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Old Jan 21, 2006, 9:24 PM   #1
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Folks, I recently tried to stitch two photos and the result was not bad. I am a complete novice in this area and would like to know a bit more. Can any kind heart tell me exactly what is involved in this process. Let say how many pictures do I need. Must they be of the same size, etc. We might use different software but I am sure the process will be the same. Kind of difficult for me to say exactly what I am looking for but let's hear from you. Kind regards. Jaki.
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Old Jan 22, 2006, 7:56 AM   #2
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I´m not a pro, but few guidelines have worked for me:
  1. Use a tripod, or be careful and put the horizont at the same level in every pict.[/*]
  2. Do not use any polarizing filter.[/*]
  3. Neverset your lens to the widest aperture, due to the barreel distortion. 50 mm (equiv) wil work fine.[/*]
  4. Set the camera in manual mode, fix the aperture (for panoramas, I suggest a high aperture number) measure the ligth in all the frames and set the "middle" speed.[/*]
  5. Shoot fast, don´t take many time between shoots, or the ligthing conditiond will change.[/*]
  6. Be careful to overlap your shoots at least a 10%
[/*]
You can stich any number of pictures, I've seen up to 42 pictures together. I usually take 3 or 4.
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Old Jan 22, 2006, 9:56 AM   #3
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msantos wrote:
Quote:
[*]Never*set your lens to the widest aperture, due to the barreel distortion. 50 mm (equiv) wil work fine.[/*][*]Set the camera in manual mode, fix the aperture (for panoramas, I suggest a high aperture number) measure the ligth in all the frames and set the "middle" speed.[/*]
Aperture doesn't have nothing do to with distortions and itsn't measured in millimeters. Also better stitching softwares correct distortions.

All non-SLR digicams have magnitude bigger depth of field than film cameras or bigger sensor dSLRs so there's no sense to use smallest apertures (biggest number) which just cause softening of details. (lenses generally give sharpest picture when using middle apertures)

But zoom (focal length) has to be kept same while taking shots intended to form one panorama, also locking exposure is mandatory to avoid lightning changes caused by changes in exposure.
And also don't move camera sideways, just rotate it while taking parts of panorama, especially if there's details close to you... moving camera causes change in perspective of details between shots.
You can visualize this perspective change for example by looking landscape so that there's some power line pole near in front of you... if you move even little position of that pole changes in relation to background.


And in case of cheap or free basic programs it's better to zoom in little for avoiding biggest distortions, also something like at least 20% overlap is good for those softwares which correct distortions.


These two are propably the most versatile programs:
http://www.ptgui.com/
http://www.tawbaware.com/ptasmblr.htm

This one doesn't have so much distortion corrections.
http://www.panoramafactory.com/


PS. This is what big panoramas means...
http://www.imaging-resource.com/NEWS/1070414103.html
http://jancology.com/blog/archives/2..._panorama.html
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Old Jan 22, 2006, 12:10 PM   #4
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I agree with ET: there is no reason to avoid short focal lengths unless you have a remarkably bad lens that you wouldn't use at the short end for any shot and/or are using very simple software. Some of the best panos that I have seen were shot with an 8mm (equiv) focal length lens: see http://communitywalk.com/map/109

Panorama Tools with one of the graphic front ends (PTGui, PTAssembler, Hugin, PTMac, ...) is the most powerfull stitching program. It is also the most difficult to learn so getting one of the autmagical stitching programs is worthwhile.

Acouplemore rules are touse nodal point rotation and alevel tripod.

I have found that there are all kinds of "rules" for shooting panoramas. They can all be broken, but you will be able to use simpler software and will have fewer failures if you follow them.

IMHO, the most important issue for shooting panoramas is the same as any other photo: picking the place to stand when you shoot. That is harder with panos since you cannot frame the shot with the viewfinder.
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Old Jan 24, 2006, 10:59 AM   #5
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Thank you very much Msantos, E.T, and BillDrew. I am complete novice and the imformation is overwhelming. I want to do some ground work, then I can have questions for you. This has been very imformative. Kind regards, Jaki.
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Old Jan 24, 2006, 11:04 PM   #6
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If a tripod was necessary for panoramas I wouldn't take very many. With practice you can swivel your body and keep them straight and aligned. That works only if you are taking the panoramas in one plane though. If you want to stitch both horizontally and vertically it is very hard without a tripod and panorama head.

If you are using manual exposure to keep the exposures the same, don't forget to also set a white balance rather than leave it on auto. Also keep in mind that aperture and shutter priority are automatic modes and your exposures will vary with them.

If you are using a camera without manual exposure controls or a panorama mode that sets the exposures the same, you can use continuous mode on many cameras. I have had three cameras that continuous works fine for. My current pocket camera buffers the first shot so the second comes pretty quickly, but it is about a second a shot after that. Continuous is different from burst on many cameras – you just hold the shutter to do continuous. Most cameras fix all of the settings with the first shot in continuous so you can stitch with simple and fast software. Continuous is too fast on my large camera and I have to set everything up in manual. I would prefer to shoot in continuous with that as well. Pre-meter on what you think is the average exposure and then reframe and hold the shutter while take the individual shots. It really works well if continuous isn't too fast like my FZ.

I shoot most panoramas at the widest angle and have no problems with the stitching. I run most of my shots through PT Lens so there isn't any distortion when I stitch them. PT Lens is a free plugin that even works in Irfanview, but you have to process them one at a time in Irfanview where you can run it in bulk in a better image editor.

I shoot most of my panoramas with the camera sideways with the longest side vertical. You get more in the panorama that way.

As BillDrew pointed out, if you shoot with the exposure and WB the same for all of the shots you can use simple software to stitch. That kind of software is quick and easy. They also require less overlap.

If for some reason you can't shoot with the same exposures I think this is the best freeware available: http://www.cs.ubc.ca/~mbrown/autostitch/autostitch.html It expires occasionally and you have to download a new version, but it is worth the hassle IMO.

PT Tools is extremely competent and free, but there is a difficult learning curve if you don't buy one of the front ends E.T. linked.

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Old Jan 25, 2006, 12:00 AM   #7
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Thanks Slipe for giving me this new dimension. You have been very informative. I will download that software. Because I am still new to this trade, I cannot say much have to practice a bit before I can say anything coherent.:-). Kind regards. Jaki.
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Old Jan 25, 2006, 12:31 PM   #8
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Slipe made some good points. Don't worry much about things - just get out and start shooting. You don't have to show (or even admint) your mistakes, but you will learn from them.

Slipe is much better at holding the camera level than I am, but even the ones that are way off can produce a pano good enough for documentation on the web.


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Old Jan 26, 2006, 8:59 PM   #9
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Thanks BillDrew will do exactly that and post. Keep your fingers crossed. Kind regards. Jaki
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Old Jul 3, 2006, 3:57 PM   #10
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Hello,

I like simple things so here is my simple solution. Use a camera with a very wide angle lens both of very good quality or better. I use an Olympus C-5060WZ with a 0.7x wide angle lens so I get about 19mm EFL in a single shot which is pretty good. However, the far corners (most distantfrom the center as far as pixels) of even a single 19mmlandscape shot are distorted (warped) enough to be noticeable. To help alleviate the noticeability of the corner distortion in a picture such as the one I attached, I like to hold the camera in portrait mode and take 2 shots overlapping themsomewhere between 25% and 50% depending on how wide I want the shot by rotating the camera (from a fixedposition) horizontally for the 2nd shot. This usually puts the area of maximum distortion up in the sky or down in the water,grass, sidewalk...where it is not as noticeable.It is also good to aim at the horizon to make it pass thru the centerof the frame for both shots. That will help minimize distortion. Taking 2 portrait images this way for a panoramic has 2 really good results: 1) it puts the aspect ratio back to (or very close to) 4:3. If you want it exactly at 4:3 you can crop. Generally with a 5MP C-5060WZ, after stitching and some minor cropping you can get it almost exactly to 8MP. 2) it is effectively like having a 2nd level of wide angle lens but without any additional distortion. In effect, you are reducing distortion or at least hiding it in spots where it is not as visible. I don't know the exact angle of view using this technique and combo but I would estimate somewhere around 14mm EFL. The 2 images can be metered using automatic mode because most likely both will have similar light (such as 50% sky, 50% nonsky each). If that is not the case, you can use a manual exposure whichshould be set to the exposure of the brighter scene and locked to that for the 2nd shot of the panorama.It is better to underexpose in a shot than to overexpose. By locking the exposure, you are preserving the relative brightness of both shots and can correct the entire stitched image as a whole in postprocessing. Simple is good! It is easy for me to carry around a camera with a wide angle lens attached instead of a tripod, pano head... Here is an example of a simple approach to a 2 shot panoramic. Notice the generous amount of water and sky in the shot with only slightly bending of vertical lines which is acceptable and can even be fixed in software if you are a perfectionist. I like one camera for super wide shots and another for super tele shotssince no single camera can do it all well. Usually I know ahead of time what shots I will be taking either super wide or otherwise. Have fun and enjoy my pic.


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