How often do you landscape photographers use tilt?

"Diffraction is not an issue until around f256. Our lenses only go to f90 or f128"

 

If I remember correctly, Joel Meyerowitz said most of his daylight Cape Cod shots were at f/90 and around 1/2 second.

While what you say about stopping doen imapcting enlarging is true, the argument holds even for shots made at f/5.6. Any enlargement that exceeds the information thresholds in the negative will show a lack of resolution on the print. Also, even if you were enlarging, it is worth keeping in mind the different effects of a lack of DOF and losses to diffraction. A lack of DOF will show some areas in focus and some not in focus (and particularly in comparison to the parts in focus). However, diffraction is typically first noticed in a loss of resolution in small detail over the entire image area (while large detail will be sharp over the entire image). In general, the latter is less disturbing than the former. So, even if you were enlarging, it could be argued that inadequate DOF is more annoying than diffraction losses. Cheers, DJ

of course, there's also no reason a landscape has to be sharp or in focus from foreground to background.

 

Just be cause we can doesn't mean we have to...

i tend to work around the 'sweet spot' in the aperture range... that is, staying as close to the sharpest ap and using moves to bring the rest into focus(if at all possible). as my peer above said so correctly, a little(movement) goes a long way.

 

i enlarge mostly,

 

me

This is a great Thread!!!!! SOOO much INFO...Thanks Guys!!!!!

 

 

 

Seattlechronic

Paul Hansma's excellent article was the key that gave me an "Aha!" moment in deciphering a few of the mysteries of the large format camera. (For those who haven't read it, it can be found on Q.-Tuan Luong's large format pages. There is also a related article by Stephen Peterson; together, the two articles provide some keen insights into the effects of diffraction and defocus effects. Here are the links to the individual pages of the Hansma article:<P>

http://www.largeformatphotography.info/articles/hansma-dof.1.gif<BR>

http://www.largeformatphotography.info/articles/hansma-dof.2.gif<BR>

http://www.largeformatphotography.info/articles/hansma-dof.3.gif<BR>

http://www.largeformatphotography.info/articles/hansma-dof.4.gif<P>

In answer to David's question: I use tilt nearly always, swing less often but every shot will be analyzed to see if using tilt and/or swings will bring the scene into better focus. My technique is to first use tilt to align the focus plane from foreground to background, then lock that movement before checking to see if a swing will improve things from side to side. If any swings are used, then I recheck and adjust the tilt, and so on. One or two iterations of this process is all that's needed. At this point you should have as much of the scene in sharp focus as possible. (I'm sure it's possible to make both movements simultaneously, but this works for me.)<P>

With many scenes, it just isn't possible to get everything sharp at once; that's why we need to stop down for more DOF. At this point, I decide which points will be the near and far limits of the area I want to optimize, and rack the focus in and out to measure the spread, set the camera midway between the two, and use Hansma's formulas to pick the optimum f/stop. Deep breath. Take picture. :o)<P>

I guess the main thing to point out, is that Hansma specifically mandates a couple of "basic principles," one of which is "minimizing the focus spread by using tilts and shifts."

This type of thread comes up every now and again. It seems that some people overcomplicate things so much. I have to agree with Michael A. Smith, just look at the ground glass. That's the great fun of LF! Use tilts/swings to get what you feel is most important in focus (with lens wide open) and then stop way down to get as much as possible of the rest in focus. As DJ said: "it could be argued that inadequate DOF is more annoying than diffraction losses". I agree totally. I regularly shoot 8x10 at f90 if the subject matter requires maximum DOF. Since I only contact print 8x10's, f90 is absolutely no problem.

 

When I shoot color 4x5 (for enlarging) I'm not afraid to shoot at f45 if the scene needs it.

Let me give you a scenario, let's say your shooting a landscape on a windy

day. This will come under the "intuitive" auspices. You want to stop down for

the maximun depth but due to the wind, you don't want the movement of the

leaves in the picture. The movements in the front will allow you to use a more

open apeture giving you a higher shutter speed usually alleviating the

movement. Pulling a polaroid is always helpful and even better a type 55 so

you can look at the negative. These are some of the many decisions that we

contend with and one of the reasons why it takes awhile to compose and

shoot an image.

Scott brought up an important consideration and one which I face daily since I live and work on the plains. Windy conditions are a fact of life here. That is another reason that I work at achieving focus through the use of movements whenever possible. Even with Tri X rated at it's true EI I have a difficult time with wind. At F32 I am consistantly in the 1/15 to 1/30 second range. It is difficult to stop movement in nearby grass or leaves with those speeds. Throw a filter into the mix and things go downhill further. When I shoot Bergger BPF 200 (at it's true EI) I find myself down another stop and 1/3.

 

I think that someone seemed to think that the choice was between defraction loss and unfocused portions of the scene. I don't shoot anything intentionally out of focus, I work at having everything in focus (near to far). Not saying that all things need to be that way, just that my personal ethic is such.

 

Again, I also contact print and in that situation defraction does not enter into the equation. I just feel that since probably more of the participants enlarge negatives then contact print that defraction needed to be addressed. The greater the degree of enlargement the greater the apparent effects of defraction, in my experience.

My heartfelt thanks to all of you who took the time to respond to my question. What an extraordinary thing it is to post a question and be able to get almost immediate assistance from experts all over the U.S., and, indeed, the world!

 

In response to your responses, I have a couple of additional comments and questions:

 

1. I agree with Dhananjay N. that diffraction losses are far less distracting than those due to focus problems. However, my four years of printing LF negatives have convinced me that there really is a visible sharpness difference between pictures I was able to take at f22 and those I had to take at f64. There is a ... pop (sorry, I don't know quite how to put this) to the pictures taken at or near my lenses' optimum apertures that is missing from those taken at the smallest apertures. That is why I have begun to reconsider my unwillingness to use tilt movements.

 

2. Leonard Evens, though math is not my strong suit, I will read your article with care. Thank you for pointing me to it. My question to you, and other photographers who use some variant of the focus spread method, is how do you measure focus spread AFTER YOU HAVE TILTED? If I understand the animations on Merklinger's website, once you have introduced tilt, as you rack the standards back and forth to focus, the "wedge" of the in-focus area actually pivots about a line below the camera. If that is true, then surely the near and far points you use to measure the focus spread must be chosen with great care, and (here is the important point) probably will NOT be the same two points you picked to measure the focus spread before you tilted the camera.

 

3. Consider the following hypothetical situation: You are standing on the shore of a lake with your camera; there is a mountain rising from the far shore of the lake. You want the low rocks in front of your camera to be sharp, and you also want all of the mountain to be sharp. Obviously your near point for the plane of best focus will be the low rocks on the shore in front of you. But where is the best far point going to be: a. the far shore of the lake? b. half-way up the mountain? c. the top of the mountain? I guess part of what I am asking here is how is the area of acceptably sharp focus distributed around the plane of focus once you have introduced tilt? Is it 1/3 nearside - 2/3 farside, or something else?

 

Again, thanks to everyone who had been kind enough to contribute an answer.

 

David

"...how do you measure focus spread AFTER YOU HAVE TILTED?"

 

Same as with no tilts. That might sound trite, but consider: tilts and swings change the orientation of the plane of sharp focus. With the lens/film tilted, you still only have a plane that is sharply focused; for example the bottom of a foreground object might be tack-sharp, and the top of a tree some distance away, while the base of the tree is not guite sharp, nor the top of the foreground object. You can rack the focus to bring the top of the foreground object sharp, which is now the near point, then rack to bring the base of the tree into sharp focus as the far point. Measure the spread between those two points.

david -- i believe that you will discover that the hansma method works equally well regardless of where the plane of sharp focus lies. needless to say, once you have tilted/swung, you need to be much more astute about measuring your focus spread, since the effects of changing focus will often be nonobvious. this is where the "just rely on the ground glass" crowd has it about right. after applying camera movements, the effect of changing the focus point can be very surprising. you must scrutinize the entire glass to avoid unexpected results. however, once you have a firm understanding of what is going on, and made your aesthetic judgment about what you want in (and maybe out) of focus, you can measure the spread in the normal fashion to determine optimal taking aperture/focus point. you can then compare the spreads from the titled and untilted modes directly to see if your tilt was an improvement. ideally, and this is the basic point, applying a tilt will allow you to reduce the effective distance between your focus points by aligning the plane in such a way as to "slice" the scene as efficiently as possible. the thing that makes assessment of efficiency in this sense tricky is that dof is as much a fuction of magnification as distance from the POF. once you tilt, you can easily exacerbate dof problems with vertical foreground elements where none existed before. again, the gg is an important tool. finally, as to how often one tilts, it would be very interesting to put the answers here on a grid that correlated frequency of tilting with preferred focal length. people do tend to have favored focal lengths and i wouldn't be at all suprised to see that there is a strong connection between tilting habits and preferred lens length.

About your question about using focus spread after tilting, let me first say that you should take anything I've said (as well as anything else your read) with more than a grain of salt. The problem is that the discussions proceed on the basis that there are no focusing errors and you can tell when you have things exactly right. That of course is an idealization not realizable in practice. In particular, my distinction between two parts of the process can't be taken as a hard and fast rule, but I find it helpful to think that way as long as I remember its limitations.

 

But back to the question you ask. The important thing is to realize that you are doing two things. Tilting the lens determines the position of the hinge line, and racking the rear standard back and forth pivots the subject plane and the wedge about the hinge line.

In practice it is not possible to entirely separate these two operations, but conceptually it helps to do so in your mind. When you first choose the near and far points, the purpose is to use them to determine the tilt. Once you fix the tilt, the hinge line is determined. For this purpose, I think it is more important to concentrate on the near point, since no matter what you do, you are not going to get much near depth of field because of the wedge shape of the region. The choice of the far point is a guess based on what you expect to happen with depth of field after you have focused critically and stopped down.

 

Having established the tilt, your next problem is determine the dimensions and orientation of the wedge as it pivots about the hinge line. This is done by racking the rear standard back and forth on the rail. (If you have to move the lens instead, except for closeups, it doesn't really make much difference.) You do this more or less the same way you do it when the lens and film plane are parallel. Look in one or more planes more or less perpendicular to the subject plane. In most cases, the tilt will be small enough that you can use vertical planes. In each such plane, note the extreme positions ON THE RAIL you would like in focus. The point on the rail corresponding to your original far focus point will be somewhere between these. Use those extremes to determine the focus spread. Now position the (rear) standard in the middle of the spread. Then use a table (or the method I describe in my article) to determine the needed f-stop from the total focus spread. Stop down and see if everything looks right. (You probably want to stop down further when taking the picture if can manage to do so without compromising other objectives.)

 

You may find you need to go back and adjust the tilt slightly and iterate the process.

 

The problem with this method, and indeed all methods, is that there is inevitably a certain element of lifting yourself by your bootstraps. The problem is that you can't pick the precise subject plane, and hence the tilt, until you know the size and position of the wedge, but you can't do that until you know the hinge line, which requires knowing the subject planei i.e., the tilt. In choosing the tilt, the near point will usually be pretty clear since it will be close to the hinge line, and pivoting on the hinge line slightly won't make a lot of difference. What you are really interested in the distance is how the wedge interacts with the subject, but you can't figure out the dimensions of the wedge until you have tilted the lens and fixed the hinge line. Different choices on that mountain will make a difference as to where the hinge line lies, and ultimately where on the rail you place the standard and how much you have to stop down. It is here that rules of thumb like one third up the mountain would be useful. But none of them is going to apply in all situations. Which means that you have to practice on different types of scenes until you come up with something that works for you.

 

Since the process is basically iterative, you may find that, in practice, you don't want to split it as I have suggested. But I think, no matter what you do, if you keep in mind the different effects of tilting and moving the standard, you will find it easier to keep track of what is happening.

I suggest you find a nearby spot where you can make a series of test photographs. A local park would be fine. The composition does not have to win any prizes, just provide repeatable information. Bring any kind of objects which will help you identify individual negatives later. Make several exposures at different apertures. I made a series of exposures at all apertures (f9 through f128) when I first got my 300mm Nikon M lens. The prints were quite revealing. Make exposures without tilt first. This will show the effect of changing aperture stops. Then try using tilt with different stops. Take your time and make careful notes. The prints will tell the story. If you are testing to see the effect of diffraction make prints of the size you normally make. If you make 8x10 prints, what difference do 32x40 enlargements make? Try to keep the conditions the same as your normal routine. I think this kind of an open forum is very nice. Welcome the sharing of others, but base your final decisions on your own experiments. For the record, I use tilts quite often and swings less often. I generally prefer to keep the back plumb, even in landscapes. I will use back tilt if I want to emphasize the foreground. I usually prefer more quiet images, and use the front tilt so as not to minimize the foreground. I like having the choice. Making actual exposures is one of the best training tools available. Try several ways. Eventually you will be able to visualize the effects. The view camera will spoil you for any other kind of camera. Good luck!