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Author Topic: Stitching Panoramas with Clouds?  (Read 1764 times)

Smoothjazz

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Stitching Panoramas with Clouds?
« on: June 21, 2015, 09:39:38 pm »

I have just started doing some stitching, and plan to do more panoramic landscape photography with an Alpa camera. My questions is this; if I am doing a three shot panorama, and also bracketing the exposures, for a total of nine images, what will happen to clouds in the photos when I merge it all together?

There must be some mechanism in the software that adjusts for this to some degree in Photoshop or other programs. I am thinking it could take up to one minute or more to take all the pictures, during which the clouds could move quite a bit. Anyone have any pointers in this regard?

I am pondering this because I am debating which wide angle lens to obtain, and the wider the angle lens, the fewer shots I would have to merge together; two images versus three images.
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Bart_van_der_Wolf

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Re: Stitching Panoramas with Clouds?
« Reply #1 on: June 22, 2015, 03:30:59 am »

I have just started doing some stitching, and plan to do more panoramic landscape photography with an Alpa camera. My questions is this; if I am doing a three shot panorama, and also bracketing the exposures, for a total of nine images, what will happen to clouds in the photos when I merge it all together?

There must be some mechanism in the software that adjusts for this to some degree in Photoshop or other programs. I am thinking it could take up to one minute or more to take all the pictures, during which the clouds could move quite a bit. Anyone have any pointers in this regard?

Hi,

A bit of planning to get the area involving the clouds done without delays helps. Then additionally, the stitching software should be capable of intelligently blending the overlapping areas. Software like PTGUI Pro also offers a manual masking capability, and allows to use alternative blending engines, e.g. Smartblend.

As for the planning part, if you shoot multi-row panos, try to shoot the clouds row as a single row, that reduces the time required and it reduces the number of overlapping seams. Shooting the camera in portrait orientation helps with the vertical coverage, and using a proper overlap, say at least 30% can also help. If there is a lot of wind with distinct clouds, it may also help to shoot the sequence in the opposite direction of the cloud travel direction, to avoid having the same clouds turning up in multiple frames. Using a pano rig with a rotation through the entrance pupil of the lens should allow to take images in a short time, especially if you use a click-stop indexing rotator, thus also reducing the risk of visible ghosting.

As for the software, dedicated pano stitcher applications usually have good blending engines that can manage to avoid clearly visible issues, and offer some masking capability for manual intervention in case it's needed.

Quote
I am pondering this because I am debating which wide angle lens to obtain, and the wider the angle lens, the fewer shots I would have to merge together; two images versus three images.

If you  take single row panos at daytime, it shouldn't take a minute to record but rather a certain number of seconds depending on the number of images, even if HDR bracketing is involved. I would let the scene and the required output filesize dictate the pano requirements (single/multi-row and focal length). But if you only take a single row (which simplifies the pano-gear requirements a lot), then the required vertical Field of View coverage is leading, and using portrait orientation will help. On full-frame 35mm sensors, a 24mm will give you a lot of coverage (73.7 degrees vertical in portrait orientation). So depending on the sensor size on the Alpa, you could aim for something with a similar angle of view.

Cheers,
Bart
« Last Edit: June 22, 2015, 07:41:51 am by BartvanderWolf »
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PeterAit

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Re: Stitching Panoramas with Clouds?
« Reply #2 on: June 22, 2015, 07:16:15 am »

Are you sure you need to bracket? I don't know Alpas, but most modern digital cameras have enough dynamic range to capture outdoor scenes without HDR. Use your histogram and expose carefully and you can greatly decrease the time the clouds have to move.

Also, getting a wider lens can be self-defeating because it reduces the pixel count, and hence the detail, in the final pano.
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maddogmurph

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Re: Stitching Panoramas with Clouds?
« Reply #3 on: June 23, 2015, 12:31:42 pm »

I'm doing the same thing you are it sounds.  Struggling with luminosity masking, stitching & focus stacking.  Photo-merge may try to stretch your photograph which seemed to work on a (2) bracket exposure I was working on last night that I could see the clouds had moved ever so slightly in.  I am guessing you don't have a minute for that type of shot unless you're doing time lapse exposures.  The following is a 9 shot blend using 30 second time lapses only because I wanted to print this very large and have high resolution.  You can see this works because it smooths out the clouds up top.  I also shot the sky in consecutively.  So this is one way you could make your idea work... time lapse at night.

The Day of the Warriors by Maddog Murph, on Flickr

Lenses... 24mm introduces some distortion but not much.  I've been doing most of my stitching on my 70-200mm as it gives me ultra high resolution which for me is generally the point of stitching.  Otherwise I'd just shoot around 24mm and crop to achieve the pano look, which actually works very well if you're just doing web work.
« Last Edit: June 23, 2015, 12:36:48 pm by maddogmurph »
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