Panoramas and stitching...?

[BelaMolnar]

A year or two, I had an argument, with two of my photographer buddies. We where start to talk about,

how to do panorama shoots, or multiple shoots for stitching. Normal one row, or 2, 3 rows. I said,

you has to do it, camera in total MANUAL mode, including focus. The two of my friends cried out

loud, " how can I said such a stupid things, it has to be "A" aperture priority, and only aperture

priority and definitely not in manual mode. After a couple of minutes, I give up. The technical how,

and why, didn't worked. Now, I find an article By Trevor Sherwin, STITCHING. And the article clearly stating my opinion, to set the camera in "MANUAL' mode! Can somebody answer this letter

and tell me, and others as well, what is the proper technical way, to shoot for stitching ( for

panoramas or for other reason). I keep shooting in manual mode, and never had a problem to stitch

the image together. Thank you for your reply.

 

Bela Laszlo Molnar

[cooltpmd]

I may get some grief, but the technology of "stitching" and alignment rely greatly on software to match the images by common landmarks.

 

If I were gambling on which method was most reproducable (less variable) in taking a photo, I would think auto-focus would be most consistent.

 

In manual mode, you may frame/focus/expose an image differently enough to confuse the software.

[emre]

Constant exposure is no longer necessary in sophisticated stitching software. Autopano Pro even prefers them to be otherwise, in order to extend the dynamic range.

[ellis_vener_photography]

"The two of my friends cried out loud, " how can I said such a stupid things, it has to be

"A" aperture priority, and only aperture priority and definitely not in manual mode. After

a couple of minutes"

 

"If I were gambling on which method was most reproducable (less variable) in taking a

photo, I would think auto-focus would be most consistent."

 

 

They are completely wrong. You definitely want to lock down both focus and exposure

[iliafarniev]

Just manual, all way around.

[garydem]

you can shoot in aperture priority but that means the camera will select its own exposure. and there are some software that work quite well with different exposure in trying to avoid verticl bands where the 2 exposures meet. but why ask your software to do this when it can be prevented in the field with the camera?

 

for panos see below-

 

To do panoramas-

for panoramas- -use tripod. you must keep it level with the horizon. if your tripod does not have a level builtin then buy one that slides into your flash hotshoe. again make a max effort to get the camera level.

-for exposure. set the exposure by pressing halfway and noteing the fstop and shutter speed. you are trying to find the brightest part of you panorama scene to be. once you have found the brightest check the fstop and shutter speed. put camera into manual metering mode and use those settings. do not change them for any part of the panorama.

-lens selection. i shoot mine with a 20mm. tried a 35mm didn't work, the individual shots didn't overlap. the angle of view wasn't wide enough. note: SHOOT THE LENS VERTICALLY. this is the only way to get some vertical scene, otherwise the panorama will be shaped like a hotdog. this is why i went to a 20mm. in vertical you are cutting your angle of view way down. my tripod has degrees engraved in the mount, i was shooting at only a 15 degree spread and in looking at the shots before stiching there wasn't that much overlap. i later shot panoramas with 35mm 50mm; the hot dog effect was more pronounced. the panorama itself did work.

-determine in advance the center point of the scene and try to go X number of shots on each side of it. for me with my setup a 120 degree scene is 7 shots; the center and 3 on each side. if i go with a 35mm lens then a 120degree scene will take 13 shots. no matter what lens you use realize that you are adding only 33% new scene with every shot, the rest is overlap for the right and left adjoining shots. the only exceptions are the end shots in the whole scene. it is possible to add another row above and/or below the first one. this would help the vertical look especially if you are using a 50mm or longer.for multiple rows are the same as 1 row, but you know have to overlap on the vertical as well as the horizontal. you must make sure that there are no gaps.

- i stick my hand in front of the lens and shoot, then shoot the panorama, the 7 shots, then put hand in front of lens and shoot. later i know that everything between hands is the panorama.

-i have used cs2 or the panorama factory software to make the panorama. for either couldn't be simpler simply select the shots and it does the work. this is where using a level pays off. the software is leveling the scene to make the long rectangcal, but if the scene was not as level as possible in the first place the vertical becomes less and less(you end up with hotdog shape). so having the tripod and camera level is very important. also when mount and shooting vertically make sure the camera really is vertical, carefully check by looking threw the viewfinder. some tripod vertical adjustments actually go past true vertical, mine does even though it says 90 degrees.

-be sure to use a cable release or the selftimer.

-on focusing- what i do is to simply preset the 20mm lems at infinity, because of depth of field everything from 5.64ft to infinity is in focus at f11.0 distance 200ft. you can also use a hyperfocal focus setup. but thanks to the DOF table, just setting the lens at infinity is simpler. -i left WB alone, that is set at AWB; or you can use a preset setting like sunny or cloudy, but once set donot change it till panorama shots are done.

-online depth of field calculator available here- http://www.dofmaster.com/dofjs.html

-parallax error. It is usually not so much a problem outdoor shooting. This is because the distances are greater than inside. In any event if you shoot panorams outside and at short distrances OR any inside any building, you should be thinking of getting a panorama tripod head. This is to eliminate parallax error.

-for panoramas, the software i use is either panorama factory orPTGui or cs2. the one that works best for me is PTGui. i have since gotton PTGuiPRO, expensive but worth it. has many features and abilities that the other software does not have, including the ability to process 360 and 720degree spherical panoramas, plus many projection types.

 

 

[kari v]

"If I were gambling on which method was most reproducable (less variable) in taking a photo, I would think auto-focus would be most consistent."

 

For landscape just place your focus and f-stop so that you get the DoF you want and shoot away. It defies logic to say that autofocus is more consistent than fixed focus.

 

Same with exposure. Why would you want the camera to meter each shot differently even if your software can compensate (hopefully) for it?

 

Of course whatever works can be the "right way" but I can't see how inconsistent focus points and exposures help.

[kelly_flanigan1]

think about it this way. You shoot a 180 panoramic image where there are variations in light sources; one actually aiming towards the lens. Then most all the subject matter is at infinity but then in some parts its a few feet away. The autoexposure and auto focus means the exposure will be different with each frame; the point focused on will too. Thus two frames side by side to be stitched can have different exposures; one with a *effective* longer focal length; since the lens is racked out. ie the infinity shot might have the lenses prime point 50mm away from the sensor/film; the close focus frame 53mm. Thus for stitching one might have to down size the one frame and adust its exposure too. doing this say over many frames adds time.