The Blog at Paul Nguyen Photography

Artistic tutorials, news, reviews, and photo therapy from the Mofotographer himself

The Hyperfocal Focusing Technique: how to maximize depth of field for easy landscape photography

March 09, 2012  •  1 Comment

 

Whenever you are photographing landscapes, like a good landscape shooting mofotographer, you almost always want to get the maximum depth of field possible; you want everything from near you all the way out to the horizon to be in sharp focus.  There is no room for fuzzy, blurred backgrounds in this kind of photography, as there would be in, for instance, portrait or close-up photograpy where only the main subject needs to be rendered in sharp detail. 

We've learned in Photo 101 that the higher f-stop numbers (corresponding to smaller lens apertures) give the most depth of field.  And most of your landscape photography will be done with wide-angle lenses, which naturally have more depth of field at any f-stop than telephoto lenses do.  So achieving maximum depth of field when shooting landscapes could be as simple as setting your f-stop to a high number, like f/22 or above, and focusing on just about anything in the scene, and you'd almost guarantee that everything in the scene is in focus.  But, if you are to be a true mofotographer, there's a slight problem with that:

Most lenses, even many higher-quality ones, tend to suffer from some kind of image degradation at their extreme apertures (either the very high or very low f/stops).  A lens that is opened up to its widest apertures (lowest f numbers) often produces soft images, because the depth of field is so small.  And a lens at its narrowest apertures suffers from a image-degrading phenomenon known as diffraction, which, in my non-technical mofo way of describing things, is caused by rays of light being dispersed by the blades of the lens diaphragm (the part that regulates the aperture), leading to a reduction in resolution.  So that leaves us with the idea that the optimum, sharpest, apertures to shoot at are the middle ones -- f/8 to f/11, and if you would like to push it, f/16.

So how do we shoot at the naturally sharpest apertures while still maintaining the maximum possible depth of field?  Be prepared to take your camera off of autofocus for the next step of your progression from ordinary photographer to Supreme Mofotographer Extraordinaire.  And besides, so much of landscape photography is done in low-light conditions, and most autofocus systems won't be able to focus on anything when it counts anyway.  So you'd better be prepared to rely solely on manual focusing.

A lens of a given focal length, set to a given aperture, has a pre-determined focus distance called the hyperfocal distance at which the absolute maximum depth of field is obtained.  Technically speaking, when a lens is manually set to its hyperfocal distance, everything from half that distance all the way to infinity will fall within the depth of field and be rendered in sufficiently sharp focus*, and it is impossible to get any more depth of field from that lens without switching it to a smaller aperture.  So the idea is that objects near and far will be in focus, which is just what we mofos are looking for in landscape photography.  Example: A 12mm wide angle DSLR lens, set to f/11, has a hyperfocal distance of 27.6 inches (2.3 feet).  If you were to manually set the focus on that lens to exactly 27.6 inches, everything from 13.8 inches in front of the camera to infinity would fall within the depth of field.  The hyperfocal distance is determined by mathematical calculation, and it is impossible in practice to set your lens at exactly the hyperfocal distance, because the distance marks on the barrel of the lens are never precise or accurate enough. 

An important point to remember is that the hyperfocal distance also happens to be the absolute closest distance at which you can focus the lens and still get objects at infinity within the depth of field.  In the above example, if we focused closer than 27.6 inches even slightly, down to 27.0 inches, objects at infinity would no longer be in focus!  The depth of field would drop drastically, extending from 13.53 inches to about 485 feet.  While 485 feet is still quite far away, it ain't infinity, and so objects on the horizon would be considered out of focus.  On the other hand, if you focus at any distance beyond than the hyperfocal distance, infinity would still be in focus, but you would lose some depth of field at the near end, usually an insignificant amount if you don't go too far beyond the hyperfocal distance.  So continuing with above example, if we set our lens' focus to 36 inches, our depth of field would extend from 15.5 inches to infinity.  We'd lose just a few inches of depth of field on the near end and still have depth of field to infinity.  The moral of the story then, is that it's much better and safer to focus beyond the hyperfocal distance than to try to focus right at the hyperfocal distance and risk accidentally focusing closer.  Given how imprecise manual focus is anyway (because distance marks on the lens are in whole feet, not inches), I always consider the hyperfocal distance to be a minimum, and I focus liberally beyond that.  In the example scenario of our 12mm lens set to f/11, where the hyperfocal distance is 27.6 inches, I set my focus to be somewhere between 36 and 48 inches, and I've got more than enough depth of field for almost any landscape shot.  If I do happen to have subjects even closer to the camera than 18 inches or so that I need to have in focus, or I just want to add an extra security blanket, I then sometimes close down the lens aperture a bit, to f/13 or f/16, and that guarantees me even more depth of field. Remember that the scene, when viewed through your viewfinder, will not appear to be in focus from near to far, because the viewfinder image is produced with the lens at it's widest aperture (which gives the least depth of field).  You have to use your depth of field preview button to see what the image will look like at the f-stop you've actually dialed in.  If you do enough landscape photography, you will just start to trust the numbers, and you won't need to use the preview so much. 

You will generally only be using the hyperfocal focusing method with wide angle lenses, because with telephoto lenses, the hyperfocal distance is quite far away, and so the depth of field on the near end also starts quite far away.  Not practical for landscapes where you want the foreground objects to be sharp.  That's okay, because you'll be doing most of your landscape photography with wide lenses anyway. 

Okay, so you're probably thinking, "this was supposed to be easy, but this mofo is going to make me solve mathematical equations.  I just want to go out and take frickin' pictures!!"  Just relax.  I'm not a mathemetician either, so I don't do my own hyperfocal distance calculations.  And most photographers don't like to do math either.  In the days of yore, photographers would rely on pre-made tables of hyperfocal distances and depth of field for lenses of different focal lengths.  Now, we simply rely on the omniscient tome of knowledge known as the internet.  There are numerous websites out there that can calculate your hyperfocal distance and depth of field for you, one of which is here: http://www.dofmaster.com/dofjs.html  You enter your lens' focal length and the f-stop you've chosen, and the calculator figures out your hyperfocal distance.  And if you enter the focus distance you've set on your lens, it calculates your total depth of field and your near and far focus limits.   An interesting tidbit of knowledge here is that since depth of field is a function of lens focal length, focus distance, and f-stop, it is consistent across all lens brands.  So it doesn't matter if Nikon, Canon, or Uncle Ned made your 12mm.  The calculations work. 

And for smartphone users, we have (drumroll)... apps!  I use an Iphone, and I rely on two apps for hyperfocal focusing: one called "f/8" and another called "Depth of Field Calculator", which do the same calculations as the website above.  If you use an Android phone, check to see if these are available, or else something equivalent will exist surely. 

 

 

 

 

 

 

 

 

This app called f/8 is cool because it lets you create a virtual "camera bag" with different lenses, including zoom lenses, and you can use a slider to move across the entire focal range of your zoom lens and see how the hyperfocal distance and depth of field change.  The slider feature overall, though, is sort of annoying, because on the touch screen, the sliders are very sensitive and it's difficult to keep them to stay on the number you've set when you move your finger away. 

 

 

 

 

 

 

 

This other app I use, simply called Depth of Field Calculator, makes you input the numbers manually instead of using tricky sliders.   This is both good and bad, because manual entry allows you to easily input the exact number you want, but at the same time, you don't get to zip through all the different focus distances from near to far to see how the depth of field changes as you would with sliders.  The visual representation of your depth of field here is a nice perk, though.   

 

 

 

 

 

 

As usual, there's no clear-cut winnter, and I choose to use both apps depending what I need at the time.  The nice part is that as you do more and more shooting using manual focus and hyperfocal distance, you will no longer need to refer to these calculations every time, and you'll have memorized a few key settings that you will use often.  After all, you don't want to miss the few golden moments of a beautiful sunrise because you were staring down at a smartphone, do you?  For me, the one combination of settings on my Tokina 12-24mm lens that I use the most is this:  12mm, f/11, focused to approximately 40 inches.  With these settings, I know I'm using the sharp part of my lens' aperture range (f/8 to f/11), I can be sure that I'm beyond the hyperfocal distance of 27.6 inches, and I have depth of field from 16 inches in front of my camera to infinity.  If I think that I need just a few inches more depth of field in the foreground to get everything in focus, or want to be safe, I go down to f/16.  With a good lens you will not notice a loss of resolution at f/16 vs. f/11. 

So, mofos and mofitos, let's go shooting.  Here are your key points to remember:

  • For landscape shooting, put your camera into manual focus, and quit worrying about whether your autofocus will focus on the right thing.
  • Use a wide angle lens when focusing with the hyperfocal method.
  • When possible, use the middle f-stops of your lens (usually f/8, f/11, f/16) because they produce the sharpest image.
  • Use the internet or a smartphone app to find the hyperfocal distance and depth of field range for the lens you are using, and the f-stops you will be shooting at, and make sure you find a combination of settings that gives you the depth of field you need to keep everything in your scene in focus. 
  • Hyperfocal distance and depth of field depend on three factors that we care about: the focal length of the lens, f-stop, and focus distance.  It doesn't matter what the brand of the lens is.  So it's about the stats, not the name. 
  • Focus beyond the actual hyperfocal distance, rather than risk accidentally focusing nearer.  You will lose much more depth of field, perhaps catastrophically, if you focus under the hyperfocal distance, whereas you will lose only a few inches of depth of field, all on the near end, if you focus a bit beyond the hyperfocal distance. 
  • Memorize at least one or two combinations of settings that you will use frequently, so you will be ready to dial in your camera when the time comes. 
  • Remember that the scene you see in your viewfinder will not be representative of the depth of field you will actually have in your photograph, because the viewfinder image uses the lens' widest aperture, not the one you've dialed in.  Use the depth of field preview button to see how much depth of field you actually have. 

 

*And now for the stuff we don't really need to care about:  There's of course some subjectivity in determining what is "sufficiently sharp" when deciding what falls within the depth of field of a photograph, and in reality there is no abrupt transition between sharp and blurry, but rather a gradual transition.  Calculations of hyperfocal distance and depth of field use a concept from physics called "circle of confusion" that sets an agreed-upon numerical upper limit on what should be considered sharp by a person of typical visual acuity, under typical viewing conditions, etc.  I won't go into detail, because I don't understand it fully myself (dammit Jim, I'm a photographer, not a mechanic), but basically the part of an image that is considered sharp falls under the circle of confusion number.   The agreed-upon circle of confusion changes with the size of the camera's sensor/film.  So when you are using a depth of field calculation website or app, be sure to correctly enter your camera body into the program to be sure that your calculations are being done with the correct circle of confusion number. 

 

 

 


Shooting the Moon, for folks who don't play "Hearts"

February 29, 2012  •  Leave a Comment

Today's post comes in response to a comment on the last entry about shooting by the light of the moon:

"Hey Paul! Thanks for setting up the Q&A! I was awed by the night sky on 02/26/12 when Jupiter and Venus came very close to a beautiful crescent moon. Hurried outside to take a picture only to find out I don't have the skills for such a feat yet! I was wondering if you could give me some starting points for taking such a shot. Apparently I will get another opportunity on 03/13/12, I want to be locked and loaded then...
Thanks so much for the advice but especially for the super helpful blog. Hoping to join the badass mofotographers one day."

Thanks Cintia for reading and getting involved.  Welcome to the Foto Mofos. 

A true mofotographer always has his/her tripod, and that's just the most important detail to remember when doing any kind of low-light shooting, and shooting the moon is no exception.  Yes, it's possible to aim your camera right at a full moon with a very long lens (300mm or greater) and take a hand-held shot at a reasonable ISO setting, but with anything less than a full-moon, you will find that you'd be better off with a tripod, or you'd have to use a high ISO setting to avoid camera shake, and the resulting image quality would be compromised.  It's amazing how much more light there is with a full moon than with a half moon, and certainly a crescent moon.  The human eye tends to adapt to different brightnesses very well, so there doesn't seem to be as much apparent difference between the various moon phases, but a camera never lies.

Another interesting thing about the moon and our perception of it is how when we look at a real-life scene that has the moon in the sky, the moon always seems to look much bigger than it does when we photograph that same scene. If you've ever photographed a scene using a wide angle lens, you've been disappointed that the moon looks no bigger than a street lamp!  So the point to remember is that to take a picture of the moon with any amount of detail, you need a super-telephoto lens.  I'd recommend a 300mm or greater lens.  I usually use a 400mm focal length on my Canon 7D body.

Another tool I like to have hand for night shooting is a cable shutter release.  This allows me to fire the camera on the tripod without actually touching the camera body.  This prevents the possibility of causing excessive camera shake. 

It sounds like Cintia's ambition was to take a picture of the moon with Jupiter and Venus isolated in the sky without any earthly landscape in the composition.  So here's a quick and dirty mofotographer-style take on how I'd photograph that.  

  1. Set up your tripod and camera to aim at the moon and make sure the other celestial features you want are in the frame.  You'll be surprised at how much sky is around the moon even with a 300 or 400mm lens, because like we mentioned before, the moon looks much smaller to lenses of most focal lengths than it does to the human eye. 
  2. Set your camera to Aperture Priority mode, and dial in the largest aperture (smallest f number) you have.  On my 100-400mm lens zoomed out to 400mm, that would be f/5.6.  You don't need any depth of field to shoot anything in the sky, because it's already at infinity focus, so just open that mofo wide as you can.  The one exception is that some poorer-quality lenses are very soft at their widest aperture, so you'd want to close it down to something with reasonable sharpness.
  3. Set an ISO of 100 or 200.  You have a tripod, so speed is not of the essence.  Go for the highest picture quality.
  4. Attach your cable release if you have one.  If not, set your self-timer to 2 seconds, so you can take the shot without the camera shaking when the shutter fires.
  5. Focus on the moon, either with autofocus, or manually focus to infinity.
  6. Meter the scene and take the shot.
  7. If you're shooting digital, make sure that the moon appears with sufficient detail and that you didn't clip any highlights at the right side of your histogram.
  8. Apply exposure compensation as necessary, and repeat the shot 5 more times. 

An uncropped, unedited capture of the full moon in the night sky would like this:

 400mm lens on a crop-sensor camera, f/5.6, 1/160 second, ISO 100  

 

 

 

 

 

 

 

 

Expect that a crescent moon would require one or two more stops of exposure. 

 

OK, now for the mofo part:

What's even more fun than photographing the moon is incorporating the moon into a landscape photograph.  After all, a moon is a moon is a moon, and it kind of lacks character without some earthly features to put it into context.  But most landscapes are taken with wide angle lenses, and like we said at the beginning, the moon looks like such a wimp through a wide angle lens -- small, lacking in detail, and if you're properly exposing for a night landscape, the moon is no doubt overexposed.  NOT badass.  If you've tried it, you know what I mean.  So how do we make the moon look like it does, perceptually, to our eyes?  WE CHEAT!  Actually artists never cheat, only scientists cheat.  Artists have no rules, and when there are no rules, it's impossible to cheat.

So how do we cheat?  We take two separate exposures and combine them:  Capture the landscape using your wide angle lens; Then take an entirely separate capture of the moon isolated against the sky using your super-telephoto lens.  Then once you're at home in the comfort of Photoshop, crop the moon shot down so it's just a square that includes the moon.  Layer the moon shot over the landscape shot, and scale down the shot of the moon so it looks perceptually the size that it did to your eyes.  Or if you have a flair for the dramatic, make it a bit bigger. ;)  At this point you'll see that the moon still has an ugly black box around it.  So, this is the most important part: Change the blending mode of the moon layer to "Lighten" or "Screen" depending on which one looks better.  These blending modes will make the dark part of the moon layer become transparent, and thus match the color of the sky in your landscape shot.  Amazing!  It looks seamless, really.  Mofo-licious!

 

Landscape: f/6.3, 4 minutes, ISO 200, 13mm lens

Moon: f/5.6, 1/15 second, ISO 200, 400mm lens


By the Light of the Moon

February 24, 2012  •  2 Comments

 

 

 

 

 

 

 

 

 

 

 

 

 

Castle Hill Lighthouse illuminated by the full moon.  Canon 7D, with Tokina 12-24mm lens on a tripod.  F/4 for 6 seconds at ISO 3200. 

Welcome mofotographers.  Outdoor photography is the decathlon sport of the mind.  You often have to know the weather, the tides, the phase of the moon, the sunrise/sunset and moonrise/moonset times, how to do some quick calculations in your head (or with your smartphone), and be a bad-ass mofo with your camera all at the same time.  Oh, and you need to be an artist, too.  And then, from a physical standpoint, it requires lifting and carrying heavy things, often over challenging terrain, and in poor light or no light.  The fact that it encompasses just about every skill imaginable (other than tax accounting and cooking) is the exact reason why I love it so much. 

And even when you've got all of those factors accounted for, you still don't know how the shoot's going to turn out until you actually show up.  So throw in a little luck, too.

For this shot of Castle Hill Light, all those factors came into play, and I thought I'd give an explanation of how I went about making this shot, because it provides a good framework and method to my outdoor landscape photography.  It's a bit long, and I promise that subsequent posts will be shorter, because I won't have to repeat all this again.

First the luck part:  If you go to a shoot location multiple times, you increase your chances of getting the exact conditions you want.  I went to Castle Hill Lighthouse in Newport, Rhode Island (which is about two hours from where I live) probably 8 times over the course of a few weeks, trying it in different lighting conditions from late afternoon into the dark of night.  I really dig lighthouses, as you can see from the other shots in my catalog, and I wanted this shot to not only be distinctive among my own lighthouse shots, but also be different from other photographers' renditions of this particular lighthouse.  Castle Hill is a beautiful little light, because it's built right into the granite bedrock without all the junk that surrounds other lighthouses; things like a house for the keeper, a lawn, a parking lot, a flagpole, a harbor, a tourist vistor center, etc.  It's just a rugged, gritty little lighthouse.  Strange, considering it's Newport, RI.  So about 7 trips into the 8 trip series of shooting this lighthouse, the opportunity arose for a full moon shoot on a clear, mild winter night.  I'd never seen such a shot of this lighthouse, so why not try?

Tip for newer foto mofos: When making any shot, think about what your main artistic considerations are, and then make your in-camera decisions to address those considerations.  A little bit about me:  I'm not one of those artists who tries to express in each photograph "the delicate and ambiguous nature of good and evil" or "the inner conflict that exists within the heart of every man" or crap like that.  That stuff's for art students.  My goal is to just make every picture evoke some kind of emotional response in the viewer by showing them something they haven't seen before, whether it's a different perspective on a common subject, interesting and emotional colors, unique textures, whatever.  I never even try to describe that emotional response in words, like happy, sad, or impressed.  But there has to be something about the experience of looking at the photograph that would make it feel different even from seeing it in real life, or seeing it on TV, or through someone else's photograph. 

My main considerations for this particular shot of Castle Hill Light were simple:  I wanted to have the lighthouse and it's surrounding granite illuminated by the full moon, and I wanted to render the water in an abstract sort of way, where the motion of the water is blurred, but you could still see the details of the wave splashing against the tidepool in the foreground.  So the first consideration: the moon.

The full moon on a clear night is bright enough to illuminate the landscape sufficiently well for a long exposure shot of a few minutes at a low ISO setting like ISO 100 and a moderately wide f-stop like 4.0 or 5.6 with no supplemental lighting needed (flash, light painting, etc.).  As a comparison, a moonless night in a remote area with just stars in the sky does not cast enough light to illuminate the landscape even if you leave the shutter open for the entire night.  So having a nice bright moon in the sky gives you an opportunity to grab some shots that you wouldn't be able to get on most nights.  For this scene at Castle Hill Light, at your camera's lowest ISO setting, which for most people is ISO 100, you would get a nice exposure in about 3 minutes at f/4 (on a tripod, of course).  ISO 100 gives you the highest picture quality with very little grain, and 3 minutes is not very long to wait in the grand scheme of things, especially if you have some interesting apps on your iphone to whittle the time away with (guilty as charged).  This is a great setting for most full moon landscape shots.  So why DIDN'T I just shoot this scene for 3 minutes at ISO 100?  Because that would have interfered with my second artistic consideration: rendering the water abstractly, but not so blurred as to obscure all details of the water movement in the foreground tidepool.

Over the course of 3 minutes a lot can happen in a tidepool.  Waves splash repeatedly over the same area (in this spot, about once every 10-20 seconds), and when exposed for the full 3 minutes on a sensor or film, the repeated motion of frothy water can create a "cotton candy" kind of blur, which makes the area look like an '80s rock concert with a fog machine backstage, or you dropped dry ice in a bucket of water.  It can be a nice effect, and I do employ '80s rock concert sensibilities into some of my shots, but it wasn't what I was looking for here.  To capture the blurred motion of just one wave splash, my judgment and experience tells me I would need about a 6 second exposure, timed to coincide with one of the wave splashes.  So to get the equivalent exposure value in 6 seconds to what you would have gotten in 3 minutes at ISO 100, while keeping the f-stop the same, you need to so some (drumroll) math.  In the interest of sparing you yet more length in this post, I will save the explanation of the math for another post, and just tell you that ISO 3200 is what you need to dial in to get the exposure you want.  Set your camera to Manual mode, and tell it who's boss, yo: F/4, ISO 3200, 6 seconds.  Take the shot, and you'd see that the photograph looks more or less the same in terms of brightness as what you would see in your 3 minute shot at ISO 100, but the water retains more detail, and has less of that dry-ice-in-a-bucket-of-water look. 

And then, make use of luck once again.  Put a cable release on your camera, and take several, and by several I mean dozens, of shots of the surf splashing in the tidepool, timing your shot to coincide with an incoming splash.  I assume you will be shooting digitally, so check your LCD after each shot, and after a while you will either get bored or decide that you got the "golden mofo" shot and are ready to call it quits, or hopefully both. 

The final consideration when shooting at ISO 3200 is that the level of noise that your sensor produces will be high, so be sure to use the in-camera high-ISO noise reduction feature if you are shooting JPEG, or do some noise reduction in the software post-processing if you are shooting RAW.  If you want to get fancy in post-production and agree with me that the art of photography is not just made in the camera, you can combine elements of different shots that you took of the same scene to get the visual effect you are after. 

Checklist of take-home points to remember:

  • Come back multiple times to the same shooting location; luck plays a part in getting the Golden Mofo shot
  • Bring a tripod
  • Sometimes a longer exposure at low ISO is what you want, but sometimes a shorter exposure at higher ISO is the ticket; try it both ways
  • Take many, MANY shots of the same scene until you are bored/happy
  • Reduce sensor noise either in-camera or in the software if you shoot at a high, noisy ISO setting

 

 

 

 

 

 

 


And so the Mofotographers Blog begins...

February 23, 2012  •  Leave a Comment

Thanks so much to my website host Zenfolio for integrating a new blog feature into the website!  I figure this is where I can post technical and artistic details on some of the shots from my portfolio, news on upcoming shoots, and updates on events where I'll be selling and exhibiting my work.  I'll even post an occasional review of some piece of gear, new or old, that I've been using, in case people are curious about the technical merit of some shiny expensive toy they've been mulling over in their brains.  I'll also answer some of the common and general how-do-I photo questions I get from people on a daily basis, as I've found myself in the position of being the go-to-guy in my circle of acquaintances when it comes to dispensing advice.  You might say I'm a photo therapist.

And mind you, I'm really not a techie-dork when it comes to photography compared to some people out there (although some folks would beg to differ).  I take a very intuitive, artistic approach to photography, so when it comes to gear, a shot, a technique, or anything for that matter, I tend to make a does-it-work-for-me-or-doesn't-it final value judgment.  Kind of a Roger Ebert thumbs up or down approach.  You will not hear me talking about barrel distortion, sharpness measurements, or anything like that when I evaluate something.  I have no tools for measuring lens specifications; just eyes and a somewhat cluttered brain. 

So that's why I refer to myself and my fave photo brethren as The Mofotographers.  We're just regular mofos who care only about making kickass shots.  Yes, we do plan, but when we show up at a shoot, we just make a few rapid fire judgments and then start shooting.  We don't do calculations or bust out a hand-held meter.  That sh*t's just too complicated for a simple-minded mofo like me. 

So if you fancy yourself a photo simpleton, who would prefer not to think about photography, but just feel it, this blog might be right up your f/16.  Welcome my mofos... Mwahahaaahaaa.

Where do we begin?  Let's start with the most recent photo I did...

 


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