How does rear tilt affect front tilt?

[Vaughn]

Starting with the camera zeroed, I'd find my spot 1/3 of the way into the scene, stop down until everything came into focus, check the aperture, close down another stop or two or three depending on the wind/exposure time and load the film up.

I'd use all my movements at the neutral/zeroed position.

[Kiwi7475]

Can we go over an actual focus scene? I believe I set the asymmetrical axis line on the top of the barn than tilted the back standard to focus the near fence. I then used f22 because of what other said they usually use.
How would you focus and tilt this one and figure the f stop in a better way?
Craig House 1 by Alan Klein, on Flickr

I don’t think this is a good image to apply movements since you have near vertical items in the foreground that expand the whole composition (fence). Tilting will compromise their sharpness (hard to say for sure without being “there” but that’s my suspicion). So all you can do is focus at the middle point between the near and far (or some intermediate point) and close the aperture until both near and end are in focus. If you measure the mm between far and near then multiply by 5 or 6 and you’ll get the fstop needed, as a rule of thumb.

[Doremus Scudder]

Alan,

You've posted a perfect example of a scene in which movements won't give you any advantage at all (except for maybe the slight bit of tilt that gets the low jutting post end and the top of the nearest post into focus, which probably wouldn't be much). The verticals in the foreground go all the way to the top of the frame. Any subbstantial tilt you apply will just throw the tops of the fenceposts out of focus. The fact that you got everything sharp and used tilts means you likely used a smaller f-stop that you would have had to with the camera in "zero" position.

Nice image, btw!

Best,

Doremus

[Alan Klein]

Alan,

You've posted a perfect example of a scene in which movements won't give you any advantage at all (except for maybe the slight bit of tilt that gets the low jutting post end and the top of the nearest post into focus, which probably wouldn't be much). The verticals in the foreground go all the way to the top of the frame. Any subbstantial tilt you apply will just throw the tops of the fenceposts out of focus. The fact that you got everything sharp and used tilts means you likely used a smaller f-stop that you would have had to with the camera in "zero" position.

Nice image, btw!

Best,

Doremus

I focused on the asymmetrical line on the far chimney. Then tilted the back standard to get the front part of the fence focused. I used f22. 75mm lens no CF Tmax 400. Why the top part of the fence is focused, I have no idea. But I understand your point. It could be that the reduced pixels and sharpening I did in post corrected it. Don't know.

[Alan Klein]

Here's a better one. No foreground trees or fences going up to the top. I think I set the far asymmetrical focus on either the clouds or the top of the barn. Then tilted the back standard to get the water pump in the front in best focus. Then set it for f22 because everyone seems to use it. 150mm. Tmax 100.

So how would you do the initial focus then do the DOF f stop focus adjustments?

Barn #1 by Alan Klein, on Flickr

[Alan Klein]

If you click on the picture, it will take you to FLickr where you can expand the photo and zoom in better.

[Vaughn]

I would level the camera, keep the front and back straight up, use rise/fall to frame image, focus on the front of the building and close down the lens until the pump and the clouds come into focus. If the pump is taking its sweet time coming into focus, I might bring the plane of focus a little closer. If that still does not work, I might try a slight front tilt -- that would throw the tree tops a little out of focus and bring the pump a little more into focus -- which closing down will hopefully counter.

Of course there is the wind -- how I focus is influenced by the wind. The more breeze, the shorter my exposure time might have to be -- which can determine my f/stop -- which can determine how I focus.

[Kiwi7475]

Here's a better one. No foreground trees or fences going up to the top. I think I set the far asymmetrical focus on either the clouds or the top of the barn. Then tilted the back standard to get the water pump in the front in best focus. Then set it for f22 because everyone seems to use it. 150mm. Tmax 100.

So how would you do the initial focus then do the DOF f stop focus adjustments?

Barn #1 by Alan Klein, on Flickr

My opinion, this can be focused without tilts quite easily and without giving up resolution due to lots of diffraction.
Really a tilt is best suited to a situation when there’s a clear tilt of the subject (like a close up photo of something in a slanted terrain, or an angled wall, etc) or when something falls within an angular wedge in front of you (say the ground in the near foreground and the distant mountains, or a rock in the water in the foreground with a somewhat distant waterfall, etc).

[Doremus Scudder]

Here's a better one. No foreground trees or fences going up to the top. I think I set the far asymmetrical focus on either the clouds or the top of the barn. Then tilted the back standard to get the water pump in the front in best focus. Then set it for f22 because everyone seems to use it. 150mm. Tmax 100.

So how would you do the initial focus then do the DOF f stop focus adjustments?

Barn #1 by Alan Klein, on Flickr

Well, here's what I would do (a bit different approach than Vaughn and Kiwi).

Since it's a building, I'd want the verticals parallel, so I'd set up the camera with the back level and check the verticals against the grid on my ground glass, adjusting the tripod tilt to get them right.

Then I'd use a little bit of front tilt, using the nearest point on the ground at the bottom of the frame as the near reference point and the nearest point on the barn roof (likely the lower edge of the roof) as my far reference point. This would tilt the plane of sharp focus just a bit. I've found that this tiny bit of tilt normally allows me to use a larger aperture than not using movements.

That focus position after the tilt was applied, i.e., with the ground at the bottom of the frame and the edge of the roof both in focus would then become my "near" focus point; I would note the position of the standards on the camera bed/rail.

Then I'd look for the farthest point from that plane to use as my "far" focus point. That would probably be where the ground meets the base of the tree line far left, or maybe the distant hill behind the trees. I'd check both of them, focus on whichever one was most distant and then note the position of the standards on my camera bed/rail (I have mm scales on all my cameras just for this).

I'd then note the difference between the "near" focus point position and the "far" focus point position. Just for fun, let's say that it's 3 mm. I'd set the focus exactly halfway between the two extremes, that is, at 1.5 mm shorter than the "near" position.

Then, I'd check the handy table I have taped to the side of my camera that would tell me that for a focus spread of 3 mm, I need to use f/32.2. I'd set my aperture to the closest setting to that depending on the shutter speed (since speeds are in whole stops, I might have to choose a slightly smaller aperture).

Then "click."

BTW, the fact that you're using a 75mm lens for the shots you're posting means that with these, there will be very little focus spread between near and far, likely a mm or less. So, you don't have real depth-of-field issues with that lens. Try checking near/far positions in such scenes with a 210mm or 300mm lens and you'll quickly get into focus spreads of 4-6 mm or more.

Best,

Doremus

[Louis Pacilla]

BTW, the fact that you're using a 75mm lens for the shots you're posting

Doremus

Hey Doremus Allen posted he used a FL of 150mm for his (latest) example image.