Stitching & stacking workflow

[Joco]

Not sure if anyone has experience here - focus stacking of stitched panoramas. I got the idea from Michael Erlewine's publications and for this purpose purchased the Proshift+ add on to my Novoflex Balpro1 bellows.

The work flow is rather labor intensive, so I am hoping for any tips on how to optimise.

The shots are 3 times 8 photos, i.e. 8 3-shot panorama's. Btw the photos are taken in portrait, movement is 10 mm to the left respectively to the right.

Workflow:
1) copy files to disk
2) import into CaptureOne (C1)
3) export from C1 to full size 16 bit TIFF
4) load first 3 into PtGui
5) input focal length
6) align
7) add control points for bokeh-only photo
8) size and crop panorama
9) export to TIFF
10) remove source images
11) repeat 3 to 10 (7 more times in this case
61) import the 8 TIFFs (the panoramas) in C1
62) crop all to the same size (PTGui's output files are all slightly different in dimensions)
63) export the 8 cropped pano's to 100% 16 bit TIFF's
64) from now on standard stacking

Suggestions for improvements?

Btw here's my first result which isn't spectacular, but more of a trial to what goes wrong (various things go wrong the first time I try something). A bit of vignette was added. The Zeiss S-Planar 100mm f4 (for Contax bellows) appears to have no problem covering the extended image circle.

zwampano by Hans van den Bosch, on Flickr

[Lou Jost]

If you use a stacking software allows it, and, if your setup is stable and your lens is modified to be telecentric, you could turn off all alignment options including scaling. Then you could do the stacks in succession and stitch the stacks.

[rjlittlefield]

Hi -- I'm Rik Littlefield, the fellow who wrote & supports Zerene Stacker. I've had a fair bit of experience talking with people who do things like this, including Michael Erlewine in particular.

various things go wrong the first time I try something

If it's only the first time, you are truly blessed. For me they keep going wrong forever, though fortunately with rapid falloff in the rate.

Suggestions for improvements?

I notice that you are stitching first, stacking second.

I usually recommend to do it in the other order: stack first, stitch second.

The problem with stitching first is that slight alignment errors often creep in between one panorama stitch and another. These result in panos that are slightly different "shapes". For example they might be stitched so that the centers of the frames make a slight curve up in one pano but down in another. The alignment step in stacking cannot correct for such changes in shape, so the resulting misalignments can produce echos or halos in the stacked result.

Stacking first is not foolproof either, because slight alignment errors can also creep in between one stack and another, so that for example one stack curves slightly one way while another stack curves a different way. Those discrepancies result in parallax errors in the stitching, which again can produce echos in the stitched result.

However, the problems from stacking first will be limited to the stitch regions, while problems from stitching first may be distributed across the entire image.

With larger panos and deeper stacks there are other issues that kick in. If you stitch first, you may run into memory limits for stacking large panos. With other shooting setups, there also may be trouble getting the same focus for all source frames within each pano.

My general sense is that on average it's less trouble to stack first, stitch second, hence the recommendation.

Also, you don't specify what parameters you are inputting to PTgui, but just to cover the base I'll mention that you're doing what PTgui calls "mosaic" stitching. See their FAQ on "How can I stitch mosaics, like partial scans from a flatbad scanner of a large image?", currently at http://www.ptgui.com/support.html#5_5 .

--Rik

[Joco]

Thanks Lou for commenting, my setup is pretty stable but in the field, fiddling with the bellows and the Shiftpro part I do get variation between the shots. - btw very interesting site!

Thanks also Rik - thanks for creating Zerene which I use a lot.

And thanks for the advice, with the pros and cons. Makes perfect sense.

The reasons I chose to stitch before stacking is I feared I would edit the 3 stacks slightly differently, creating a noticeable difference in the overall image. Stacks containing a lot of 'bokeh' tend to need some retouching (DMap), and this image clearly does. But I will definitely give it a go.

Good tip on the PTgui parameters. It actually crossed my mind that the this way of making a panorama is different then 'usual' (i.e. rotating camera/lens in the two planes), but did not make the connection that I needed a different approach in the software.

[ohdeeremee]

Joco, FWIW,
I usually stack individual parts, then do the panorama. This seems to work for me. This image was made in a 2 x 4 matrix, 8 stacks of about 210 images per stack, some less. The input images are JPEG's from a Nikon D90 (max resolution). The 8 stacked images, again JPEG's, run through Lightroom Merge Panorama function, which creates a DNG. I usually use PTGui, but it left some areas not properly merged, but LR did a fine job.

[/img]

I used to do RAW images, but the file sizes got too huge, and I see little or no difference using the JPEG files. Lightroom Pano and HDR both create DNG files, which can be very large, which I convert to 100% JPEG and delete the DNG. I do keep the original source images, and can re-do everything. A 400MB DNG file will go down to about 40MB JPEG.

It's not a perfect image, but it took about 3 days to create. 1582 images in it, and the bad part is that by the time your done, and find something wrong, (back leg could have been better...) the critter is too brittle to mess with... Oh.well...

George

[Joco]

Thanks Ohdeeremee for sharing your work flow and experiences.

The result you got with the beetle is really crips (with or without back leg) - nice project!

[BugEZ]

I have used the stack then stitch work flow. This has worked well for the wings of tiny flies that are a bit too long for my 10x lens to capture in one stack. My horizontal rig allows me to shift the camera latterly between stacks.

An example... note that the stereo images were created with Zerene and stitched with photoshop, then placed side by side.

http://www.photomacrography.net/forum/v ... hp?t=28409

Another non stereo stitched wing

wing panorama by Keith Short, on Flickr

Keith

[Joco]

Amazing wing-picture Keith!

[Joco]

Second attempt, taking on board all advise given. I.e. first stack, then stitch. And using the mosaic settings for PTgui.

It could have been better, but the workflow is ok now. It's just me being negligent (undershot one of the three stacks, did not check the aperture on the lens which was fully open @f4, did not check the stacks as I assumed they would be perfect with this amount of details and so forth). Nothing to blame but me :-).

An improvement in the photographing workflow was make all shots for a stack, then shift the camera, make the series of pics and again shift and shoot. In my normal pano-photoraphy I am used to changing the camera position after each shot, so that was a habit.

The end result is an 85MP file. Which is full of detail. I love that, but obviously there is hardly a practical purpose in this kind of shot. But then again it is just my hobby so it does not need to be useful :-).


blarderdek by Hans van den Bosch, on Flickr