Stitching Question - Digital SLR vs 4x5

[Gordon Moat]

i had kind of visualised this effect, although i have to say that i have no experience of stitching but obiously the software seems more sophisticated than i thought. which is really interesting news.

Apple's early QuickTime VR Studio was one of the earliest software packages that corrected the distortion. There is still that aspect of capturing shapes at the edges of your images that will seem slightly odd looking, something like what QT mentioned is similar to a very wide rectilinear. Obviously the effect is greater when the scene view is even wider. Current software packages provide some better solutions to this. The end result would still look different than a single shot on a view camera with the same field of view. When you are aware of this, it is possible to consider it in composition, and to correct later in post processing (as much as possible).

It might seem like trading one set of problems for another. There is a slight disconnect between composition, capture, and post processing. I think that becomes more seemless with practice and experience. This approach will always seem different than a single shot on large format, which is why I view this as an alternative and not a substitution.

I have some experience doing QuickTime VR images, which when you think about it is stitching. The difference is that usually a superwide or fisheye lens was used and rotated around the nodal point, though it would have been possible to use longer focal lengths. As for more normal stitching, I have done two, three or four shot film captures stitched together, though the positioning was done by shifting, and not by rotating the camera. A substitute method to simulate shift would be a sliding rail, sort of like a sideways macro position plate; this avoids the need for spherical correction later.

Ciao!

Gordon Moat
A G Studio

[adrian tyler]

thanks gordon, yes, i can see that shifting would create a different result verticaly than rotating, and rotating will produce something rather like a normal "panorama", however a sliding rail would need to be mighty long to make an effective "travelling panorama" for a landscape say, no? (...sorry to be so slow on the uptake!!)

[David Luttmann]

Figured you would take a swipe at my question David, which is why I don't put much credence in most of what you say. 30 years of shooting for a living has taught me a few things, and I still don't feel digital is superior to film, even stitched images. The best digital images look cold and without depth to me. But as has been stated by a few, including me, that is my preference.

Dave

Not taking a swipe....you said that based on your experience, your opinion is that a stitched image cannot equal 4x5. Yet you then ask about how stitching works because you didn't understand. I'm sorry if you're feeling offended....but I am curious as to how you know stitching can't be better than film, yet you don't know what stitching is.

Simple question really. Or maybe you don't care that the quality can be better regardless....which is fine with me as well. Like you said, shot with what you want. I would add though that maybe in the future, if you don't know what something is, maybe you shouldn't be so quick to claim it inferior.

Hopefull this wasn't too shrill for anyone to digest ;-)

[Dave Parker]

Not taking a swipe....you said that based on your experience, your opinion is that a stitched image cannot equal 4x5. Yet you then ask about how stitching works because you didn't understand. I'm sorry if you're feeling offended....but I am curious as to how you know stitching can't be better than film, yet you don't know what stitching is.

Simple question really. Or maybe you don't care that the quality can be better regardless....which is fine with me as well. Like you said, shot with what you want. I would add though that maybe in the future, if you don't know what something is, maybe you shouldn't be so quick to claim it inferior.

Hopefull this wasn't too shrill for anyone to digest ;-)

David,

Where you are mistaken is, I do understand how stitching works, I didn't realize people were multiplying the total frames to come up with a MP number, I don't care how many frames you stitch together you still have the same bit depth in all the frames, your bit width may increase, but if you stitch 10, 10 megapixel frames together you still have a 10 megapixel bit depth.

But don't be mistaken, I do understand how to stitch frames together and actually have done it...I just happen to feel, differently about it. As far as equal or better, I still feel that 10 frames stitched together don't equal a properly scanned 4x5, but that is me...and I can tell the difference in a picture that I see in person, as far as looking at images on the net, I discount those due to the limitations of monitors and computers. But in the long run, it don't matter what I think at all does it, and about the only thing I really care about, is if my clients are happy with my work and pay me...

Dave

[Lazybones]

Say it, Dave. Say it...

[Sheldon N]

David,

Where you are mistaken is, I do understand how stitching works, I didn't realize people were multiplying the total frames to come up with a MP number, I don't care how many frames you stitch together you still have the same bit depth in all the frames, your bit width may increase, but if you stitch 10, 10 megapixel frames together you still have a 10 megapixel bit depth.

But don't be mistaken, I do understand how to stitch frames together and actually have done it...I just happen to feel, differently about it. As far as equal or better, I still feel that 10 frames stitched together don't equal a properly scanned 4x5, but that is me...and I can tell the difference in a picture that I see in person, as far as looking at images on the net, I discount those due to the limitations of monitors and computers.

Dave

For clarification sake..Bit depth is an entirely different issue than megapixels.

Bit Depth refers to the number of colors or shades of grey that an image can contain, basically how fine of a gradient you can create without showing steps from one shade/color to the next. A high bit depth image can display a perfectly smooth gradient with no perceptable steps, while a low bit depth image will show a gradient more like a step wedge.

Megapixels simply refers to the number of pixels contained in an image, derived from pixel width multiplied by pixel height.

There is no connection between the two. Bit depth is a function of the sensor & digital capture system built into the design of the camera

You are correct that a stiched image does not contain any greater bit depth than a single image. It does however contain more total pixels.

I believe we all understand and agree with your intended message - just because a digital stitched image is bigger and higher resolution than a single digital image, that does not take away any of the inherent disadvantages (or advantages) of the fact that it is a digital capture.

[Dave Parker]

Say it, Dave. Say it...

As I said, It don't matter what I think, I happen to feel the nuances of film are better, so what, I am just expressing my opinion as anyone else here does..

Dave

[Jack Flesher]

you still have a 10 megapixel bit depth.

Dave, I like you, respect you and respect your right to express your opinions here, so please understand this is not intended as a slam but rather added clarification...

The expression "10 megapixel bit depth" is entirely meaningless in the digital world... It is akin to me saying I don't like Tri-X because of its inferior dye transfer layers.

Pixels are the individual photon receptor sites. There are two significant things worthy of referencing when discussing them; the total number of them and their diameter, which in turn correlates to their density on the sensor. The more of them there are, the more information we have to render image detail over a given area. More pixels is the digital equivalent of using larger format film.

Bit depth is simply how many distinct gradations of color an individual pixel can render in each of the three primary color channels. 8-bits per channel = 24-bit color (3 primary x 8-bits for each) = 2^24 distinct colors being able to be rendered. The more bit-depth, the more colors we can replicate. This, when coupled with the definition of the working color space, would be reasonably equivalent to the color response curves or tonal range in film.

Dynamic range is the ability of the pixel to respond to and accurately render different intensities of light. This would be equivalent to exposure latitude in film.

Cheers,

[Dave Parker]

Dave, I like you, respect you and respect your right to express your opinions here.

However, FTR the expression "10 megapixel bit depth" is entirely meaningless in the digital world... It is akin to me saying I don't like Tri-X because of its inferior dye transfer layers.

Cheers,

Jack,

Sheldon, explained quite well what I was trying to express.....This is an argument that will only be settled when a true 4x5 sensor is available to the mainstream photographer. And we can compare results of that sensor to the stitched images...

One thing I do find interesting, the Sh*T sure hits the fan on photography websites, when either someone says "digital can blow away" or the other says "digital is inferior to film"

And as I continue to say, we each have our opinions and at this point in time, when someone tells me, digital is superior, I am going to disagree based on what I do, but and have to agree with an earlier post today..why does it have to be them or us..both sides could take a lesson here and stop with the this is better than that, cause us arguing is never going to change anyones mind.

Dave

[Jack Flesher]

Dave,

I am not "arguing" with anything you said, but rather discussing it... FTR, I have not claimed digital is superior to film, nor have I claimed film is superior to digital -- FTR2 I personally shoot both!

I simply felt it necessary to give some standard definitions so everybody starts speaking the same language -- only then can we all understand what it is we are trying to discuss when making comparisons.

If folks don't like what I wrote, by all means let the mods delete it.