I was wondering if there is any DOF charts that can apply to a lens when it has a tilt applied ?

I've got some really handy charts on how much tilt to apply to get everything on the plane of focus sharp at a given subject to camera distance, but that obviously only applies to a flat plane.

In other words, I can tilt the lens downwards and get everything on the ground, which would be my plane of focus sharp from very close the camera to infinity but if there is a tall tree sticking up, the top of it might go soft because its out of the plane of focus.

Stopped down of course helps widen the area that falls into that plane of focus, and the more distant an object is, the more likely it is to fall into the plane, but I was wondering if there is some sort of chart or table that list this info ?

So that if I want lets say a 1 foot plant 2 feet from the camera, and also a 15 foot tree 60 feet from the camera and a 15,000 foot mountain 3 miles from the camera all to be sharp, how much I need to stop down, in addition to how much tilt I need to apply, which is already known.

I don't know if anyone has ever made one. The tall thing close by sticking up has always been the bane of view camera shooters whether it was a landscape, or studio tabletop. It used to be experience that told you to under correct and favor the tree. But with digital capture, it is easy to do what is known as 'focus stacking' and make two exposures focused accordingly and layer together in post. Trying to stop down to f22 to 'get it all sharp' usually results in too much diffraction, and then nothing looks good.

jjlphoto wrote:
I don't know if anyone has ever made one. The tall thing close by sticking up has always been the bane of view camera shooters whether it was a landscape, or studio tabletop. It used to be experience that told you to under correct and favor the tree. But with digital capture, it is easy to do what is known as 'focus stacking' and make two exposures focused accordingly and layer together in post. Trying to stop down to f22 to 'get it all sharp' usually results in too much diffraction, and then nothing looks good.


I've experimented a bit with Helicon Focus but fit it sort of hit or miss in its results even under calm conditions. When its windy and things are blowing it really has problems. Its a nice alternative for some scenes though and for something like the southwest desert where objects dont really blow I think it could work great.


I've been trying to learn a bit through trial and error but its still proving tough to figure out what taller objects are or aren't going to work in a given composition when you factor in the tilt

It sort of is a double edged sword as its awesome to solve one problem but can compound another

i have such problems figuring out how much tilt I need to get what in focus....

kodakeos wrote:
i have such problems figuring out how much tilt I need to get what in focus....

Practice, practice, practice. For those of us from view camera backgrounds, it is second nature as we were trained on focusing a large 4x5 ground glass under a dark cloth. I agree that trying to learn "Scheimpfluging" on a small 35mm viewfinder would be frustrating.

I made an Excel spreadsheet, LensTScalc, that uses the Hinge Rule (derived by Scheimpflug, see "About FOCUSING the VIEW CAMERA", http://www.trenholm.org/hmmerk/) to calculate how much tilt I need to get the horizontal ground plane in focus, as a function of focal length and height of the camera above the ground. It generally works pretty well. Note that it doesn't explicitly account for DOF variation as a function of distance from the camera.

Here's a few example images from some lens comparison tests I did recently with tilt on my Mirex M645 to EOS adapter, to help decide which of several M645 lenses I should sell. I first used the T-S spreadsheet to figure out how much tilt I should use (about 3 deg for an 80mm lens on a 1.64m tall tripod), and then dial it in on my Mirex. I didn't account for a small reduction in tilt due to the lens axis pointing down at about 30 degrees, but I was shooting at f/8, and so there was sufficient DOF. For shooting landscapes with tilt, I use the spreadsheet to get started, and then follow 'standard' LF focus techniques to focus for near and tilt for far, as it usually needs some tweaking.

The first image is the full image with an 80mm lens. The second image shows two 100% crops from the very top of the frame; on the left is f/8 with 0 deg tilt; on the right is f/8 with 3 deg tilt (from LensTScalc); both taken with M645 C 80/2.8N on 5D, 1/6 sec, ISO 400, MLU, tripod, etc. The third image shows basically the same top crop for the M645 A 150/2.8 lens; 0 deg tilt on left and 5 deg tilt on right. No sharpening, yes auto-contrast.

You can get a copy of LensTScalc at http://www.jcolwell.ca/photography/calc-info/

Remember, you get what you pay for.

millsart wrote:
I was wondering if there is any DOF charts that can apply to a lens when it has a tilt applied ?


Cambridge in Colour has a good tilt DOF tool: http://www.cambridgeincolour.com/tutorials/tilt-shift-lenses2.htm

Here's a good read with some useful charts:

http://www.luminous-landscape.com/tutorials/focusing-ts.shtml

Hope that's helpful.

Cheers!

akclimber,

The charts at the bottom of your link was very helpful insight

Thanks for all the info, Jim etal. I clearly need to keep the training wheels on my Mirex adapter. Used too much tilt and some vertical elements went OOF. I have seen both focus near and tilt for far and the converse written.
Jim has great chart for use of the Mamiya T-S bellows + mirex for macro. How does one choose where to tilt when using the bellows and the Mirex? I would think the framing would change less with one of the choices.

On the new 24 PC-E, I simply focus first on the closest element I want in focus, then move the Live View focus point to the rear-most element, and tilt carefully until it is in focus, then recheck closest element, reframing and/or refocusing slightly as necessary.

Re. the LL article charts (which address degree of tilt required to get the ground in focus from near to far, plotted against height from lens to ground): if you look at them, you will see that the closest and furthest measurements span only 4'3" (1 degree) to 7" (8 degrees) with a 24mm TS lens, so overestimating tilt in landscape applications is common. The author claims that in these situations, knowing eye height (standing) and eye height (crouching) are key if hand-holding and this seems like very practical advice.

If on a tripod (my preferred way of working) the first method mentioned above works for landscapes as well as products. cheers, kl

Thanks KL,
Mike