Help me to understand a focus technique problem

[Roger Rouch]

I?m looking for some advice on a focusing situation that I continue to wrestle w ith. I mostly photograph in the mountains where there is often an implied need for forward tilt to bring the close foreground and mountain background to the cl osest difference in focus (thinking of the tutorial on the LF homepage). The te nant and problem being that, as the lens is tilted the focal plane becomes paral lel to a horizontal landscape. As you draw a horizontal line between closest an d farthest objects, only the objects or parts of objects that touch the plane wi ll be in focus. Everything above or below that plane will not be in perfect foc us.

My dilemma being how to be more precise with getting these objects below the pla ne in focus while still using the close/far difference in focus to determine opt imum f-stop. It appears that Fielder (very generally stated) brings close and f ar objects into focus using tilt and then compensates for the mid-ground using f -stop. Doing it this way requires me to go back to my millimeter ruler on my fo cus rail and focus again on the mid-ground objects in order to determine my opti mum f- stop (by using the technique where f-stop is determined by the differenc e in focus between the two extremes of close and far). Others have suggested th at you use a focus point for far focus as something, say, only a third of the wa y up the mountain when adjusting tilt. Again, this seems to require a refocus o n the top of the mountain to determine optimum f-stop?

Assuming I?ve bumbled through this enough to make sense, am I approaching this p roblem correctly, and can you offer suggestions to help me get better at this? Thanks for the help.

[Roger Rouch]

(Might add that Ive been through Merklinger's web articles a couple of time as well.)

[Jeff White]

One question for you Roger. How many degrees of tilt are you giving your lens?

[Roger Rouch]

Hi Jeff, With far mountains and no real close foreground maybe 5 degrees or less. In this situation with no valley or depressions in the mid-ground the standard technique of "focus far tilt near", use the difference for optimum f-stop, and split the difference for focus works fine.

In more extremes of close tall peak and/or close foreground maybe 10 or 15 degrees (estimate). It is in these situations or where there are mid-ground valleys or depressions where I seem to get complications.

[Ellis Vener]

Well sometimes in situations like this it is best to just forget using swings or tilts and just go to a deeper f/stop, or to rethink your image.

[Jeff White]

Well, in my experience with 4x5, most lens won't need more than a 5 degree tilt. 1 or 2 degrees is more the norm. I tend to take a guess at the tilt needed and then use the technique outlined on this large format site for focusing on the far and looking at the scale mounted to my camera and then focus on the near and checking the scale again. If the focus spread is too much then I rethink my tilt. I will try to guess where the error is, too much or too little tilt and then try again an see if there is an improvement. When in doubt I go with Ellis' advice and use less tilt and stop down more. I remember at a John Sexton workshop in the southwest, many people including John were photographing an unusual situation. It was an object very close and below us and a distant dramatic landscape. I hoped to engage John in a discussion about tilts to which he replied, "no tilts will help this, all you can do is stop down".

[david clark]

Hi Roger, I'm not a tilt focusing expert. I think photographing in situations similar to your's, the solution for me was to stop down. Maybe if I understood tilt more, it would have helped me. But stopping down did the trick for sure. The optimum f-stop was the smallest I had avalible. Best, David

[David A. Goldfarb]

The technique you're using is pretty much what I do with 8x10", and it works well for me. I'd rather tilt and stop down than just stop down, so the horizon will be sharper, recognizing that I may be sacrificing the base of the mountain a bit. The additional sharpness that draws the viewer's attention to the foreground with the tilt is part of the "large format look" for me.

[Thomas A. Castelberg]

Roger - given that there are no moving objects like flowers or sorts in the foreground you surely can afford longer exposures. From my experience then, if you choose between tilting and stopping or stopping down only, tilting and stopping down does the better job. This way you make sure to get a tack-sharp fore- and background and stopping down will push the sharpness deep into the valleys. I'm sure you do it right the way you describe it.

[Lyle Aldridge]

Roger, it looks like everyone missed your point of confusion, in the last sentence of your third paragraph. I was having the same issue until someone walked me though it at a pace my short-legged brain could handle. You've obviously already figured out a lot more than I had.

If you pick a ?far? focus point that is only part-way up the mountain, then tilt forward to focus on a ?near? point, you?ve put the top of the mountain above the focal plane, in the ?near? part of the wedge of focus. This is confusing, because it?s counter- intuitive, but you can confirm it by noting that it will take slight movement of the lens plane AWAY from the film plane to bring the mountaintop into focus.

So, using the "far" spot only part-way up the mountain is part of the solution, but you don?t usually want to use the top as the refocus point to calculate f-stop. Because the mountaintop is physically farther away, out in the wide part of the focus wedge, it will come into focus with too little lens movement, causing you to calculate an aperture that is not small enough. You?ll bring the mountaintop into focus, but still have a soft spot in the mid-ground.

The ?Fielder method? described first in your post avoids that by forcing you to refocus on the point that will require more lens movement, and thus a smaller calculated aperture. The mountaintop will be in focus, but so will the soft spot that would have been missed by using it as the refocussing point.