Ditto. I'm guessing forward tilt on the back? That's just a guess, I'd like to know to to be sure.Quote:
Originally Posted by John Olsen
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Ditto. I'm guessing forward tilt on the back? That's just a guess, I'd like to know to to be sure.Quote:
Originally Posted by John Olsen
...backward base tilt on the back (similar to forward front tilt, except for little field displacement vs. front tilt) - pretty much essential as I was using a 90mm lens which is marginal for 5x7 with movements, and needed to preserve what coverage I had available (front tilts move available field relative to film, rear tilts not so much) . The price of course (for this back tilt) is a bit more perspective distortion, but not overtly distracting in this case. Other data...orange filter, PMK Pyro. Light was fading so fast that I was only able to obtain one image...glad it worked! Actually, there is a bit of blur in the extreme upper left (had to work quickly, also exhausted from having sprinted two miles with gear to get here in time)...unfortunate as this has, so far, limited me to printing this to 30x40 - whereas if it were sharp overall, I'd love to go to 40x60! Will likely do this (40x60) anyway...just because!
Gotta admit that my previous post was a bit political...in defense of staying true to ourselves and not ascribing to others generalizations. Just sayin! :)
Thanks for sharing your thought process. Every bit helps me get my best results out in the field.Quote:
Originally Posted by John Layton
"...backward base tilt on the back (similar to forward front tilt, except for little field displacement vs. front tilt)"
Nice dune image John Layton. Just curious if you would have preferred the benefit of front tilt vs rear backward tilt for this image? I ask because the backward rear tilt as you say distorts the image as if you were using a wider lens than 90MM. Moving the film plane away from the field of view would "elongate" the image away. In other words, did you view the image in advance with the "elongation" effect? I say that as for some, having the film plane perpendicular to the ground (assuming flat ground) is necessary to retain WYSWYG. Of course for base architecture imaging, this used to be the "standard" approach for many pros. (The didactic in me comes out again). I appreciate your insight.
PDM
I don't want to get into an argument over this again, but...
Rear movements along with a subsequent tilting of the whole camera forward are identical to front movements, in terms of "distortion." There is nothing about rear movements that inherently creates distortion, only the tilting of the image plane, which is just as possible with front movements along with tilting the whole camera backwards. Compositions will vary but some rise/fall of one of the standards corrects this (but it sounds like there was a lack of available image circle).
Corran,
I don't believe I asked you for your input on this, nor am I aware of any prior "argument". Obviously if the rear backward tilt brings the film plane perpendicular to the ground, than it's the same as front tilt. If the rear tilt goes beyond that, then distortion does come into play. So your comment is a "half truth" as such. Let's not put your popularity and number of images posted as the basis for elbowing others who have knowledge of this. Ok?
Excuse me pdm but I'll put some input in if I feel like it. No need to be a jerk. Ok?
It's simply a common misconception that rear movements inherently cause perspective distortion. Which is, as you say, a "half-truth" and a more refined understanding could help others who happen to be reading.
Call me what you want, but there is an intrinsic need for some subscribers to learn and I am simply trying to keep the dialogue clear, accurate and open minded. There is inherent distortion in rear tilt other than when the film plane is perpendicular, whether fore or aft. Go back to Adam's The Lens and his discussion points on the subject. If your and H20s attempts to dismiss dialogue of these basis skills in this thread smacks of a private club. I know of nothing that should limit discussion in this or any other forum. If there are new limitations that have been set forth, please advise.
I personally enjoy these discussions as I enjoy learning something new. OK?
I have no idea what you are talking about. Nothing I said limited discussion. In case you are unaware, more than one person can reply and I am sure Mr. Layton will give his personal input. I brought up an additional point to consider which in a different thread some time ago was contentious, for one member, as he seemed to believe that rear tilt = distortion, always. I think it's important to point out that this is not exactly true, it is instead the relative angle of the film plane after movements are applied. I have noted that some newer LF users do not quite realize that both rear and front movements can be applied equally in this manner.Quote:
Originally Posted by pdmoylan
I haven't the slightest idea why you suddenly snapped back with such vitriol, but if you need it, feel free to judiciously use this tool: https://www.largeformatphotography.i...?do=ignorelist
So why does a building change shape as I tilt the back relative to side of a building (no matter what I do with the front lens)? Changing shape of an object is a 'distortion', unless there is some photo-related use of the word that is different.
Edit: re-read the prior posts. Semantics again...damn.
Changing the position of the film plane (same as the plane of the back) relative to the scene will reshape the image of the scene on the GG. This power to change the shape of the image is sometimes called a distortion, but should have no negative connotations. We are manipulating the shape (the geometric properties?) of the scene, not 'distorting' it.
But I have been wrong before.