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Adventures in pano stitching

photoSmart42

New member
I decided to try may hand at some panoramic stitching using my GH1. I figured out the nodal point of the 14-45 lens the night before using a macro rail. Using Photoshop CS4 to do the stitching. Here's my first attempt in San Diego harbor. I think it's not too bad.

Panasonic GH1+14-45mm @ 14mm; ISO 200; f/11 @ 1/500s; 7 exposures @30% overlap


Please feel free to comment, and to add your own pano stitch composures =).

EDIT: guess you can't pull up the photo as I uploaded it on Flickr because I'm a cheapskate and haven't upgraded to the Pro account yet =/
 
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ggibson

Well-known member
Nice work! Pano-stitching can be difficult to match exposures sky or water (basically any gradient). Here are a couple I did with the 20mm (before I picked up the 7-14mm):



 

photoSmart42

New member
Nice work! Pano-stitching can be difficult to match exposures sky or water (basically any gradient).
Thanks! Likewise!

I've been reading a lot about proper techniques for doing pano stitching, so I ended up leaving my camera in manual mode after setting the f-stop I wanted and setting the exposure to the average level across the scene I wanted to capture. After that, I did area focus for every shot, with a 2-second timer to eliminate any vibrations from moving the camera around.
 

Jonas

Active member
Hi Dragos,

I think your technique for taking the pano is about the same I use. "area focus for every shot" can work unless you experiment with shorter distances. I try to avoid it. Did you try different projection methods when stitching?

I like stitching. It is like making a bigger sensor in the post processing, and as a life saver when you haven't brought the right lens for the job. I sometimes use it for land- or cityscapes for the traditional wider shot but here are two other ones:


Above: G1, Zuiko OM50/2 Macro, handheld, 2 images just to cover the scene. It was about -7 degrees Celsius and there was spraying water so I didn't care for switching lens. I also had a shorter shutter time for the top part to handle the DR.


The image above is over 30 exposures with hefty overlap. I was out walking with one lens only. The light happened to be right for the building and I fired away. The grid overlay is great (I just wish one could turn it grey instead of the intense white). Here is the initial result before further processing:


Good luck with the panos, I think it is fun and rewarding.

/Jonas
 
J

jwestra

Guest
Really good nice! Might save me some money on a wide angle lens. Is Photoshop the best software to do this? Or is special software like panoramo editor in the example above more suitable?
 

pellicle

New member
Jonas's post doesn't explicitly plug PTGui, but it is the best.

Fantastic

my suggestion is manual exposure (to prevent any exposure drifts) and pick either a specific white balance or do your own custom or shoot in RAW and convert to whatever you want.


click for larger


4 images taken with FD50mm @ 5.6
 
J

jwestra

Guest
Thank you, I just downloaded the trail version. I should also avoid refocussing right?
 

sangio

New member
Jonas's post doesn't explicitly plug PTGui, but it is the best.

Fantastic

my suggestion is manual exposure (to prevent any exposure drifts) and pick either a specific white balance or do your own custom or shoot in RAW and convert to whatever you want.


4 images taken with FD50mm @ 5.6

I would add using manual focus at one preset distance to Pellicle's suggestions.
Photoshop Elements has a stitching feature that works quite well. The attached was stitched together from 14 images in a 2x7 array. The horizontal FOV is approx 220 degrees.

regards; Santo
 

photoSmart42

New member
Hi Dragos,

I think your technique for taking the pano is about the same I use. "area focus for every shot" can work unless you experiment with shorter distances. I try to avoid it. Did you try different projection methods when stitching?
Hi, Jonas. I should add that I set my white balance manually also, so I think that helped keep the exposure levels true across the entire scene. The only 'automatic' feature I had enabled was the focus. Area focus seemed to work OK, but I'll have to look at the details in the photos to see how they came out at that level.

I haven't tried other projection methods for stitching yet. The tutorial I was reading suggested starting out with the default projection in PS4, so that's what I used. I'll play with other projection methods as well. I did look at trying PTGui, and I'll download the trial to see how the end result would be different for the shots I took.

BTW, your pano of that building is awesome! Looks like it was shot using a LF view camera. Very nice!
 

pellicle

New member
Hi

Thank you, I just downloaded the trail version. I should also avoid refocussing right?
well, it depends ... as Jonas suggested above he got some sort of "tilt" focus effect by having the focal plane essentially altered as his images "panned" down and also used differing exposures (probably not by much).

I suggest that the only 'rules' are ones you see don't look right ... experiment experiment experiment

of course with wider angles focus is a lesser influence.

An old acquaintance of mine from nearly a decade ago has a nice although perhaps decreasingly well known site. From one page of that:

Tilts and shifts are used to change perspective and change the plane of best focus to help obtain a greater depth of field. Can mosaics of digital camera images do the same thing, and can they achieve the same resolution needed to make large sharp prints? This articles discusses some of these issues.
he essentially shifts focus in rows as he covers the rows further back

it can work nicely (I might add that I don't 100% agree with everything he writes despite his credentials and we have had dialog over this over the years)
 

Jonas

Active member
Jonas's post doesn't explicitly plug PTGui, but it is the best.

my suggestion is manual exposure (to prevent any exposure drifts) and pick either a specific white balance or do your own custom or shoot in RAW and convert to whatever you want.
(img)
4 images taken with FD50mm @ 5.6
pellicle, I think I miss some nice flowing water in that pano?! It's an exciting image making me curious about what more to see at the same place.

Thank you, I just downloaded the trail version. I should also avoid refocussing right?
See below

I would add using manual focus at one preset distance to Pellicle's suggestions.
(img)
The horizontal FOV is approx 220 degrees.
220 degrees is pretty wide Santo, no?!

Hi, Jonas. I should add that I set my white balance manually also, so I think that helped keep the exposure levels true across the entire scene. The only 'automatic' feature I had enabled was the focus. Area focus seemed to work OK, but I'll have to look at the details in the photos to see how they came out at that level.

I haven't tried other projection methods for stitching yet. The tutorial I was reading suggested starting out with the default projection in PS4, so that's what I used. I'll play with other projection methods as well. I did look at trying PTGui, and I'll download the trial to see how the end result would be different for the shots I took.

BTW, your pano of that building is awesome! Looks like it was shot using a LF view camera. Very nice!
I always set everything to manual. As I shoot raw the white balance doesn't matter really. More on that later.

Manual exposure helps to get the seems invisible. Manual and locked focusing helps to avoid any unwanted affects from the lens changing focal length during the series of images, and possibly from other odd artifacts as well.

Here's another pano from San Diego harbor.
(img)
I like that one better than the first. It's something with the projection in the first making it look too much distorted to my eyes.

Hi

well, it depends ... as Jonas suggested above he got some sort of "tilt" focus effect by having the focal plane essentially altered as his images "panned" down and also used differing exposures (probably not by much).

I suggest that the only 'rules' are ones you see don't look right ... experiment experiment experiment

of course with wider angles focus is a lesser influence.

An old acquaintance of mine from nearly a decade ago has a nice although perhaps decreasingly well known site. From one page of that:

he essentially shifts focus in rows as he covers the rows further back

it can work nicely (I might add that I don't 100% agree with everything he writes despite his credentials and we have had dialog over this over the years)
I didn't suggest anything like that pellicle... I "always" have the focusing fixed and untouched during the shooting. I also didn't change the exposure, it's in the image of the flowing but frozen water I used a shorter exposure time for the top part. That was only to handle the dynamic range inthe image.

I think I use two methods for taking panos/mosaics, then mixed with a third one.

Manual exposure, manual focusing, manual WB and a choice of aperture making the whole subject within the DOF all helps.There are exceptions though.

1) Tripod and pano head. This is very good for tricky panos with a lot of background details. Everything manual as above.

2) Handheld. With some exercise one can get good results also in semi tricky conditions. One trick is to check a nearby detail against a far away detail at the right side of the viewfinder (provided you are taking images from the left to the right) and check they align approx the same when having turned the camera.

x) Automatic settings. When the DR is very wide I have experimented with having the exposure set to Auto (aperture priority!). PTGui handles this pretty well but the image does of course need some extra help during post.

x) focus shift. The top image in my first post is an example; I changed the focus slightly between the two exposures to get an impression of wider DOF. The OM50/2 handles this OK. Some experimenting with the favourite lenses are at place.

On white balance:
Most panos cover a wide area and the dynamic range we want to capture often exceeds what the camera can handle. We are somewhat helped by the size of the resulting image where we can lift the shadows more than usual and still not get a lot of noise. Exposing to the right is very good. So, I set the camera to one of my custom white balance slots, the one I have set to UniWB. Then I take some test exposures checking the resulting histogram and placing it as far to the right as possible.

Here is a pano, or mosaic, taken with this method, a sloppyweb version quickly developed right now:

Above: using UniWB for the exposure saved the dark garage doors by allowing for exact exposure with the white wall on the limit to get burned out. Here a tripod was necessary for the exposure time, and a pano head for the alignment.


Above: Mainly for fun, a 100% crop giving us an idea about what size the panos can be printed to.

But as mentioned by pellicle above; there are no rules. Experiment and have fun! To me panos and stitching is the second best feature with digital photography, something that couldn't be done in the darkroom and at the same time increases the image quality.

regards,

/Jonas
 

photoSmart42

New member
I like that one better than the first. It's something with the projection in the first making it look too much distorted to my eyes.
Thanks, and I agree. I think there's something about the elements in the two photos that create different optical illusions. In the first one, the boats are closer to the camera than the pier that trails out of the top of the photo, so when stitched it amplifies the illusion of curvature away from the viewer. In the second one, even though the photo covers a wider FOV than the first one, I think the fact that all the elements are contained and framed within the center area make it seem less distorted, and more pleasing. Something to consider when composing future pano shots.

Oddly enough, the second photo I posted was the first pano I took =).
 

m3photo

New member
Re: Building Stitch

Here is the initial result before further processing:
Jonas: Just curious - Do you de-vignette each individual image in ACR beforehand for the master shot or is what you've shown here the one you do your "further processing" on? If so, it's a lot of work, isn't it?

By the way I loved this image when I saw it the first time.
 

Jonas

Active member
Jonas: Just curious - Do you de-vignette each individual image in ACR beforehand for the master shot or is what you've shown here the one you do your "further processing" on? If so, it's a lot of work, isn't it?
I went back to the archive and checked. In this case I had a lens with very pronounced vignetting (read: doesn't cover the sensor). I loaded the full images into PTGui. There I cropped one of them a bit to get rid of the corners and told PTGui to crop them all the same way.

In the next step the software tries to align the images and the window you see is the "Panorama editor" window where one can try different projections, straighten the horizon and such.

From there the software takes over for the final stitching process and the make of a PSD file (or TIF, or JPG or...). Among the available options I have set as default the software is told to "blend" the images with each other for a seamless stitch.

This works very well and for the most of the time there is no need to do anything else. Maybe a touch-up at a couple of places. As I try to expose to the right I also adjust some things in Photoshop, like levels/curves, gamma and such. That is usually not more work than it is with any other image.

We have been discussing PTGui here but I don't doubt any advanced panorama software (Autopano Pro, for example) does the same thing.

By the way I loved this image when I saw it the first time.
Hey, thank you Michael.

/Jonas
 

pellicle

New member
Hi Jonas

pellicle, I think I miss some nice flowing water in that pano?! It's an exciting image making me curious about what more to see at the same place.
well there is actually a small weir there which holds back the water a bit. I thought it looked artifical to include it, as there are indeed lake shore and river mouths looking more like that here.

Just down from the weir is a small rapid (like 2 meters)


click for larger


which is also nice ... but I didn't have any ND filter for my 4x5 and so the shots are too 'fast' for my taste. Although if I was working more telephoto (as a zoomed in segment from the 4x5 shows) I would perhaps have enough motion blur for my taste


click for larger


for interest, the above is about 1600dpi scan from the 4x5 neg. Looks sharp enough under my loupe to tolerate a nice 2400 dpi scan from a better scanner than my Epson 4990, which would be about 10,904 x 8,608 pixels from my image area on the film. Considering I use a 90mm lens, I'll insert 4/3 relevence to this post by saying that a mosaic done with a 50mm lens on a 4/3 camera will be as sharp and is the reason I want a tilt lens for my G1 ... mosaics of things which aren't at infinity and aren't at a flat angle to the camera.

I do sometimes think its easier to take one sheet with the 4x5 however...

sorry about inserting misunderstandings into your posts :)
 
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m3photo

New member
Re: PP Corrections

I appreciate the explanation, as I am sure many others will have learnt a little more on this fascinating subject.
Thank you Jonas.
 

Jonas

Active member
Re: PP Corrections

I appreciate the explanation, as I am sure many others will have learnt a little more on this fascinating subject.
Thank you Jonas.
No problem.
What anyone new to panos should do is to read one or two of the numerous tutorials freely available. We'll all forget a lot of things trying to squeeze anything into the forum format.

regards,

/Jonas
 

Diane B

New member
Hi Dragos,

I think your technique for taking the pano is about the same I use. "area focus for every shot" can work unless you experiment with shorter distances. I try to avoid it. Did you try different projection methods when stitching?

I like stitching. It is like making a bigger sensor in the post processing, and as a life saver when you haven't brought the right lens for the job. I sometimes use it for land- or cityscapes for the traditional wider shot but here are two other ones:


Above: G1, Zuiko OM50/2 Macro, handheld, 2 images just to cover the scene. It was about -7 degrees Celsius and there was spraying water so I didn't care for switching lens. I also had a shorter shutter time for the top part to handle the DR.


The image above is over 30 exposures with hefty overlap. I was out walking with one lens only. The light happened to be right for the building and I fired away. The grid overlay is great (I just wish one could turn it grey instead of the intense white). Here is the initial result before further processing:


Good luck with the panos, I think it is fun and rewarding.

/Jonas
You've shown that one before and I marveled at the number of shots as I do again. (I've never tried more than 9 total-- 3 over 3 on tripod with shifting on TS lens--I've done handheld, but usually 4--2 over 2). Thanks for the workflow you give in another post.

Diane
 

sangio

New member
220 degrees is pretty wide Santo, no?!


/Jonas[/QUOTE]

Thanks Jonas,

I keep looking at that multi shot building pano, it's a great capture.

I've done a few 360 degree pans, but they're not easy to print. Here's a 360 pano that I wrapped around itself using polar coordinates in PS.

cheers
Santo
 
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