Why don't image files have any camera orientation info?
why don't the image files from Nikon, Canon, etc. have information in the image files specifying the exact orientation of the camera (at least roll) at the time the picture was taken?
Depending on the subject, background and perspective issues, it is sometimes a bit difficult to determine the horizon reliably. Sometimes trees, columns and beams in the middle of the photograph are not really horizontal or vertical. It would be nice to have this information ready for the post-processing.
The technology for this should exist already; game controllers and smart phones know their attitude, e.g., to drive a car simulator. However, currently only coarse portrait/landscape orientation is supported.
What do you think?
#1. "RE: Why don't image files have any camera orientation info?" | In response to Reply # 0Sun 10-Jun-12 11:59 AM | edited Sun 10-Jun-12 12:30 PM by ZoneV
The level on the camera body does not really tell you that the horizon is level. Rather, it tells you it is straight in your photo. There is a difference. A straight horizon is not necessarily an absolutely level one.
Further, the orientation sensor has similar limitations the way it's currently implemented.
There are too many variables necessary to determine a level horizon just from picture data alone...you don't really have enough data using a single, tripod-mounted camera. Think about professional surveying techniques, and how they almost always employ multiple points to determine linear orientations. So how would the camera and software really know what level was without sampling at least one other point (preferably two more)? It could guess, but it would probabaly miss often.
Now if you want Nikon to put a directional gyro w/compass into the camera, that'd be a whole different thing. Perhaps one day, the lens's VR system sensors would be sophisticated enough to utilize for this purpose...some day.
Nikon user since 2000
#2. "RE: Why don't image files have any camera orientation info?" | In response to Reply # 1bkinthebay Registered since 27th Feb 2010Sun 10-Jun-12 12:30 PM
Some cameras, including my D700, already have a virtual horizon function that can help in setting the camera horizontal or vertical.
What is strange is that this data is not included in the exif information of the picture.
#3. "RE: Why don't image files have any camera orientation info?" | In response to Reply # 2Sun 10-Jun-12 12:34 PM | edited Sun 10-Jun-12 12:38 PM by ZoneV
>Some cameras, including my D700, already have a virtual
>horizon function that can help in setting the camera
>horizontal or vertical.
>What is strange is that this data is not included in the exif
>information of the picture.
But that data relies upon user feedback. You have to physically align the camera to the virtual horizon. It does not do it for you. I believe the purpose of the virtual horizon is actually not to give a reference to absolutely level the camera. Rather it is a guideline that you can reference when positioning your horizon. You need to determine the angular correction needed based on your perspective, and apply it yourself.
Due to landscape features, the actual horizon is seldom the same angle as the ground the tripod is placed upon. Further, perspective (due to lateral camera position variation) determines the actual angular correction needed for a level horizon to appear level in the photo. So the virtual horizon is simply a guide that uses the camera orientation sensor as a starting point...it's not meant to be used as an absolute reference to determine if the camera is level. It does not always work for this task. Yes, it would work if you had a perfectly flat environment and a head-on camera angle. But how often do we really have that setup?
Nikon user since 2000
#4. "RE: Why don't image files have any camera orientation info?" | In response to Reply # 3bkinthebay Registered since 27th Feb 2010Sun 10-Jun-12 12:39 PM
It's certainly not bulletproof, but at least the same amount of guidance could be made available during post-processing if the virtual horizon data was included in the picture.
Let's say the virtual horizon recorded you took the picture with a -1 degree angle with respect to the horizon, applying a +1 degree rotation during post-processing could be a decent guess.
#5. "RE: Why don't image files have any camera orientation info?" | In response to Reply # 4Sun 10-Jun-12 12:55 PM
>It's certainly not bulletproof, but at least the same amount
>of guidance could be made available during post-processing if
>the virtual horizon data was included in the picture.
>Let's say the virtual horizon recorded you took the picture
>with a -1 degree angle with respect to the horizon, applying a
>+1 degree rotation during post-processing could be a decent
That would be useful and cool. Why don't you write to Nikon and suggest it?
Nikon user since 2000
#6. "RE: Why don't image files have any camera orientation info?" | In response to Reply # 1
thanks to everyone for your comments!
I was looking for a gravity solution, not trying to analyze the picture for the landscape or anything like that. Well, the gravity does not always pull vertically down to the horizon... Anyway, using the virtual horizon is viable for static objects (except that it is behind menus in D3). The point is that it is not an option when shooting sports while looking through the viewfinder.
I shoot girls' soccer a lot - I use monopod - and sometimes I need to catch the action in the field and then I turn the camera so quickly that it is not horizontal when I press the shutter release button. I like to stand on the side line and then the girls run fast by me and my camera.
I might be standing too close sometimes. I had a close call the other evening. While having my eye on the viewfinder the ball hit a player in front of me and passed my head so close that I felt my hair moving!
#7. "RE: Why don't image files have any camera orientation info?" | In response to Reply # 6Sun 10-Jun-12 04:51 PM | edited Sun 10-Jun-12 05:01 PM by ZoneV
The best way to keep the camera level when shooting sports is practice on your own time. Hold the camera normally, and practice panning at various speeds while keeping it level. Then try to flip as quickly as possible to vertical orientation while rotating exactly by 90 degrees, or as close to that as you can get. Keep practicing these maneuvers, and eventually you will get 95% of your shots within 2 degrees or so of correct orientation.
This is one of those situations where a pro body...with its square shape, good grip, bigger viewfinder, well balanced mass, and vertical grip can really help out.
It also helps to remember that the viewfinder is not just a window you're viewing through, but actually a representation of the final scene, with its borders and orientation.
If it helps, you can also enable the viewfinder gridline feature. Personally, I tend to just go by feel...I can tell when the camera is roughly alinged properly. I shoot very quickly, especially in sports. My camera is almost never still, always panning, and I sometimes even will run up and down the slideline as fast or faster than the players, in order to better follow the action on certain plays (in order to have maximum mobility I shoot with one body, I don't use a monopod, and typically use a relatively compact lens--a 300/4), but I still get the majority of my shots aligned ok. I rarely have to rotate the frame in post. Practice!!
Nikon user since 2000
#8. "RE: Why don't image files have any camera orientation info?" | In response to Reply # 6KnightPhoto Nikonian since 18th Dec 2006Sun 24-Jun-12 02:16 PM | edited Sun 24-Jun-12 02:18 PM by KnightPhoto
One of the best things I ever learned is to take my camera off of level for dramatic effect. I use this technique in portrait and theatre but you may want to try it for sports. A perfectly flat orientation is mundane, whereas if you introduce uphill and downhill you can add drama to the capture.
Effect can be subtle, a degree or two, or more dramatic per taste. You can try it in post as long as your image has some cropping room by using the level feature of your post processing software. Take an already dramatic image and rotate it downhill by 5 degrees and then re-crop it per the new orientation.
I sometimes take this too far while shooting, but can moderate it in post as long as I didn't compose too tightly.
Best regards, SteveK
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#10. "RE: Why don't image files have any camera orientation info?" | In response to Reply # 6Ned_L Charter MemberSun 24-Jun-12 11:44 PM
I think we could define the horizon as the apparent line that divides the earth and the sky. That being said you are right that the horizon isn't necessarily perpendicular to gravity. Therefore, we can pretty quickly say that gravity based horizon information won't be a good solution, except perhaps for a seascape, to show you the actual horizon.
Moreover, if you're out in the natural world, items such as trees aren't at all necessarily vertical, as you mentioned, but in the human-made world, generally the orientation of columns, but not necessarily the edges of the columns (Parthenon), and most exterior walls of most buildings are vertical and run parallel to gravity. In fact most building construction these days is vertically "plumbed" via gravity, or laser sited via gravity. From there they get the horizontal the building should be built to. So, a gravity based horizon should work nicely for cityscapes.
Yes it would be a nice feature if Nikon would include horizon information in the exif data, for cityscapes, but to be honest by using a vertical or horizontal guide in Photoshop, I've really not had a difficult time "straightening" my photos as necessary.
As to the virtual horizon in the D3. It doesn't have to be behind menus, if you think it's important to you to have at your fingertips. For example, your could assign it to your FUNC. Button. (See pages 331-333 in your manual.)
As to shooting sports, it takes conscience practice, but you can get darn good panning quickly on a monopod, and keep your camera horizontal. If it's off, use visual guides to help you rotate the image to correct the problem. Lay the guide on something you feel is either horizontal or vertical.
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#9. "RE: Why don't image files have any camera orientation info?" | In response to Reply # 0
Yes, it would be nice to include pitch and roll information in the EXIF data. And then get Adobe to update Lightroom etc use it as an approximate guide, if I wish. The D800 knows this because it shows us in the viewfinder or live view. Its just not writing this information to the file in a form we can read later.
OP asked about using the pitch and roll information to help with post processing. For those times when it may be confusing to work which is level. Or spur of the moment grab shots where the horizon is the last thing on my mind.
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#11. "RE: Why don't image files have any camera orientation info?" | In response to Reply # 0
I'm not sure how useful this feature would be "after" post processing.
Because with the way some software can allow cropping in different angles or straightening a picture by lines drawn on the screen, the info in the Exif would be incorrect afterwards.
When you rotate a picture CCW or CW will the software you used to rotate the picture be smart enough to change the Exif?
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#12. "RE: Why don't image files have any camera orientation info?" | In response to Reply # 11