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Excellent read - Field Techniques for Technical Cameras – Lenses and Accessories by Dave Chew in PhotoPXL

vieri

Well-known member
Next installment is up that includes my crazy descriptions of tilt 🙄

Ciao,
Dave
Hey Dave,

I really enjoyed the last of your articles - as well as the previous ones - and your "crazy description of tilt" is actually one of the simplest yet "working" explanations I have read, like, ever :)

Thank you for putting the series together, looking forward to the next one! Best regards,

Vieri
 

MGrayson

Subscriber and Workshop Member
Note: The following is completely irrelevant to the USE of tilt in the field.

I've never thought about WHY the Hinge Rule makes sense. Scheimpflug is just some unpleasant geometry. But Hinge makes sense without math. The question is: what is special about the plane, H, one focal length in *front* of the lens? Answer: it is the focal plane when the sensor is infinitely far behind and parallel to the lens. Since infinity is messy to deal with, replace it by "very very far". Now consider a point on the sensor plane very high up - like 10 kilometers. With any downward tilt, that point is now very far from the lens plane. One degree of tilt puts it about 174.5 meters behind the lens plane (10 kilometers * Sin[1 degree]. I know I said no math, I lied). So where do all the points 174.5 meters behind the lens plane focus? On the plane verrry slightly in front of H. For a 30mm lens, the distance in front of the lens is 30.0516mm. (Yes, that's 51.6 microns in front of H, or about one human hair thickness.)

And why is the Hinge where the plane H intersects the vertical plane through the lens (actually, parallel to the sensor)? Light from this point 10 kilometers up on the sensor is heading down towards the lens at an incredibly steep angle - it is practically a vertical line (yes, yes, it's 6 arc seconds from vertical, or about one tenth the angular width of the planet Jupiter as seen from Earth). And so it hits H almost exactly where a vertical line dropped from the lens does.

Apologies if that made no sense at all. Like I said, it's irrelevant in practice, but it makes me feel better knowing WHY the rule is there.

Matt
 

dchew

Well-known member
Thank you for all the positive comments and support.
Fantastic articles, Dave. I missed no3, but just read it. Yea, the 10 step lens changing routine pretty much describes what I already do, with minor differences. Thanks for the writeups. Very helpful. I am still trying to understand no4. And apply it to tabletop macros that
I do. Read it trice already.
It's funny that I've been wrestling with the lens changing process on my new GFX system. Those lenses are so much bigger than I'm used to. It is difficult to grab everything the way I've described in the article. I will need to practice!!

Thank you so much Dave! I appreciate the time and what has to be considerable effort into making an informative article. These have all been fantastic and I've awaited this latest as patiently as I could muster. I'm looking forward to digesting some more and trying some of the techniques this weekend. I've been trying to master tilt and I've been missing a few things this article nicely pointed out. Again, one of the things I appreciate about the people here is their willingness to share and teach. We need more of this in the world. :)
Ray, I'm glad you are enjoying the series. I should stress what I said in one of the articles: These are my processes that related to my photography. They should be treated as curious procedures that may help your photography; they are not by any means THE way to do things. Just an input to your workflow in the field. Just like there are 25 ways to do something in Capture One and Photoshop, there are countless ways to do things in the field.

Hey Dave,

I really enjoyed the last of your articles - as well as the previous ones - and your "crazy description of tilt" is actually one of the simplest yet "working" explanations I have read, like, ever :)

Thank you for putting the series together, looking forward to the next one! Best regards,

Vieri
Thank you, Vieri! I get such a charge out of discussing and debating the dynamics of tilt. It really is fascinating to me how it works (and how it doesn't work).

Dave,

Superb, and to the point!

Matt
Thank you, Matt. I laughed at your "to the point" comment. I feel like I'm breaking some article-length records with these. :rolleyes:

Ciao,
Dave
 

Ray Harrison

Well-known member
Ray, I'm glad you are enjoying the series. I should stress what I said in one of the articles: These are my processes that related to my photography. They should be treated as curious procedures that may help your photography; they are not by any means THE way to do things. Just an input to your workflow in the field. Just like there are 25 ways to do something in Capture One and Photoshop, there are countless ways to do things in the field.
Oh, totally Dave. I look at it as another perspective I can take in to see what works for me not as a cookie cutter :). Thanks again!
 

vjbelle

Well-known member
Dave.... a great contribution for the understanding of camera movements. Thanks so much for taking the time (I'm sure lots of it) and effort for a great presentation.

Best.....

Victor B.
 

ThdeDude

Active member
Very impressive write-up. Writers are generally quick to state the first part of the Scheimpflug rule (film plane, lens plane, and plane of focus converge) but tend to ignore the more complicated second part (plane of focus, front focal plane, and parallel-to-film lens plane converge), and the rather complicated relationships of how these converging planes actually interact.

I agree with Dave that for field work an empirical, iterative approach is more suitable than using a theoretical approach trying to compute the required tilt.

For a given scene, I decide whether a tilted plane of focus (generally, horizontal plane tilted upwards) would be advantageous (needed) or not. Select a close point and far point (objects in the scene) of the desired plane of focus, start with some tilt, focus on one of the two points. If the other point is also in focus, the amount of tilt applied is correct; but if in order to get the other point into focus need focusing movement towards the tilt (suggesting not enough tilt) or focusing movement away from the tilt (suggesting too much tilt) [hope I got this the right way round!]. Adjust tilt accordingly, and repeat until both points are together in focus. Check whether objects outside the plane of focus are sufficiently in focus (or out of focus, if this is desired). If not, try a slightly different plane of focus, and repeat.
 
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Geoff

Well-known member
Ray, I'm glad you are enjoying the series. I should stress what I said in one of the articles: These are my processes that related to my photography. They should be treated as curious procedures that may help your photography; they are not by any means THE way to do things. Just an input to your workflow in the field. Just like there are 25 ways to do something in Capture One and Photoshop, there are countless ways to do things in the field.
Yes, but your way works! Not to be taken lightly.....
 
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