Originally Posted by Thomassauerwein
here is no doubt about the effect. The question was whether tilting the easel really equals tilting the film plane of the camera. Nor does anybody doubt that using a softening filter on either the camera lens or the el-lens will yield a softer image. But the effect is not exactly the same in both cases. While the difference is a matter of taste or artifical expression in the latter case, you may get in serious trouble if you need to correct the perspective of e.g. a shot of an architecutral model afterwards.
I agree that there is a subtle difference between using rear tilt/swing and tilting the easel (or its digital equivalent of using perspective transformation in Photoshop), but I don't think that the difference is in the rendering of the relative size and shape of objects in the frame. Either method can be used to correct convergence in one plane in the image.
Rear tilt/swing or easel tilt alone will not correct a complex composition with multiple planes at multiple distances, which is best corrected with rise/fall of either standard on the camera, and post-processing methods will have no effect on the plane of focus in the image.
The advantage of applying rear tilt/swing in the camera over doing it after the fact is that it can be done without the loss of image quality that would result from varying the enlargement factor across the frame, and without the need for cropping the trapezoidal image that results. Doing it in the camera also eliminates the need for stopping down the enlarging lens to compensate for the easel tilt on enlargers that lack a tilting lens stage.
That said, the kinds of corrections usually applied in the darkroom are typically small, and for small corrections, easel tilt is quite effective.
Thinking about this, I remembered an article in the dear, departed ... and severely lamented Camera and Darkroom, expressly about easel tilting and its comparison to view camera tilts, swings, rise, fall ... and other esoteric "jiggling". The tiltle of the articel WAS "The Brick Trick".
Simple easel tilting is effective to a point; the correction of *all* errors that would, more or less, be corrected by T,S & R,F are not possible by this method... but *significant* improvements in "falling down" buildings, for example, can be realized.
I remember an "architectural" photograph, with pronounced convergence of vertical lines, as the camera was *much* below the center. They then corrected in camera and took another image. They took the first "converging" image and tried to correct to the same degree by easel tilting.
The result: Almost! All vertical lines in the in-camera corrected image were perpendicular and nearly parallel.
One (1) dormer on the roof of the tilted image was not, but the overall improvement was well worth the effort.
I *miss* Camera and Darkroom.
Ed Sukach, FFP.
Thanks everyone for your input. I understand now that the 2 things are almost the same.
The effect is identical, as far as I can tell. I used to take architectural photos with my 35mm camera back in the 70's, and I corrected the perspective by simply tilting the easel. It works very well, if it's just a matter of correcting converging lines. All you have to do is to use a smaller aperture so that the whole picture remains in focus. I uploaded a scan of a 1975 print I made this way in the Technical gallery (Old office building).
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This topic brought to my mind an ancient reading and - yes, I found it! - at "Enlarging" - C.I. Jacobson and L.A. Mannheim, Focal Press, 22th ed, where they extensively cover correcting parallel lines with enlarger movements. Some clever equations show that real distortion can come into the scene if specific relationship among camera and enlarger lens focal lenght, angle of tilts and magnification are not considered. Perspective and proportion control can be thought as diferent subjects and precisely calculated to include even Scheimpflug's law.
Obviously, it's really quite, quite technical. Almost boring...
[quote="Ed Sukach"]Thinking about this, I remembered an article in the dear, departed ... and severely lamented Camera and Darkroom, expressly about easel tilting and its comparison to view camera tilts, swings, rise, fall ... and other esoteric "jiggling". The title of the article WAS "The Brick Trick".
That was a great publication, and I treasure the ones I have in my bookcase. There was a similar article where someone grafted a four-bladed easel to a ball head and used that to correct distortion. I also seem to remember some company advertising a similar product.
Me I don't use bricks they always leave a mess behind, but use books and any other suitable object I have lying around.
I have done the same thing, using this to "straighten out" buildings. My "secret recipe" was to use books of different thicknesses, so I could have some control over the amount of tilt. That, and a piece of graph paper which was a guide for knowing when it was right.