Newbie Question Re Tilt and Focus
I'm just getting started using a view camera, a Gowland monorail, and have read the articles on how to focus and how to choose the f stop from the main page at LFPhoto.info. I also have Steve Simmons' book on the way, but in the mean time I though I could at least figure out the most common movement. But I'm having a hard time understanding what the end point is. I thought I had to find a tilt position where the near and far focus points are both in focus at the same time (i.e. in the same focus position). When I follow the iterative sequence described in the article, however, I just keep tilting more and more and refocussing on the far point until I run out of coverage, and the tilt angle is beyond 45deg.
So I'm thinking that maybe the endpoint isn't what I though, but then I don't know what it is. This is reinforced by the procedure for choosing the f-stop, which requires measuring the Distance between focus points, after making movements. So if there's a distance, they're not both focused at the same time at the sam3 place (i.e. D isn't 0). So then, what are you aiming at with the iterative procedure, either the one measuring the distance and adjusting tilt or the one without measuring?
Alternately, just tell me how you do it in the simplest most practical terms. We're talking near-far, no-frills landscape tilt. Thank you.
I know nothing about Steve Simmons' book but from long experience I can guarantee you will not need more than 5° tilt (forwards at the front or backwards at the rear) for a landscape with the camera on a tripod at average height (5 feet or so). Don't know your camera either - does it have on-axis tilt? If so, this makes life just a little easier, but in any case I would forget the theory and simply focus the camera and apply tilt at the same time. The amount required will of course vary depending on the camera height and the focal length of your lens, but as I said, it won't be very much to get full front-to-back sharpness.
As regards the f stop, f16 to 22 will do it almost every time, unless you require considerable depth of field on a plane other than the one you have covered with the tilt movement. If you are having problems with lens coverage, use back tilt only (this is easier anyhow while you are practising focusing and tilting at the same time).
I frequently use a back tilt, since I mostly do landscapes. You really don't need a lot of tilt, only a few degrees or so. Try focusing first on the furthest point you want in focus (it will be on the bottom of the ground glass), when reposition your loupe on the closest point you want in focus, and tilt the back until it is in focus and lock the back standard. You may have to go back and forth a couple of times until everything is right, but remember, you will get more depth of field back in when you stop the lens down.
As a suggestion, get a copy of Jack Dykinga's "Large Format Nature Photography", it has a good set of illustrations on how to do the technique I use.
I've got that book, but I can't remember how specific it is on focusing. What I do is focus on the farthest object I want to be sharp, then tilt to bring the nearest object into focus. Often, I have to do this twice, but only very infrequently is it needed three times.
I found some of the techniques in the LF Forum articles to be a bit technical for someone of my experience, as it sounds like you have found them. In my experience, many photographic concepts that at first seem overly technical become more valuable in time, but if I try to force understanding early on, I end up building up a block to that piece of information that is hard to get by later. I find that as my experience grows, I desire to have more and more control of the process, and upon review concepts that previously were overly technical make perfect sense.
Try working with the simple method I am using now and see what you think. Then, as you get more proficient and want to get a more precise handle on it, try reading those articles again and see if they are useful to you. Just use the knob to focus on the far object, then tilt a bit until the near object is in focus, then repeat. Don't forget to stop down the lens either, and get a cheap loupe at first so that you can examine the ground glass while the lens is stopped down. Most of my negatives were made just past the middle of the aperture scale rather than fully stopped down.
Hope this helps!
One thought to keep in mind. The greatest depth of field occurs with the standards being parallel to each other. It is only the subject that makes a tilting of use in normal rendition of scene.
Claire (Ms Anne Thrope is in the darkroom)
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As Robert indicates, you can focus on the far and tilt toward the near with the camera back. The same holds true for working with the lens standard. With either, particularly with center axis cameras you will need to refocus several times. It is frequently easier to use the movements with the front standard than using the rear. When using the front standard, you are not changing the position of the film and potentially changing the shape of your subject. I use either or both standards for my adjustments depending on the subject and lens. I particularly use the adjustments with the rear standard particularly with my telephoto lenses like my Nikon 500 T ED lens due to both the size and weight and the nodal point of the lens. As has been mentioned for landscapes you will not usually use beyond about 5 to maybe 7 or 8 degrees of tilt for most images.
Originally Posted by roteague
Last edited by naturephoto1; 05-31-2006 at 05:35 PM. Click to view previous post history.
John Sexton gave me a tip at one of his seminars. The normal relationship is you extend the bellows to bring near things into focus and retract for far. When that relationship reverses, you have introduced too much tilt
Simple but very effective.
"Focus on the far and tilt for the near" is a good mantra. Remember the Scheimpflug principle, though (and read up on it if you don't know it already). Any time you tilt the lens or back so they are no longer parallel, the plane of focus is now tilted as well. As you stop down the lens, the depth of field remains with that tilted plane of focus.
In doing this, you have to choose your significant near and far points for the particular image. Focus on the main "far" point and then tilt the rear standard to bring the main "near" point into focus. You will then probably have to adjust the rack-and-pinion focussing a little but a a bit of back-and-forth should bring it all together in a few seconds.
As several others said already, the rear tilt is not that much -- just a few degrees. Check it visually as you do it. Once nice effect of using rear tilt is the "looming" effect you will get on near objects. This changes the visual relationships between objects in the photo, but the change is usually pleasant and makes the near objects loom larger so you can "read" them better in the image.
Most large format photographers, at least of the more traditional "rocks and roots" and landscape schools, tend to go for total focus. With 4x5 negs, I never shoot at less than f22 or 32, often going to f45 or f64. A nice rule-of-thumb is to do focus and tilt as described above, then stop down while looking at the image on the ground glass. Once you get the focus to where you want it (and hopefully it's dark enough under the cloth to see the ground glass at this point!), stop down one more stop to be safe. That should give you a very adequate range of acceptable focus that will stand up to big enlargements.
Tilting the rear standard is one of the main reasons why I like field cameras as opposed to monorail cameras where the rear standard rotates around a center axis. It's usually easier (at least for me) to use the tilt while looking at the ground glass and then adjusting the focus a little to make it all nice and crisp.
Great points Michael. For landscape work the back tilt is invaluable, but is practically unknown in the commercial world - I once remarked to a commercial photographer that I frequently used a back tilt to increase depth of field, he kept insisting that you had to use a front tilt; different world, different purpose. I had forgotten about the rear standard with the center axis, so I am glad to see that brought up - like you prefer the flat bed field cameras.