Tutorial Ultra-Wide-Angle vs Kit & Stitch, featuring a fish!

[Teflon-Mike]

Teflon-Mike submitted a new resource:

Ultra-Wide-Angle vs Kit & Stitch, featuring a fish! - Come with me on a walk on the Wide-Side, and an introduction to Wide-Angle photography.

This tutorial starts with what is probably a quite common question: "I'm quite new to all this and I'm hoping to purchase a wide-angle lens because I would like to be doing a lot of landscape photography" Now, I will admit to having a bit of an 'agenda', and offering the conclusion in the introduction, my advice is "Don't do it!" More Land, does not better landscapes make!

But, let me take you on a walk on the wide-side. After quarter of a century hankering for...

Read more about this resource...

 

[Terrywoodenpic]

I have a feeling that this tutorial is no more than an introduction of the basic concept of stitching.And a little more needs to be said.

I made my first panoram in the early 70's In those days it was a cut and past process and could not adequately compensate for even basic cylindrical pans.
Come digital and the introductions of programs based on Helmet Dursch's PT algorithms and projections, almost anything became possible. Stitches with out any distortion became possible using normal, wide angle or fisheye lenses. I chose as my stitcher ( and still use) PTAssembler Written by Max lyons, It is very similar to the very popular PTGui, which in some respects is easier to use.

My first Digital stitches were made using a wooden but extremely accurate home-made bracket that precisely placed the entry pupil at the no movement point. However it could not work with multiple rows. For that I progressed to the first version of the Nodal Ninja Bracket, and have never found the need to go beyond the Mk3 version.

Such brackets are fully capable of stitching 360x180 VR pans , But they now make far simpler Brackets for using with Fish-eye lenses. As I have no interest in VR pans I have never bothered to purchase one.

My main interest is in Single and multi row pans. which I mostly take hand held (But with monopod), as the more recent versions of the mentioned software is more than capable of coping with some movement around the entry pupil. This soft ware can cope with mixed orientations and even changes to the focal length, It simply does not matter.

Such problems as converging verticals and other distortions are corrected automatically. With a choice of dozens of different projections to deal with curved lines and dimensional distortions.
Basic Panoramic software like that included in photoshop has very few of these tools and projections, and are only suitable for the most basic stitches.

Part of the process of stitching is the process of blending. Recent blenders can cope with parallax, uneven exposure, vignetting and variable colour balance.
Such blenders and stitchers can even remove duplicated people in crowd scenes by the use of masks, provide of course that there is sufficient overlap in which to place a mask.

Stitching Is not the process of joining together. It is rather the process of reshaping and orienting each digital images to fit on the surface of a sphere centred on the entry pupil. These images are slid on that imaginary surface to their correct position that is established by control points. The overlaps are than traced and equalised to create an invisible join. The more recent Blenders are content aware, so as not to place joins in inappropriate places though they can be changed by appropriate masking.
The last stage in the process, is to recalculate the chosen area using a suitable projection, back on to a flat surface for viewing

In Both PTAssembler and PTGui all this can be achieved either fully automatically, Or the advanced user can alter and override any and all stages to achieve any desired result.

Stitching Is not only the only way to take particular difficult photographs and achieve special results. It is also Fun.
In the field it can be done quickly hand held, or by using specialist mounts. It can allow shots to include an entire building from unobstructed viewpoints but so close that no wide angle can manage alone. It can included entire crowds from a position in their midst. It is not just a landscapers tool.(I will put up a few examples in a subsequent post.)

 

[Terrywoodenpic]

Shows a stage in PTAssembler where you can correct a number of factors such as Yaw, pitch and roll. Masking is done on another screen to sort out the people.
the finished pan is shown below.




For some reason this one may not be showing But it is a five shot pan three exposures at each position and exposure fused as the strip lights are lighting the scene.
It was also output with a projection that eliminated the curve in the side walls that you get with pans.



Same place different day new view point opened up as they had removed some trees

From the view point I had chosen I could not get everything in so I made a pan

Again I chose a very close viewpoint to the spectators to avoid a long narrow scene So a pan was the answer


Here the viewpoint was very restricted, And I could fit in neither the height nor width so took four shots.


Added one taken some years ago on my old canon G3 using an early version of PTAssembler Showing a mass of people.

 

[Teflon-Mike]

I have a feeling that this tutorial is no more than an introduction of the basic concept of stitching.

As far as stitching is concerned, It wasn't even really meant it go that far, TBH!
It was aimed at a camera-newby, with the idea that to take 'better' landscapes they needed a better lens, and for big scenery, that meant the wider the better!
And to compare that idea with what they were possibly told in the shop, when they were being nudged towards the 'wow' factor of huge zoom-range, that they didn't really need 'wide', they could get that from stitching with the software in the box.... ( and chuck in a bit of fish, 'cos well, great source of protein, omega oils, vitamins, and.. oh.. sorry wrong sort of fish! ;-) )
It was a little intro into 'going wide' in general rather than anything more in depth in the arena, let alone stitching specifically.

And a little more needs to be said..

It undoubtedly could be! And I suspect more than a little! Those images are quite impressive, and show a lot of the thought, care, attention and diligence I alluded to being useful to create more successful stitches.... And an area of expertise I have hardly scratched... I have used the bit of 'free' stitching software that came with my first compact camera, and the 'automate' photo-merge in Photo-Shop, and even that, not very much....

So, start there; Write ME a tutorial; Teach me about Stitching!

- I have a camera, I just about know how to use it... I have a computer, I just about know how to use it!
- What's stitching good for? It's just for panorama's and stretched 'wide' landscapes, isn't it?
- When does it offer anything I cant get any other way?
- When does it offer an 'easier' way to get something?
- When and where should or could I be using it? And why?
- When or where SHOULDN'T I be using it? And why?
Of what I have been able to garner from the web; I have been frustrated, with the topic being either paid lip service to (As I have done, I confess!) with photographers more concerned with how to use a camera or light meter, and offered little more than 'Turn the camera round' and 'Shoot Manual to keep the exposure consistent', OR they have bee obsessed with the software, and obscure key-stroke short-cuts and sliders menus, and have assumed you have photo's to stitch or merge before you start. So..
- What should I be looking at, thinking of, and doing' to shoot to stitch?
- how should I be preparing good 'sections'?
- What issues am I going to run into over 'ordinary' one shot photos?
- How should I address or avoid them?
Then.. having got my stitch sections, with the sort of software I already have; what came with the camera or is in Photoshop:-
- How should I be trying to put them together?
- What or how much pre-process should I need be doing to get good stitches?
- Where am I likely to have problems?
Assume I were to go back to that hill or the warf I tried the wide out at in this tutorial, or somewhere similar, with an entry level DSLR and only the Kit 18-55.. what can do to have a dabble and see what I can do with stitching?
Could be quite fascinating and most illuminating.

 

[Terrywoodenpic]

It is a very big subject and as I taught myself... As most have to.... it is hard to know where to start.

I remember it was very difficult to get a good stitch with PTAssembler to begin with. So I built myself a bracket. If you want to see click on the cross.

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However though accurate I still got bad stitches. Stitching software knows exactly how to frustrate beginners, and the learning curve can lead you to think that the software is rubbish, and that you need an expensive Pan bracket to do a decent stitch. Neither of these things are true.

Most stitchers that come with cameras are not fit for purpose. Probably the best way to start is with the one that comes with Lightroom and photoshop. as it is easy and always seems to work. However it is extremely basic and soon leads you to want to do more. There are other free ones out there and people swear by them, But ones like PTGui do charge as does PTAssembler. But PTAssembler does not charge for updates.( but is not good at 360x180's.) Most professionals use PTGui.


These days I just feed in my picture files and try everything on auto, 90% of the time the result is excellent first time. But not always.... That is when you need to know what you are doing.

The First thing the software does (even in photoshop, where you can not see them), is to select "control points" the problem is Their function is many fold and vital, they mark matching pixels in adjacent photographs and define virtually everything the software needs to know, that it can not obtain from the EXIF data.

The problem is the software for picking is very dumb, and always finds some matching points on moving objects, like clouds, leaves, branches, water even people. This is VERY VERY BAD. and leads to just about every sort of problem.

With out going into further detail the better programs allow you to fix these and other problems very easily "when you know how".

Resulting Pans should need very little correction at all in Photoshop, except for the odd break in phone lines and the like.


You mentioned Manual settings... this is actually essential or nothing will match between shots. Colour balance, aperture, Shutter speed ISO and focus should all be set manually and not adjusted between shots. However you can mix shots taken in different orientations, but the whole image must be covered with suitable overlaps.


The biggest advantage of stitching is that it allows you to chose your viewpoint to suit what you want to see. View point is what makes any image look the way it does.

You can use any lens you like, from a fisheye to a tele... the only difference it makes is the number of images needed to cover the subject. Lens distortion and Key-stoning is automatically sorted in the software. focal length also changes the magnification and number of megapixels captured in the final image.


To Cover the subject of Stitching thoroughly, is a mammoth task and I am not sure I am either qualified or energetic enough to tackle it.

But I will look up some suitable sites and references later.

 

[ianp5a]

So, start there; Write ME a tutorial; Teach me about Stitching!

It is a very big subject and as I taught myself... As most have to.... it is hard to know where to start.

There is a great opportunity here.

I have found that it is often better if the newbie writes the tutorial, with support of the expert. As they will ask the stupid questions about the tricks that the expert takes for granted.

 

[dave.hallett]

Here's my very short series of tips on the subject.
Advantages of stitching:

• cheaper lenses can be used with good results compared with expensive UWAs
• you can go as wide as like!
• there is free software available
• you get a lot of resolution for large prints (but who prints that big?)
• you can have a very shallow DoF if you want (Brenizer method)
• it's good fun! (IMO)

Disadvantages of stitching:

• things move (windy days are not great, the sea is only possible with a long exposure)
• light changes (don't be like me and try to do a 20-shot stitch just as the sun is coming up, it will not go well)
• you may want more DoF than your lens can provide (e.g. for landscapes) as you can't shut down the aperture the way a medium format camera can without incurring diffraction limits (the theoretical answer is focus stacking, but it will be very hard work without a proper pano head, and not easy even then)
• it's harder to get the exposure right (I often bracket, HDR can be useful)
• it's harder to get a good composition (this is the biggest single issue, IMO) because you can't see the whole thing at once
• it's time-consuming and easy to mess up

Tips:

• keep it level (a tripod with a pano head is ideal, but if doing it hand-held, a camera that has a built in level indicator will keep you on the horizontal, which really helps)
• overlap shots by 20% or so
• use manual focus
• set fixed white balance or use RAW
• set manual exposure (same shutter speed and aperture across the picture)
• whether to HDR (or exposure blend) before or after stitching depends on the software: in LR CC I would HDR and then stitch, but some programs don't stitch 32 bit images well (or at all)
• really long exposures are good in theory, because all movement is evenly blurred, but watch out for changing light levels between shots