Any tips on using front tilt as opposed to rear tilt? I haven't been able to tilt the front and get the near and far to focus. It seamed much easier to use rear tilt. I'm using a Cambo SC monorail.
Thanks
Chris
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Any tips on using front tilt as opposed to rear tilt? I haven't been able to tilt the front and get the near and far to focus. It seamed much easier to use rear tilt. I'm using a Cambo SC monorail.
Thanks
Chris
http://www.largeformatphotography.in...-to-focus.html
Note what it says about using front or rear tilt. Also the proceedure to focus using tilt.
I don't recall if the Cambo SC has base or center tilt. With base tilts, I "focus-far, tilt near" (focus on the far point using the focus knob, then tilt until the near point is sharp) and then repeat 2-3 times until everything is sharp. Usually, it takes far less tilt than one might think initially.
The repetition is needed because as you do the first (base) tilt, you also effectively increase the bellows extension, causing the far point to go out of focus. Repeating the sequence fine tunes the combination.
The near point, far point method works reasonably well with either base or axial tilt.
You focus on the far point and then on the near point and note the approximate distance you have to move the standard on the rail or bed. The greater the spread, the more you tilt. There is a way to estimate the amount of the tilt, but most people will do just as way by guessing. The first guess should be at most 10 degrees. Once you've tilted, focus on the far point, and then refocus on the near point. If you have to bring the standards further apart, that means you have to increase the tilt. If you have to bring the standards closer together, that means you have to reduce the tilt. If you follow this rule, you should be able to get it right on in a few iterations.
It is a bit easier with axial tilt provided you have points of interest at the tilt axis. Then you can see-saw about the tilt axis and try to get both near and far points in focus simultaneously as you tilt. But you may still need some iterations as above to get it exactly right.
The above procedure just lets you set the exact plane of focus. Usually, you are also interested in a range above and below that exact plane of focus. The range narrows down to a line below the lens, called the hinge line, and widens as you move away from the lens. The shape of the DOF range is a wedge centered on the hinge line. With fixed tilt, as you focus, the entire wedge swings on the hedge. It makes sense to choose the reference points for the exact plane of reference in the center of this wedge, but some focusing may be necessary to shift it up or down. You determine the angular width of the wedge by stopping down appropriately. To do this, pick two points, one above and one below the plane of exact focus. With the tilt chosen, focus first on one and then on the other and note the focus spread between them on the rail. The actual focus position should be vertically halfway between, which should be reasonbly close to where you originally placed the plane of exact focus. If you multiply the focus spread by 10 and then divide by 2, that will give you a rough estimate of the proper f-number, but you may want to stop down further.
After my first major trip back from Colorado and using 4x5with tilt capability I have a few images I messed up on. I usually used too much tilt. There is one image that I used tilt to get the forground flowers in focus and mountains out of foucs but the middle distance somehow is soft. I haven't figured out why yet. Used F22or 32.
It's easy to see when you've used too much tilt. Normally when you move the lens forward by extending the bellows things close to the camera come into focus and when you move the lens backwards by compressing the bellows things farther from the camera come into focus. When the opposite starts happening (e.g. you move the lens forward and as you do objects in the distance come into focus) you've used too much tilt and you need to back off until the camera starts behaving normally.Quote:
Originally Posted by 65Galaxie
I can't see the picture you posted well enough to tell what's in focus and what isn't. However, if the near and the far (i.e. flowers and mountains) are both in focus and the middle isn't it's usually because something in the middle was outside the plane of focus you created by tilting the lens. Tilting does nothing for objects that are outside the plane of focus. Those kinds of things can be made to appear sharp only by stopping down sufficiently. It sounds like f22 or 32 wasn't enough.
Think about the wedge that Leonard described. The middle ground slopes lower than the foreground, so it's quite possible that the middle ground flowers were below the DOF wedge.Quote:
Originally Posted by 65Galaxie
Yes.Quote:
Originally Posted by Ralph Barker
This is one of those examples that shows that tilt isn't the answer to every question. Scenes like this occur more often in landscape work than one might think. For many scenes like this, all you can do is rezero your standards and go the "hyper-focal distance and stop way down" route. For this particular scene, I doubt that would work. It's often very difficult to get your feet and the distant mountains and everything in between to be in acceptable focus.
One thing you could try in this instance, paradoxically, is even more tilt. That is, instead of making the plane of sharp focus run from the near flowers to the tops of the distant mountain, make it run from the near flowers to the middle (or even the base) of the distant mountain. This will lower the plane a bit which might be enough to pick up some or even most of the middle ground. The only way to know if it'll work is to try it and see: trust the ground glass; it seldom lies.
Putting the plane of sharp focus where you need it and then stopping down the right amount sounds so simple. But it takes lots of practice for it to become second nature. Some would say a lifetime of practice ;-)
65Galaxie,
I can't make out what your posted image shows, but it appears to me that there should not be much trouble getting everything in such a scene in adequate focus. There does not seem to be any significant vertical extent in the foreground, and the wedge starting on the hinge line below the lens should not have to open very wide to encompass everything in the scene. The comments Ralph and Brian made seem appropriate.
Here is how I would approach such a scene. I would pick a near point in the flowers in the foreground and a far point on the the trees in the middle distance. The far point should probably bee about halfway up, but if there is a diip in the ground further out, you may want to put it lower. Use the method I described to set the plane of exact focus through the near and far point. Use the method Brian and I described to tell if you have too much or too little tilt and iterate until you have it about right for the near and far points. Finally, with the tilt set, refocus so the top of the trees are in focus and then so that the lowest point in the midddle ground is in focus and set the focus halfway in between. The foregournd and mountains should remain in focus, but getting all of the trees and the rest of the middle distance in focus may require stopping down. I would be surprised if you have to stop down below f/22 to accomplish that.
The only potential problem I see with that is that you probably won't be able to get both the tops of the flowers and their roots in focus, but it doesn't appear that much below the tops of the flowers is visible in the scene.
Thanks for the replies on focusing. Here's some of the pictures at max upload. You can see detail in the flowers but in the middle ground picture it's very soft. The top of the mountains are very sharp.