Let’s Get This Straight

EDIT: This blog has MOVED. You’re on the old, dead blog. Everything (including this post) has been migrated onboard my website. Here’s the direct link:

http://scotthargisphoto.com/blog/

Update your bookmarks! See you there!

We now continue with our original programming….

****UPDATED****

I’ve recorded an updated version of this video. Read the new post HERE. The video below is still relevant if you’re relying on the Photoshop transform tools to correct lens distortion, but the new video addresses the transform tools now available in Lightroom 3.x, and the concurrent versions of Adobe Camera RAW, allowing us to perform corrections on RAW images.

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It’s usually the very first bit of feedback you get when you’re starting out in Interiors photography: get your verts straight! I heard it first from Mark Costantini, grizzled veteran PJ at the San Francisco Chronicle, when I was a stringer shooting hotels for the Travel section. Mark would review the 100 or so images I had uploaded for an assignment, pick out 2 or 3 to run, and admonish me on nearly every aspect of the shoot, starting with the verticals.

I’ve had the opportunity to coach more than a few shooters through the early stages of their interiors work, and correcting the verticals is always one of the first items to come up. I’ve seen a few tutorials on the web about this, but here’s my version, along with a little intro. I uploaded the video nice and big, so (after my face is safely off the screen) click the “full screen” button in the bottom left if you want to see what’s happening a little better.

Got your own technique? Share it in the comments!

59 responses to “Let’s Get This Straight

  1. Good show! “Nobody will take you seriously!” You’re right on. Verticals seem to be a difficult concept with most beginning real estate photographers. Even photographers experienced in other areas that move into real estate have a difficult time getting this issue.

  2. Well done, Scott! Slightly different for those of us using Photoshop Elements:

    1. View > Grid (to establish horizontal and vertical)

    2. Image > Rotate > Custom (to get the middle of the image vertical. May be a better way to do this, but that’s how I do it. After a little bit of practice, you can usually nail the rotation in one try.)

    3. Image > Transform > Skew (to straighten verts)

    4. Image > Transform > Distort (to regain the correct proportions. Use “aspect ratio” of windows and doors as your guide. The “Undo History” palette is invaluable for doing a “before/after” comparison.)

    One thing I do differently: rather than stretching out the tops of verticals that are leaning in, I generally scrunch the bottom. It’s more a philosophical thing than a reaction to any observation, but it’s always been against my religion to stretch pixels.

  3. Nice video Scott, here’s another tip when correcting the rotation of the image; if you select the ‘measure’ tool, click on a feature in the middle of the image that should be vertical [or horizontal] and drag the ruler along this feature then let go; the correct angle to straighten the image will be automatically entered into the rotation tool [including the rotate canvas shortcut: shift + Ctrl+R].

    In the interest of efficient workflow it’s worth looking again at the CS ‘filter>distort>lens correction’ module. I can get the whole job done in around 6 clicks. No need for guides as there’s a grid overlay, no need to stretch the image, as the vertical perspective correction slider stretches the top whilst compressing the bottom [or visa versa]. If I’ve shot from an extreme point of view then I might need to finesse the image with the transform tool, but for 98% of images it’s a quick, acurate, solution.

  4. Scott, you are the king! I remember a few years ago, posting my first images to Flickr. I thought they were the best RE photos EVER! Then you came in to straighten (literally) me out. My verts were horrible, and you took the time to provide amazing feedback. I’m now shooting covers for apartment magazines, and I owe a great deal of my success to you. Thank You! I have a staircase I’m doing post on now just for you. lol

  5. Thanks Scott. Great tutorial. Even us old grizzlies never stop learning new tricks. Thank you Larry for putting it up.

  6. I prefer the use of PTLens. It works easier with less clicking involved. And PTLens also corrects the barrel/pincushiondistortion of your lens. That problems persists with this method.

  7. Allan MacKenzie

    Nice one Scott, you are the man.

  8. @ John, Good point, I think Scott wanted to just focus on the perpective issue, but it should be noted that whatever method you use for straightening verticals, it should be done AFTER correcting for barrel/pincushion distortion; the ‘lowest’ of low hanging fruits.

  9. Thank you Scott for posting this tutorial. I’m saving this to my favorites — so I can refer back as needed!

  10. Ileen Cuccaro

    Great Tutorial Scott, I certainly learn something new everyday when I come in here, thanks so much

  11. Thank you so much Scott. I’ve been doing this by just my eye but the guide lines are very helpful and I also hadn’t known about the concept that the eye level needs to be straight and the top can show the camera position. I’ve driven myself insane trying to get the everything straight.

  12. Great tutorial Scott. I’ve been using DCE Tools to correct my verts, but this is much more controlled. I’ll definately give it a try!
    Thanks.

  13. great! very helpful, really appreciate your knowledge sharing!

  14. Great video, Scott! For those of you using Photoshop Elements, the easiest way to start is by using the Straighten tool. A lot of people avoid this tool because they think it can only be used to straighten horizontally. Actually, it can be used vertically by holding down the CTRL key.

    Choose a portion of the photo close to the center that should be vertical. With the Straighten tool selected, click at the top of where you want to start then, HOLDING DOWN THE CTRL KEY, move your cursor down along the vertical axis. If you want PSE to automatically crop after rotating, change the Canvas Options to “Crop to Remove Background”.

  15. Glenda, that’s a great tip! I’d never known about using the CTRL key for straightening verts; you just saved me about 30 seconds per image.

  16. Very nice tutorial that will help people who’ve been befuddled by this problem that’s a bit complex to solve, especially when starting out. Like a number of other people, I use PTLens. I’m going to play around with some images similar to your example to see if I can truly get all the components as “straightened out” as you have in your example. Thanks for the effort in doing this.

  17. I would also note that you will lose image quality slightly by doing this, making images bigger (dragging outwards for correction) will give some quality loss.

  18. Thanks Scott – Great tutorial!!

  19. Thanks Scott: Learned even more on correcting my verticals!

  20. Well – this was certainly popular! Thanks for the kind words, everyone. I’m going to do a follow-up tutorial on Barrel Distortion in the near future.

    @ John B. & Glenda — thanks for the tips re: Elements

    @ Marcus — YES – Adobe Camera RAW and Lightroom both have a feature where you simply trace a line following a natural feature in the image and it rotates to match with a click. I always do that while making my RAW adjustments. But I wanted to illustrate the concept and since not everyone uses an Adobe product….
    Lens Correct Filter works great for a lot of people…I just find that little slider really hard to control when it comes to making fine adjustments. And, it assumes that the problems are symmetrical, which is often not the case. That’s especially true when it comes to Barrel Distortion, which I’m going to address in the next installment.

    @ Shaun — Pass it all forward to someone else, dude. Makes the world go ’round.

    A few people made the good point that there is some image degradation inherent in the process. Very true. I’m not convinced that “scrunching” the pixels is any less damaging than stretching them, however. I do think that it’s better to get everything corrected in one “go”, and not be going back again and again to whatever method you’re using.
    Also, regarding the “scrunch” method: In the example I used, and I think this is typical, the perspective is most accurate at the bottom of the photo. The house gets “pinched” more and more as you progress along the vertical axis. “Squeezing” the bottom of the image to match the top would just result in an un-naturally skinny house, wouldn’t it? And then you’d have to use the Distort tool to stretch it back out on the horizontal axis, with all the image-degradation you were trying to avoid.

    Or am I not understanding what you’re suggesting?

    This is so great, everyone – keep the comments and tips coming in!

  21. Thanks Scott for sharing your workflow! In my workflow I’ll use the same corrections but in a faster way.

    Open your image. Press ctrl+t (transform tool), press ctrl+’ (shows the PS grid). Then rotate to a straight line in the middle. Then hold the ctrl key and your pointer changes into a skew pointer. Then skew like you do. Let go of the ctrl key to finish the transform with stretching.

    In this way you do not have to go through the menu steps and dragging the markers. It’s very fast (for me).

    I do have one question: is there a way to measure the lenght how much you have to stretch the image up or down in order to get the right proportion?
    My way is to measure by eye how much wider the image has become on both sides. Add up these two spaces on the sides and that will be the same what you have to extend at the top or the bottom. It’s less guesswork and looks natural.

    It’s great to discuss this workflow!

  22. Scott an d Ruud, this is one reason why I prefer the lens correction filter [ptlens can also work the same way I believe]; as you apply vertical perspective correction the image ’tilts’ around the horizontal axis, so that the top is stretched as the bottom is squeezed. This removes the compression effect seen in Scotts example, and the need to guesstimate how much to stretch the image height back to regain realistic proportions.

    Re: barrel / pincushion / moustache distortion correction, I agree that the photoshop lens correction filter is not a very good tool for this, I always run imaged through PTLens first.

    I disagree about the symetrical problem though Scott. If you’ve got the image lined up so that the center is truly vertical then there shouldn’t be any need to apply asymetric corrections. A simple tilt around the horizontal axis should correct the vertical distortion. If I ever find that its not working, then I go back a step and double check that I’ve got the image dead straight. I can’t think of a case where this didn’t solve the asymetric issue.

  23. Scott,
    Your blog is out a sight! Going to have to spend some real time going through it all. Thanks for the generosity and effort.

  24. Marcus- I agree with you. That’s the reason why I use the lens perspective correction as well. I find that I don’t need to compensate vertically for the squashed result. I use the barrel / pincushion, as well as the rotate within the lens perspective correction and find that i can correct for all 3 problems in just a few seconds.

    Yes, the barrel / pincushion correction is not the best. I wish I could specify the center of where to apply the barrel / pincushion corrections. That would help.

  25. Thank you for the video Scott. I always make sure this step is taken in my photographs, but it is always great to see how others do it. I think that it is important to make sure there is not stretching or minipulation to final image. You did a great job conveying that.

  26. Hello from Russia!
    Can I quote a post in your blog with the link to you?

  27. Thanks, Scott. Your dedication to education goes beyond generous! It is also greatly appreciated.

    I’ve been liking PTLens lately, but do notice that sometimes it creates a worse pincushion look to an image (?), and then I’m back in Photoshop anyway. Anyone else ever experience that?

  28. Wonderful. Thank u for sharing. Feel like I just took Photoshop 101.

    Thanks again.

    Dimples

  29. Great stuff Scott!! Thanks for taking the time in sharing and showing your workflow.
    And the old lesson of ” you learn more when you teach others” is probably playing along…:-)
    My flow has been to use PT lens first and most of the time don’t need to go to PS.
    I have lost faith in the CS3 lens/distort way, cause i suppose it becomes judgemental, whereas PT lens does the thinking for me…just seems quicker!
    I find myself going to PS after PT lens for Transform/Skew to correct the way out stuff, and was always mystified with the various choices under transform, and which ones to use when. So your examples helped me there.
    Thanks again
    Cheers Milton

  30. I would rather do one action, i.e squeeze, then move to the next, if you do it all at once, you can’t use the history palette if you make a mistake. I would rather do one action at a time, so I can step back if necessary.

  31. Nice one Scott!

    I use PS’s Lens Distortion Filter instead as I find that Lens Bulge or Barrel Distortion needs to be corrected when using the superwides. I do this first.

    The trick to using PS LD filter is to type in increments rather than use the sliders. My barrel distortion is 2.20 so thats an easy one.

    Vertical and horizontal perspective corrections are usually minor since I level on the tripod, so it’s +/- 0 to 1.x-ish – very easy to get used to. (I lean to the left, so I sadly have to correct to the right, lol)

    What I do not like about using the Transform method is that you create distortion and are actually changing the size of the home/room/walls/interior, if even just a smidge, which I prefer to avoid – that said most pro’s get it 98% correct or similar, but noobs should beware they do not alter a room any more than the superwides do.

    *Tip for barrel distortion / lens buldge – you need to shoot what Ken Rockwell calls ” A wall of shame” that is, a wall that has some kind of grid in it, like a plain brick or tiled wall. It will show your superwide lens’ distortion quite clearly.

    (W.O.S. examples at the bottom) http://www.kenrockwell.com/canon/lenses/16-35mm.htm

  32. Dale, the trouble with that workflow is that very few modern lenses have simple distortion characteristics. Many have what is known as ‘moustache’ distortion, where there is both barrel and pincushion distortion evident. PS LD can’t fix this.
    That’s why PTLens is such a good tool, it will automatically correct complex distortion.

    I have PTLens on a shortcut key “ctrl+.” then hit “return” job done in less than 2 seconds then open PS LD [again on a shortcut key] to correct the perspective. Then crop to fit. The whole thing takes about 20 secs.

  33. I’ve read that DXO handles all this quite well but I cannot get my head around it’s quirky workflow, (or my quirky head around it’s normal workflow..)

    @Marcus – Which lenses are you talking about? Never heard of that one – I haven’t tried PT Lens and only have one superwide lens, a Tokina 12-24 f/4, which has sharpness issues at the edges more than distortion issues.

    The root problem of course is shooting at 12mm, with a zoom no less – you really do have to spend the money and get top-notch optics. 20 – 24mm seems to be the sweet spot for me, when I go full frame I am switching to primes.

    Another problem is small rooms, which sort of demand 12-mm (for PFRE) and I have never been a fan of perspective distortion created by the SW’s and cropped sensors (I cannot afford FF) but in the end its all about the room and light anyways.

    Again the problem with using transform is creating more distortion – you are essentially taking a piece of putty and stretching it out by hand to try and make it square, so anyone without a lot of experience should be careful – and do an A/B at least to compare.

  34. Dale, looks like your Tokina is blessed with simple distortion that is relatively easy to correct.
    Here’s a useful comparison of corrections made to the tokina, nikon 12-24 and sigma 10-20 by PS LD and PTLens:
    http://waalsdorp.nl/~alson/uwa-distortion-ptlens/

    I use the sigma, so PS LD isn’t an option for me.

  35. Dale said:”Another problem is small rooms, which sort of demand 12-mm (for PFRE) and I have never been a fan of perspective distortion created by the SW’s and cropped sensors (I cannot afford FF)
    It’s been said many times before, this WILL NOT be solved by moving to FF.
    When capturing the same wide FoV from the same position, a crop sensor and FF sensor will give precisely the same perspective [anamorphic] distortion [and you’ll probably have more edge issues on the FF]
    There are other reasons to go FF though 😉

  36. It takes a while to start seeing some of the wackier “moustache” etc. distortion. Most WA lenses exhibit it, if the PFRE pool is any indication. And it changes with focal length, and distance to the subject. Lens Correct will NOT fix those, it assumes that everything is perfectly symmetrical. It ain’t. Ditto for verticals, actually. Near objects will appear to lean more than distant objects.

    Dale, one thing that you commented on stands out for me:
    “..What I do not like about using the Transform method is that you create distortion and are actually changing the size of the home/room/walls/interior…”

    What? Not sure what you mean, but are you implying that the LC filter doesn’t do what you’re talking about?

    Look, guys — the Lens Correct tool is doing the same things to the image as the Transform tools. The difference is that with Transform, YOU are in control of every step, not an algorithm. No assumptions need to be made about the nature of the distortion that exists in the original image.
    Both methods will degrade the image quality; no matter how you accomplish it, you can’t squish/stretch/interpolate pixels without losing some sharpness and image quality. In this respect, I think that Lens Correct Filter and Transform are about equal. I just personally find Transform to be easier to use, and again, it doesn’t assume symmetry, which doesn’t usually exist in my images.

    I’m going to be doing the “Barrel Distortion” tutorial next, so I’ll be taking all the suggestions in this thread and rolling them into that video.

    I really appreciate everyone’s input on this! Hopefully we’re all learning some new stuff here; I know I am.

  37. To the best of my knowledge, when you transform one corner of a square / rectangle shape you distort the subject matter.

    You cannot replicate exactly the same amount pulling the opposing corner(s) “by eye” which is why I prefer the PS filter, which simply corrects/changes X,Y and Z planes or Vertical, Horizontal and Rotation (CW, CCW) evenly.

    I like Scott’s method although there are far less steps using PS filter – and you edit barrel distortion at the same time in the PS filter.

    @marcus – I should have been clearer (more clear?) – it is the focal length I was referring to – 12 mm creates more perspective distortion (PD) that a 24mm so I would prefer to use FF at 24mm than cropped senor at 12mm.

    Thanks for the input

  38. yeah but..
    A FF at 24mm isn’t the same FoV as a crop sensor at 12mm.
    A true comparison would be a FF at 24mm to a DX [1.5x]crop at 16mm. In this case both the FoV and any perspective distortion would be identical.

  39. Right! I am shooting 12mm / Nikon at 1.5 so I am at 18mm – then after LD corrections it ends up at 20/22mm.. so I would rather shoot 24mm at FF

  40. …then shoot your tokina at 18mm instead of 12mm, according to the link I posted above there’s practically no distortion at 18mm. There, I just saved you about $4k !!

  41. Or shoot a couple of photos of the subject, say 2, one of the left, one of the right, join those images, say with photomerge in photoshop for example, then correct that much larger image, then you have a wide angle shot, with minimal effects on degrading.

  42. Lots of valuable info here, so I’ll bookmark it and give it a go later. However, as a relic of the film era, I’m not comfortable somehow with all this bending, skewing and distorting— especially with a subject as objective as a house. I find I can avoid most perspective convergence problems simply by making sure my camera’s always level. That won’t always give me the framing and composition I want, so I shoot wide (11mm) and crop from the top and sides, eliminating the extra ceiling and sky. It’s a very simple and quick method, and it doesn’t leave me puzzling over judgement calls (“Does that look too tall/squat/worked over?”). This may not allow such a wide range of adjustments as the PS/PT Lens methods, but it’s adequate for 90% of my work. Think of it as a virtual shift lens. The lens doesn’t move, but through the cropping process, the image plane does.

  43. Can someone tell me what the effective difference is when using, as I’ve been, the cropping with the perspective box checked, bringing in the upper left and right corners to be parallel with verticals, then going to the distort tool to pull up the ‘too squat’ image?
    By the way, my website stuff will show keystoning and other issues that I am a ware of but left.

  44. When using Photoshop CS3, I find that the image quality that results from the Transform tool is poor, compared to Lens Correction or to PT Lens.

    With the Transform tool, lines which are at a slant, for example, countertops or roof edges, end up being jagged, for me. So far, I have not found any way to prevent that from happening.

    Otherwise, I would agree, that the Transform tool does in some cases give more control to the user.

  45. Excellent post – thank you so much for sharing!

    I use DXO Optics Pro – in its newest version 6 it’s a breeze to use and does a tremendous and very intuitive job in correcting perspective: it’s all about drawing 2 lines!

    Blaise

  46. Thanks for sharing Scott. You never cease to amaze me.

    You’ve been a tremendous inspiration and useful source for making me a better photographer.

  47. I was asked to give an interior decorator a bid on a job. I have never shot for her before. Do you charge an additional hourly rate for post processing or is that included in your shooting time? Thanks.

  48. hey Scott,

    Just stumbled across your website. This is a great tutorial!

    I’ve taken dozens of uncorrected wedding photos in churches that are making me cringe right now.

    Thanks!

  49. Scott, thanks for the helpful tutorial. You’ve mentioned another tutorial for barrel distortion. I haven’t been able to find it – is it still in the works?

  50. Endless hours of frustration, just swept away.

    Thanks for all you share.

  51. I know this is an old article, but Lightroom 3 has a wonderful Lens Correction area.

    Also, why not just use TS or PC lenses? Expensive, yes, but seems easier to me.

  52. Indeed an old post and things changed for me. I’m now using the lens correction in LR most of the time. Since 3 months I’ve got the Canon 24 TSE lens. This is really great! It takes a little more time on the scene to set it up (lens must be completely level, has manual focus and light metering is different depending on the amount of shift). The field of view is like a 20mm lens where you have to correct in post. And if I need a more wide angle I stitch 2 or 3 shifts. I use this lens 99% of the time, the best buy for me since years.

  53. Simply awesome Scott!

  54. Dear Scott, I was amazed when I stumbled into your “Let’s Get This Straight” Video.
    I had my first RE gig today in Chicago. A self taught photographer, I was forced to shoot the front and back slightly off center, due to trees and street lights – which caused distortion much like the yellow house in your video.

    After a short period of thought, I remembered a lesson from some long ago Photoshop book and accompanying CD ROM for Photographers that covered this issue. Although four years removed from the lesson, I began with the center vertical and transformed outward accordingly. I simply went with my instincts, and developed a more acceptable photo. (Not quite as successful as yours, however.)

    I’m happy to have ‘stumbled’ into you, and will return soon. Also, I returned to Chicago decades ago from San Raphael. (Biggest mistake in my life) Once I’m on my feet and established as a photographer, I’m going to return to the Bay Area for life.

    God Bless,
    Jack Rohan

  55. It’s so frustrating now, when I see RE photos that aren’t straight. This makes it so easy to fix.

  56. kurtvandeweerdt

    Nice video! How do you get in the Transform menu from the canvas screen? Right mouse + something or…?