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- an afternoon with her little boy
And now for something a little different. I rarely do this sort of thing… People ask me all the time to come take family pictures (or weddings and these sorts of things) — I always regretfully say NO because, well, I never really have a great excuse other than it takes too much [...]
Переслать - Diffraction In Perspective
By Ctein
Last column I introduced you to diffraction. This time, I'm going to explain why you shouldn't pay it so much attention.
How do the component blurs in an optical system combine? Usually, the following equation is a good approximation to the total amount of blur you'll get:
TotalBlur^2 = Blur1^2 + Blur2^2 + Blur3^2...
In English, the total blur squared is the sum of the squares of the individual blurs.
Just to make sure you understand this equation, imagine you have a camera with a film and lens resolutions of 100 line pair per millimeter (blur circle of 10 µ). Then the total blur will be 14 µ and the final resolution will be 70 lp/mm.
Up the film resolution to 150 lp/mm, and the final resolution will be about 83 lp/mm. If your film resolves 200 lp/mm, then you're near 90 lp/mm. That's close enough to the resolution limit of the lens that further improvements in film aren't going to produce a visible gain.
Rule of thumb: if your worst blur isn't twice as bad as all the other blurs, then improving any of the blurs will improve the image, although (obviously) improving the weakest link gets you the biggest gain.
With film cameras, you've got five major sources of blur to worry about: film resolution, vibration, focus error, lens aberrations, and diffraction. Until one of them is twice as bad as all the others, improving any of them helps.
Focus error is the biggie that photographers don't think about. Cameras usually have SERIOUS focus errors, if you're trying to work on the scale where diffraction actually matters. The error has a variety of sources, from a mismatch between the distance to the focusing screen/autofocus sensor and the film/sensor plane to the finite step size in the encoders and servomotors in electrically-focusing cameras. It's a bigger problem than you would imagine. In an otherwise-good system, it is often the biggest source of image blur.
Film resolution is easy to characterize; digital sensor resolution is almost impossible! For a start, there are all the reasons mentioned in the article by Ruben et al. Add in several more:
• Even a 2 x 2 pixel array is a bare minimum. Does fitting the Airy disk into a square provide high quality image data? Nope. You're going to see improvements in the quality of the fine detail up to at least a 4x4 pixel array.
• Sensor pixels don't even operate entirely as discrete elements. There is charge leakage (analogous to a halation in photographic film) between adjacent pixels. This degrades sensitivity, sharpness, color fidelity, and noise, above what "theory" would tell you.
• Finally, there is the image processing that produces a viewable image. Some of you may have noticed how peculiar it is that the number of lines of resolution in many digital cameras is about the same horizontally, vertically, and diagonally! That's impossible if you're talking about a physical blur circle. This is a synthesized image. The resolution you get is not a simple mapping of pixel data.
Put it all together and claims that pixels have become too small because of diffraction effects loses all credence. There's too much stuff going on that muddies the picture (literally).
The same test photograph as last time. This figure is at 150% full-size [after you click on it to enlarge it —MJ]. The camera is my Fuji FinePix S100fs. Pixel pitch is around 2.5 µ. Nothing much changes in terms of sharpness all way down to ƒ/5.6. Sure, the pixels are minuscule and diffraction is getting worse, but everything else matters much more. Even at ƒ/8, the impact of diffraction is modest, although the Airy disk is twice the pixel size. It's only going that final aperture from ƒ/8 to ƒ/11 where diffraction truly dominates image clarity.
The only way to figure out if diffraction is important in your photographs is to run some very, very careful tests and understand how to interpret the data. For most of you, honestly, it's a waste of your time comparable to running endless film tests instead of making nice photographs.
_____________________
Переслать - Wings Over Houston IX
Sorry going back and forth between Wings Over Houston and my Japan trip. I'm just having too much fun processing these fine aircrafts. Yes, I added the B-25 in the distance from another image. Could not help it! It was just begging for an object in the background.Переслать - London Exhibition Round Up
I’ve been in London this week and happily discovered my visit coincided with East London Photomonth which has given me the opportunity to visit some fantastic (and free) photography events around the city. My favourites so far have been the: Getty Images Gallery’s London Through A Lens showcasing some fantastic black and white images of London [...]Переслать - File>Open Recent
Under Photoshop>Preferences (PC: Edit>Preferences), you have an option called File Handling. In the Recent File List Contains field, you can specify how many files you would like it to remember.Переслать - Sea Otter Photo Tour in Less Than 30 Days, Are You In?
Participants Gallery From Past Trips My next Sea Otter Photo Tour is just under 30 days away and there are only a few spots left. We had a blast last time and with the chance of seeing pups this time around those in attendance are likely to have an even more memorable time. Photographed way in [...]Переслать - More 3D on Layers TV | Bond is Back
If you guys are thrilled as much as I am about the new 3D stuff in CS4 then go over and check out the newest episode of Layers TV. This week I play around with 3D and show numerous way you can use it in your work. Even wrapping a video clip around a 3D [...]Переслать - "Heute schon geblitzt ?" - Eine Buchrezension
Dies ist ein Gastartikel von Nicolai Wiegand. Er ist Facharzt für Anästhesie und fotografiert leidenschaftlich gerne in seiner Freizeit, womöglich als Ausgleich für seinen ausfüllenden Beruf. Nicolai lebt intensiver seit er fotografiert und möchte andere daran in seinem noch jungen Fotoblog unter http://goodlight-photography.blogspot.com teilhaben lassen. Buchinformation Heute schon geblitzt ? Dirk Wächter mit Unterstützung von Canon 2. überarbeitete Auflage [...]Переслать - Random Excellence: The Best of Barack
Emmanuel Dunand, U.S. Democratic presidential candidate Illinois Senator Barack Obama disembarks from his campaign plane at Midway airport in Chicago, Illinois, October 19, 2008 (AFP/Getty Images).-
Few extended events are covered as thoroughly as U.S. Presidential campaigns, as news organizations from all over the world ask photojournalists to come back with unique and expressive photographs from heavily covered, repetitive opportunities. Boston.com has gathered 35 of the best photographs of President-Elect Barack Obama from the campaign of 2008.The photographers in this set are Jim Young, Chris Carlson, Emmanuel Dunand, Alex Brandon, Stan Honda, Jae C. Hong, Doug Mills, Jason Reed, Yoon S. Byun, Joe Raedle, Jeff Fusco, and Pouya Dianat.
Jae C. Hong, Democratic presidential candidate, Sen. Barack Obama (lower right) waves as he arrives at a rally of 100,000 supporters in St. Louis, Mo., Saturday, Oct. 18, 2008 (AP Photo).______________________
Mike (Thanks to Adam McA.)
Featured Comment by Bill Bresler: "Nice gallery. I've photographed nearly every presidential candidate since Ronald Reagan. Every time I've done so, I've had a gut feeling about the candidate. History tells me that I need to listen to my gut. I photographed Barack Obama in early September. If my gut reaction is still accurate, this guy is the real deal.
"Here's my favorite from that campaign rally. I couldn't help but notice these pauses, before he would continue speaking."
Переслать - How to Photograph Mushrooms
During the Photo Tour in October I came across many mushrooms. These elements of nature ( I can’t call them either plants nor animals), have beautiful shapes and sometimes amazing colors. Most of the time I came across groups of mushrooms hidden in the death leaves. How you “see” your subject will portray the way it [...]Переслать - Mastering Digital Photography and Imaging - Photography Book
With a three or more megapixel digital camera or a good scanner, affordable image-editing software, and a photo-realistic printer, you have all the tools you need to create absolutely stunning images. But understanding all your options and getting the best possible results can be daunting. What features should you look for in a digital camera? [...]Переслать - On Frozen Pond
I probably should not have been standing in the middle of this frozen pond. But when you are raised in Texas and you rarely get to see anything frozen, you get fascinated by large frozen bodies of water. I just stared at it for a long time like a deer that’s never seen headlights in [...]Переслать - Willow Gulch ColorsRaoul
Willow Gulch Colors . Photo taken and uploaded to Flickr by not ansel Posted to Photografr.com by Raoul Pop Posted in PhotographПереслать - ATP Photofinder Mini - Reinventing Geotagging (Product Review)
For all interested in Geotagging of image files, here is a hands-on review of one of the newest geotaggers available, the ATP Photofinder Mini. Related posts:- GeoTagging - Is it worth it?
- Still on Geotagging
- “The Invention of Solitude”, Paul Auster - Book Review
- “The End of Faith: Religion, Terror, and the Future of Reason”, Sam Harris - Book Review
- Understanding Composition, Steve Mulligan - Book Review
Переслать - Tokyo Subway
I'm still processing my Japan images and I'm not too pleased with most of them. We only had one day off and it was very overcast skies. I took this image when we were heading from Tsukuba (where JAXA is located) into Tokyo for the day. After flying for 14 hours in coach and spending a total of 24 hours getting from my front door to the hotel, I didn't 'feel' too creative.Переслать - Opening Multiple Images in Photoshop CS3
To open multiple images in Photoshop CS3, you can Shift-click a series of images in the Open dialog, and then click Open. You can also select noncontiguous images by Command-clicking.Переслать - Bildvorstellung : Lonely
Es ist ja wirklich schon sehr lange her, dass ich hier eins meiner Fotos gezeigt habe. Und so manch einer hat sich bei mir schon beklagt, dass ich viel zu wenig über meine Fotos schreiben würde. Nun, aus diesem Anlass zeige und beschreibe ich Dir heute mein aktuellstes Foto mit dem Titel “Lonely”. Dabei möchte [...]Переслать - Pixels Are Like Cupcakes. Let Me Explain.
By Russ Juskalian, The New York Times
It happens to all of us: the moment when one finds out that more megapixels and better photographs aren't always the same thing. To be disabused of the Megapixel Myth—this decade's analog of the Megahertz Myth—can lead to an existential buyer's crisis in miniature.
Disbelief, at first, gives way to a sort of embarrassing self-questioning: You mean, 15 megapixels isn't three times better than 5 megapixels? This year's model isn't better than last year's? I spent all that money upgrading—for nothing?
READ ON at nytimes.com
________________________
Mike (Thanks to Aaron Dill)
Переслать - Sam Abell: The Life of a Photograph
Sam Abell's fine, generous, and personal new book The Life of a Photograph
has been available for a couple of weeks now. It's a book about process: he shows other frames taken "around" some of his favorite pictures; pairs of picture taken over time; sequences; even failures. Along the way he gives the reader a genuine glimpse inside his sensibility, and visual, not theoretical, indications of what it is that makes his pictures his. The effect is of a gentle, pleasant guided tour of what it's like behind one famous photographer's eyes.
There's not much text, and what there is is elliptical and personal. Much of the information here is visual as opposed to verbal, which could leave more literal, less visual readers feeling shortchanged. The Life of a Photograph requires contemplation. You'll have to purposely slow down the frantic and hasty intake of information that many of us are encouraged to indulge in by modern technological tools and the pace of life today; this book is more of a meditation. Taken on its own terms it has plenty of depth, but it's poetic, condensed, direct.
Ironically it's also very easy—superficial readers could get a lot out of it in one quick pass, too.
In any event it's certainly an enjoyable experience, and I think an insightful and rewarding one. I've been through it (slowly) three times now, and have enjoyed it more each time. It's this week's "recommended by M.J."
_____________________
Mike
Переслать - The Epic Red Epic
Convergence from the other direction: Check out the infinitely-configurable Red Epic DSMC (digital stills and motion camera), as the name implies a digital motion picture camera capable of shooting high-quality stills. Most of the money pictures are on page three of the linked thread. For one thing, it's the camera many have been asking for, on which you can replace the sensor only while keeping the rest of the camera intact. And speaking of sensors, check out that sensor option page: you can choose any sensor size you like, up to the "Mysterium Monstro," a 186x56mm digital "6x17"! Zowie. For once, a hyperbolic product name seems just right.___________________
Mike (Thanks to Iñaki)
Переслать - OT: Voting Day in the USA
We vote on the first Tuesday in November in the United States for sensible but long-outdated reasons. A century and a half ago, we were overwhelmingly an agrarian nation. Early November is after the harvest but (generally) before the snows fly. And why Tuesday? Because America is a such a vast, far-flung land, and transportation methods were primitive before oil became king. Citizens would expect to go to church in their hometowns on Sunday. Many needed Monday to travel—by horse, or horse and buggy—to their polling places, usually the county seat. Then on Tuesday they'd vote and enjoy a day of electioneering, parades, songs, and patriotic frolic, and travel home again on Wednesday, for market day.
Made sense. In 1845, anyway.
A Brief Guide to Election-Watching for Interested Foreign Spectators (nobody in America needs election-watching tips from the likes o' me, and I realize that for those of you in Europe all the excitement happens literally in the middle of the night; but here goes): Turnout numbers (and breakdowns) will probably be interesting. The modern record is 64% in 1960 and the all-time record is 66% in 1908, when Republican William Howard Taft beat William Jennings Bryan, whom you might remember from the part he later played in the Scopes Monkey Trial, dramatized in the 1955 play and 1960 movie "Inherit the Wind." (That's Taft doffing his top hat in Denver in 1911, below right.)
Early voting has been heavy in the 30 or so States that have it. (I voted last Tuesday here in Wisconsin. Since then I've had a sign on my door that reads, "This household has ALREADY VOTED." It's kept the door-knockers at bay. There is unfortunately no similar way to discourage the robo-calls.) In Colorado, reportedly, a whopping 46% of the electorate have voted early! Heavy turnout might contribute to late counts and delayed "calls."Polls close earliest in Indiana (leaning McCain), New Hampshire (leaning Obama), and Kentucky (solid for McCain), but generally, poll closings follow the setting sun from East to West, and the East Coast reports first. The bellwethers to watch are likely to be Virginia and North Carolina. Virginia (heartland of the old Confederacy) is formerly red (Republican) and trending blue in polls this time, but still essentially a toss-up. There are relatively few electoral-college pathways to victory for McCain, and most of them involve winning Virginia. So if Virginia is called for McCain, that could mean a tight race, a long evening, and a delayed result; but if Virginia goes to Obama fairly clearly early on, it probably signifies an Obama victory. North Carolina is a "next level" bellwether...it's a solidly red State that is polling anywhere from pale pink to a toss-up. If it goes for Obama early, it most probably signals a blowout nationwide in favor of the Democratic candidate.
Of the three big battleground States of Pennsylvania, Ohio, and Florida, two, Ohio and Florida, are states that traditionally have lot of problems with voting and counting, and they're both tossups this time, so they could be late being called. To amuse yourself in the meantime, watch Indiana. Indiana is also historically Republican but has been polling too close to call. It's not an essential state for Obama, but if McCain loses it, it indicates weakness where he needs to be solid. Ergo, Indiana is a bellwether, but only if Obama wins it. As I say, the polls close early there, so it could be called early too.
If Pennsylvania goes red, then Obama could be in trouble. If Obama loses Pennsylvania, Ohio, and Florida, he could still win, but probably won't. If those three states plus Virginia all go red, it's probably Obama = footnote of history and "President McCain." So keep an eye on those four if you're a McCain supporter.
But at the outset, watch Virginia and North Carolina. If they're both red, it's a good sign for McCain, although no sure thing; it more clearly signals that the decision will take a while. If Virginia turns blue and North Carolina is red, it portends an Obama victory overall, albeit possibly a modest one; if both are blue, look for a possible Obama landslide.
But then again, that's all according to the polls. And you know what they say about election polls: the last one is the only one that counts.
_____________________
Mike (Hat tip to Cenk Uygur and whytuesday.org)
Featured Comment by Dave Kee: "Forty-five years ago in August, two young white men and two young black men rode in an old Volkswagen from Chicago to Washington D.C. to listen to a man talk about his dream. Today, in perfect weather, two old white men and two old black men rode their bikes together on the Old Plank Road Trail. As I drink my celebatory champagne tonight I am so proud to have been a member of both groups."
Переслать - Photography Articles Around the Web #9
October Selection Environmental photography The title is simple, but the article is complex and reached deep into my heart. The images used as examples left me with a strong taste about the world we live in. It’s always great to read articles from Magnum Photo. Pregnancy Photography Tips This is another subject that will never fail to reach the [...]Переслать
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