Large Format Landscapes

[pdmoylan]

"...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

[Corran]

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).

[pdmoylan]

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?

[Corran]

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.

[pdmoylan]

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?

[Corran]

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.

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.

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

[Vaughn]

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.

[Corran]

That's a fair point Vaughn, about the "negative connotations."

I get perplexed by this discussion sometimes. No one says that front tilt is the only way to manipulate DOF - of course it is understood that rear movements can also change the DOF in a similar manner, albeit with opposite angles. But it seems rear tilts have been pigeonholed as the only way to change the geometric shape of objects relative to the camera, in many discussions. Therefore, someone without rear tilt movements, say someone using many older press-type cameras, may think they can't use movements to alter shape. But they can - just use front movements and tilt the entire camera itself to compensate. I have seen posts here on the forum about this, folks thinking they need a camera with rear tilts to do shape-altering movements.

I personally ran into this with my first 8x10, which didn't have front tilt. I wasn't used to using rear tilt and discovered the change in shape to sometimes be undesirable. I then figured out I could use rear tilt and then tilt the whole camera to have, essentially, front tilt and a perpendicular image plane. That's when I figured out that movements of the front or rear standard can be made to be identical, in terms of DOF/shape.

[Vaughn]

Okay, so why get upset over semantics? Tilting the back relative to the scene will always change the shape of the scene. Does not matter if you tilt the whole camera or just the back of the camera.

As far as semantics, it is not the image plane that has anything to do with shape-changing, but the film plane. The image plane exists as a result of the positioning of the film and lens planes.

[rfesk]

Sometimes, of course, rear tilt must be used if there is no excess coverage of the lens.