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10/08/2003 03:37:14 AM · #1 |
I think alot of people need to check a quick primer on how to rotate pictures so that buildings are perpendicular to the photo.
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10/08/2003 06:56:21 AM · #2 |
| Where can I find that information.... so many of the buildings I took were so tall and to get them without powerlines I had to be closer than I wanted to be. I know how to get them straight horizontally but they still seemed to lean forward or backward. I did not know how to fix that part. |
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10/08/2003 06:59:18 AM · #3 |
There is a perspective correction tool that works for that and its use was discussed in another thread, but what I believe MrCaN is referring to is the left to right tilt in many of the shots. That can be fixed with simple rotation.
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10/08/2003 04:14:14 PM · #4 |
| Don't forget that some people do that on purpose. Just so it looks different and possibly more interesting. |
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10/08/2003 04:27:42 PM · #5 |
Plus, using the perspective correction tool isn't legal for a challenge photo because it moves pixels and adds them.
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10/10/2003 11:36:18 PM · #6 |
Yea, I was talking about leaning left and right, so many pictures look like the buildings are falling over in the photos.
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10/10/2003 11:39:29 PM · #7 |
I think because of the other thread about perspective correction and the legality. People did want to tweak to much.
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10/10/2003 11:57:01 PM · #8 |
| my shots often, wide angle, do this they 'lean in'. I believe it is the way my lense reads it, sometimes I like the effect sometimes I dont. Would like to see the thread how to fix that if can. |
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10/11/2003 12:41:21 AM · #9 |
If you dont want buildings to lean so much zoom in a little bit. Telephoto lens compress things together whereas wide angle lens tend to distort things close to the lens.
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10/11/2003 12:51:50 AM · #10 |
This is normal perspective distortion in many cases. With an average camera and lens, you must keep your lens surface parallel to the architecture to prevent it. If you tilt your camera up or down, your verticals will not remain vertical in the photograph. They will tilt in or out...
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10/11/2003 01:26:00 AM · #11 |
Yeah my picture is actually leaning in on both sides which creates an interesting thing, I tried to fix it and the other side looked crooked as well. I just left it how it was taken.
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10/11/2003 01:40:27 AM · #12 |
Thank you MrcaN. Would you like to enlighten us on how to do this with out altering the shot so its still legal.
Byetko said zoom in. And that is very true. So its great advise. Or you could just get closer.
What are your words of wisdom>? I think if you have a "quick primer" you should share it with everyone. |
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10/11/2003 05:21:28 AM · #13 |
| I think he was talking about the few pictures that were more than slightly off, leaning to the right or leaning to the left, not leaning in because of the distortion caused by the lens or from the perspective the picture was taken at. A simple 1 or 2 degree rotation would have corrected everything, type of photo. I found that type of leaning frustrating also. More so because it could be corrected so easily. |
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10/11/2003 07:04:31 AM · #14 |
I am not too sure that all leaning of images can be corrected with the Photoshop perspective tool. Although I am inexperienced with this tool, I did try it on my image recently and found that it failed to correct the ultra wide angle distortions resulting from the 17mm lens that I used.
Is there are way to deal with this fisheye effect too? |
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10/11/2003 07:49:42 AM · #15 |
Originally posted by Morgan:
Is there are way to deal with this fisheye effect too? |
Check out the excellent article by Bob Atkins about fisheye to rectilinear conversion. Also, there's a luminous landscape article which provides links to other software.
Message edited by author 2003-10-11 07:50:32. |
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10/11/2003 08:23:50 AM · #16 |
Dale,
The Atkins article is good! There are in fact two Russian fisheye lenses that are worth considering, the 15mm Zenitar, and the 8mm Peleng.
I own the Peleng, and I feel it was a very good value, although it's fully manual and quirky.
I would add to Mr. Atkins' analysis that if you projected a 180 degree fisheye image on the inside of a half-sphere, and viewed it from the center of the sphere, you would see a natural, undistorted scene. The fisheye is certainly a mathematically "truer" depiction of ultra-wide-angle scenes, but the effect is not always pleasing. I've found that by carefully choosing the camera angle, then only partially correcting the distortion, can give a great combination of ultra-wide FoV and minimal apparent distortion. I need to correct slightly to eliminate the black areas at the corners of my sensor that are not illuminated by the lens (on a full-frame 35mm sensor this lens yields a circular image like this ne taken with a circular fisheye adapter on my Nikon 995):
I've tried full correction of the 8mm images, and the extreme stretching of the corners is very apparent and not at all pleasant. You also lose a great amount of your FoV (See Atkins) and this effect is even worse at 8mm than at 16mm, of course.
For those who like to dabble in extreme wide angle, I feel the Plelng lens is a good value, given that focusing is rarely necessary because of the extreme DoF. The only thing that puts me off slightly is the very strange aperture control, and that you can get used to.
Like Mr. Atkins, I use PanoTools to do all of my correction. Bear in mind that the corrections yield non-DPC-legal images :^{
Message edited by author 2003-10-11 08:30:15.
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10/11/2003 10:04:10 AM · #17 |
Originally posted by kirbic:
Dale,
The Atkins article is good! There are in fact two Russian fisheye lenses that are worth considering, the 15mm Zenitar, and the 8mm Peleng. |
I'll be dabbling with the Sigma 15mm diagonal fisheye soon and, with the FoV crop and less extreme distortion, I expect to do near full corrections and still have an adequately wide shot.
Once I've pushed my own envelope beyond that point, I will certainly heed your advice and look into the 8mm Peleng. It seems to me that lens sharpness at the edges is most critical with a fisheye, especially if you plan on doing any corrections. What's your experience here?
There's also the possibility of using a mirrored sphere (large ball bearing) with multiple shots to achieve similar results with a little more work.
Originally posted by kirbic:
I've found that by carefully choosing the camera angle, then only partially correcting the distortion, can give a great combination of ultra-wide FoV and minimal apparent distortion. |
I'd love to see samples, corrected or not, using your Peleng 8mm.
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10/11/2003 10:59:14 AM · #18 |
Originally posted by MrCaN:
Yea, I was talking about leaning left and right, so many pictures look like the buildings are falling over in the photos. |
Sometimes it might look that way to you, yet the building might still be perpendicular to the horizon line, but not at one of the edges (either the photo edge or at the edge of the building), instead the perpendicular line would be somewhere towards the middle (or 1/3) of the photo). IMHO that sort of perpendicular works much better.
I think on first impression you might say, "This photo would get a much higher score if it were perpendicular," but, are you sure it isn't? I'm afraid you might be making a snap judgment here without really looking at the photo.
Oh well.
Ursula
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10/11/2003 11:06:56 AM · #19 |
@Dale:
I find that the Peleng lens is reasonably good acros the field. Not razor sharp, but sharper than I expected. Contrast is decent too. The problem arises when applying correction. Some areas get stretched severely, and of course detail suffers in these areas, no matter how sharp the original image.
I've also thought about using a mirrored sphere, and I will certainly experiment with this when I can find a suitable shpere. If you come across any sources, definitely post them! I'm thinking that the sphere would have to be several inches in diameter at minimum for best results. You'd want to be as far away as possible to minimize image of the photographer & camera. I've seen "combined" shots where the camera is eliminated but not of course DPC legal.
I'm thinking of experimenting with a "gazing ball" which is available at most garden centers, but I know this will not yield the best results, as I think they are not first-surface mirrors (they're silvered on the inside)
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