Stitching - A Toronto Church Interior Example

[Ed Richards]

I hope folks will not be offended that the original images were from a D600. This is an example of a large, high rez image built by stitching. I have included a link to full size file (95 megs) so that folks who have been interested in what you can achieve this way and how it compares to LF can pixel peep to their heart's content. This was built from 40x2 images - a 40 exposure stitch done with two exposures to control the DR. This was stitched in PTIGui and HDR mapped in Photomatrix.



Full size (95 megs)

Nikon D600, ASA 200, 85mm F1.8, f9.5, 0.7 sec and 6 sec. (Done by hand.)

[DennisD]

Hi Ed,

Beautiful job ! Despite the camera, the final format is certainly large ! I haven't completely loaded the full size file yet, (taking some time), but so far the image appears to be excellent and perfectly stitched.

Could you describe in more detail the camera / tripod setup (i.e. how carefully did you follow panoramic guidelines). Also more specifics on your processing workflow.

I assume 2exposures were taken, then you shifted camera to next position-total of 80 exposures ?
Was the orientation of the lens horizontal / vertical ? 4x10 layout ?
What was sequence of stitching and HDR ?
Anything else of interest would be great including any other processing info.

Thanks for sharing a very interesting project.

[Ed Richards]

Nikon D600, ASA 200, 85mm F1.8, f9.5, 0.7 sec and 6 sec, everything set to manual, of course. The camera is on my Gitzo video tripod, which has a leveling head built in. The actual tripod head is a pan/tilt head (rotates and tilts in one axis - it is my view camera head). That lets me level the camera independently of the head, so I can then rotate the head and everything stays level. it is an 8x5 vertical matrix, done strictly by eyeballing the overlap. The camera was set to lock the mirror and bracket, so each shoot took for four clicks - up mirror, shoot, up mirror, shoot, with the camera shifting the exposure for me. Very tedious and you need to stay alert or you will lose track and have to start over. The Nikon 85mm f1.8 has almost no distortion or vignetting, so I just loaded the raw files directly into PTGUI Pro. It auto aligns them. It will manage the exposure, but I had it output a 32bit HDR file, which I then tone mapped in Photomatrix. The master 16bit TIFF is about 2 gigs. I cropped and tuned it a bit in Lightroom 5. I should have shot at f11, the near pews could be sharper. The 85mm gives a unique perspective because it avoids what would otherwise be wide angle distortion if I had used a single exposure and very wide lens. I was in the choir loft which was high enough to let me shoot in the middle of the church. The final file has more resolution than a drum scanned 8x10, and I am not sure I could have managed the contrast as well with film. If I do this very often, I am getting a panorama tripod head with index points.

[Bill_1856]

Why? What is the point? Is there some final product you are planning which requires 95 megs? What is your final print size?

[DennisD]

The Nikon 85mm f1.8 has almost no distortion or vignetting, so I just loaded the raw files directly into PTGUI Pro. It auto aligns them. It will manage the exposure, but I had it output a 32bit HDR file, which I then tone mapped in Photomatrix.

Appreciate the detailed explanation, Ed.

If I understand correctly, PTGUI handled the stitching and the integration of both sets of exposures - the .7 sec and the 6 sec exposures of which there were 40 each for a combined total of 80 images. I thought PTGUI was primarily for stitching and was not aware that It would output an HDR file. Cool !

Thank you very much.

[Ed Richards]

Why? What is the point? Is there some final product you are planning which requires 95 megs? What is your final print size?

Dangerous question on this forum.:-) I doubt 5% of the folks shooting LF are making prints that need LF.

I used the 85mm for the perspective, that drove the number of images. The resolution allows crops for details that will still make good prints. The multiple exposures tame the dynamic range better than I can do with film. I have also stitched 4x5 to get better perspective, but when you start doing multiple exposure stitches with 4x5, you have ask if it is the right tool. Churches with stained glass are a challenge to shoot when you are traveling and don't have the option of waiting for the right light. I don't have the resources to add light, or the time, and it would require special permissions. Maybe even a generator.

[Jim Galli]

That's it! The 8X10 is officially dead. Anyone want this crap, come and get it.

[Ed Richards]

That's it! The 8X10 is officially dead. Anyone want this crap, come and get it.

It is, commercially. But that is not why you shoot it.:-) This is a particular imaging problem I have that has proved frustrating to solve with LF. It lends itself to this solution because it is completely static so I can use an imaging technique that takes 20+ minutes for an exposure. I am interested in solving it because I shoot for the images and prints, not the fun of the technology. But if I want to mess with perspective, esp. wide angle perspective, I will still use the 4x5. I will also use LF if I am doing an outdoor shot where clouds or other movement is an issue. If the camera fairy gave me a top end MF digital back and a 6x9 camera, I would dump LF because it would not make sense to use it instead for the images I shoot.

[polyglot]

You can still get the wideangle perspective, you just need to choose the appropriate projection in the final assembly. You've got what looks like cylindrical (or similar variation) here; if you choose rectilinear then you get the traditional wideangle look. And note that because the stitcher performs a spatial remapping of EVERY pixel, you can use any length lens you want for the source material and have the final result come out the same, geometrically. Choosing a longer objective lens just means taking more images and gives a higher output resolution for a given total angle of view.

This is arguably digital LF, though obviously the exposure is made piecemeal and then assembled. Assuming 40 exposures with an average of 60% area overlap (50% in each dimension, less the edges) implies a total exposure area somewhere between that of 4x5" and 5x7".

[bdkphoto]

It is, commercially. But that is not why you shoot it.:-) This is a particular imaging problem I have that has proved frustrating to solve with LF. It lends itself to this solution because it is completely static so I can use an imaging technique that takes 20+ minutes for an exposure. I am interested in solving it because I shoot for the images and prints, not the fun of the technology. But if I want to mess with perspective, esp. wide angle perspective, I will still use the 4x5. I will also use LF if I am doing an outdoor shot where clouds or other movement is an issue. If the camera fairy gave me a top end MF digital back and a 6x9 camera, I would dump LF because it would not make sense to use it instead for the images I shoot.

It seems like an awful lot of unneeded work for an interior like this. Something like a 5dmkII would give you a single file of 128MB in size, a 2 or 4 frame stitch (4 is total overkill IMO). No need for HDR either.