A case where "stitching" and quality didn't go together!

I guess this is one of those things I had to learn the hard way. I told a customer I would attempt to do prints of her 5ft x 6ft painting with my 828 by taking photos of sections of the painting and stitching it so that I could have the most resolution possible once it was all stitched. I tried using both Elements 3.0 and Autostitch. (I found Autostitch was smarter) In one case I took six photos and tried to stitch them - that was a mistake because I didn't think about how the camera's exposure would change based on the tones in each section of the painting. So when stitched, I had different exposures, duh. Secondly, if I wasn't careful enough to keep the camera the excact distance from the painting for all six photos - it didn't stitch well, if at all. So I tried four photos, then three, then two. Well when I finally thought I had a good stitch of two photos, I thought I'd zoom in and compare the pixelation of my "two photo" stitch to the "one photo" shot. How disappointing!!! I spent hours working on stitching only to find that my stitched photos were blurry when compared to the one photo I took of the entire painting. Am I making sense?

Is it true that stitching loses resolution? Anyone else run into this before?
--
Tessa HD
Love to dream and dream in color
(eight-twenty-eight user)

Tessa: To start with, go to the Help page on PSE3 on Photomerge and you will find the necessary procedures that should be used to make good pano's. Basic needs are: lock the expossure settings in Manual, use a tripod if you can (careful hand holding can be used), overlap at least 25%, move from left to right and make sure this sequence is adherred to in you stitching programs. There are many more helpful hints that you can find in these forums beyond what I can offer but this is a basic start. Good luck, Gale

is that you aren't provinding your stitching programs with images that it knows how to interpret. the short of it is that your camera is moving each time, whereas the program expects it to have stayed still. without special equipment, this is going to be very, very hard. in addition, you need to be perfectly parallel to the work, and you must be precisely the same distance each shot you take.

my suggestion... hang it on the wall, use a tripod, grab as many shots as you want from as far away as you can get (to help flatten the field) and shoot it like a normal panorama. stitch in your favorite program.

this will produce a slightly distorted reproduction. now, remap it to a rectangular space (PT lens will do this) or distort it by hand in photoshop.

give that a shot.

ed

--



ed murphy ----------- AIM: monky9000

What are the intended uses of the shot?

If Printing, what size print are you anticipating? (this is critical)

If for the web there are diofferent issues involved.

Jules

lulalake said:

What are the intended uses of the shot?

Click to expand...

giclee print for an artist

lulalake said:

If Printing, what size print are you anticipating? (this is critical)

Click to expand...

I can print up to 24x36 - and have been requested to often, however this one may not get quite that large. And so far the unstitched "one shot" is clearer than any stitched one I've done.

lulalake said:

If for the web there are diofferent issues involved.

Jules

Click to expand...

--
Tessa HD
Love to dream and dream in color
(eight-twenty-eight user)

Yeah, I felt stupid afterwards about forgetting to lock the exposure. This is certainly a live and learn experience for me!
--
Tessa HD
Love to dream and dream in color
(eight-twenty-eight user)

I guess that makes sense that it would be blurry if I were not at the precise distance for each shot. Guess I hadn't thought of it that way. I'm thinking it's not worth the hassle and that I need to realize the limitations of the resolution of this camera.
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Tessa HD
Love to dream and dream in color
(eight-twenty-eight user)

While I like panoramas, I often have trouble with the seams having a bit of softness. While in theory it sounds like a good idea, I don't think I'd try to do what you're doing. It's hard enough photographing distance, but when you're shooting up close like that, I would think that you're going to get a lot more error introduced. Autostitch does a great job, tho....

We might have better results using an expensive bracket that kept the camera rotating at just the right spot (and all mounted on a leveled tripod, of course). That's just too much effort and expense for what I'm trying to do, but for pro work, I'd cough up the money for some tools.....

Tessa H.D. Campbell wrote:
....

Tessa H.D. Campbell said:

I can print up to 24x36 - and have been requested to often, however
this one may not get quite that large. And so far the unstitched
"one shot" is clearer than any stitched one I've done.

Click to expand...

You might consider a couple of different techniques. First, you can stack multiple photos on top of each other, and this will reduce any noise that might be present. (May not be an issue worth dealing with in this particular situation assuming that the lighting is good, however, it's easy to do.) Since you only have so many pixels, you might as well try to get the "best" pixels that you can.

Then, if you need more pixels, you can use special techniques to "upsize". Don't use the typical "bicubic". Try something more exotic. The free "Image Analyzer" has a fractal interpolation plugin that looked pretty good, what little I've tried. I hope you have a lot of RAM. ;-) Seriously, what I like about the fractal interpolation is that it will look "sharper" than if you did the bicubic. On the downside, it can look wierd if you overdo it. It may or may not be something you like.

At any rate, if you feel like you really need to push it, I would give those things a try.

By the way, keep in mind that with autostitch, to get the full resolution out of it, you have to go into the options and change the settings. The last time I played with it, it defaulted to something like 25%!

--
Gary W.

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Tessa HD
Love to dream and dream in color
(eight-twenty-eight user)

While stitching can be great for landscapes,and having read the other ppl's answers,I wonder.The 828 can do a great job for reproducing art,sometimes beyond expectation,but a giclee print has to be sharp,has to have a look as if it is the painting itself,with your eye very close to it.If the stitching idea has to be abandoned,then the job is not for an 828.You should try to rent 1DS2 or even a medium format camera to compete with thr original giclee printing tecnique.

Regards,
Walter
--
http://www.leonhardsgallery.com

Hello:

He has stitched 196 seperate images to create a 1.09 billion pixel print...Read everything he has to say and you'll learn a bunch...

http://www.tawbaware.com/maxlyons/gigapixel.htm

LW...

Tessa H.D. Campbell said:

I guess this is one of those things I had to learn the hard way. I
told a customer I would attempt to do prints of her 5ft x 6ft
painting with my 828 by taking photos of sections of the painting
and stitching it so that I could have the most resolution possible
once it was all stitched. I tried using both Elements 3.0 and
Autostitch. (I found Autostitch was smarter) In one case I took
six photos and tried to stitch them - that was a mistake because I
didn't think about how the camera's exposure would change based on
the tones in each section of the painting. So when stitched, I had
different exposures, duh. Secondly, if I wasn't careful enough to
keep the camera the excact distance from the painting for all six
photos - it didn't stitch well, if at all. So I tried four photos,
then three, then two. Well when I finally thought I had a good
stitch of two photos, I thought I'd zoom in and compare the
pixelation of my "two photo" stitch to the "one photo" shot. How
disappointing!!! I spent hours working on stitching only to find
that my stitched photos were blurry when compared to the one photo
I took of the entire painting. Am I making sense?

Is it true that stitching loses resolution? Anyone else run into
this before?
--
Tessa HD
Love to dream and dream in color
(eight-twenty-eight user)

Click to expand...

It actually works better than Autostitch for single-row stitching. The resultant stitched image should have the same resolution/quality as the individual photos.

Birk Binnard
http://www.birkbinnard.com/photography

If you can't get far enough away to take undistorted pics (ie curved lines that should be straight), I find that you can get a better result by sorting that out (I use PTLens) before running through the stitching software. For example, Autotostitch very much prefers rectilinear images to work on.
Your softness issue, I'm not so sure about - perhaps output quality settings.

in order to get a good looking reproduction of the art work,your camera has to be on exactly the same distance of the work,and always at an angle of exactly 90 degrees.(that goes for paintings,not for sculptures).For a somewhat bigger work,you would need a special rail to mount your camera on,so that it can be moved from left to right and up and down very precisely.Again,for landscapes,it will work,not for this.

Walter
--
http://www.leonhardsgallery.com

If I was going to do this I would mount a thin shelf or rail on the wall and move/slide the artwork instead of the camera. Also I seem to have better luck on stitching by layering the images over each other in a larger workspace and taking advantage of the transparency tools. I would say set the opacity of the 2nd image to 40%, overlap it to the first image and line it up, reset the opacity back to 100% and then fade or use the gradient tool on the overlaping area to blend it in. (I mostly use Corel Photopaint which has the interactive transparency tool that makes it a lot simpler for me.)
--
http://airbrush.smugmug.com/

....using lesser cameras than the 828. I know it was frustrating, on your first try, but don't give up!

Heres what you DON'T want to do:

Don't use stitching software. The processing in stitching software, EVERY stitching software makes geometry modifications by stretching and pulling and pushing the data around, and yep, that makes it soft...worse, it makes it soft in overlap areas but not in other areas.

Don't use varying opacities in your overlaps...this sounds like a great idea on the surface, but ends up creating the exact same "softness" in the overlap area...in fact, its usually worse.

Heres what you DO want to do.

1. tripod the camera
2. get as far away from the subject as you can
3. use only the CENTER of each shot you take

this will guarantee you don't have geometry issues, I use the center 20% of the image...in the case of the 828, thats 1.6 mp, which means if you stitch together 12 shots, you get a better than 19mp finished product using only the "heart" of the lens and sensor.

4. Definitely have the camera on manual, to insure the same exposure.

5. put a piece of tape on the floor, parallel to the subject, set two feet of your tripod on the tape. now you can slide your tripod left and right for each shot. tighten down all your tripod controls and use that crank to raise and lower to get each shot.

6. stitch the shots together manually...using layers..slice away the overlapping data keeping any feathering to a minimum.

Try this on something non critical first!

hope this helps...I have some files I've created from 20 stitched 707 shots, you could look at them with a microscope and you won't find my stitches! And it sounds like a long process, but all total it was maybe 45 minutes.

dave

--
Amazing what we can do with just three crayons, red green and blue!
http://yourbattlecreek.net

--
Tessa HD
Love to dream and dream in color
(eight-twenty-eight user)

I'm surprised it only took you 45 min!
--
Tessa HD
Love to dream and dream in color
(eight-twenty-eight user)

just one other thing which i have not seen mentioned - you may also have to play with the settings in Autostitch. sometimes i forget to set the jpeg quality to 95-100% and get a low res image that is of very poor quality the moment you begin to zoom in. just something you might want to look at -- the stitching will take longer, but you will get a better result.

gk

--
http://gaurav.smugmug.com

Tessa H.D. Campbell said:

I guess this is one of those things I had to learn the hard way. I
told a customer I would attempt to do prints of her 5ft x 6ft
painting with my 828 by taking photos of sections of the painting
and stitching it so that I could have the most resolution possible
once it was all stitched.

Click to expand...

Your logic is quite sound!

Tessa H.D. Campbell said:

I didn't think about how the camera's exposure would change based on
the tones in each section of the painting. So when stitched, I had
different exposures, duh.

Click to expand...

Reading through the other posts I see that fixed exposure has now been ticked off. But since nobody else appears to have mentioned it I'll throw in the reminder to use manual white balance as well (or at least one of the fixed presets e.g. daylight). Just as with exposure, WB will float around if you leave it on Auto.

Tessa H.D. Campbell said:

Secondly, if I wasn't careful enough to
keep the camera the excact distance from the painting for all six
photos - it didn't stitch well, if at all.

Click to expand...

No, it wouldn't. A tightly controlled location for the camera is du rigueur for this sort of work. I'd be using a tape measure and a mark on the background to ensure that the camera lens axis is exactly perpendicular to a wall, and then sliding the painting across in stages to do the shoot. I'd reckon on using a matrix of 4 or 6 images. For the bottom strip I'd probably leave the tripod untouched, and raise the painting on a couple of milk crates or somesuch which will still leave you able to move it left and right. You could instead move the tripod using tape on the floor to emulate a rail system, as David has suggested; but it's important that you keep the lens axis always normal to the painting.

Other things to note:

• Set focal length to a value that doesn't give you either barrel or pincushion distortion. That means somewhere well away from either full wide (especially) or full tele; you'll need to experiment. This will then dictate your approximate shooting distance.

• Use at least 1/3 overlap, preferably more.

• I tend to agree that auto stitching software is likely to be inferior to the job you can do manually for this particular project. As David cautioned, be careful about excessive feathering/transparency at the joins.

Tessa H.D. Campbell said:

So I tried four photos,
then three, then two. Well when I finally thought I had a good
stitch of two photos, I thought I'd zoom in and compare the
pixelation of my "two photo" stitch to the "one photo" shot. How
disappointing!!! I spent hours working on stitching only to find
that my stitched photos were blurry when compared to the one photo
I took of the entire painting. Am I making sense?

Is it true that stitching loses resolution? Anyone else run into
this before?

Click to expand...

Not true. You should be gaining resolution.

--
Mike
Melbourne