1. ## Easy-Bake Scheimpflug Recipe

Easy-Bake Scheimpflug Recipe

Do you want to use tilts and swings on your large format camera to change the plane of focus? Of course you do, but you’re not a professional “chef” who’s been doing this for years.
Pro chefs don’t need instructions, since they do it all by “feel”, but that doesn’t work for the all the jr apprentices out there. Here’s some basic instructions for all yous’ jr apprentices who want to graduate from “clumsy Luigi” status. Best of all, you can do this from your own home without fear of embarrassment or social ostracism.

Ingredients:

1) A view camera with tilt and swing angle scales on the front standard. The scales should be marked in 2 degree increments, or smaller (the smaller the better).
Substitutions: If your camera doesn’t have a scale to show the actual tilt or swing angle, you could use a protractor, but it makes thing much more difficult, and is probably not worth the trouble.

2) The view camera should have some sort of focus scale for the rear standard. Any sort of scale that shows focus change in mm should work well.
Substitutions: If your camera doesn’t have a focus scale, you could easily jury-rig one with a piece of masking tape marked in mm.

3) A ground glass with grid markings, preferably in 1cm squares.
Substitutions: Any sort of grid system should work, but it’s easier to do the calculations if the grid is metric, and in squares.

4) Any cheap scientific calculator or cell phone calculator app that has the arctan function. (Often shown as tan-1 on calculators)
Substitutions: You could tabulate potential results on a piece of paper, so you could carry that in your pocket instead of an electronic calculator.

5) Something to record notes with. A pad and pen works great (pencil works too). Anything that you like to keep a record of values to enter into the calculator.
Substitutions: If you have a very good memory, that could potentially work too (but I wouldn’t know).

Baking Instructions for Lens Tilt:

1) Compose your scene on the ground glass, and decide if you’d like to change the plane of focus by tilting the lensboard. If you decided that a lens tilt would be beneficial, then proceed to step two.

2) Choose two features in your scene that you would like to be in focus. One of these should be nearer to the camera, and the other further away. Focus one of these features on the ground glass using the rear standard focus knob. Record the reading of the rear standard focus position in your notepad.

3) Focus on the other feature, also using the rear standard focus knob. Record the reading of the rear standard focus position for that one in your notepad too.

4) You should now have two focus position readings in your notepad. The difference between these two readings will probably only be a few mm. It’s that difference between readings that we need to use.
It’s basically the amount of focus shift at the ground glass when you focused each feature. We’ll call that focus difference “FD”, since it represents the displacement of the film plane between the two focused positions.

5) Next, we need to measure the vertical distance between the two features on the ground glass. This can easily be done by counting grid squares on the ground glass. If one feature is 5 squares above the other one, then the vertical distance on the ground glass will be 50mm, if each grid square is 1cm (10mm). You can also estimate ½ squares and ¼ squares to get 5mm and 2.5mm. We’ll call that the ground glass vertical distance “GGVD”, since it represents the vertical height difference between the two features on the ground glass. Write the “GGVD” value in your notepad.

6) The front tilt angle can now be calculated using the “FD” and “GGVD” measurements. The front tilt angle = arctan(FD/GGVD). Plug that into your calculator. The result will be the front tilt angle in degrees.

7) Tilt the front standard to the result calculated in step 6. You need to have a tilt angle scale on the front standard in order to do this with any accuracy.

8) Once the front tilt angle is set and locked, go back to the ground glass and refocus on one of the features. If you check the other feature, they should now both be in focus (or very close).

Baking Instructions for Lens Swing:

1) Compose your scene on the ground glass, and decide if you’d like to change the plane of focus by swinging the lensboard. If you decided that a lens swing would be beneficial, then proceed to step two.

2) Steps 2 thru 4 are the same as for lens tilt, so see above.

5) Next, we need to measure the horizontal distance between the two features on the ground glass. This can easily be done by counting grid squares on the ground glass. If one feature is 5 squares to the right of other one, then the horizontal distance on the ground glass will be 50mm, if each grid square is 1cm (10mm). You can also estimate ½ squares and ¼ squares to get 5mm and 2.5mm. We’ll call that ground glass width distance “GGWD”, since it represents the horizontal width between the two features on the ground glass. Write the “GGWD” value in your notepad.

6) The front swing angle can now be calculated using the “FD” and “GGWD” measurements. The front swing angle = arctan(FD/GGWD). Plug that into your calculator. The result will be the front swing angle in degrees.

7) Swing the front standard to the result calculated in step 6. You need to have a swing angle scale on the front standard in order to do this with any accuracy.

8) Once the front swing angle is set and locked, go back to the ground glass and refocus on one of the features. If you check the other feature, they should now both be in focus (or very close).

2. ## Re: Easy-Bake Scheimpflug Recipe

The customers left the restraunt because the new chef forgot his calculator and the food was out of focus.

Thanks for writing that up. I'll keep to doing everything on the GG as usual, where I generally judge focus, movements, and aperture needs by when both near and far points come into focus on the GG at the same, or close to the same, time. In low light situations, I do find it handy to move a standard halfway between the FD and have a solid starting point.

3. ## Re: Easy-Bake Scheimpflug Recipe

.... a little background.

This came out of a discussion about the Sinar f2 over at Photrio. The poster was asking about one of the scaled knobs on the left side of the camera at the back. He was asking what it was for.
I didn't know either, so I looked it up. It turns out it's a tilt angle scale for focus adjustment, but I had no idea how this could work on a Sinar f2. The Sinar f2 has basic base tilts, and not the fancy in-frame asymmetrical tilt of the P series. It didn't seem to me that it would be possible to determine tilt angle on an f2.

I found a description for use of the tilt angle knob for the f2 (also f1, but not f), also on Photrio. When I read through the description it became immediately clear how it worked, and that the basic principle could also be useful for other cameras. With the Sinar f2, there are horizontal marked lines on the ground glass 35mm above and below the center line. There are also vertical marked lines 35mm to the left and right of the vertical center line. On the P series, these lines represent the asymmetrical tilt or swing axis (depending on orientation). These same lines can be used on the f series using completely different methodology to determine tilt or swing angle.

The Sinar lads were very smart, so they deserve all the credit for this. By focusing the back at two different points on the upper and lower marked lines, they could create a right angled triangle with the focus displacement as one leg, and the vertical ground glass displacement as the other leg. The angle of the resulting hypotenuse is the required back tilt angle. It's just simple high school trigonometry.
Since the vertical displacement on the ground glass is already fixed at 70mm, the only unknown is the focus displacement. Since the focus displacement is proportional to the rotation of the focusing knob, they only needed to put angle scale markings on a secondary knob that rotates with the focus knob. There is no need for a separate calculation.

The big downside of the Sinar system is that your two focus points have to reside on the marked lines. That's probably not going to be practical for many shots, since there may not be convenient points to focus on along those marked lines.

Nonetheless, it is indeed ingenious for Sinar to come up with this system, since it was an easy add to the f series, and would make use of the marked lines already on the ground glass for the Sinar P.

The method I'm using here is just an adaptation of this Sinar approach, but can be used with any camera with any two points on the ground glass. You're not limited to points along a marked line, but you will need a calculator to compute the tilt angle.

4. ## Re: Easy-Bake Scheimpflug Recipe

Originally Posted by Vaughn
The customers left the restraunt because the new chef forgot his calculator and the food was out of focus.

Thanks for writing that up. I'll keep to doing everything on the GG as usual, where I generally judge focus, movements, and aperture needs by when both near and far points come into focus on the GG at the same, or close to the same, time. In low light situations, I do find it handy to move a standard halfway between the FD and have a solid starting point.
You're right, it's the McDonald's approach, not the Maison Lameloise.

5. ## Re: Easy-Bake Scheimpflug Recipe

sharktooth,

I'm sure your method will work flawlessly. And I'm sure I'll never, ever bother using it. In real-world practice, you don't need to calculate a thing to apply the proper amount of tilt or swing, using either standard or even both.

Really, all you need is steps 2 and 8 in your baking instructions at a bit of patience. Here's my "recipe" for applying tilts:

1. Choose a near and a far point that you want to be in the plane of sharp focus. Focus on the far point (bottom of the ground glass).

2a. If you have axis tilts, make sure one of your focus points lies on the tilt axis. Then simply tilt while watching the other focus point with your loupe (remember, tilt the front forward or the back backward to bring a nearer point into focus). Stop when the second point is in sharp focus. If you've done this right, your first point should still be in sharp focus too. Et voilą, tilt has been applied. If the first point is not quite sharp, then repeat the process and refine focus till both points are sharp. Note that this same method works for asymmetrical tilts on either standard as long as you get one of your focus points on the tilt axis, be it center or off-center. And, if your focus points don't lie on an axis, don't despair, just use step 2b instead.

2b. If you have base tilts, e.g., on a folding field camera (or if one of your focus points doesn't conveniently lie on an axis line), then carefully tilt, while watching the ground glass without the loupe. Stop when both points look equally out of focus. Refocus the first point and repeat. After a couple of iterations, use the loupe to make final refinements. For me, it usually takes three iterations to get both points in sharp focus. Et voilą, tilt has been applied.

Swings on any view camera I've worked with are axis swings, front and back, so steps 1 and 2a are all that are needed to apply swings, just 90° transposed.

The real challenge when using swings and tilts is choosing where you want the plane of sharp focus to lie in the scene to optimize the depth of field you desire. Once the position of the plane of sharp focus has been decided upon, then choosing a couple of focus points and a couple of steps tilting are all you need.

Not to be a wet blanket and pour water on the more mathematical approach, but I don't think I'd ever do any such calculations in the field.

Best,

Doremus

6. ## Re: Easy-Bake Scheimpflug Recipe

This one is simpler than Easy Bake but may take longer:

Focus on the far,
And tilt toward the near,
Then fiddle with the camera,
Until everything is clear.

7. ## Re: Easy-Bake Scheimpflug Recipe

Chef Boyardee!

8. ## Re: Easy-Bake Scheimpflug Recipe

very good. thanks for sharing. when presented in its simplest form, it makes sense.

9. ## Re: Easy-Bake Scheimpflug Recipe

Originally Posted by Paul Ron
very good. thanks for sharing. when presented in its simplest form, it makes sense.
Thanks, man. Admittedly, this approach has limited practical application, but it's still interesting to discover that you can actually "calculate" the tilt angle, without physically tilting anything.

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