Talk:Scheimpflug principle

message: This article is screaming for some additional figures.
Fig. 1 is awesome, pulls you right in.
Where is the same picture showing in focus achieved by lens tilt?
Where is the same picture showing focus achieved by backplane tilt (perspective loss)?
Demonstration of the Scheimpflug solution would add tremendously to the impact of this article.
Note: a single object must be for all three example images to consummate the paper.  Changing objects detracts from the message.  — Preceding unsigned comment added by 59.27.183.94 (talk) 20:33, 29 July 2013 (UTC)
thread_title:  Scheimpflug 

message: Hi, I'm new to wikipedia, so please excuse any transgressions in protocol.  But I noticed what I think are some sign errors in the proof for the Scheimpflug principle and wanted to point them out.  The first time magnification is defined, there is a minus sign in front of the ratio.  But the third time m appears (after the phrase "On the image side of the lens, again from Figure 6") there is no minus sign.  So the convention isn't consistent.
Also, looking at the last line (y_v = -(a - b/f)v + b), there is a sign error in front of the b/f term.  The previous line shows that it should have the same sign as the av term.  —Preceding unsigned comment added by Pixelatedcode (talk • contribs) 20:15, 4 September 2010 (UTC)
replies: text: Protocol is to point out the error so that the idiot who made it can fix it ... I've (hopefully) fixed the errors, and attempted to explain the combination of normal Cartesian coordinates and the optical sign convention that shows object distances increasing to the left of the lens plane. See if this works. JeffConrad (talk) 02:52, 5 September 2010 (UTC)

text: Looks good to me.  Also seems to match the result I got from a different proof-method I tried.  Btw, I like your proof approach.  It uses some simple geometry to make for a more straightforward and intuitive proof (my independent attempt was more algebraic).  —Preceding unsigned comment added by Pixelatedcode (talk • contribs) 19:19, 5 September 2010 (UTC)
thread_title:  Errors in proof 

message: I've made a couple of minor changes in attempt to clarify how the examples were calculated. I've used Merklinger's approximation for DoF on a plane parallel to the image plane because it's simple, and to my knowledge, he's the only published source. But his approximation isn't the best one for large values of tilt; specifically, as distance increases, the image distance , but the line-of-sight (rail) distance , so at the hyperfocal distance, the DoF on a plane parallel to the image plane is approximately  rather than . At the hyperfocal distance, the difference between v and f is negligible, but with large tilt, as may be used on a large-format camera, the difference between  and 1 may not be negligible. As a consequence, to be strictly correct, I've used to notes to explain the differences. If this makes an already arcane concept too confusing, we could simply use the more accurate approximation and have nothing that needs explaining. The down side of course is that someone familiar with Merklinger may notice the apparent disparity and wonder which is correct. The “exact” formula that he gives on p. 126 is indeed exact, so no qualification is needed.
Though it may seem like I'm making a big deal out of a small detail, the DoF distribution on a plane parallel to the image plane is a key concept in choosing the best position for the plane of focus in a typical scene that isn't strictly planar, and to my knowledge, it had not been described prior to Merklinger, and I think his contribution here is due some deference. JeffConrad (talk) 07:45, 23 September 2010 (UTC)
thread_title:  Edits of 22–23 September 2010 

message: I'm struggling with the Angle of the PoF section. My difficulty stems from the magnification terms in the final equation. For a system with no magnification, I believe I should take m = -1, which then gives \tan \psi = 0, placing the focus plane vertical and parallel to the image plane, irrespective of the image plane angle. I may have the sign convention wrong and m = +1, this would give \tan \psi = 2 \tan \theta whereas I would expect \psi = 2 \theta by symmetry. I think my confusion arises because figure 6 defines the magnification differently, as m=-\frac{y_v}{y_u} which is along the axis of the lens normal (magnification is a function of the ray angle). In figure 7 the magnification is expressed along an axis tilted with respect to the lens normal. Nick.hawkes99 (talk) 17:33, 2 March 2018 (UTC)
thread_title:  Question about magnification 

message: The statement "Of course, the tilt also affects the position of the PoF, so if the tilt is chosen to minimize the region of sharpness, the PoF cannot be set to pass through more than one arbitrarily chosen point. If the PoF is to pass through more than one arbitrary point, the tilt and focus are fixed, and the lens f-number is the only available control for adjusting sharpness." is not true in practice and unless I have misunderstood the wording, I believe this section should be revised. With swing and tilt it is possible to have what is in effect a plane of focus angled across at least three points in the depth of the space that is framed by the camera.  Jamesmcardle(talk) 21:56, 4 February 2019 (UTC)
thread_title:  Incorrect to say "the PoF cannot be set to pass through more than one arbitrarily chosen point"