View camera Focusing Front Tilt

[thecatt]

Is it possible to use front tilt and obtain sharp focus with a scene that has a tall tree or object in the middle of
the scene? Or with tall objects in the scene in general? I have no problems with scenes that are semi flat or an object in
the front of the scene and objects that are far in the back ground but the tall trees are throwing me off. How can
I obtain sharp focus all the way through?

Thanks

 

[Sirius Glass]

Welcome to APUG

Instead of tilts, have you tried to use rise only?

 

[ic-racer]

Front tilt moves the plane of focus so it is no longer parallel with the film. The focal plane remains a plane.

 

[Alan9940]

IMO it's possible, but many factors are involved and a lot depends on your definition of sharp focus. The best advice I could give, in general, is to have the top of the tree and something near the ground in the distance at about the same defocus/out of focus/fuzziness whatever you want to call it. Then, watch the GG carefully as you stop down the lens. If you get near or at the smallest aperture and everything is still not in acceptable focus, then open the lens back up, re-position the focus point, and try again. It's a trial-n-error type thing and, depending out subject specifics, may not be possible.

Good luck!

 

[RobC]

my bet is that a tall tree in the middle of the scene will be far enough away to be well inside the hyperfocal range. A small bit of tilt will most likely not affect the top of the tree.

Yes its possible to optimise the image with both tilt and rise or fall. BUT only wihin limits. This is where you really need to understand 100% about your camera and how far you can take the adjustments. Rodenstock used to produce a handy little pocket dial to DO all the calculations and measure the distances and angles. Not sure if you can still get them, I'll have a look online.

yes found it: http://www.bhphotovideo.com/c/product/155145-REG/Rodenstock_260700_Depth_of_Field_Calculator.html#!

Note: This provides a lot more than standard DoF. It gives DoF according to angle and tilt.

Also note that this gizmo will get you close but you must verify everything on the GG. This is where it gets difficult becasue you need to do it at taking aperture and not wide open to see if its correct. Fact is that its damn near impossible to see the GG well enough at at taking aperture to verify it. That means you need to be 100% totally obsessive perfectionist to get it to work reliably. You need to be truly expert otherwise just don't use tilt in this situation and trust to normal hyperfocal range.
And if you want your clouds in sky sharp then forget any tilt at all.

LF doesn't look like quite the panacea everyone thinks it will be now, does it.

 

[Sirius Glass]

Using the Scheimpflug principle can require both the front and rear standards to be tilted.

 

[David A. Goldfarb]

Generally, this is the kind of situation where you'll want to use no tilt and stop down to get the desired amount of depth of field.

 

[Grif]

Other than focus, what's the front tilt for?

 

[David A. Goldfarb]

Other than focus, what's the front tilt for?

You can also use it for indirect rise or fall by tilting the front and rear standards in parallel.

Most people use rear tilts to change the shape of objects in the frame, but sometimes that also requires a compensatory front tilt to keep everything in focus.

If you have a camera that only has front tilt (or an SLR with a T/S lens), but you want to execute a rear tilt, another option is to tilt the camera and then tilt the front standard back to plumb. Typically this also requires rise/fall for reframing.

 

[RobC]

Other than focus, what's the front tilt for?

Introducing aberrations. Most LF photographers seem to ignore the fact that lenses are designed to project onto a flat field from a perpendicular lens. When the lens is not perpendicular the circles of confusion become ellipsoid in shape. i.e. they are no longer circular and they cover more area than when lens is perpendicular. And if you have swing as well then that makes it worse. These introduced aberrations degrade image resolution. So there is a trade off between DoF and loss of resolution too.

All these little things add up to the point where 4x5 is only marginally better than MF. And thats only if you get your adjustments perfect.

 

[wiltw]

Front tilt moves the plane of focus so it is no longer parallel with the film. The focal plane remains a plane.

Sorta...the Scheimpflug Principle makes DOF zone a trapezoidal shape, with the projected apex at the same point as the intersection of the focus plane w/ lens board plane with film plane. See illustration.

The DOF zone does lay over so that it includes more distance along the ground, but it also cuts off the tops of some trees noticeably (what was in the black box falls outside the blue box).

I will be the first to admit this is not technically 100% correct, but it is intended only the illustrate some of the principle of tilted lens DOF

 

[RobC]

the problem with illustrations not being drawn to scale is that they can lead to a lot of mis-understanding. The Dof either side of a tall tree is likely much larger than your illustration shows. You might know that and I might know it but anyone just learning LF probably won't.
If you put DoF from half way between camera and tree to same distance behind tree it puts a completely different complection on what will and won't work.
If you've learnt how scheimpflug works properly you can tilt and get tree top in focus but it depends on a lot of variables.
The rodenstock gizmo takes it all into account once you get your head around how to use it. Well worth getting one if you're going to take your LF seriously.

 

[ic-racer]

Other than focus, what's the front tilt for?

Be glad it only does one thing. Unlike rear tilt.

 

[thecatt]

I thank everyone for their quick responses. I have a Toyo 45cf. Only front movements and no DOF scale. So hyperfocus is a bit tricky.

 

[wiltw]

the problem with illustrations not being drawn to scale is that they can lead to a lot of mis-understanding. The Dof either side of a tall tree is likely much larger than your illustration shows. You might know that and I might know it but anyone just learning LF probably won't.
If you put DoF from half way between camera and tree to same distance behind tree it puts a completely different complection on what will and won't work.
If you've learnt how scheimpflug works properly you can tilt and get tree top in focus but it depends on a lot of variables.
The rodenstock gizmo takes it all into account once you get your head around how to use it. Well worth getting one if you're going to take your LF seriously.

I made no suppositions about shooting aperture, nor the use of Hyperfocal distance. DOF just might have been quite shallow, if the lens was not stopped down a lot, and my primary plane of focus was on a subject standing the opening between trees 2 & 3 (as depicted by the DOF zone placement with the untilted lens standard). And I quickly threw together the illustration, to illustrate a concept of DOF zone on a tilted lens -- but not to illustrate an educational tome, where 100% accuracy is important!

 

[Doremus Scudder]

Wilt's graphic above, while not to scale (as Rob points out) does give you the basic idea. As you move the plane of focus from parallel to the standards to tilted from front-to-back in the scene, the DoF moves with it. And, as we all know, DoF is shallower closer to the camera than farther from it, so the shape of the zone of acceptable sharpness becomes trapezoidal.

In you scene, with a tall tree or other vertical object in the center, using front tilt risks leaving the top or the bottom of the tree outside the zone of acceptable focus.

That said, a smidgen of tilt can often be used, especially if you have a long stretch of flat foreground. The good thing is, you can check this. Just check the focus spread between the nearest and farthest points you want to keep in focus. The trick is, you have to kind of know where the plane of focus is in the scene after you apply the tilt! Referring to Wilt's graphic, you can get the idea that you will have to check points at ground level by the tree bases and the treetop as well.

What I do in situations like this is set up the camera with movements at zero. I then pick my focus points and check the focus spread. I'll then apply a bit of tilt and search around with the loupe while focusing to fine the two points that have the greatest focus spread. These will NOT be the same points as with the movements at zero. Keep in mind you have to look above and below the plane of focus when using tilt and that the DoF will be shallower close to the camera. Near tall objects, bases of distant mountains, etc. are examples of things that are now farthest from the plane of focus. After you find your two focus points, compare the focus spread to that with the movements at zero. If it is smaller, then the tilt has helped, if larger, then not.

Hope this helps,

Doremus

 

[RobC]

But do you do that at taking aperture or wide open becasue the result will be different. Taking aperture will be the correct one but at taking aperture you'll be very lucky to have enough light on GG to see what is and isn't in focus. However, if you check the focus spread with aperture wide open you will leave yourself a wide margin of error when you close down to taking aperture.
But in a tricky subject where accuracy is critical you may well need the focus spread at taking aperture but you can't see on GG cos its too dark.
LF is difficult to get right without being an obsessive perfectionist. Just a warning to OP.

 

[RobC]

I made no suppositions about shooting aperture, nor the use of Hyperfocal distance. DOF just might have been quite shallow, if the lens was not stopped down a lot, and my primary plane of focus was on a subject standing the opening between trees 2 & 3 (as depicted by the DOF zone placement with the untilted lens standard). And I quickly threw together the illustration, to illustrate a concept of DOF zone on a tilted lens -- but not to illustrate an educational tome, where 100% accuracy is important!

I realise that, it wasn't meant to be a criticism. I was just alerting OP to fact that one has to be very careful when looking at illustrative diagrams when you have no idea whether it's drawn to scale and what the all the parameters are.
I would however say that DoF isn't ever likely to be as shallow as your diagram shows for a tall tree and the distances involved in getting the whole tree in view and the probable taking aperture.

Once again for the benefit of the OP, get the Rodenstock DoF calculator I gave a link to. It has a full set of instructions and allows to work out required aperture with correct DoF for the tilt angle you are using. It's a very good learning tool to get your head around what is happening when put in tilts of back and front. They are a bit pricey though but best you can get I think unless someone knows of an app which does it for you.

 

[Maris]

Is it possible to use front tilt and obtain sharp focus with a scene that has a tall tree or object in the middle of
the scene? ......

I do a lot of landscape work with view cameras and this challenge comes up all the time. To get front to back and top to bottom sharpness use focus and tilt to get things along the top of the ground glass (the foreground) sharp as well as placing the plane of focus halfway up the important tall tree. Because optical law hasn't been repealed there is only one thing more that you can do; stop the lens down. As you reduce the aperture the plane of focus thickens equally above and below the original plane. It becomes a wedge shaped "slab" of focus still relatively thin near the camera but much thicker further back. Eventually as you stop down while watching the tree image on the ground glass this "slab" becomes so thick that it catches the top of the tree at the same time as it catches the bottom of the tree. The ground glass will be dark at small apertures but often the top branches of the tree are against a bright sky and can be inspected with a good loupe even at the tiny apertures you might have to use. Good luck!

 

[RalphLambrecht]

Is it possible to use front tilt and obtain sharp focus with a scene that has a tall tree or object in the middle of
the scene? Or with tall objects in the scene in general? I have no problems with scenes that are semi flat or an object in
the front of the scene and objects that are far in the back ground but the tall trees are throwing me off. How can
I obtain sharp focus all the way through?

Thanks

when you stop down a lens you are extending DOF front to rear;with tilted lfront lenses DOF extends as an enlarged angle from the central axis and therefore extends up and down

 

[Doremus Scudder]

But do you do that at taking aperture or wide open becasue the result will be different. Taking aperture will be the correct one but at taking aperture you'll be very lucky to have enough light on GG to see what is and isn't in focus. However, if you check the focus spread with aperture wide open you will leave yourself a wide margin of error when you close down to taking aperture.
But in a tricky subject where accuracy is critical you may well need the focus spread at taking aperture but you can't see on GG cos its too dark.
LF is difficult to get right without being an obsessive perfectionist. Just a warning to OP.

Rob,

Check focus spread with the aperture wide open. Then determine the optimum taking aperture based on the focus spread. I use the method described here: http://www.largeformatphotography.info/fstop.html and focus as described here: http://www.largeformatphotography.info/how-to-focus.html.

However, the OP was just looking to find out if tilt might help. If tilting results in a smaller focus spread (wide open), then it has helped, if not, then it hasn't; that's all there is to it.

Deciding what aperture to take at is a different issue entirely. Many stop down and check their focus points, some "stop down till everything is sharp and then stop down one more stop," etc. I don't even bother to check the ground glass after finding my focus spread and setting my focus halfway between. I simply consult the chart I've made for the optimum f-stop for focus spread and stop down to that. There isn't a "wide margin of error" at all; it is very precise. I rarely (very, very rarely) miss the DoF I'm shooting for, and then only in extreme cases (e.g., foreground 6 inches from the camera and a scene to infinity).

Back to the original topic for one more comment: studying what movements do with an eye to how they move the plane of sharp focus around in front of the camera (and not just what happens on the ground glass) is extremely helpful in determining how to apply movements in the field. I usually picture where the plane of focus should be placed in a scene to get optimum DoF before I set up the camera. By then, I have a good idea of what movement(s) need to be applied. Trickiest, of course, are scenes with lots of near/far and lots of close verticals that extend up into the top half of the scene and close objects with distant ones behind them. Sometimes simply stopping down a lot is the best solution, but often, the focus-spread test shows that a skosh of tilt and/or swing helps, and allows one to use a larger (more optimum) aperture.

Best,

Doremus

 

[RobC]

Rob,

Check focus spread with the aperture wide open. Then determine the optimum taking aperture based on the focus spread. I use the method described here: http://www.largeformatphotography.info/fstop.html and focus as described here: http://www.largeformatphotography.info/how-to-focus.html.

However, the OP was just looking to find out if tilt might help. If tilting results in a smaller focus spread (wide open), then it has helped, if not, then it hasn't; that's all there is to it.

Deciding what aperture to take at is a different issue entirely. Many stop down and check their focus points, some "stop down till everything is sharp and then stop down one more stop," etc. I don't even bother to check the ground glass after finding my focus spread and setting my focus halfway between. I simply consult the chart I've made for the optimum f-stop for focus spread and stop down to that. There isn't a "wide margin of error" at all; it is very precise. I rarely (very, very rarely) miss the DoF I'm shooting for, and then only in extreme cases (e.g., foreground 6 inches from the camera and a scene to infinity).

Back to the original topic for one more comment: studying what movements do with an eye to how they move the plane of sharp focus around in front of the camera (and not just what happens on the ground glass) is extremely helpful in determining how to apply movements in the field. I usually picture where the plane of focus should be placed in a scene to get optimum DoF before I set up the camera. By then, I have a good idea of what movement(s) need to be applied. Trickiest, of course, are scenes with lots of near/far and lots of close verticals that extend up into the top half of the scene and close objects with distant ones behind them. Sometimes simply stopping down a lot is the best solution, but often, the focus-spread test shows that a skosh of tilt and/or swing helps, and allows one to use a larger (more optimum) aperture.

Best,

Doremus

Yes, apologies I got that focus spread wrong. I was thinking of DoF near and far spread. I stopped doing LF quite a few years ago and have got a little bokeh on the subject.

 

[Tom Taylor]

Try this:

1. Using rise/fall and back placement (vertical or horizontal), find the composition that is pleasing. The Toyo 45CF is a center tilt camera, so,
2. Focus on the foreground that you want sharp.
3. Using front tilt, focus on the far background that you want sharp.
4. Redo steps 2 and 3 above until both the foreground and the distant background objects are in sharp focus simultaneously.
5. Stop down until everything in the mid ground are in sharp focus.

Thomas