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Perspective Distortion In Real Estate Photography

June 7th, 2011

A very real issue in real estate photography is perspective distortion. It comes up all the time because real estate photographers use wide angle lenses which are famous for two types of distortion:

  1. Barrel distortion: This is a lens defect prominent in ultra-wide zooms where straight lines near the edge of the image are curved.
  2. Perspective distortion: This distortion is a feature of wide angle lens. The perspective looks exaggerated because it’s different than the human eye/brain is used to seeing.

Barrel distortion can be corrected with Lightroom 3, Photoshop or other photo editing software but the only way to get rid of perspective distortion is to zoom your ultra wide lens to a longer focal length. How do you tell if a image has perspective distortion? If it looks strange, that’s how. Many would say that perspective distortion is a matter of personal taste. I submit that we only notice perspective distortion when the focal length of the lens is significantly different that the focal length of the human eye. What’s the focal length of the human eye? If you google this, you’ll find that there are a number of answers. I believe the correct answer is between 22 and 24mm. Here’s why:

  1. For starters, there are a number of scholarly research papers (see bibliography here) that measure the focal length of the human eye. 5 claim it’s 17mm and 2 claim it’s between 22 and 24mm.
  2. If you consult a wide variety of photographers, architects, designers and photo editors most will express a preference around 24mm.
  3. Most accomplished architectural photographers use a 24mm tilt and shift lens.
  4. If you look at high-end Architectural publications most if not all the photos will be shot with a 24mm effective focal length lens.

My conclusion it’s not an accident that visually sophisticated preferences gravitate to around 24mm, because that’s very close to what the human system is use to.

I know, real estate marketing images shot with a lens with an effective focal length less than 24mm are very common. Images shot at 14mm and 16mm are used all the time Super wide has almost become a “real estate marketing” look. But in my experience, the farther you get below about 22mm effective, the more likely it is you will get negative feedback from clients and viewers. Some will not notice or care but many will. I had one home seller call my 16mm images of his home “cartoon like”. It took me a while to even figure out what he was talking about but it was the perspective distortion. Another common criticism you hear is that agents are trying to “make rooms look bigger than they really are”. Many home buyers feel scammed when you use super wide shots.  I’m not saying always shoot at 24mm, I’m saying be aware of the fact that not everyone thinks ultra wide shots are cool.

I’m going to even go a step further. Most visual distractions in marketing photographs are created when images contain visual effects that are radically different than what the human visual system is used to. For example:

  1. Perspective distortion
  2. Unusual white balance or overly saturated colors (radioactive HDR)
  3. Converging verticals
  4. Horizontals that are not horizontal
  5. Barrel distortion
  6. Unusually dark photos
  7. Unusually bright windows

All of these visual effects in interior images distract from the strength of an image because they make images unusual and unbelievable to the human eye/brain. The more visual distractions, the harder it is for the viewer to focus on the real purpose of the photo. Removing all these image problems will make the image will be stronger and more effective.

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22 Responses to “Perspective Distortion In Real Estate Photography”

  • Good article. I agree! I have the Nikon 14-24mm f/2.8, and as tempting as it is to use it at the wide end all the time, I find I typically either crop a little in post, or zoom into around 20mm in the field to remove some of the drama and make a room look more natural. It’s incredibly easy to falsely advertise the size of a room, and I try very hard to show a house as it really looks, with correct wall and floor colors, perspective, etc., and yet make it look inviting of course.

    Now, for landscapes and scenic photography, it’s 14mm all the way baby! 😛

  • Great article and I could not agree more. Perspective distortion is at the root of a “how wide is too wide” discussion that we had on another thread a few weeks ago, but this articles defines the issue and effect much better than I ever could have. I don’t know if I would put over-saturation or white balance in the same category because the human eye/brain seems to have the ability to immediately process and translate those elements as intended art/creative features or settings errors. Perspective issues such as converging verticals, super-wide refrigerators or curves, seem to leave the eye/brain with a sense that “something is wrong here” longer.

  • Yes! My major complaint with ultra wide shots is the exaggerated distances in trying to show an entire floor plan. Some of them look like you need a bicycle to get across the living room. Even worse is the Goldie Locks Effect: the foreground chair looks too big, the distant chair looks too small, but the middle chair is just right.

  • Great post Larry. Although I’m inclined to disagree with the part about the effective focal length of the human eye. From my own experiments, I have found that an effective focal length just under 50mm yields the closest approximation to what my eye was actually seeing. Try it. Grab a zoom lens that will cover at least 24mm – 50mm, point the camera toward the subject at 24mm and look through the viewfinder. Move the camera away from your face and compare to what you are actually seeing. Now try the same thing at 50mm. It may just be me, but the image in the viewfinder at 50mm is pretty darn close to what the subject looks like just standing there looking at it, in terms of volume and distortion anyway. On the other hand, you actually have much more field of view in real life and perhaps that is why the 24mm number may make sense.

  • Just curious – if a 24mm tilt/shift (24mm effective for medium format) is the standard for architecture, what would be the specific use for Canon’s 17mm tilt/shift?

  • @Iran- I didn’t make this up, there are more than one physicist that has come up with the number of 22.6mm as the human eye focal length. Here is the math: http://galileo.phys.virginia.edu/classes/531.cas8m.fall04/l11.pdf

    @dbltapp- tilt/shift lenses aren’t just used for architecture.. it’s a great landscape lens. Also, I’ve heard some real estate shooters say they like the 17mm tilt/shift. Another explanation of why Canon made the 17mm tilt/shift is that on a APS-C sensor it’s a 27.2 effective tilt/shift… pretty close to 24mm.

  • I agree with Iran Watson. I’ve done the same experiment with my Nikon D-90 camera and found that the image through the viewfinder looks the same when I’m just looking at the object without the camera.

  • After my last comment, I pulled out my D-90 and tried it again. the 50 mm setting appeared to be the same distance, but the 24 mm setting looked more like what I saw when I included peripheral vision. So, Larry, I agree with you now.

  • The 24mm ts-e is for taking accurate, beautiful crystal clear architectural images. The 17mm ts-e is for making your clients happy after they tell you that your shots don’t show enough of the room.

  • While a good post, Iran is correct – 50mm with a 35mm camera is what is called the “normal” lens because it most closely approximates the human eye perspective. To most closely approximate the human eye, the focal length should equal the diagonal of the film sensor. So, on a 35mm it is 50mm, on a medium format Hasselblad, for instance, it is 80mm and on a 4×5 camera (chime in Dan) it is 150mm. Whether it is street photography, documentary, journalism, etc., the 50mm has always been the standard and the classic lens for a 35mm camera. Go back and take a look at all the famous street photographers and find out what they used. For instance, HCB, probably one of the most famous, spent his whole life using the 50mm prime lens on his Leica.

  • @Amy- Yes, I understand that conventional wisdom considers 50mm normal… but look at the scientific research. No scientist is even arguing that it’s 50mm. Scientists are arguing whether it’s 17mm or 24mm. This is not an issue photographers get to decide, it’s a scientific matter and there is not scientific agreement.

  • Larry, I’m sorry to disagree, but that scientific paper is only about the capabilities of the human eye and has nothing to do with the human eye vs. perspective distortion in photography. Perspective is a complicated subject and too broad to discuss here, but it is rooted in the science of optics. What you haven’t accounted for is “marginal distortion” – this is created by the flat plane of the camera lens vs. the curvalinear plane of the human eye. Since the scientific papers aren’t concerned with photography, but only the capabilities of the human eye, it has nothing to do with perspective when it comes to photography. It’s apples to oranges. But scientists all agree that the angle of view of normal vision is about 50 degrees. They also all agree the viewing distance is normally 10″. This paper has no relationship whatsoever to camera lenses or photography. The window pane theory of explaining perspective still holds. Nothing new here. I went back to my books called ‘The Focal Plane Encyclopedia” which is authored by scientists and re-read the issue on perspective.

  • @Amy- Let me take another run at my argument and leave out all the scientific stuff and just make an intuitive argument:

    As I sit here looking out my office window, I can see the whole end of my office. The window and walls to the left and right of the window. I can see an angle of view of at least 90 degrees very clearly. If I hold up a finger on each hand and move my hands as close to straight out one hand to each side of my head I can sort of see 180 degrees with my peripheral vision. Sort of because at 180 degrees my fingers are fuzzy so the sharpness of my vision drops off in quality and sharpness from 90 to 180 degrees field of view.

    Now, if I mount my 24-70mm zoom on my 5D MkII (full frame) and look at the end of my office, if I rack the lens all the way to 24mm I can see the whole end of my office (actually somewhat less) just like I can when I’m not looking through the camera and lens. If I crank the lens down to 50mm all I can see it the window, nothing to the right or left!

    From this simple experiment, I’m forced to conclude that the horizontal field of view and perspective that I see with my eyes is much more like my lens at 24mm than it is 50mm. Maybe I shouldn’t be talking about the focal length of my eyes. It probably makes more sense to talk about horizontal field of view and perspective.

  • The real question is why is there a fisheyed pic of my college’s library accompanying this article? LOL!

  • What focal length is most “natural?” I think there’s two visual principles at work here, leading us to two different answers. The field of view, or amount of peripheral vision, produced by two normal human eyes is close to 90%, give or take a few– I think we can all agree on that. In 35mm terms, it takes a lens in the low 20 mms to match that. But that lens won’t deliver realistic renditions of objects at near and far ranges, without perspective distortion. For that, you need closer too 50mm. Why?

    The missing variable here is print size. An ultrawide interior shot looks wildly distorted in a small web-page display, but I bet that if you printed it 2×3 feet, mounted it on a concave board and studied it with you nose 10 inches from the paper, it would look realistic indeed. Normally, we don’t look at photos that way; we look at reduced images, hence the apparent distortions.

    None of this theory changes the way I shoot interiors. Over six years of doing this, I’ve progressed to ever-wider lenses. That’s improved my work, I believe. They give me the choice of all-inclusive, panoramic stills, and the freedom to crop whenever and wherever I need (yesterday, I cropped a scene of a distant pool from 24 to appx. 75mm, just because I was too lazy to change lenses).

    As the proud owner of a Sigma 12-24, mounted to a Sony full-frame camera, I usually shoot quite wide. That allows me to include all the fixtures in small bathroom, or show a glimpse of the third wall of a small bedroom, or show vaulted ceilings in larger rooms. Usually I crop each image to improve the framing, when I’m back home at the computer. I take an image shot at 12mm, wide and on the level, and crop away 20% of the top and sides. That gives me some of the benefits of a shift lens without the expense and hassle. I’d guess the final images would average about an 18mm (FF) perspective. I’m careful to crop away the most disturbing distortions, such as the outside edges of stretched refrigerators and ovaled table lampshades.

    Bottom line– my clients love this look. Homeowners like to see their home look bigger. Agents notice that I’m doing something that obviously their pocket cameras can’t do, and that gives me a value-added selling point for my photos.

  • John McMillin (above) is 100% correct in everything he said. I too shot a Sony a900 with the Sigma 12-24, for the same reasons he mentions. Now I use a 35mm lens on a 1.5X crop camera, mounted to a Gigapan. I shoot everything in the room, stitch the file in PTGUI and render a 100+ degree FOV final. The benefits are higher resolution, elimination of lens distortion, and the ability to choose perspective. The downside is that it takes more time, the rig weighs more, and you have to correct the occasional stitch error.

    Take a peek at my portfolio of architectural interiors. Most were shot as a mosaic (stitched rows and columns) and all were shot and rendered with HDR/exposure fusion techniques. http://imagicdigital.com/portfolios.php?group=0

  • (runs to get his camera to try this himself)

    🙂

  • This website is incredible … I’m exploring real estate photography as my next career and the information here is so helpful. I’m not in a position to “reinvent the wheel” and I so appreciate the sharing of information and support between all of you. I’m considering starting with a Canon T3i body to take advantage of the tilting LCD screen and read this thread to pick up tips on lenses. I’ll research the Sigma 12-24. I’d welcome any advice and thanks again for the great information … PRFE rocks !!!

  • Concur on the 24mm school of thought and that some wide lens can work on certain applications, when you are herding in a large inventory of listing images, time is crucial and consistency in the look, feel. The other key is the first image and the time to add one or maybe two insets, even very limited copy so the photo captures, conveys more leading in to the real full motion video to finish it off in engagement, connection and “delivering” the eyeballs and ears of the surfer to the property or area event. That is powerful.

  • Thanks for the article. Made me check into tilt shift lenses and I probably will to the plunge now

  • Just looking for confirmation or correction… You are speaking in terms of FX sensor; and I should adjust for my D90 1.5DX sensor.

    I’m on a D90 & a Tokina 10-17mm 3.5-4.5 DX. Does that mean that my 10-17mm is acting like a 15-25.5mm? And for me, the ideal focal length is 11-16mm (to achieve the 17-24mm)?

    Thank you in advance… Cheers!

  • @Andrew– Yup, you’ve got it. To get effective focal length you multiply your camera’s crop factor (1.5 for Nikon cropped sensors like the D90) by the lens focal length. Then when you are shooting interiors keep the effective focal length around 24mm because that’s the kind of perspective that the human eye is used to seeing. Shots that are wider than 24mm effective start to look strange to the human eye. Many agents like to have their listing shot with a15 or 16mm effective lens because any room starts to look way bigger than it is because of exaggerated perspective.

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