The Online Photographer

This week's column by Ctein

[A late addendum to last week's column—there are now links in the Featured Comments to the two photos by Kathy Li that I referred to, so you can see what I was talking about. —Ctein]

Some photographic subjects need to be periodically revisited, to inform newcomers, to stamp out persistent misconceptions, and simply to reach the folks who somehow managed not to read my deathless prose (ahem) the first time around.

Depth of field is one of those, as some recent questions I got from readers reminded me. Mike and I beat that topic thoroughly to death, or so you'd think, several years ago, in "Depth-of-Field Hell" and its Sequel. Of course, these are among the undead topics of the photographic world, and even shoving silver halide stakes through their hearts isn't enough to put them down permanently.

Now here's the thing. Depth of field isn't a theoretical concern; it's a supremely practical and pragmatic one. Theoretically, there is no such thing as depth of field—the lens image is sharp at one and only one distance from the subject. Well, okay, for real-world lenses, which can't take light down to an infinitesimal point of sharpness, there's actually a very, very thin range of distances. But you get the idea.

Depth of field assumes you can tolerate some blur in a photograph. Emphasis on you. The standard equations all make assumptions about what a standard viewer and viewing situation is: an 8x10-inch print viewed at normal close distances. For a viewer of normal sensibilities, the acceptable blur is in the range of four line-pairs per millimeter (4 lp/mm) in the print. Some of us print bigger, some smaller. Some of us press our noses against prints and others don't. Some of us are just plain fussier about fine detail. Failure to understand this variation is part of what drives some people crazy about depth of field.

The other practical concern is that it's all about how much total blur you can tolerate, not just how much blur comes from the lens being out of focus. There's blur caused by the lens being out of focus and that caused by the lens itself, and what you see is the combination of the two.

A mediocre lens, for example, one which is barely sharp enough to be acceptable to you, is going to have negligible depth of field. That's because you're already at the limit of the amount of blur you're willing to tolerate; adding in much more from the parts of the scene that are out of the plane of best focus is going to push beyond your pain tolerance. A sharper lens provides more depth of field.

The same thing can happen if you stop down too far, and macro photographers run into this all the time. The standard assumptions work out to around 30–35 lp/mm in 35mm film or a full frame sensor. Sparing you the math, once you've stopped down to a real aperture of ƒ/32 you've run out of depth of field: stopping down any further causes diffraction blur to increase so much that your total depth of field goes down. In fact, stopping down beyond ƒ/22 doesn't gain you much; diffraction is already important enough that you've got 90% of the maximum amount of depth of field you can get.

Now back to that matter of print sizes and tolerances. Some of the folks engaging in medium format digital photography are convinced that they're getting less depth of field than they did with film photography. Mostly, that's not true—it's a little bit true, because the digital sensors are modestly smaller than the film formats were, but this is not majorly visible. The larger problem is that the folks who are likely to indulge in that sort of equipment are also likely to be pixel peepers. Who can blame them! If they weren't that fussy about image quality and sharpness, they'd buy something cheaper. So, what happens when you pixel peep a medium format image?

Well, for a start, you're typically talking about 6 micron pixels, which works out to a real physical resolution of 50–60 lp/mm from the sensor. Now the thing is, for medium format film the standard assumptions about depth of field worked out to 15–20 lp/mm on film. If you're aiming for pixel-level sharpness from that medium format camera, you're talking about a tolerance for blur that is only one third of that assumed for film. That means much, much shallower depth of field, not because there's anything strange about digital but because you're working to much tighter standards.

Okay, you may already understand this, and you only view the file at 50% size on the screen, just to avoid dwelling too much on the minutia. Well, if you're talking about, oh, say, a 35-megapixel sensor and a normal resolution monitor, that's still a lot like looking at a 20x24" print. Which is a hell of a lot bigger than the canonical 8x10. Problem is, for previewing on screen, you can't really take it much smaller than that because screen resolutions aren't all that high. You really have to print out the photograph to get an idea of just how sharp it looks on paper.

When you do that, most of the imagined differences between digital and film depth of field disappear. As we often say about photography...It's all in how you look at things.

©2013 by Ctein, all rights reserved

Weekly columnist Ctein comes into focus on Wednesdays on TOP.

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(To see all the comments, click on the "Comments" link below.)
Featured Comments from:

Gordon Lewis: "Oh no! Not depth-of-field again! Lock the doors. Cover your children's eyes and ears. Pray that the violence and bloodshed will be brief."

Ed. replies:

Mark Johnson: "Ctein, that may have been the best article I've read of yours. Detailed, yet concise, with your normal sprinkling of humor. Well done. (BTW, thanks for turning me onto the wider world of tea. It has been a pleasure trying some of the teas you mentioned in articles past.)"

Fig. 1. A scan of a cracked and crinkled photograph.

This week's column by Ctein

Here's a wonderful little trick I learned last year from one of my readers, Carl Kracht.

One of the difficulties that pops up with scanning prints is that if there are any creases, folds, ripples, tears or cracks in the paper, they catch the directional light in the scanner like you wouldn't believe. Figure 1 is a great example of it; notice how below the crack is darker than above it. It's not hard to use spot healing or cloning tools to get rid of the actual cracks, but what you do about the patches of different brightness? My old answer to that would be lots of tedious dodging and burning in in an adjustment layer. Carl gave me a much better one.

Fig. 2. Same photograph rotated 180° and scanned again.

Rotate the print 180° and make a second scan, as shown in figure 2. Reversing the direction the scanning light comes from reverses the pattern of shadowing and highlighting in the paper.

Then average those two scans together (figure 3). It eliminates that problem! It can even make some fine cracks and damage disappear.

Fig. 3. The Statistics/Mean blend of the two scans in figures 1 and 2.

In Photoshop CS6 Extended, this algorithm is buried under "File/Scripts/Statistics... ." Choose Stack Mode: Mean and point Photoshop at the two files you want Photoshop to combine. Make sure that the "Attempt to Automatically Align Source Images" box is checked. Click OK, and Photoshop generates an averaged blend of the two files.

Any image processing program that has a similar averaging function can do this. (Don't ask me which ones they are. Betcha our readers know, though.)

In theory you can get even better results by averaging scans in four directions at 90° to each other. In practice many scanners have a very slightly different pixel pitch across the sensor array than in the direction of carriage travel. Normally, the fraction of a percent distortion doesn't matter, but it may make a sharp blending of scans at right angles to each other impossible.

I make it easier for Photoshop to produce a sharp result by modifying my scans in Photoshop to bring them into very close alignment before blending them. I open both files, make a copy of "scan 2," and paste it into "scan 1," where it appears as a new layer. I set that layer's opacity to 50% to make that easier to see what's going on and rotate and translate that layer until I get a good match. I copy out the modified second layer, paste it into a new file, save it, and use that file to blend with the scan 1 file.

It takes longer to do a scan this way, but I save a whole lot more time by making a whole lot of crap disappear so that I don't have to clean it up later.

©2013 by Ctein, all rights reserved

Ctein's weekly columns, which scan best from top to bottom, appear on Wednesdays on TOP. He is the author of Digital Restoration from Start to Finish: How to repair old and damaged photographs from Focal Press, now in its Second Edition.

Original contents copyright 2013 by Michael C. Johnston and/or the bylined author. All Rights Reserved. Links in this post may be to our affiliates; sales through affiliate links may benefit this site.

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(To see all the comments, click on the "Comments" link below.)
Featured Comments from:

Matthew Miller: "This also works really well for scans of prints on textured paper."

Stan Greenberg: "As per Matthew's comment, this trick very often works for scanning textured photos. Always worth a try, because everything else essentially boils down to making the image selectively fuzzy. Yes, this trick can be done in Paint Shop Pro, using layers. One other additional trick: when aligning the two scans, use 'Difference' as the blending mode. When the blend is pure black (or as close as you can get to pure black) the two layers are aligned.

"Another maybe superfluous comment: you have to perform two physically different scans, you cannot simply tell the scanning software to rescan the second time with a 90 degree rotation. (May sound obvious, but I had to learn this the hard way.) This is a wonderful technique—I think I discovered it on a Retouch Pro web site forum. Stan Greenberg, Kibbutz Kabri, Western Galilee."

Ctein replies: Yeah, works well with textured papers. Doesn't always work with the embossed "honeycomb" portrait papers, because sometimes there's an actual difference in the density. But always worth a try. The difference trick for alignment sounds Fine. I knew that...but forgot it! Thanks. Yes, the print needs to be physically rotated on the scanner platen, so it's facing the opposite way during the second scan. Thanks for emphasizing that.

This week's column by Ctein

For most photographers, lens designs are simply magic, and that's the way they should be. Knowing what goes into a lens design and what trade-offs have been made honestly won't do a single thing to improve your photographs. A side effect of this, though, is that some photographers become puzzled, even disturbed, by some of the choices lens designers make. Why isn't some new lens a stop faster, or smaller, or why did they "cheapen" the product by correcting some flaws in software instead of in glass?

A camera lens is a barrel of compromises. To appreciate this, think about the simplest lens—a cheap magnifying glass. It exhibits geometric distortion, spherical aberration, flare, astigmatism, coma, and lateral and longitudinal chromatic aberration up the wazoo. It's so bad that Newton was driven to reinvent the reflecting telescope, because he was convinced that lenses presented unsolvable optical problems.

Happily, he was wrong about that. You can combine single lenses to reduce aberrations. The groundbreaking two-element achromat proved that it was possible to reduce (but not eliminate) chromatic aberration. As a rule, you can't entirely erase an aberration, not over the entire field of view, over all apertures and working distances, and over the entire spectrum. Worse, reducing one aberration can increase another. Optimizing lens performance is a complicated balancing act.

Each time you add a new point of control to the lens design—a new optical glass, another lens element, an aspheric surface—you have another opportunity to improve the balancing act. Each time you add something new to the lens design, you increase its complexity, size, weight, and/or cost. "Optimize," though, is subjective; it depends on what you decide is most important. Also, if you don't test for the right things, you may not hit the optimal design. After all of that, you're still stuck with an imperfect compromise. Sometimes you just can't get there from here.

In practice...
That's what happened to me with one of the prescription lenses for my new SuperFocus glasses (which I last wrote about a few weeks back). Eyeglass lenses are optimized for acuity—how much fine detail you can see. Sometimes, in the real world, that's not, um, optimal.

In the doctor's office I could read text beautifully, but as soon as I got out of the office I noticed something odd. Bright lights, like stop lights or car's brake lights seemed slightly smeared. Ditto the LED lights on the various appliances at home. In the evening I stepped outside to look at the stars and distant city lights and there was very obviously a difference between the two eyes.

This is a sketch I made to show you what my left and right eyes saw when looking at pinpoint lights. The E is about the same size as the letters on the 20/20 line of an eye chart. The second illustration, below, shows what happens when looking at an extended bright object, where all those wispy comet tails get superimposed. It looks very much like what I saw looking at the LED and traffic lights.

Rotating the prescription lens rotated the tail about the light. OK, it's in that lens, not in the SuperFocus frame optics. When I put on my old glasses the lights were less sharp, but I didn't get the tail.

Back at the doctor's office, the refractometer showed that the lens matched the prescription. Dr. Kennedy ran me through a new eye exam and, in terms of visual acuity, a new prescription matched the original one. But, remember what I said about testing for the right things? I was now looking for something else. A normal eye chart, with dark letters on a white background, won't show this tailing; small dark objects on a light background will merely have a light wash of background light overlaying them. The contrast will be a bit lower, but there won't be any obvious artifacts.

I had modified an LED flashlight so it only emitted a half-millimeter beam. I rigged it up on top of the chest chart frame so that it was pointing at me. Now I could easily evaluate the tail. I also paid attention to the sharp edge of the white rectangle of the chart, to see how much it smeared out into the surrounding dark wall.

The problem I'd identified in the field was readily visible once I was running the right kind of tests. Dr. Kennedy adjusted the prescription to make the tail go away. Unexpectedly, the only way to make it disappear entirely drastically reduced visual acuity, to worse than 20/50 (my best left-eye acuity is 20/13). Fully correcting this one optical defect made others much worse.

How puzzling! My old glasses could eliminate the tailing with much less image degradation. So, Dr. Kennedy measured them on the refractometer and dialed that prescription into the phoropter.

It didn't work! The old glasses eliminated the tailing but the same prescription dialed into the phoropter didn't.

So, what was different? My old glasses had thick, low-refractive-index lenses. The new glasses require thin, very high-refractive-index lenses. Thick and thin lenses with the same surface curvatures don't behave the same way; there are different prismatic and second-order effects. It would appear that, by happy chance, the thickness of my old lenses just happened to correct the tailing well.

Unfortunately, that type of lens isn't an option within the physical constraints of the SuperFocus frames. I convinced Dr. Kennedy to let me look for a different optimum, one that didn't produce the highest visual acuity but was the best balance of acuity vs. the annoying tail. Eventually we settled on a prescription that was about a half diopter different from the original. It reduced the noticeability of the tailing by about two-thirds. It also degraded visual acuity in that eye by a third, taking it down to 20/20. I could live with that; it was a good compromise.

The new lens does work much better in the real world. The tailing is suppressed enough that I don't notice it unless I look for it. My overall vision is ever so slightly less sharp than it was prior to the re-optimization, but the overall image quality is so much better.

That's the way it is with lens design in the real world.

©2013 by Ctein, all rights reserved

Original contents copyright 2013 by Michael C. Johnston and/or the bylined author. All Rights Reserved. Links in this post may be to our affiliates; sales through affiliate links may benefit this site.

(To see all the comments, click on the "Comments" link below.)
Featured Comments from:

David Dyer-Bennet: "Don't forget price! I want camera lenses smaller, a couple of stops faster, twice the zoom range, and cheaper. But I'm a reasonable guy; I don't want a pony!"

By Ctein

For the holidays I usually give you all a column that delves into some far-flung aspect of science. This time I'm waxing a little more philosophical, but it is most decidedly not off-topic—it sprang out of, and directly relates to, photographic discussions here and abroad.

Here's an important difference between mathematics and science. Mathematics is fundamentally an intellectual exercise. You start with a set of postulates or axioms and you see how far you can run with them, creating an extensive and self-consistent (more or less) system of theorems and proofs. It's all in the logic and it's all internal to that system. The system you create doesn't necessarily relate to the real world nor to any other mathematical system you create. It's a beautiful entity unto itself.

Now, there are some wonderful mysteries about this. Many mathematical creations that were created purely as an intellectual exercise later turn out to be of real practical value. Sometimes it takes decades for the practical value of a particular intellectual edifice to be revealed. It is as if you arranged gears and cogs and levers on a table purely on aesthetic and compositional principles and 20 years later someone realized that would be a great working machine for their task.

Another is that deep connections sometimes turn up between an entirely different and apparently independent mathematical creations. Both of these things create wonderful arguments for mathematical philosophers having to do with whether mathematics really is just an intellectual creation that happens to be useful or if it's a genuine discovery about a physical reality. We're not going there today. The main thing to realize is that in mathematics connection to the real world is not a necessity, just sometimes useful.

Science is all about the real world. You can construct the most elaborate and apparently ironclad logical analysis, based on indisputable first principles, and if a laboratory experiment (properly done, of course, and that's a lot harder than most photographers realize) disagrees with that analysis, you have to toss the analysis out. It doesn't matter that you can't figure out what's wrong with it, the real world has told you something is wrong with it.

Here's how this ties into photography: lots and lots of would-be photographic experts treat photography as if it were mathematics. You see this most especially in discussions of the "quantitative" aspects of the craft like sharpness, resolution, diffraction, depth of field, exposure ranges, etc. I call them "would-be experts" because they never subject to their analyses to testing. They then issue pronouncements about how digital cameras cannot match the resolution of film, or how you simply can't stop down a lens beyond a certain point without obvious and visible degradation, or that depth of field does this that or the other, or...you get the idea.

These are the kind of pronouncements that folks with real expertise and experience debunk regularly. Said debunking is regularly disbelieved by an unfortunate fraction of the populace. Why? Because they are entranced by the theory and the analysis.

If someone has produced an extensive and learned discourse on the effect of diffraction on image resolution, but real-world experience and experiments show that the photographs don't behave that way, many people still feel that it needs to be explained where and why the logic is wrong. They believe that the argument really isn't settled until that is accomplished.

Sorry; that's not the way science works. That's the way mathematics works. If you create a theorem and a proof in mathematics and I say it's wrong, I have to show where the logic fails. If you do the same thing in science, all I have to do is show that real world results do not correspond to the intellectual edifice. It's not my job or problem to figure out why the edifice falls down. It's the responsibility, solely, of its creator.

Those are the words of wisdom I want to leave you with this holiday season. Photo-tech is science, not mathematics. Data (emphasis: good data) always trumps logic and theory.

•     •     •

Note: Further breaking my vow that I was going to stay off-topic until I got caught up through the new year, next week I'll be tossing your way a peculiar photographic puzzle I've run into. Then maybe I'll get back to being off-topic. Or not. I did warn you about "shinies," didn't I.

Ctein

Trained in physics, experimentalist Ctein (it's his only name, and it's pronounced "kuh-TINE") has been writing for photography publications for four decades. His weekly column for TOP appears on Wednesdays.

Original contents copyright 2012 by Michael C. Johnston and/or the bylined author. All Rights Reserved. Links in this post may be to our affiliates; sales through affiliate links may benefit this site.
A book of interest today:

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Featured Comments from:

Miserere: "My father-in-law is a mathematician at a prestigious American university; his field of research is differential geometry, and his particular work has no practical applications. He is fond of saying, 'reality is overrated.' As an astrophysicist, I usually respond, well, crap, reality is all I have to work with!

"I see parallels here with arguments in photography that I see happening every day on photo forums. My favourite is how big a print one can make from an x-megapixel image. I have wonderful 30x20-inch prints made from 10MP images, whereas the Internet Sages tell me (and continue to misinform others) that those files can only be printed up to 13x8.7".

"I hope they read your column, Ctein, and put away their damn calculators and just make a print already."

Edd Fuller: "Seems like a lot of people believe the translation of Descartes' 'Cogito ergo sum' is 'I think, therefore it is.'"

Doug: "Even after years of it, I'm still amazed when someone posts a question on a photography forum that they could've answered for themselves with a few trial snaps. Digital is virtually free, folks. Do the experiments.

"See also this xkcd comic."

Zalman Stern: "In my experience, there is little disagreement between good mathematical analysis of photographic systems and their performance in practice. Doing a correct analysis without measurement is generally impossible unless one has the full set of design parameters for the lenses, sensors or film, camera mechanicals, etc., but the state of the art in modeling is up to the task of predicting reality reliably. E.g. lens correction profiles can be generated from design data without measurement or computed from calibration test shots without design data and both methods produce good results. (And yes, in both methods there is often some hand tweaking involved to fix problems from the correction model not being accurate enough.)

"Diffraction is very well understood and can be modelled mathematically to high precision.  Such analyses generally show a very gradual falloff in resolution, which matches experience. There are plenty of reasons one might choose to shoot at slower apertures even if they are less optimal in resolution at the plane of focus.

"A certain contingent of pundits around digital photography have made diffraction an issue, largely on the basis of overestimating the value of attempting to exactly optimize resolution. I suppose if you've spent $50k+ on a medium format digital back, any photo that doesn't exhibit exquisite sharpness comes as an affront to one's sensibilities and absolutely requires theoretical explanation. After all, every pixel is sacred. This is not about the disconnect between mathematical theory and photographic reality, it is about promotion of half-baked analysis in service of equipment bias.

"All that said, when it comes to advice on how to actually practice photography I have a pretty simple approach: I look at the person's photos. If they have work that I can learn from, I solicit their advice. Otherwise not. Neither mathematical analysis nor experimental technique is all that relevant."

Mahn England: "I'm an Architect by training. At University we were introduced to the applied sciences of structural engineering, acoustics, and lighting. In 30 years of practice since graduation I have never had to calculate a bending moment, reverberation time, or the spectral output of a luminaire. But as I have found also with photography, others are trained specifically to bother with these important things so that I can get on with what I do knowing that I will get somewhere near the mark...designing a building or taking a photo. To paraphrase the Roman architect/engineer Vitruvius: Firmness, Commodity and Delight...in equal measure."

John Woods: "Sir Arthur Eddington, who provided experimental tests of Einstein's theory of gravity, was interested in the philosophy of scientific method. He famously said: 'Do not trust a theory until it has been supported by experiment; and do not trust experimental results until they have been supported by theory.'"

By Ctein

There are some aspects to the magazine business that may not be instantly apparent to some readers. The first is that repetition is mandatory if you're going to serve the entire readership. Different readers come in with different levels of expertise. Not everyone learns everything the first time they read it (truthfully, hardly any of us do). Also, there's a significant turnover in readership from year to year, so the article you wrote two years ago is going to be news to quite a few people today.

For those reasons, articles on the basics, which can bore long-term and experienced readers, have to be part of a magazine's stock in trade.

This is going to be one of those.

•     •     •

This is not specifically about the Nikon D800 and D800E, even if they do provide the talking points. It applies, in general, to any camera between 28 and 50 megapixels.

Sharpness isn't an either-or phenomenon. It exists on a continuum, where each contributor of unsharpness plays its part. Recommended practices aren't absolutes, neither obligatory nor guarantees of success. They just make things better.

Tripods
If this sounds vague and unhelpful, consider the number of people who took Nikon's technical recommendations for getting the most out of the D800 as gospel. Nikon recommends using a tripod. That's a good idea. Is it necessary, all the time? Absolutely not. It's quite possible to get pixel-perfect sharpness handheld; you just need to use a short enough shutter speed*. How short? That depends on you. A good starting point, if you're using a 50mm lens, is 1/125th sec. Really, though, it depends upon your technique, skill, and practice.

Tripods: Sometimes you don't need 'em. Sometimes you need two.
(Ctein in action in 1991. Photo by Paula Butler.)

You may very well find that your threshold for consistently sharp results doesn't change directly in proportion to the focal length. If you can handhold the 50mm lens well at 1/125th sec., you might be able to hold a 24mm equally steady at 1/60th sec, but maybe not. Different lenses give different balance to the camera that can make it more or less stable in your hands. Image stabilization systems have different efficacy with different lenses. I wasn't comfortable handholding my Olympus Pen with the 45mm lens below 1/25th sec, but I could routinely stay sharp with the 12mm lens at 1/4 sec.

Long lenses are tricky because they shift the balance point away from the camera body. With my Pentax 67, I could handhold the 105mm lens at 1/60th sec. easily; with care I could go down to 1/30th. I needed 1/250th sec. and above with the 300mm lens.

I found all of this out by trial and error. That's the way you'll find out.

Lenses
Nikon provides a list of lenses that they think perform especially well with the D800. But, just as with tripods, they are recommendations, not marching orders. When you're down in the ƒ/8 range, it's hard to tell most good lenses apart. I'm not talking about exceptional, rare and costly lenses. Yes, there will be nuances that separate out the exceptional, but they will be subtle and slight, even with mondo megapixels. So, where do you see the big differences for your money? At the wider apertures. Exceptional performance at low f-numbers is usually what you're paying the big bucks for.

Apertures
Finally, diffraction is not the big bugaboo people try to make it out to be. Yes, somewhere between ƒ/5.6 and ƒ/8, it will start to subtly degrade sharpness. Note the emphasis. The effects remain subtle until you get below ƒ/11. They don't get really serious until you're pushing ƒ/16 and smaller. That's all you need to know about it. Really, truly.

Let's put this all in a historical perspective. In 35mm terms, the new Nikons are capable of resolving 70–80 line pairs per millimeter. That's really, really sharp, it's more than twice what was considered "acceptable" sharpness in 35mm film photography. But it's not unbelievably, extraordinarily sharp. Film photographers managed to achieve this, handheld, with lenses mortals could afford, and they had to live with two handicaps digital photographers don't: poor film flatness and no image stabilization.

If they could do it, you can do it. Just practice, and learn your and your equipment's behaviors.

•     •     •

Here's another aspect of the magazine business: there's no shortage of good ideas for articles. What there always is is a shortage of space, time, and creative energy. I throw away lots of ideas (so does Mike), not because they wouldn't make great columns, but because something else takes precedence. Or, at least, they get perpetually deferred, as something shinier wanders across my mental landscape.

That's been happening to my off-topic columns. The last two were four and six months ago, respectively. I mean, it's not like I'm obligated to write one of those a month, but I'm way behind. Meanwhile, teas, and starships, and graphic novels, and maybe even parrots, are clamoring for space. I'm going to indulge them through the end of the year, as kind of a holiday gift. I won't say every column for the next four weeks will be an "off topic" one; most likely I'll get distracted by some technological shiny along the way. I know my weaknesses. But I'll try for at least three out of four.

Until next time....

Ctein

*Or flash with a short enough duration, in situations where it provides all or most of the exposure. —Ed.

Regular columnist Ctein sharpens you up every Wednesday on TOP.

Original contents copyright 2012 by Michael C. Johnston and/or the bylined author. All Rights Reserved. Links in this post may be to our affiliates; sales through affiliate links may benefit this site.
A book of interest today:

(To see all the comments, click on the "Comments" link below.)
Featured Comments from:

Hugh Crawford (partial comment): "My three tricks for sharper handheld slow-shutter-speed photos are: increase the polar moment of inertia of the camera by attaching a collapsed monopod or tripod to the camera, or just bolt a 2x4 to it. If you are using an eye level camera, try to have the camera make firm contact with your head. Holding it upside down with the body pressed against your forehead works. I used to have a small block of wood with a accessory shoe attached that I would put in the hotshoe of the camera so it would make firm contact with my head. You are effectively adding five pounds to the mass of the camera. Of course this works even better if you are a chicken (I'm not kidding; Google 'camera on chicken'). [Seriously, Google it. —Ed.]

"Waist-level viewing with a taut neck strap beats all the above. The best advice for handheld marginal shutter speeds is to shoot three-exposure bursts, then pick the sharpest one later. Usually it turns out to be the second one but not always.

"Tripods work best of course, the heavier the better. (Unless you are on a bridge or a dance floor, where handheld with knees bent works better.) Once upon a time the hot setup was to fill the center column of a Tiltall with lead. If you aren't using a heavy tripod usually exposure times longer than 1/2 second are sharper than 1/4th."