Focussing / tiltgreenspun.com : LUSENET : Large format photography : One Thread
I know it's a bit basic - but how do others focus a 4x5 camera, in a typical near/far situation which requires lense tilt?
Do you focus first on the foreground, then tilt to get the background in focus, and then fine-adjust? Or the other way round? Or some other technique?
-- fw (email@example.com), July 29, 1999
I focus on the far, background as it were, and then tilt until the near, or foreground, is in focus. Then re-focus on the far and then tilt for the near, etc. etc. until I have the far and near in focus, and then stop down to get the middle in focus, and re-adjust as necessary. It is a lot easier to do, with a LOT of practice, than it will ever be to explain.
-- Marv (firstname.lastname@example.org), July 29, 1999.
I use a 4x5 and don't have any really long lenes so in a typical situation the tilt will be between 1 and 5 degrees. I make the best guess that I can as to whether it is closer to the 1 side or 5 degrees side and tilt the lens accordingly. Then I focus on the far and look at a millimeter scale on the bed of my camera and look at one of the pointers the I have positioned to point at the scale. Next I focus on the near and look at the same scale. I then split the difference of those two numbers and focus at that number. Aperature is then determined by the focus spread. If the spread is too much then I need to rethink the tilt.
Jeff White http://www/jeffsphotos.com/index1.htm
-- Jeff White (email@example.com), July 29, 1999.
The hard part in focussing a view camera is in knowing where the plane of best focus lies. In other words, for a scene that includes a rock at your feet and a distant tree(200" away) that is seen against a far away mountain or similar, where should the plane of focus fall? Front of rock/top of tree/face of mountain? I set my back standard vertically and try to imagine where the best plane for focussing should be. I focus on the rock and then on the top of the tree. Then I split that distance on the rail/bed of my camera and focus somewhere in the middle. Next I tilt the front standard to a point where there is the same amount of blurriness at the top and bottom of the GG. Most times the front tilt is very small. And it depends on if you have axis or base tilt ability on your front standard. I have axis tilt so my composition stays the same when I tilt. If you look at the side of the camera when you figure out what the best plane of focus is going to be you can imagine a vertical line running along the back of your camera intersecting a line running along your front standard and intersecting with a line running along the plane of best focus. Then you adjust your aperature to take up the slack. James
-- james (firstname.lastname@example.org), July 30, 1999.
I'm with the focus near, tilt, go to step 1 camp. I find I have to check focus carefully in the center of the image with this technique or I get surprises.
I find some success with Scheimpflug [sp?] estimations in closeups
-- John O'Connell (email@example.com), July 30, 1999.
I think it depends very much on the camera design. I am going to assume we are taliking aboud a landscape situation. With axis tilt cameras I focus the center horizontal line first and thn tilt by observation. Most of my experience is with base tilt cameras (yaw-free and not yaw free). With base tilt cameras I focus on the background first, and tilt until the foreground comes into focus.
-- Ellis Vener (firstname.lastname@example.org), July 30, 1999.
Do you have a problem with the image changing as you raise or lower the front to keep the same perspective? I always had problems with it until I went to axis tilt cameras. James
-- james (email@example.com), July 31, 1999.
With base tilt cameras I've been told that you focus first on the far, then on the near. With axis tilt cameras you focus first on the near, then on the far. At least that's what I was taught in Tom McCartney's large format workshop. Having said that, the easiest way I've found to focus a view camera is the method outlined in a "Photo Techniques" article several years ago. This method requires that you attach a milimeter scale and a small pointer of some sort to your camera in a manner such that you can see the difference, in milimeters, between the near and the far focus points. Technika and Tachihara cameras have places on the camera where it is very easy to do this. I don't know about other cameras. You then split the difference (i.e. focus at a point that is exactly midway between the near and the far points on the milimeter scale). You can then try a small tilt (or any other adjustment) to see if the distance between the two points decreases. If it does, continue the tilt (or other adjustment) until the distance between the two points stops decreasing. That is the point at which you have achieved maximum benefit from the tilt or other adjustment and you then can use the widest possible aperture (to maximize shutter speed and minimize diffraction) that will produce enough depth of field to make everything appear to be in focus (assuming, of course, that you want everything in focus). This is a synopsis, and slight oversimplification, of the method outlined in the article. Steve Simmons recommends focusing in a manner such that the near and the far are equally out of focus. Very experienced large format photographers can perhaps do this by looking at the ground glass. The method I'm describing is, I believe, just a more scientific way of achieving that goal and it can be used without a lot of experience. I don't have a citation to the article handy but if you're interested send me an e ail and I'll dig it out.
-- Brian Ellis (firstname.lastname@example.org), July 31, 1999.
I just returned from a week of LF photography. It was my first full field-campaign with the view camera. I recommend practice. Focus on the background, and then tilt a LITTLE bit and see the background get worse while the foreground gets better. I then refocus and iterate again. As a beginner, I was able to get the near/far focus perfect within about 4 or 5 iterations, taking a whole 20 seconds or so. I must emphasize that the tilt each time is very small, a couple of degrees at most. If things seem to be getting worse, start over again from a neutral position. At first I tilted too much too quickly, but with a bit of practice, this technique becomes second nature. I wouldn't bother with taking measurements and splitting the difference since the light would be gone by the time I got it focused.
-- Ray Dunn (email@example.com), July 31, 1999.
Thanks for all the responses above. My technique has so far been very similar to Ray Dunn's, i.e. a process of iteration, which can sometimes work very quickly, and at other times take forever (while your head is getting boiled under the darkcloth!). Then I read the Sinar introductory guide to LF, and given that they seem to have a mechanical technique for determining tilt, I thought that this could easily be replicated manually. I'm going to try all the suggestions above to see if I can establish a practical technique. Regards fw
-- fw (firstname.lastname@example.org), August 01, 1999.
I'm using a Sinar f2, which I consider an outdoor camera. It has actually build-in tilt- and depth-of-field calculators which are easy and safe to manipulate. No guesswork any more. To my knowledge, no other brand of view-camera has that feature, although very logical. However the mechanical realization seems to be somewhat difficult. As a second there is a manual tilt-angle-calculator made by Linhof. I have never used it but they say it works very well and is supposed to be very affordable. Write me if you want to know more.
-- Thomas A. Castelberg (email@example.com), August 10, 1999.
focusing a 4x5 has just been made easy. If you own a palm pilot you can purchase a $15 piece of software that will tell you where to focus and how far to stop down for any given lense you own.
E-mail me and I'll share the particulars.
-- Barry Wolf (WolfVisual@Compuserve.com), November 04, 1999.
The software is from focus+. It is available from the main download menu of palm software. All you do is pump in your lens, it's max F- stop and the program calculates from near to far depth of field. As an example it might tell you that your 150mm will focus from 6' to 00 at F45. It will also tell you where to focus (exam. 12' into the shot) and at what F-stop to get the max depth of field.
If you can't find the software let me know.
-- Barry Wolf (WolfVisual@Compuserve.com), November 04, 1999.
Barry, what if I don't want max depth of field by stopping all the way down and how does it deal with the effects of a swing or tilt?
-- Jeff White (firstname.lastname@example.org), November 04, 1999.