Advantages to stitching images?

[ShaneS]

Lately I have noticed that a few members are posting shots where there are three or more images stitched together and I am wondering about this technique from both a 'how to' and a 'why' perspective.

It seems to me that many of the images posted could have been taken in one shot so I wonder what the point is to taking multiple images and then stitching them together? I get the concept when you are trying to create a really wide or tall panorama but is there a reason for it in other situations?

I understand the basic concept of stitching images together and needing overlapping space on the sides of 30% or so and some room at the top and bottom that a crop can be done to eliminate any empty space from the stitching. Is this all done in Photoshop or is there a specialized program that is used? Are there any other 'tricks' to the post processing of these types of shots?

If I wanted to give this a try would I just place my camera on a sturdy tripod and set my camera to manual (including focus) and then rotate the camera in between shots? I would likely be shooting landscapes or city scenes and would guess that the more static the subject the better the outcome would be.

Please enlighten me

[Colin Southern]

One good reason to do it is if you don't have a wide enough lens. Yes, Photoshop will do it, but so will other tools such as Panorama Factory & PT Tools .

Ideally, between frames you need to rotate the camera around the nodal point (more or less the end of the lens), not the sensor, or foreground objects won't align properly (parallax error). A nodal bar is used for that.

Other than that the only other advantages I can think of is the extra resolution that can be gained and that it can be used for trick shots, eg

[dje]

It seems to me that many of the images posted could have been taken in one shot so I wonder what the point is to taking multiple images and then stitching them together?

Hi Shane

Yes I think the main thing in this situation is you get a higher resolution image, You can increase the vertical resolution by using the camera in "portrait" orientation. Whether you need the extra resolution or not depends on how it is to be used I suppose.

I guess the technique has become popular because the stitching software can do such a good job these days.

Dave

[IzzieK]

Shooting in wide angle for me is not really the same as shooting panorama. When we had a snow storm in early 2006 I stood in the middle of my driveway and photographed the whole street, including the road at the end of our street in portrait mode. I used a 50mm lens. It was nice and sharp and when putting it in a presentation, I can pan the whole scene for story-telling drama, if you know what I mean. And I did it all handheld using my ankle as my rotating point. It was fun and worthwhile.

[Manfred M]

It is a great way to create panoramic images. I've been playing with the technique a bit lately and while it is idea to use a long rail (ideally the lens should rotate around the optical centre of the lens; there is a technique for figuring out where this is; it will vary slightly for different focal lengths on the same zoom lens), I have done some hand-held shots too, that have worked out reasonably well.

Yes, manual exposure for sure; you don't want the camera adjusting the exposure or focus for each indivdual frame (makes things a pain to blend), so I will select an ISO setting and aperture and scan the scene to see how the light varies (i.e. check the range of shutter speeds required) and I will pick a middle value. I will also turn off autofocus after the camera has been focused.

I will take a series of shots with up to 1/3 overlap from the previous frame and will then do my stitching in Photoshop.


I use an "L" plate so that I do my shots in portrait format.


I did these in late December.






Clicking on the images will give you a better, larger view...

[lenelg]

I have done a number of landscape panoramas handheld, without worrying about nodal points etc. As long as there are no objects close it works surprisingly well. You need a bit of practise to make sure you keep the horizon at the same level though, handheld it is easy to start creeping up or down with each new exposure. And, unless you are only going to join two or three exposures, using portrait orientation is a good idea - a tapeworm-shaped panorama has rather limited uses..

[Colin Southern]

It is a great way to create panoramic images. I've been playing with the technique a bit lately and while it is idea to use a long rail (ideally the lens should rotate around the optical centre of the lens; there is a technique for figuring out where this is; it will vary slightly for different focal lengths on the same zoom lens), I have done some hand-held shots too, that have worked out reasonably well.

Usually the front element is "close enough"

Yes, manual exposure for sure; you don't want the camera adjusting the exposure or focus for each indivdual frame (makes things a pain to blend), so I will select an ISO setting and aperture and scan the scene to see how the light varies (i.e. check the range of shutter speeds required) and I will pick a middle value. I will also turn off autofocus after the camera has been focused.

Picking a middle value isn't really best practice - any frame in the sequence is till governed by the maximum light the sensor can handle, so I work out what the max shutter speed for the sequence is and then shoot them all at that. Assuming one is shooting RAW then there's usually plenty of data to be drawn on if needed. Having just said that though, there is often a large variance in lighting across a very wide angle scene - and sometimes that's what dictates where a scene is cropped to.

[ajohnw]

There is a free application called Hugin as well. Best look through what it can do. Rather a lot.

John
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[Manfred M]

Usually the front element is "close enough"

I've found that for landscapes, this tends to be true, but if there is something fairly close to the camera, like the railing in the first image I posted above, I find that this will cause serious distortions in those objects. With a long focus rail and if you have figured out where the optical centre of the lens is, these nearby objects don't get distorted. With my 24-70, the optical centre is some 7 cm from the front element of the lens. If I don't use the nodal plate, I have to crop that part of the image.

Picking a middle value isn't really best practice - any frame in the sequence is till governed by the maximum light the sensor can handle, so I work out what the max shutter speed for the sequence is and then shoot them all at that. Assuming one is shooting RAW then there's usually plenty of data to be drawn on if needed. Having just said that though, there is often a large variance in lighting across a very wide angle scene - and sometimes that's what dictates where a scene is cropped to.

Yes, assuming that you have a very bright area that will get blown out by the mid value; I would have to agree with you. But most of the scenes I've shot only vary by about 2 or 3 stops over the 180 degrees I am shooting, so the mid-range speed seems to have given me the best results with only ±1 or ±2 stops to deal with. I've done some shooting with a 2 or 3 stop grad to tame the sky while shooting, so that I'm not fighting the sensor dynamic range limitations.

[ShaneS]

Thanks everyone!

I had seen your images previously Manfred and was impressed by them. Just to clarify those are 180 degree panoramas?

Since I don't have a nodal plate I will have to get out and experiment hand held the next time I'm out and about. So, the pivot point s/b approximately the end of your lens if I have read correctly? If you pivot on a traditional tripod mount will that give more of a fish eye type of effect?

[rpcrowe]

Manfred, I love your winter images!

For everyone...

Here is an excellent post, from another website, that illustrates the difference between shooting with a wide angle lens and shooting a pano and stitching it together. This is one of my favorite examples of the difference in the two techniques.

http://www.dpreview.com/forums/post/17572474

I personally think that the stitched image has more appeal than the wide angle image. However, there might be some w/a aficionados who prefer the w/a shot...

A downside of a stitched pano is that it really has to be displayed in a large size. Showing the entire pano, let to right, on a computer monitor does not do it justice...

BTW: we often her about the need for exotic equipment to do panos, especial;ly panos with the camera in the portrait position. However, if you use a RRS L-Plate (Arca Compatible); that plate places your camera in a way that it rotates closely around the nodal point. Maybe not absolutely exactly, but close enough for most work...

http://www.youtube.com/watch?v=G4iOxH5vyCo

[Manfred M]

Shane, both shots started off at 180° (and even a touch more), but were cropped in post. The first one is probably about 130° and the second one around 170°, in the final version.

While I prefer doing them with a tripod and all of the associated gear, I will hand-hold in a pinch, but in general the results are not as good (generally, not as straight as with a tripod, which means I end up cropping more unusable material).

This shot is one I did a couple of weeks ago, while we were in Guatemala, and I shot hand-held. Unfortuantely, I was not shooting level and the camera rose from left to right and I had to do a more agressive crop than I would have hoped for.




Jist some quick shots of the gear I use for Panos; it's fairly basic (i.e. you can get some expensive speciality items).

1. Ball head with two bubble levels. One is on the tripod itself (the bottom one) and one is on the quick release plate. Both the tripod and quick release plate ones should be level to eliminate the risk of distortion. This is more of an issue when shooting architecture.







2. Camera is mounted in portrait position using an "L" plate. This is then attached to a long focus plate (sometimes called a nodal plate). Notice how far from the sensor the optical centre of this lens is.







The way you determine how far you need to offset the camera on the long focus plate is by aligning to vertical surfaces some distance apart (in my case I positioned them about 20 ft / 6 m apart). You place the camera on the setup and align the two vertical points at the centre (i.e. they are right on top of each other). Rotate the camera so that the two vertical surfaces are now near the edge of the frame. If the two a misaligned (i.e. not right on top of each other), adjust the long focus bar to move the camera in or out and repeat. Once you find there is no misalignment of the two verticals, you have located the optical centre of that lens (on a zoom, technically this could change as you change the focal length). Write that information down somewhere, so that you can set things up in the field.

[PhotomanJohn]

Write that information down somewhere, so that you can set things up in the field.

I have a note on my iPhone where I have listed the settings (using the distance scale on the plate) for each lens over their zoom ranges so I always have the values with me. Fun stuff.

John

[Manfred M]

I have a note on my iPhone where I have listed the settings (using the distance scale on the plate) for each lens over their zoom ranges so I always have the values with me. Fun stuff.

John

And I have it attached to the bottom of the focus bar, that way I have the information, even if I don't have a phone along.

[ShaneS]

Wow - I thought it would be a lot simpler than this! I am a minimal accessory photographer at this point and in some ways I envy those of you with all the 'toys' but know that it would make my life infinitely more complicated to have them...

I have a sturdy tripod, my camera, three lenses and a polarizer. I'm thinking about getting a ND filter but am waffling on the strength that I want/need.

I may try a hand held shot from our balcony just to see how it all works though and appreciate all of the information.

[Manfred M]

Shane - that is actually the "simple" setup, and I am adding one more element to it, a perspective correction lens (actually more for architectural photography, but it will have uses in panos as well). I already had the "L" bracket (for stable portrait format shots on the tripod)

You don't need the setup for a lot of basic work and you can make some perspective corrections in post. The following shot was taken with just the "L" plate on the tripod, without the long focus plate, and you can see that while the backgound looks great, I had to crop out some strange looking elements in the foreground.




Cropped and reworked in post gives me this:

[chauncey]

I'm not quite as particular about my technique as some of the other folks...more of a point and shoot kinda guy, usually, but not always, with focus locked in. I do make sure that a lot of overlap exists. Shooting handheld is often necessary when shooting BIF images.



Software is exclusively PS, using whatever mode coughs out the best image.

[ShaneS]

I gave it a try to see what I could come up with. It's a rainy overcast day in Hawaii so this is a try at the technique more that an effort to create a stunning image

The effort darn near killed my laptop as this one image is a panorama from our lanai (balcony) was stitched together from eight individual shots with my 50mm lens mounted on the tripod.

Overall I think that the photo merge function in Photoshop did a good job but I tried to do a perspective correction and think that I went too far or the wrong direction as the building on the right has a funny lean to it. I gave up because Photoshop was lagging and shut down a couple of times during the editing process which was probably due to the fact the the file is 1.3GB. I also found it hard to do a meaningful edit on the small lap top screen.

Anyway, here it is...The file is 3000 pixels wide and is probable best viewed in the lightbox.



The original images were shot in landscape mode and I will probably try again doing them in portrait mode so I get a taller image. (Slaps self on head because that was suggested earlier in the thread )

Any and all feedback welcome

Aloha from soggy Hawaii!

[Manfred M]

Nice first try; yes, the files are HUGE and you need a decent amount of RAM on your machine to process the files. Too bad about the weather not cooperating, but you've got the hard part (capturing the images) down nicely.

[ShaneS]

Thanks Manfred. The sunsets from here are quite nice but I am tempted to try again today with the portrait orientation just to see what I get.

For those that are interested this is the view from Koko Crater (Koko Head Park) on the left to the edge of Diamond Head on the right (just behind the tall condo). https://www.google.com/maps/@21.2769.../data=!3m1!1e3