Are we diffraction limited?

[Edwin Beckenbach]

Problem is that packing more and more pixels onto a sensor after a point only improves marketing brochures. It's hard to imagine APS-C ever performing up to 4x5 standards outside of special circumstances. Bigger pixels on bigger sensors is where it is at and Medium format digital, which basically performs on par with 4x5, is getting cheaper all the time but it still seems like it will be many years before its anywhere near affordable by any reasonable standard. The Pentax 645D is a big step in that direction. Look for a used one in five years.

[rdenney]

A Canon 5dII with a 24mm TSE II lens will make a very detailed image that will probably support a 16x24" color print at the capability of the printer and paper. That is pretty amazing from a 24x36 capture area, and it has tilt/shift capability (up to a point). Only the Live View makes it possible to adjust the focus plane really usefully for fine control of what is IN focus (other than for "artistic" effects of making things OUT of focus). And if you are going to use Live View, you are now on a tripod and spending real time on each image, so the convenience is lost.

Sure, we can stitch a million pictures made on a tiny sensor with an ultra-short lens that has huge depth of field so that we no longer have to focus. We could also hire a robot to make our pictures for us.

But the camera and lens together cost just shy of $5000. When people can enlarge those 5-micron sensor sites to the size of a pixel on their computer monitor, suddenly they see all the flaws in those lenses. Those flaws can be corrected, but only at a price.

And while digital cameras are depreciating, the lenses are not. I could routinely sell my 24mm TSE Mark I lens, that I paid $1100 for new two or three years ago, for $1000. And that lens is not a top performer like the Mark II. I could sell my 1987-vintage Canon 135mm soft-focus telephoto for $250-300, and it cost that new.

On the other hand, I replaced much of my large-format kit last year. I bought a Sinar F, an F2 front standard, a wide-angle bellows 2 (the camera came with the standard bag bellows and a standard pleated bellows), a 65mm f/5.6 Super Angulon, a 210 Sinaron (APO-Sironar-N), a 240mm Caltar Y, a 12" Ilex-Caltar, a Sinar Vario back, a Shen-Hao 6x12 back, a Maxwell screen, and a Sinar tilt-head. Nobody would complain about the quality of any of those purchases. I would have to add in all the lenses I already own (a 47mm SA, 90mm SA, 121mm SA, 180mm Symmar), plus tripods, spot meters, cases, focus cloths, film holders, and 10 years worth of film to add up to what that 5DII/24TSEII would cost.

And when you have scanned a 4x5" piece of film even on a lowly V750 flatbed scanner and printed it at 16x20, you will see what people are telling you. There is value in capture area. I get about 80 million useful pixels out of one of those scans.

Sure, there are ways to do it with digital camera with software. But that isn't the point of photography for most people, unless all they want is a documentary photo. And those purposes are what digital was made for.

Diffraction is less of an effect than being out of focus, and being out of focus is what most of any picture in the three-dimensional world is.

Rick "who worries about diffraction only when photographing test charts" Denney

[jan labij]

And it's not a boat, nor is it a ship---it's a brig! perhaps a hermaphrodite brig. But, that said, it's a nice picture--look great on a calender.

[Mark Woods]

I use older lenses with not CC coating stopped down to 64 all the time with my V8, and Chamonix 11x14. I like the look and the quality of the prints. I've been printing more and more 11x14 from both formats on Ilford MG IV FBW matte paper and love it. If you want digital on steroids, look at the Better Light equipment. The price is on steroids too. ;-)

[Policar]

Mark, so cool that you're a cinematographer! I am...an aspiring one. Shot a few really bad features and am now thinking of moving to LA, joining a grip union, trying to work my way up to better material. I have a friend who just graduated from AFI, awesome program, but I can't afford graduate school (plus I'm so good I don't need it, debatably...). My hero, Robert Richardson, went there, too! It's interesting that so many cinematographers shoot large format. It was my light meter (758 cine, guilty smile) that drew me away from dSLRs in the first place.

I have no money so it's going to be 4x5 all the way for me. Just need a better camera at the moment as my current one has a broken front standard. What does interest me is the idea that at a given FOV and DOF you're diffraction limited no matter the medium: large format film, medium format digital, even image stitching (unless you also stitch focus). It seems that at current pixel densities, medium format digital cameras are reaching diffraction limits for deep focus photography, and so the image quality larger formats offer is much less significant if that's the case... But then how do you do lens movements on a 645 digital camera? The sensor is way too small to focus by eye and tilt/shift lenses are limited.

I just wonder if this means large format film is here to stay (I can tell medium format film isn't by how quickly my lenses are losing value) or that image stitching is the inevitable future? As for 11x14, well, I can tell already it's not for me--but I'd like to at least try it some time.

[Ben Syverson]

Dude, if what you want is the infinite DOF look, and you have "no money," stitching is the way to go. Don't mess around with LF. You can make HDR multi-gigapixel images with a point and shoot that absolutely annihilate 4x5. Even if you just stitch a handful of DSLR shots, you'll beat the $40,000 MF digital stuff. (How big are you printing, anyway?)

Of course, stitching makes it a lot harder to shoot a scene with moving clouds, cars, water, or people.

If you're more interested in researching diffraction mathematics, you can read all about airy disks and such. "Airy disk" is one of those phrases like "circle of confusion" that is typically used by someone who is avoiding taking a photograph.

[Dan Fromm]

This discussion takes me back to the early 1970s, when H&W Company repackaged Agfa microfilm and sold it as H&W Control Film. They also offered a wonder-working developer that oxidized into uselessness within a few seconds after the bottle was opened. Very sharp but slightly unforgiving film.

The Leicanuts of the day were very pleased with it, asserted that with the wonder film and wonder developer they could make negatives that printed as large as the best possible from 4x5. And then they pissed the advantage, if real, away by shooting handheld, at too small apertures, at too large apertures, ...

Now comes young trolli, fresh from eating a herd of goats, to lecture us about the wonders of digital. What has changed since the early 1970s except the replacement of Agfa microfilm by silicon? The story's the same, advantage, if any, with perfect technique lost to imperfect technique.

[Sirius Glass]

I have no money so it's going to be 4x5 all the way for me.

If you have no money why are you screwing with digital.

It seems that at current pixel densities, medium format digital cameras are reaching diffraction limits for deep focus photography, and so the image quality larger formats offer is much less significant if that's the case... But then how do you do lens movements on a 645 digital camera? The sensor is way too small to focus by eye and tilt/shift lenses are limited.

But a REAL medium format camera [Read: Hasselblad] shooting film does not have these problems. If you want shift-tilt-swing look at Hasselblad's Flexbody and Arcbody.

Steve

[John Whitley]

We could also hire a robot to make our pictures for us.

Ask and ye shall receive: http://www.gigapansystems.com/ <cough> <cough>

I recall a Gigapan pano of President Obama's inauguration receiving some reasonable buzz on the 'net. I also recall thinking that an 8x10 (or 4x10) wide angle shot would likely have been better. At least it wouldn't have had mysterious disembodied legs and such...

[Mark Woods]

Hello Policar,

We think the AFI Cinematography program is pretty good. Our Cinematography Fellows work every week and we do more production that any school in the world to the tune of about $700K/year. Our alumni speak to our excellence. Was your friend in the Cinematography Discipline in the last 5 years? If so, s/he was in my class.

Thank you for your kind comments.