Fun photography fact! You might not know that the human eye works basically the same as a 100-megapixel digital camera with autofocus. The main difference is in that we have two different types of pixel: R/G/B cone cells for color vision and grayscale rod cells that let us see in low light. The ‘pixels’ are also a lot denser at the middle point where we focus (the fovea) than further out in the peripheral areas.
Pic taken with the Panasonic Lumix 20mm f/1.7, a not quite aberration-
free lens with intangible image qualities that micro four thirds camera
owners love.
Our firmware also presents an interesting question. For example, the eye focuses just like my E-P1: it hunts back and forth until it finds a sharp edge. We call that contrast-detect autofocus (CDAF). Traditionally CDAF kind of sucks. One problem is that you cannot tell whether blur is too close or too far away, so half the time the lens starts hunting in the wrong direction. Even if it starts well it always overshoots and then will hunt back and forth over the ideal spot. A second kind of autofocus traditionally works faster, phase-detect autofocus (PDAF), but evolution never gave us a phase prism so that is not an option.
A few months ago Olympus announced a new version of my camera that made a few small things better plus one big thing: they claimed the fastest autofocus in the world. Chat boards predictably went a little bit nuts, since you cannot add a phase prism to this kind of camera. That means hey made a CDAF faster than PDAF, and that’s like neutrinos beating photons. Weird and a little disturbing. Though, in this case, not wrong.
Then some rumors board found an obscure Olympus patent that pointed to an answer. Maybe they seeded some infrared-sensitive pixels into the sensor and used the difference between the normal light image and the IR image to tell whether blur is too close or too far and by how much? It was a great idea, but wrong. Olympus just beefed up their processor and put faster motors in the lenses.
The eye, on the other hand, does work like that mythical Olympus sensor. We can tell whether blur is too far or too close.
Wilson Geisler and Johannes Burge, psychologists at the Center for Perceptual Systems at the University of Texas, Austin […] attempted to mimic how the human visual system might be processing these images by adding a set of filters to their model designed to detect these features. When they blurred the images by systematically changing the focus error in the computer simulation and tested the response of the filters, the researchers found that they could predict the exact amount of focus error by the pattern of response they observed in the feature detectors. The researchers say this provides a potential explanation for how the brains of humans and animals can quickly and accurately determine focus error without guessing and checking. Their research appears online this week in the Proceedings of the National Academy of Sciences.
The key bit is even more interesting. Geisler and Burge found that lens defects change the blur in small ways that make it easier for the brain to figure out which way to focus, so it’s better to have a slightly off lens than one that makes a flawless image. People who have corrective eye surgery, whose eyes are (one hopes) a lot more perfect than they were before, thus spend a while with serious focusing problems. I don’t know whether defects need to be significant to work best, but if so then the blazing fastest lenses of the future might have a slight circus mirror effect to them.
Guster
Velvety.
Raven (formerly stuckinred)
I assume this does not impact my Panasonic Luminex? It there a good place online to learn how to do more than point and shoot with this thing?
Bill E Pilgrim
Yes but it doesn’t have zoom. And on top of that, my nipple nut doesn’t seem to be working. No matter how hard I twiddle it I can’t seem to pick up Jazz FM.
PeakVT
Nikon has put PDAF on the sensor used in its new “1” system (boo on the name).
Tim F.
@PeakVT: Also boo the sensor. It’s tiny. Plus the proprietary flash mount is a joke.
Social Outcast
@Bill E Pilgrim: Wait till you try to recharge your batteries. You’re going to need an adapter.
Thoughtful Black Co-Citizen
Or in my case, one of those Kodak disposables that’s been dropped a few times.
Villago Delenda Est
Blah, blah, pixels, blah, blah.
Bottom line here is Max is one good looking dog.
Villago Delenda Est
Could it possibly be that “perfect” is in the eye of the beholder?
Nah, that can’t be it…
trollhattan
@Raven (formerly stuckinred):
“Lumix”? That’s Panny’s brand for all their digicams, from entry level to top of the line. Would have to know more about the model and how much user control one has. Some offer gobs of user control while others assume Stevie Wonder is in charge, in which case they Just Don’t Care what you think.
There are a gazillion photo web sites that cover everything from camera operations to composition to lighting to post processing, as well as two gazillion user forums. DP Review or one of the others may have reviewed your model, in which case it will run you through all the controls and give some guidance at to strengths and weaknesses.
My advice: Go out and shoot. Lots. Evaluate what works, what doesn’t work and where you’d like to get better.
dmsilev
So let me guess. You had the camera in one hand, and a nice meaty bone or something in the other hand.
RP
I have the 20/1.7 and love it.
deep cap
@Villago Delenda Est:
Here here! I just want to rub those adorable ears!!
dmsilev
@Raven (formerly stuckinred): Which specific Lumix do you have? That brand name covers a wide swath of models, some of which are basically full-auto only and some of which can be manually controlled and tweaked to your heart’s desire.
Linda Featheringill
Nice picture of Max. Lots of very fine detail.
And yes, Max is a pretty boy.
lamh32
If any of Romney’s rivals really want to stick it to him tonight, then this should give them some ammunition right?
“Records show senior White House officials met with Romney advisers on health care law – @NBCNews
Paul in KY
I would like to buy a compact auto-focus camera (digital) with a good zoom feature & will act like ASA 400 speed film does in a 35mm (stop motion in someone running/jumping).
Any good recomendations?
John Cole
The thought of that big wet nose being shoved into my armpit or side while sound asleep is enough to give me nightmares. That dog has a honker.
Raven (formerly stuckinred)
@dmsilev: Sorry , PanasonicLumix DMC-Z310 MP
I shoot tons of pics with it and my Kodak Z740 but I’n not sure I’m getting all I can since I normally use auto.
Raven (formerly stuckinred)
@trollhattan: I realize there are a gazzilion which is why I posted the question. I hoped someone might narrow it for me. I use Steve’s Digicams for buying advice.
deep cap
@John Cole: This is why dogs are better when your friends have them. You can play with them and then when the fun is over you can send them home. No cold noses in the morning.
(Same can be said for children, come to think of it.)
Yutsano
@Villago Delenda Est:
This ad infinitum.
mistermix
@Tim F: I swear that my old manual-focus SLR camera coupled with my eye was, overall, more likely to give me well-focused shots than either of the new auto-focus DSLRs I’ve used. Autofocus is continually hunting and often focusing on the wrong damn thing, and since the manufacturers now consider the viewfinder as an composing device rather than a focusing device, they give us a viewfinder that is far too dark and lacks the focusing aids they used to have. And the lenses don’t have a nice big grip to use for manual focus.
trollhattan
@Raven (formerly stuckinred):
For how-to stuff I like Luminous Landscape and The Online Photographer. Not really tailored to beginners but inspiring as to what’s possible. DP Review is piling up quite an article collection, having once concentrated on reviews they’re expanding the brand (since Google bought them).
Roger Moore
A lot of people like the slightly off lenses, too, especially for portraits. If you have a perfectly corrected lens, out of focus points are blurred into evenly lit circles, or polygons if your aperture stop is noticeably polygonal. If you slightly undercorrect for spherical aberration, though, the out of focus points behind the subject have a brighter center and dimmer edge, which makes them less visibly obtrusive. The penalty is that out of focus objects in front of the subject have brighter edges and dimmer centers, which is distracting. Fortunately, OOF objects in front of the main subject are less common than ones behind, so it’s generally seen as a price worth paying.
A lot of famous portrait lenses are designed to take this into account and deliberately leave in a little bit of spherical aberration to give the lens a nice defocus character. My favorite Nikon 105/2.5 portrait lens is even designed so that it’s well corrected when at infinity focus but develops more and more spherical aberration (and hence a blurrier background) the closer you focus. Nikon also makes a couple of “defocus control” lenses where the spherical aberration correction can be dialed in with a separate lens ring to fine-tune the effect.
Warren Terra
What about the new camera technology in the news a few weeks ago that takes a sort of multifocus picture – a picture in which you can adjust the focus after it’s been taken?
Raven (formerly stuckinred)
@trollhattan: I’m on it like white on rice! thx
trollhattan
@mistermix:
You forgot “And you kids stay off my lawn!”
My first dslr has a “pentamirror” instead of a real pentaprism and a focusing screen designed to brighten the view, as pentamirrors are quite dim. I soon learned it’s completely hopeless as an optical focusing aid (with long or very fast lenses), forcing the use of live view zoom, which is painfully slow.
Add to that the fact that focusing and DOF scales have been dropped from most dslr lenses and you’re depending on the camera to make up your mind for you on focus.
So yeah, an entry level film slr focuses manually much better than many, if not the majority of dslrs. (I upgraded to a dslr with proper pentaprism and focus screen, which allows me to use legacy MF lenses.)
catclub
@lamh32: All the hugs that Obama is giving to Romney now, in hopes that it will sink him with the GOP, will come back to bite him when Romney wins the nom and attracts independents because he is ‘knowledgeable’ about healthcare (Obama said so!).
Roger Moore
@mistermix:
The problem with dimness is usually because people are using slow lenses, not because the viewfinder is inherently dim. The focusing screens are actually optimized to give the brightest possible* image at the expense of being good for manual focus. If you really want to manual focus with a good focusing aid, you might want to look at something like a KatzEye replacement focusing screen.
*For lenses that are up to about f/2.8. Faster lenses don’t produce a brighter viewfinder, which also means you can’t get a really fine focus with them, either.
Lockewasright
Most of the dogs that I have known have turned out to be better people than most of the people that I have known, and I like people.
gogol's wife
@Yutsano:
I saw this post earlier and thought, this is a technical post about cameras, which I know nothing about, so I can’t go on there and say “I wuv Max.”
But I can.
WereBear
Mr Handsome boy! Yes he is!
That’s all. I still have a ten year old digital camera with a built in flash that I use to take cat pics. Though quality has certainly gone UP and the prices have gone down.
Yutsano
@gogol’s wife: I’m totally fine with letting the techies geek out. I have my priorities here. :)
Roger Moore
@Warren Terra:
The multi-focus idea looks kind of cool, but it comes at the expense of pixel count. As I understand it, they’re basically taking a bunch of pictures with different focus distances using the same sensor, which lets them interpolate the focus to any point inbetween. The problem is that this means that if they are taking, say, 16 different focus distances they wind up with 1/16 as many pixels at each focus distance. It’s still a neat technology, but it has drawbacks.
PeakVT
@Tim F.: I disagree that the sensor should be booed for its size. Nikon isn’t trying to make a system that appeals to people who need a bazillion pixels because they make large prints, or who just like having a bazillion pixels. Instead, it is trying to make a system that provides excellent picture-taking ability for the non-pro. 10MP is enough for how most people use their shots. Keeping the pixel count down makes it easier to do fancy in-camera processing, and of course keeping the sensor size small makes the bodies and lenses smaller. There are always compromises and Nikon’s mix isn’t unreasonable – unlike the Q, which is too small. I commend Nikon for taking this approach, though the market may not agree (or may not agree at the price points Nikon has set, which are too high IMHO).
That said, I think if Nikon had been an early entrant into the mirrorless market it probably would have developed a different system. But m4/3 already covers the next logical size down from APS-C, at about 1/4 the size of a FF sensor.
SRW1
I kind of have trouble to believe that you shot that pic of Max at f1.7 (and you probably didn’t mean to say that you did).
I went for a Nex-5 (which has an even larger sensor than 4/3) because it allows me to attach my old Minolta lenses via an adapter. Of course focusing is manual, but the old MD 50mm f/1.4, which becomes a 75 mm equivalent, and the old 250mm f/5.6 mirror tele, which becomes a 375 mm equivalent, can do nice things on that camera.
In between my old analog camera (Minolta XD-7) and the Nex-5 I had a Canon A640. When I learned that it was using ND filter to mimic different f-stops, my heart got a crack over that absence of any control over depth of field.
DFH no.6
Damn.
So I’ve gone this long, practically till my sixth decade, with no (well, not much, till recently) reason to do anything corrective about my natural vision (lucky bastard, yes I know) and now that I’ve finally decided to get some corrective eye surgery (no glasses, no thank you), I read here that doing so means that I will “thus spend a while with serious focusing problems”.
I had not heard that before, nor did any such thing come up in the several consultations I’ve had leading to the first of a couple surgical procedures on both eyes I’m scheduled for, starting next week.
Guess I’ve got one more question for the good doctor…
Very cool comparison in the post, by the way, between human vision and camera technology.
imonlylurking
I had laser eye surgery years ago-it’s been close to a decade by now-and I never experienced any kind of focusing problem post-surgery.
My colleague just had both eyes done about 10 days ago. She is experiencing focusing difficulty in one eye because she had a more difficult procedure in that eye, but the other eye is fine.
(Yes, I know-anecdata.)
What studies or surveys have been completed to determine what percentage of post-surgical patients experience focusing problems?
ETA: DOGGIE!
Roger Moore
@PeakVT:
I suspect that the higher price point for the Nikon cameras largely reflects the very powerful processing engine they’ve put in the 1 Series. The Expeed 3 is capable of processing 600 MP/sec, which is way faster than anything else out there, including the dual processor setups in the top pro models like the D3 or 1D Mark IV. That has to cost, especially because they’re the first cameras to use the new processors. Once Expeed 3 works its way into all of Nikon’s models, I expect it to come down in price and the 1 Series to come down with it.
History says otherwise. Nikon has apparently been working on the 1 Series for at least 5 years, and targeting the 1″ class sensor the whole time. We know this both from what Nikon has said publicly and from the patent filings for some of their new lenses. Obviously, though, there are still a lot of people who are hoping that Nikon will have a new mirrorless camera with a DX or FX sensor to complement their existing DSLRs.
trollhattan
@PeakVT:
We shall see whether Nikon is clever or too timid with where they slotted the new cameras. It’s clear they want to avoid parasitizing their own dslr sales, but the risk lies in whether dslr sales have peaked regardless, and are now on a permanent downhill slide. If so, Nikon will have made a poor bet. OTOH if they can snag compact digicam and phonecam owners AND dslr owners willing to invest in a second system, then the bet will pay off. I’m sure they’re scratching their heads at Fuji’s recent successes.
Completely agree they’re late to the game. The only company stodgier is Canon, who are really embarrassing themselves with having completely misunderstood mirrorless’ market potential.
DFH no.6
@catclub:
I don’t know.
I’m all for any obstacle that hinders Willard getting the fascist nomination, since he would be Obama’s most formidable opponent for a good half-dozen reasons.
Health care reform a la “Obamacare” is obviously a huge issue for the rightwing, and thus there’s good reason the Mittster has been performing perhaps the mother of all “flip-flops” with regard to the amazingly-similar “Romneycare”.
So I believe tying Romney to his own health care reform in MA is a much bigger negative for him in the primaries then any “credit” he could claim for such would be in the general.
C’mon Perry – show the fascists tonight that you truly can be “Bush III – You Know You Want It Again!”
No one else in the clown car has a ghost of a chance beating Romney to the nom. And if they did, so much the better.
bystander
I don’t know jack about cameras, and I know only a bit more about how the human eye functions, but I do know that Max is one very handsome Dobie.
DFH no.6
@imonlylurking:
Good to know. I’m feeling a bit less anxious, now.
imonlylurking
@ DFH no.6
We’ve been talking about laser eye surgery a lot in my office lately-my boss just had a detached retina and had to have emergency eye surgery (they laser-welded everything back together)-that was right before my colleague had hers done.
Are you doing the surgery that makes one eye distance and one eye close-up?
Xenos
@catclub:
And you don’t expect this to have an effect on Teapartisan voter turnout? And you don’t expect his Mormonism to have an effect on Evangelical turnout?
Obama is setting Romney up for a very unhappy, very unpredictable time in Tampa should he win the nomination. I expect we will see something very similar to the Dole convention being fubared by Pat Buchanan, but increased by an order of magnitude. Popcorn city.
DFH no.6
@imonlylurking:
No, mine will be keratectomy with a new lens in each eye. Each lens will have near and far distance (like bi-focals, is the way it was described).
Gotta say I’m nervous. Maybe I should have just gone the glasses route (too proud, my wife says, and as usual she’s right).
PurpleGirl
MAX! (that is all)
Odie Hugh Manatee
I think it’s a lot like music; ‘computerized’ music has a perfection to it that makes it unappealing to an ear tuned to the nuances of musical instruments played by imperfect humans. We’re not perfect and when we see or hear something that is ‘too perfect’, it seems unnatural. Maybe non-human even.
That’s all I gots on it. :)
BruceFromOhio
The beautiful animal pictured here wants to know, “Why are human beings such complicated creatures?”
JR in WV
My Dad had thick lenses for glasses all his life – he never knew trees had leaves (or at least that most folks could see them) until he got glasses late in elementary school. People thought he was a snob because he never waved at passers by across the street, when in fact he couldn’t see them.
Then he had cataract surgery – 20-15 vision a couple of hours after the operation, Rite-aid reading glasses if he wanted. I think that’s the way to go for surgical correction, not cutting away irreplaceable tissue with a laser, for crikey’s sake!
I saw a Panasonic Lumix (with Lietz kigt lens) back in – what, 2007 or 2008 – co-worker took a picture of a little 5 cm fossil, blew it up into wallpaper for a 32 inch monitor, no blur, beautiful photo, hand held, office lighting from the front, with Cal shading it, outdoor north light for backlight, it was on a windowsill. Amazing lenses!
But I already had a big $$ investment in Nikon, so there I am.
Paul in KY
Appreciate the help, camera people.
Ryan Brenizer
It’s getting hard to keep track of which ones are my photography blogs and which ones are my politics blogs!