at how little tilt/swing you need at times. I very rarely go over 5 degrees. What gets interesting is when you start combining a tilt with a swing and utilizing the depth of field area. Even complicated table-top setups only take about 10 minutes. Have fun!
The really interesting bit begins when you transfer the tilt from the rear to the front standard.
There's even more fun when not all of it has to go to the front.