Hi folks,
I am having trouble aligning my camera for a special series I am working on for some time. I try to explain:
I want to do "full frontal" photographs of building fronts, so that the optical axis (assuming all movements are zeroed) is exactly orthogonal to the wall of the building (in other words, the camera front and back is exactly parallel to the building). Furthermore, it needs to be "centered", so let´s say the horizontal middle of the building is exactly in the middle of the GG without any perspective distorsion. I will then later use rise/fall vor framing only. An example is the following image (courtesy of Barbara Wolff):
My camera (Technikardan) allows full front and back movements. But I am havign serious problems to achieve orhtogonal alignment of the optical axis.
I currently do it as follows:
0. Set up tripod, level the camera with spirit levels (I checked the accuracy, they are OK). I use a standard 3-way pan/tilt head. The pan is below both tilts.
1. Zero all movements.
2. Align the camera by panning, so that all horizontal lines are parallel to the GG lines. Vertical lines are parallel already because of the spirit level alignment.
Now the first problem occurs: Strangely, once it looked to me that the lines in the upper part of the building were parallel to the GG lines when the ones in the lower part are not and vice versa (depending on the amount of pan used). It was difficult to tell, since I am not sure if all lines on the building were acutally level with high precision. Anyway, when I had some of these lines parallel, it was clearly visible that the pan was too extreme and the back was not parallel to the building front. So I had a look at my spirit level for left/right levelling of the back, but it looked ok. Was it lens distortion? I use a 5,6/150mm APO-Symmar, which is screwed to the lensboard correctly (the threads do join well). I have to say that I did not check if the spirit level changes with panning...just thought about that now.
3. After maybe 20-30 minutes of fiddling with the pan setting, I finally got all lines parallel (more or less)
4. So, I tried to "center" the camera horizontally by shifting both standards in the same direction (so there is no left/right perspective added). Basically, the same as if you would move the tripod left/right parallel to the building (which is not possible precisely). This was again 20-30 minutes of trial and error, really annoying, touching the pan again, starting from step 1 again and so on. Finally by chance, I obtained an acceptable composition/alignment.
As you might see, this took almost one hour and I got really upset. I feel that there must be a better, faster and more reliable way to obtain an acceptable result. Maybe I should change the order of movements?
Any advise would be highly welcome!
Best regards,
Jan
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