OK, how many mega-pixels equals a LF negative?

In answer to the question "how many mega-pixels equal a LF negative"...

Noone really knows because they have not yet produced enough pixels... -Dave

i can pull an 800MB 16bit file or a 400MB 8 bit file when scanning a 6x9 image on my nikon coolscan 8000 at 4000dpi. my printer, an epson 3000 will let me print that image at 16"x24". what inhibits me from moving to sheet film formats from roll film formats is that great sheet film scanners start at $16000.00 and get impressive at around $70000.00. perhaps in 5 or 6 years one will be able to purchase a digital back that captures an image with 11 or 12 stops of latitude in a small fraction of a second, and at a resolution that will look good over the couch. and by then, printer drivers will all be 16bits (like the Cone Quadblack plugin) and all that technology will be judged useful. until then, i wallow in the great good fortune of having so much fun with what i have, with little thought about what's next. vincent

Think in terms of megapixels (mp), or millions of pixels - that's how CCD (used in digital cameras and backs) capturing is measured.

A 600dpi scan of a 4X5 nets an approximate equivalent 6 megapixel file. That same image takes up about 17mb of hard disc room on a computer. 6 mp cameras are available now - two years ago a 2 to 3 mp camera would have been king of the hill.

Within two years a digital camera the size of a cigarette pack will capture 20 million pixels (he said confidently). That 20mp will roughly equal a 1200dpi 4X5 scan.

The CCD industry is going through the same progress as other digital or computing devices have for years - an approximate doubling in capacity every eighteen months. So your friends will be right within five to six years, based on a 2400dpi 8X10 scan - assuming you agree there is no point in scanning an 8X10 at higher than 2400dpi.

No doubt the number crunchers at Fuji and Kodak have done this homework as well - the bulk of both firms R&D $$$ is now spent on digital products and solutions.

Hi-

A 1st rate 4x5 system with real optics and an excellent film probably can reasonably expect about 25 lpmm across the entire sheet of film. This works out to 50 dots per mm or 1270 dots per inch (dpi). This in turn leads to about 5000 X 6000 pixels. 8x10 will probably be more like 15 lpmm yielding about 6000 X 8000 pixels.

As soon as you try to get the information off the film via a scanner or enlarger the effective resolution will be degraded further.

I for one look forward to digital when the cost and convenience gets real.

jim

Mr. Mahoney (Baloney!) My 300dpi scans of 4x5 color transparencies produce a 27-29MB file - 600dpi is in the neighborhood of 40-70MB (and more). Besides, trying to determine what the resolution of a film is, based on a scan is utterly ridiculous!

We had some fun with this one. I certainly appreciate all the conceptual and subjective differences between film and digital, and obviously the contrast of compact camera vs. LF rig. For me, and I suspect for many, even if (when) digital technology surpases LF film resolution and rendering, the craft of exposing and producing traditional negative and prints, and the meaning it has for artistic vision and realization, will keep me in the darkroom for a long time. In any case, these numbers should make for some stunned looks when the next digital geek starts bragging in my direction.

Chad: Is a 'bujillion' anything like 4 or 5 thousand? Because that's closer to the number of individual colour levels you can create from 3 layers of cyan, magenta and yellow dye clouds.Each blob of dye in a film is a pretty uniform density, and it's only by overlaying those fixed densities, and dithering them side by side, that you get an ILLUSION of continuous colour tone out of film.From examining colour film under a microscope, I reckon that each colour layer is capable of only about a 16 to 1 colour variation, at the level of the individual dye clouds.

Please, let's stop fooling ourselves that film is the ultimate imaging medium. If only so that Kodak, Fuji, Agfa and Konica don't rest on their laurels.

Nathan - Could you convert that number out of metric? I have such a hard time visualizing metric units of measure.

RE: Mr. Mahoney (Baloney!)

(( My 300dpi scans of 4x5 color transparencies produce a 27-29MB file - 600dpi is in the neighborhood of 40-70MB (and more). Besides, trying to determine what the resolution of a film is, based on a scan is utterly ridiculous! ))

Matt O (Turkey!):

I'm happy you have a high enough quality flatbed and scanning skills to draw that amount of information from your 4X5's. The final file size depends on many factors, but that was not the original question.

If you read my post before spouting off you'd realize no attempt to determine the 'resolution' of any film was made.

Jim Bancroft noted above that: "A 1st rate 4x5 system with real optics and an excellent film probably can reasonably expect about 25 lpmm across the entire sheet of film."

I routinely get closer to 50+ lpmm with TMX and Velvia using modern optics on a Tachihara. More in the center. If it's less, it's due to diffraction from stopping down so far to get the required DOF. (beyond f/22) This level of resolution is easy to see with a 10X loupe.