Talk:Tilted plane focus

Confusing title

This material is a valuable addition to WP, but I find the title a bit confusing; I think it would be more clear if it were "tilted-plane focus" (as implied by the original editor's web site) or perhaps "tilted plane of focus". Even so, it's not a common term--a Google search shows only the original editor's web page. I'm not sure there really is a good common term, but most people tend to think of it as "Scheimpflug", strictly correct or not; I wonder if this material should be merged into the Scheimpflug article--I think a reader would be more likely to find it there.

It looks to me as if there are a few technical issues as well:

• Depth of focus (allowable displacement of the image plane for a fixed object distance) is used where I think depth of field (object-side region that appears sharp for a fixed image distance) is meant.
• It's stated that DoF "permits bringing into focus objects at varying distances from the camera". This isn't quite true; objects within the DoF appear to be in focus under "normal" viewing conditions, but focus is really achieved only for one plane. It's perhaps a small distinction, but one that's nonetheless important, especially because there isn't universal aggreement on what consititutes "normal" viewing conditions.
• It isn't quite correct to state that a wide-angle lens has great DoF and that telephoto lens has shallow DoF; it depends upon subject framing. When magnification is the same, all lenses in given format at a given f-number have approximately the same DoF. JeffConrad 04:40, 24 April 2007 (UTC)

Jeff, thanks for these thoughtful comments. I actually do mean 'depth of focus' because it is the displacement of the image plane with which I am concerned (affected through tilting of both lens and film panels). Yes DOF needs qualification - will attend to this. I would be happy to rename the page 'tilted-plane' focus but feel that if merged with 'Scheimpflug' the potential of this technique, which I hope will be of use to others, might be lost.[[sinarau 14:01, 24 April 2007 (UTC)]]

James, selective focus still relates to depth of field, regardless of how you tilt the lens or image planes. Depth of focus is a completely different issue; it might be appropriate when discussing the effects of film buckling.

Your comment about merging with Scheimpflug raises a question about the intent of this article: is it meant to cover only shallow DOF and not the more general case of rotating the PoF? If so, I've misread it, and will need to revise my last edit to the DoF article. If that's the case, I think almost any permutation of "tilted plane focus" could be confusing; the title should be something that makes it clear that only the shallow DoF is meant. The only term in common use for this seems to be "anti-Scheimpflug", though it's somewhat of a misnomer because it still employs the Scheimpflug principle. This again might be a reason to merge this with the Scheimpflug article. The Scheimpflug principle really relates to rotation of the PoF; the rotation can be such to either maximize or minimize the part of the image that's within the DoF. The Scheimpflug article needs a lot of work; I'll see if I can make a start on it in a few days. JeffConrad 20:55, 24 April 2007 (UTC)

Freelensing is a neologism that, if used at all, should be supported by a reliable source. The link to photojo.com does not appear to be such a source; any discussion that mentions “tilt-shifting technique” essentially impeaches itself (“tilt-shift” is not a compound adjective). Absent some indication that this source is reliable, I think it, as well as the mention of “freelensing”, should be removed. Any source that might replace it should also be reliable, not just a web site from a Google search.

Perhaps “freelensing” could be treated like “tilt-shift photography”, for which we have an article without much in the way of good sources. But as with “tilt-shift photography”, I think we're on shaky ground. At this point, I think “freelensing” could only reasonably be described as a term some people use rather than one that is well established. JeffConrad (talk) 01:56, 1 March 2010 (UTC)

Edits of 28 March 2010

I think the recent edits have improved the article. At the risk of seeming the naysayer, however, I think it still reads more like a personal essay than an encyclopedia article. Accordingly, I've restored the tag. A case could be made that a different tag, such as {{cleanup}} or one or more of its many relatives would be more appropriate, but I think the specific tag is far less important that the underlying issues, some of which I describe below.

The biggest issue I see is the use of vague, abstract, and offbeat language for ideas that could easily be described using specific, concrete, and conventional terms. There also are many subjective comments unsupported by sources.

The article title, though hardly illogical, is nonetheless a neologism that seems to find little use other than articles that ultimately point to the author's web site. I question whether this is appropriate for Wikipedia, and I question whether it's appropriate to include in the Photography portal. I'm not sure it's sufficiently notable that it merits a separate article, either, though if not, there is some question about where it belongs. We currently have considerable duplication among View camera (especially regarding movements), Perspective control lens, Scheimpflug principle, Tilt-shift photography, and arguably some others. Offhand, I don't have a great solution to propose.

Perhaps a minor point, but the lead section refers to “Tilted plane photography” rather than “Tilted plane focus” used for the title.

Some examples of vague abstractions: “Focus is relative to spatial depth”; “the scene in front of the camera can be modulated in depth”. I understand the principles involved quite well, but struggle to understand what these phrases mean.

The lead section is both subjective and unnecessarily abstract. I'm sure there's a less prosaic way of saying it, but this in essence,

Tilting the lens (or the camera back) puts the plane of focus at an angle to the image plane rather than parallel to it; accordingly, it's possible to have elements at varying distances from the camera rendered sharply.

Whether the other, subjective comments apply is a matter of opinion. In particular, many photographers would take issue with the implication that this is a more consciously applied technique than selective focus without tilt; it's simply different. Without question, it's important to carefully chose the position of the plane of focus rather than just fiddling with the tilt, as Vincent Laforet points out in this interview; perhaps that's what's intended here.

I don't understand the purpose of the section “Plane of focus”. I don't think anyone disputes that focus is on a plane rather than a point, so I'm not sure why it's mentioned. Though nearly all lenses exhibit some curvature of field, except perhaps for a Lensbaby lens, it's definitely a second-order effect for what's discussed here, and I simply don't see its relevance. I'd just eliminate the entire section.

The section Tilting the plane of focus includes the statement that tilting the PoF “will permit the photographer to select at least three points in depth in the scene in front of the camera on which to focus”; perhaps it's just me, but it would seem far simpler to say something to the effect of, “it's possible adjust the PoF so that it contains at least three points in the scene”. There's also less of an implication that it's simply a matter of adjusting focus.

I question the mention of the Lensbaby lens. Though it enables a form of selective focus different from that commonly seen, its significant curvature of field makes it difficult to use for what's described here.

The note for Prayer and Praise seems unnecessarily long, perhaps to the point that it's questionable whether it's still fair use.

The listed references include page numbers, but don't have inline citations, so it's difficult to see what they support. Perhaps inline citations would address some of my comments, but even so for someone outside Australia, most of the sources are very difficult to verify.

The article retains several significant technical errors. I repeat my earlier comment that the author confuses depth of field with depth of focus; the former is what applies to selective focus. I also reiterate my comment about the difference between focus and apparent sharpness. The ideal lens may by aspherical, but it's not parabolic. And again, it's completely irrelevant to this article.

In summary, the article contains so many vague abstractions that it's fairly simple essence is buried. It might help to make an outline of the key ideas to be conveyed and compare it with the article to see how each is addressed.

I hate to denigrate someone's hard work, and concede that my comments may seem a bit harsh. Nonetheless, I think the article has many issues that need to be addressed. JeffConrad (talk) 00:34, 29 March 2010 (UTC)

Expanded tags 1 April 2010

I've changed the tagging to better reflect the main issues.

The term itself may be a serious problem, perhaps to the extent that the article cannot stand.

• As noted above, it's an extreme neologism, and it's not even one in widespread use.
• Though the term isn't necessarily illogical, it co-opts other equally logical uses—such as using tilt and swing to render everything sharply. As such, it's misleading. Were the term established as referring to selective focus, the situation might be different. But that's not the case.

The technique is certainly valid and merits description somewhere in WP, if perhaps not here. Though it probably can be described more eloquently, the technique, whatever it's called, in plain English

• Achieves selective focus by rotating the plane of focus away from parallel to the image plane and using a large aperture to minimize the angular depth of field.
• Is distinct from “miniature faking”.
• Is probably not well described simply as “tilt-shift photography”.
• Is most effective when the position of the plane of focus is chosen carefully, as supported by Laforet's comments.
• Has been used for quite some time, as illustrated by Prayer and Praise.

As noted previously, the technical descriptions are in some cases superfluous, and in others inaccurate, and in any event, are better described elsewhere in WP.

The technique might possibly be merged into Depth of field (perhaps under selective focus) or perhaps under Tilt shift photography (if it's ever decided what that is). JeffConrad (talk) 01:22, 2 April 2010 (UTC)

Moving the page

Jeff Conrad, your comments are valid, and I thank you for pointing out that "Tilted Plain Focus" is a neologism. The contents of this page should therefore be edited so they can be moved under another banner. But where?:

• Scheimpflug Principle?

specifically we are talking about the use of shallow DoF combined with Scheimpflug to bring into focus a number of points in the photographed scene, and throw out-of-focus other parts, is a specific expressive technique. The photographer employing the Scheimpflug technique does not want the viewer to be conscious that they have done so, and will usually add DoF of a smaller aperture on top of the Scheimpflug manipulation.

...also, in contemporary photography, it is not solely a lensing technique...

• Tilt-shift_photography?

There are now well established digital software manipulations that can be employed to duplicate aspects of a 'shallow-DoF-combined-with-Scheimpflug' technique, particularly for the rather gimmicky 'minature faking' now in vogue. Therefore even though this page does mention those techniques it is predominantly about camera movements - so the Tilted plane focus discussion could be included there. I am uncomfortable with the vagueness of 'tilt-shift' and it's not only about focus. We are seeing a large amount of so-called 'free-lensing' - not a term I'm in love with, since it sounds like some form of Freebasing - but a valid, but necessarily less mathematical, application of the Scheimpflug technique which a photographer can apply experimentally and intuitively and still achieve quite sophisticated expressive effects. That usage should therefore be included under both headings.

Historically this is still a rarely used technique; hence the neologism - there isn't really a name for it. Several artists have used variations on it, perhaps re-inventing it for themselves on each occasion, going back to Julia-Margaret Cameron, though examination of her photographs will show she never actually tilted the lens in relation to the film-plane - she worked with the effect that the tilted camera produced (usually a downward tilt), placing her subjects where they come into, or out of, focus. I will include reference to these prior examples. Scheimpflug is used for overcoming the focus-in-depth limitations of the larger format camera to focus everything on one plane; typically a table-top or angled wall. 'Tilt-shift' is just another name for that, though the term seems to be becoming attached to a technique for producing an exaggeration of limited depth-of-field for one point in the image.

I will carry out the migration of the valid information on this page between the above two pages soon. However the idea of tilting the plane of focus (and making the tilt apparent in the image) is about an artistic technique, not a mathematical representation of an optical effect, there may be some clash of languages in the amalgamation of the pages!

I appreciate any assistance. sinarau (talk) 12:35, 11 April 2010 (UTC)

I'm not quite sure about your statement, “The photographer employing the Scheimpflug technique does not want the viewer to be conscious that they have done so”, but if by that you simply mean that many photographers using it wouldn't advertise it as “tilt-shift photography”, you and I agree. I can't imagine Adams ever having used it to describe one of his landscapes, either. Though his objective usually was to get everything sharp, he nonetheless relied on the Scheimpflug principle (but as a means rather than an end, much like the Zone System). The technique discussed here is of course a specific expressive technique, but the same is also true of most good photography. I agree that those who use Scheimpflug selective focus most effectively usually do more than just fiddle with the tilt to create a lot of blur for “tilt-shift miniature faking”; in addition to those we've already discussed, people like Keith Carter come to mind.

I agree that the technique here is a different topic from the mathematics of the Scheimpflug principle; I think we're better off keeping the mathematics in that article and describing more practical applications elsewhere.

The question of where is a valid one. Selective focus is normally associated with depth of field, but in this case I think it probably better relates to camera movements.

It might go under Tilt-shift photography (at least as that article now stands), or perhaps an article dedicated to Camera movements. As I've mentioned on several other talk pages, we have considerable material duplicated among several of the articles mentioned, as well as Perspective control lens and some articles about specific lenses (e.g., the Canon tilt/shift lenses).

I have some concerns with the term “tilt-shift photography”; though it's in common use, it's also a neologism, and I've yet to find a really reliable source for what it means. My sense is that it usually refers to digital simulation of Scheimpflug selective focus used to simulate miniature scenes. It's often a misnomer because any shift that's involved is usually incidental, and as mentioned, because I suspect that it's seldom achieved optically, given the plethora of “tilt-shift” images and the high cost and comparatively few sales of tilt/shift lenses. But some people do seem to use the term to mean use of camera movements in the normal sense. So it's tough to decide what the article should include—a common problem with neologisms, especially without reliable sources (Joe's PhotoBlog doesn't count ...). Perhaps the Tilt-shift photography article gives too much weight to the conventional use of movements (and I'm the one most responsible).

One possibility would be to move much of the material from Tilt-shift photography into an article on Camera movements, or perhaps a real article on Tilt/shift lenses. An advantage of talking about tilt/shift lenses rather than tilt-shift photography is that there isn't much dispute about what the lenses are, and we can find plenty of reliable sources. A possible drawback with putting this material in the latter article is the potential conflict between hardware vs. technique (much like math vs. technique in the Scheimpflug principle article). I'm not sure how the people who've done most of the work on the View camera article would feel about having most of the material on movements broken out of that article. With a movements article, an article on tilt/shift lenses could briefly mention that the lenses provide front movements, and concentrate on the features of the lenses.

Such a master plan obviously involves some effort as well as thought, in addition to getting consensus among those who've work on the affected articles. It's unlikely to be achieved overnight, if even at all. At present, I suggest trying to make some of the explanations here a bit simpler, more concrete, and perhaps a bit less subjective. As I've said, I think some of the technical areas with which I've taken issue could be removed without harm; they're covered elsewhere, and as I think we agree, this article is about technique rather than optics.

I'm not sure there's even a good term for the technique discussed here other than something to the effect of “Scheimpflug selective focus”; “anti-Scheimpflug” has been around far longer than “tilted-plane focus” or “tilt-shift photography”, but it's somewhat misleading, and it's also somewhat biased, possibly implying that the “proper” use of tilt and swing is for getting everything sharp. So I'm not sure it's a good choice.

I wasn't going to mention freebasing, but since you've saved me the trouble ... My main issue with how freelensing is currently handled is that it's an extreme neologism unsupported by reliable sources (again, Joe's PhotoBlog doesn't qualify ...). There are a few techniques that I've developed that we can't write about here because they would constitute original research. If freelensing is still mentioned, perhaps we could say something like, “Some people use freelensing to describe ...”, but of course this just invites the question, “Who?”, and the attendant tag.

Not directly related to this topic, but when tilt and swing are used to get everything sharp, there's usually more involved than just the position of the plane of focus. Most scenes are three dimensional, and rely on the DoF to get everything sharp. It's relatively straightforward to adjust the PoF to pass through two (or perhaps three) points, but less so to choose a position of the PoF that will get a scene sharp at the minimum possible f-number. So in a sense, getting everything sharp entails even more effort than selective focus, though it probably could be argued that less artistic judgment is required. The Sinar e camera manufactured in the early 1990s attempted to address this, and from what I understand, did quite a good job of it (it probably also would have excelled at passing the PoF through three points for selective focus). But its cost, bulk, and tethering requirement (to a PC-AT computer) made it impractical for most applications outside the studio. The theory is fairly straighforward, but to my knowledge, it has not been described outside of Sinar, so it's not something we can cover in Wikipedia. JeffConrad (talk) 04:23, 12 April 2010 (UTC)

Yes I am not wild about 'tilt-shift photography' as a home for this info. Your Scheimpflug page is about the mathematics as you say - but I think adding some examples of the application, including this one, would provide useful valid explanation.

I am inclined to include some history of the use of camera movements for focus effects, but that might be appropriately placed elsewhere - maybe on 'Focus' which could be expanded? 'Camera movements' is a good suggestion too. --sinarau (talk) 12:52, 12 April 2010 (UTC)

It's not my Scheimpflug article, though looking at the article, I noticed a significant qualification that was somehow omitted from some of my material (I just added it). Does the section on Selective focus (which I just tried to fix) not qualify as an example of this application? It doesn't address the artistic considerations (and it really cannot); quite honestly, though, I think the extent to which they're covered here is pushing it—not because you and I really disagree on them, but simply because some of the comments are very subjective, arguably too much so for an encyclopedia.

Some article (and I'm not sure it should be Tilt-shift photography) should cover movements used for maximum sharpness as well as for selective focus. Any such article not dedicated to the Scheimpflug principle would of course need to cover translational movements (i.e., rise/fall and lateral shift) as well as the rotational movements. There's a lot of usable material in the View camera article, but looking at it, the section on Movements needs a fair amount of work. Assuming people would agree to cover movements in general in a dedicated article, it still would need to be decided how much such an article would cover specific applications as well as the basics of the movements (much as the current View camera and Tilt-shift photography articles). In any event, the appropriate location may not currently exist, and I think a bit of thought, as well as effort, will be needed to create it.

A discussion of the history of movements, especially tilt and swing, would be a welcome addition, but it's a fairly obscure topic that would need to be supported by reliable sources.

I think the recent edits have considerably improved this article, though a few issues remain, primarily statements that strike me as overly subjective, and some terminology that may not be clear to all readers (e.g., depth rather than distance from the camera, and relative focus; if I didn't already have some understanding pinhole cameras and DoF, I'd have no idea what you are talking about). Some of these are probably easier to fix than to list; I can have a go at some of the more objective items if you like. JeffConrad (talk) 01:26, 13 April 2010 (UTC)