C&C Converging verticals

Discussion in 'Comments and Critique' started by wjiang, Jul 6, 2018.

  1. I rather like shooting architecture. I have to confess, however, that I don't like straight verticals on the whole. Sure, if I'm shooting from a reasonable distance and fairly level, and the verticals are already almost straight, then I'll straighten them properly. If I'm up close, however, I just can't seem to make straight verticals work most of the time...

    Recent examples, shot using the 8-18mm:

    8mm, framing SOOC
    1-D7017616e.

    11mm, framing SOOC
    1-D7017698e.

    I've tried to keystone correct them in PP, but it just seems to ruin the composition in both cases. I'm a bit stumped here - what's going on?
     
    Last edited: Jul 6, 2018
  2. TNcasual

    TNcasual Mu-43 Hall of Famer Subscribing Member

    Dec 2, 2014
    Knoxville, TN
    What lens?
     
  3. Not sure whether it's relevant, but updated to mention that they were shot using the 8-18mm.
     
  4. TNcasual

    TNcasual Mu-43 Hall of Famer Subscribing Member

    Dec 2, 2014
    Knoxville, TN
    I think it is relevant when you might need to change the lens correction applied. The second image, especially, has distortion.
     
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  5. RyanM

    RyanM Mu-43 Veteran

    225
    Jun 16, 2017
    Can you post versions of these images with the perspective corrected, so that we can see what you don't like/doesn't work?

    My personal observations (based on very limited experience):
    1. sometimes the exaggerated perspective is the whole point of using the wide angle lens, and getting rid of that makes the image worse
    2. since perspective correction is applied in post, I often don't have it in mind when I'm composing on the viewfinder. As a result, the cropping that comes from the correction will cut off some sort of important element. Unfortunately the only solution that I can think of is to deliberately compose wider than you intend the final shot to be, in order to allow for perspective-correction-cropping.
     
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  6. Aha, you're right. That second image had barrel distortion applied to it by mistake somehow - the 8-18mm needs residual barrel distortion correction at 8mm but not really at 11mm.

    Here it is without the erroneous barrel distortion correction:
    1-D7017698e.
     
    Last edited: Jul 6, 2018
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  7. Here they are with verticals straightened.

    This one just feels unbalanced, not enough to the right. Cropping the left away doesn't really help. I think this is mostly a case where I should have composed wider, and taken the time to make use of the keystone feature in the E-M1 to pre-visualise I guess. Fully correcting the verticals also makes it feel a little 'off' somehow... like the perspective is wrong.

    D7017698e.

    This one... I don't know, somehow the image shot in landscape orientation ended up in portrait. The top right of the building just becomes way too dominant compared to the rest of the image. Again, even though the verticals are actually straight it feels like the top is bigger than the bottom.

    D7017616e.
     
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  8. lcsolla

    lcsolla New to Mu-43

    6
    Jun 3, 2014
    I think the main problem resides in the fact that, while our eyes see like a lens, we do not. Our brain automatically corrects for converging verticals, and in the real world and most cases we really do not see them converging - except when we look at a very high building, and even more when we are at the top and look down (which can easily cause vertigo). Perspective corrections - either by software or by perspective-correcting lenses - do not work the way our brain works. That is why people talk of over-corrections - the top of the building looks disproportionately big after the correction.
    On the subject of converging verticals and the brain: when I look through a viewfinder - be it the optical viewfinder of my old Nikon FM2 or the electronic ones of my Nikon D7000/Panasonic GX1 - I should see the verticals converging. Yet I do not. What I see instead is the sides of the building standing vertical, and the sides of the viewfinder diverging. No matter how hard I try not to see this, I fail. I only see the verticals converging in a waist-level finder, held away from my eyes. I wonder if it is just me.
     
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  9. This is such a timely thread for me. I was in Amsterdam not too long ago. I saw many old buildings tilted this way or that way due to I believe uneven foundation subsidence. Using 12-40 Pro at various FL, I simply could not get the effect I was looking for, which I expected to be difficult because of line convergence. I don't yet know how to correct such a photo in post to show the tilting buildings as close to the way they are seen by our eye/brain. I may have to come back to this thread to ask for advice!
     
  10. WhidbeyLVR

    WhidbeyLVR Mu-43 All-Pro

    Feb 14, 2014
    Whidbey Island
    Lyle
    This edge-stretch problem comes about because you are viewing a very wide field-of-view image (8mm or 70+ degrees vertically) in a fairly narrow physical field-of-view (maybe 25 degrees). If you could view the image either very large or very near (my old eyes won’t do this) — so it actually filled its original field-of-view — it wouldn’t seem distorted.

    Straightening the verticals is actually transforming (reprojecting) the image to a new center of view on the horizon (your original center was above the horizon) which makes it like the top part of an even wider field-of-view image — maybe 6mm or 90 degrees vertically. So straightening makes the stretching at the top more severe.

    Other reprojections (using a tool like hugin) result in other distortions. Examples are fisheye or Panini. Panini and cylindrical projections actually do a great job on an image with only verticals (columns or trees) but work less well on images with strong horizontal lines, like your examples.

    My usual solution to images like this is to embrace the converging lines by only partially straightening them. Balance the convergence and the stretch.
     
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  11. ijm5012

    ijm5012 Mu-43 Legend

    Oct 2, 2013
    Pittsburgh, PA
    Ian
    I must say that I like the images more with the corrected verticals. As for why, I'm not really certain.

    It's one of those things that I wonder if we as photography enthusiasts worry too much about, and that the general public (or those looking to purchase a print) couldn't care less about.
     
  12. Carbonman

    Carbonman Mu-43 All-Pro Subscribing Member

    Jul 10, 2014
    Vancouver BC
    Graham
    Sometimes it's about the visual impact of something that isn't the way we see it with the naked eye. Doing this sort of thing with photography is what elevates it from a technical skill to artistic expression.
     
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  13. WhidbeyLVR

    WhidbeyLVR Mu-43 All-Pro

    Feb 14, 2014
    Whidbey Island
    Lyle
    Here is the sort of thing I meant. I moved the center of view enough to mostly straighten the people and slightly straighten the building:

    1-D7017616e-zA.
     
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  14. WhidbeyLVR

    WhidbeyLVR Mu-43 All-Pro

    Feb 14, 2014
    Whidbey Island
    Lyle
    I think your analysis is pretty good. If you wanted to keep more of the house on the right, you needed to compose wider to allow for correction. Here is a similar treatment as my previous one. I chose to make the front of the house and light poles mostly straight while allowing the right side to converge. I did this by moving the center-of-view slightly down and to the left in Hugin and rotating the image slightly counter-clockwise (anti-clockwise?) to taste. This kept a little more of the right side of the house in frame and the left side of the house is at the one-third point rather than near the middle.

    1-D7017698e-zA.
     
    Last edited: Jul 6, 2018
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  15. Indeed! The fully corrected shots actually look okay (other than being a bit unbalanced compositionally) when viewed on a small smartphone screen rather than on my big monitor.
     
  16. Actually I think our eyes are very much unlike a lens/camera system - we have a spherical surface at the back of the eye. But your overall point is made - our brains correct a lot!
     
  17. PakkyT

    PakkyT Mu-43 All-Pro

    Jun 20, 2015
    New England
    Of course the other difficulty with these shots is not only are you shooting from below and at a wide angle, but you are also shooting the buildings at an angle (from the side-ish rather than straight on).

    One thing I sometimes end up doing is taking advantage of the many megapixels we have in our cameras and my wide angle lenses. Say you are across the street from a building (not a skyscraper but one that reasonably all fits the field of view). Normally most would zoom in to fill the frame with the building so that you end up shooting slightly upward creating the converging lines issue. I instead will shoot with the camera completely level and go wide enough to get the top of the building in. What you end up with is a shot where the street is likely taking up most of the bottom half of the frame and the building only in the top half using up a third to a quarter-ish of the sensors area, but that building is likely to have perfectly parallel sides with the top of the building the same width as the bottom. Then later I can simply crop it down to just the building again. Granted my final shot might be down to half or even a quarter of the megapixels of my sensor, but an easy edit and most buildings I shoot for web/computer viewing anyway.
     
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  18. Carbonman

    Carbonman Mu-43 All-Pro Subscribing Member

    Jul 10, 2014
    Vancouver BC
    Graham
    When shooting architecture really wide, I find using the built-in camera level to get the horizontal plane correct lets me do PP corrections and minimizing keystone issues much easier. The Olympus 'Info' button is my friend!
     
  19. What do you make of the composition after straightening? Is it the straightness that you prefer or do you actually prefer the composition too?

    There are a variety of perspectives (pardon the pun) on offer it seems. Maybe this comes down to creative choice - do we emphasise the perfect geometry of a building (which true architectural photographers do I suppose) or emphasise the way we see when we look right up at a building next to us?

    Perhaps next time I should try and take a portrait orientation panorama (I've done this before with very large buildings).
     
  20. When I'm shooting from across the street, it's easy to keep the verticals straight. It's these cases where I'm looking right up at a building that I have trouble with. I suspect in such cases the only way to go is to capture more of the vertical using a portrait orientation panorama.

    As for shooting at an angle - I suppose that's where these aren't 'proper architecture' photos - they're more like street scenes with buildings in context.
     
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