Format for 60x75 inch Gallery Prints - 4x5 or 8x10?

[rdenney]

If you are up for the challenge, rent a P45+/P40+/P65+ with a Cambo Digital Wide DS and go through the process to get the 4-6 files required for a stitched image that would result in a print similar to a single 8x10 image (60x75). Only after you import to PS (or whatever software you can get) and actually attempt to stitch the 4-6 frames together will you experience my frustration. I guarantee you this is as tedious as anything and the exposures will be very tricky to blend. It will take you hours to get the image looking as you want, if you are lucky. You may have to go take more shots.

Question for the assembled masses: Is there a sliding back to fit an 8x10 camera that would allow one to make images for stitching with a P-whatever back? That would address all the issues the OP brings up above:

1. The vignetting pattern on the lens would be even across all the stitches.

2. There would be no possibility of parallax error.

3. The stitches would not be complicated by even slight geometric distortion in the lens.

4. The stitches would not be complicated by any variation in sharpness across the frame.

5. The OP would be able to compose the whole image at once.

What makes stitching images made from a repositioned camera difficult is geometric distortion, vignetting, mismatched sharpness at the edges, perspective errors, and parallax errors. Sliding a medium-format digital back around on an 8x10 camera back would address those issues, it seems to me.

Rick "working the problem" Denney

[rdenney]

> Are you trying to be funny? 10" is not a reasonable viewing distance for a 6.25 x 5' print. Neither is 20". Reasonable is 60".

I disagree, on the basis that it depends on what the image is to be used for. The OP hasn't said what he's photographing (or maybe I missed it), but what if he is documenting, say, medieval tapestries? The objective for that is to record micro-detail as accurately as possible for later study, not to make a gallery image with a rope preventing people from moving up on the image.

But I also disagree with the assumption that people don't or shouldn't move up on the image. I bought a print recently that is 20x40 inches. One of the reasons I bought it is that even from a distance, it invited me to come close and be drawn into it. That effect would have been lost if upon coming close, the print's image quality broke down. That print looks very good from 10 inches, even though I have to choose a different porthole in my trifocals to focus on it. When I move in that close, the print almost entirely fills my peripheral vision, and it quite transports me to the place it pictures. That is the print that has brought me back to large-format work--I want my prints to be able to draw the viewer in without distracting him because the image breaks down on close scrutiny.

Rick "isn't this why we do large format?" Denney

[bglick]

The problem with MF digi back with LF is.... aerial resolutions of 810 lens are very poor vs. MF lenses. You also are contending with very large capture angles once you leave the center of the print, which no digital back handles very well...hence why digital lenses were designed, to work with the finnicky sensors....

In addition, it would never be as effective as taking an SLR and a proper pan head, and stitch the captures. The reason is, when you move to a stitching head, you now use normal to long fl's, which is EXACTLY what the sensor desires for best IQ.

Again, if the subjective is cooperative, digital stitching, even with a $999 Canon 50d can blow away 8x10 resolution, specially with a high DOF shot... sad, huh.... OH yeah, one other major benefit.... for the same final print rez/size, the stitched file will be about 1/2 the size of the scanned file.... and when file sizes are in the Gig range, this by itself makes stitching the logical choice.... its great to have so many options today, both at capture, and in post processing....

You can always bring a cheap 810 for composure only....But a cardboard cut out of the aspect ratio you desire, placed at specific distances from your eye (proposed fl) ... now, you see the image in proper orientation vs. upside down and backwards.... when you have time to prepare for a shot, the options are limitless...



Rick...

Originally Posted by bglick View Post
> Are you trying to be funny? 10" is not a reasonable viewing distance for a 6.25 x 5' print. Neither is 20". Reasonable is 60".


Just to be clear, benny posted this, not me, I only commented on it....

[Drew Wiley]

Apparently some of you mistake photographs for aerosol-can gang graffiti. I personally
put my nose right up to the print, reading glasses and all. And that's also how people
view my own prints. They love the detail, the precision. Beyond the overall composition, there's the discovery of a lot of detail. That's the whole advantage of
large format to begin with. I've said repeatedly, "normal viewing distance" is a bunch of bull unless you're into outdoor advertising. But apparently, the line separating
billboards from photographic "art" is becoming hopelessly blurred nowadays.

[bglick]

> But I also disagree with the assumption that people don't or shouldn't move up on the image.


Agreed.... in todays world, everything is scrutinized to death... and for some reason, walking up close to a 60" print is considered commonplace.... 20 years ago, it was considered absurd. The better the technology gets, the more people find ways to exploit it. It becomes a new benchmark of greatness for sharpness freaks...


But, all this resolution is never fully wasted. In Cteins first book he did an interesting experiment....he continually added more resolution to a set of prints, well above the eye limit. He is meticulous with his approach and is highly qualified in this regard. He made about 8 prints, up to 50 lp/mm... he found that people could place the prints in perfect order of sharpness, up to 30 lp/mm, which case the testers could not discern any differences. This demonstrated clearly, that although we may only resolve 1 arc minute (20/20), our ability to "discern" detail goes way above this. So a 75" print that can stand up to 15" viewing distance, will still provide added benefits at the normal viewing distance... specially for those with better than 20/20 vision.

[Jim collum]

you'd be able to do it with a 4x5, at least a 33mp MFDB and the Kapture Group's quad stitch http://www.kapturegroup.com/quad/quad.html (which is 'only' $5,000 for the sliding back alone)

with a 33Mp back, you'll end up with about an 18,000x14,000 pixel stitched image, which can be printed at your dimensions at about 240dpi (and since there's no alias filter on the DB, a print at 240 dpi won't show any digital 'artifacting' even at nose to print distance.

[bglick]

Jim, remember, native pixel count does not equal recorded resolution.... which is function of the sensors MTF and the lenses aerial resolution. In this case, since you are still forced to use a LF lens, diffraction is very limiting, so you can cut the recorded resolution to half of the native resolution.

this is the beauty of stitching with 35mm gear, shorter fl's, wider apt's and you do not subject the sensor to wide angle rays at the edges and corners. Each capture is working at the"design" conditions....

[Ben Syverson]

I disagree, on the basis that it depends on what the image is to be used for. The OP hasn't said what he's photographing (or maybe I missed it), but what if he is documenting, say, medieval tapestries? The objective for that is to record micro-detail as accurately as possible for later study, not to make a gallery image with a rope preventing people from moving up on the image.

Re-read the title of the thread. "Format for 60x75 inch Gallery Prints" says to me these prints are intended for a gallery setting, not academic study. Add to that this from the OP: "I shoot primarily 5-second (plus) exposures of landscapes and interiors (devoid of people) in color."

Personally, I think both MFD and 8x10 aren't what you want for ultra-large prints of immobile subjects. Get a GigaPan with a small DSLR, and make 3 gigapixel captures. Nothing else can come close.

[bglick]

> Personally, I think both MFD and 8x10 aren't what you want for ultra-large prints of immobile subjects. Get a GigaPan with a small DSLR, and make 3 gigapixel captures. Nothing else can come close.

Ditto, ditto, ditto....

[el french]

what version PS has a poor stitching operation? I found CS4 very effective?

CS4. I usually have a lot more than 3 0r 4 images and CS4 just isn't as accurate aligning the images as either ICE or PTAssembler. My success rate with CS4 was really low and it doesn't have any redeeming features that I could find when comparing it to either ICE or PTAssembler. PTAssembler has more output projections than any other stitcher, while ICE is very automated.

Here's a recent one done with ICE and Zerene Stacker: http://img.photobucket.com/albums/v6...P7309376Fb.jpg

I'm not trying to hijack the thread, but I just wanted to point out that using CS4 as the stitcher may be the weak link in the workflow.