Archive for the ‘contrast’ Tag

Friday Foto Talk: Cloudless Skies – Part I   8 comments

In the land of the Ancient Ones: Four Corners area, desert southwest U.S.

Clear skies:  a landscape photographer’s nightmare.  Okay, maybe that’s being a bit too melodramatic.  But cloudless conditions are a kind of obstacle related to light.  You can find a general discussion of light, as important obstacle to overcome, in a recent post.  I’ve been doing a whole series of posts on Friday Foto Talk dealing with obstacles, so check them out if you have a moment.

Although landscape photography is where we most miss clouds, nature, sports, macro and portrait shooting are all potentially more challenging under clear skies.  Here are the main issues that can cause problems:

Although skies are clear, the subject here (Colorado's Sangre de Cristo Mountains) is dramatic enough to compensate.

Although skies are clear, the subject here (Colorado’s Sangre de Cristo Mountains) is dramatic enough to compensate.

  • Harsh Contrast:  Bright sunshine causes big differences between areas that are brightly lit and those lying in shadows.  Besides the obvious problem of finding the right exposure, these bright and shadowed areas are typically separated by sharp lines, creating a scene which lacks any  softness.  This tends to be unpleasing to the eye.
  • Flat Light:  Hazy sunshine is the worst, but light can grow flat under other weather conditions as well.  You know this kind of light: despite the fact contrast is not as harsh as with perfectly clear sunshine, there is really no depth to the light.  Foreground objects appear to recede into the hazy background and distant objects may not be discernible enough to add depth to your images.
  • Cool Light:  By cool I mean blue, even though you scientist-types will object, quite reasonably, that blue light is actually at a higher temperature than red or orange light.  Bright and blue light is generally less attractive than somewhat dimmer and redder light.
  • Golden Hour Blues:  When skies are clear, sunrise and sunset are, like the shadows which characterize mid-day, abrupt, sharp and relatively unpleasing to the eye.  Dawn can pass without much color at all.  And sunset is a short, unspectacular affair, where the sun sinks to the horizon surrounded by an ocean of blue.
A simple unspectacular shot, but I so enjoyed stripping & dunking my dusty body in this crystal clear (and cold!) water-pocket on top of Cedar Mesa, UT.

An unspectacular shot, but I so enjoyed stripping & dunking my dusty body in this crystal clear (and cold!) water-pocket on top of Cedar Mesa, UT.

Direct sun from the side can bring out details like this bear print petroglyph I found along a canyon wall in Utah's Grand Gulch wilderness.

Direct sun from the side can bring out details like this bear print petroglyph I found along a canyon wall in Utah’s Grand Gulch wilderness.

 

On my journey west, ever since crossing the Great Plains, dry and sunny conditions have prevailed.  The American West is in the midst of a long-term drying trend, exacerbated by global warming.  On previous trips I’ve had the luxury of being able to hang out and wait for a front (or at least a few clouds) to come along.  But on this trip I’ve been forced to take what I can get, just like an average amateur photographer on vacation.

Unlike many photographers who drop into a low-grade sulk when confronted by clear blue skies, I can still enjoy this kind of weather.  Also, I don’t want to be thought of as some sort of disturbed, gothic creature, unhappy unless things are dim and gloomy.

Cactus bloom at the bottom of a deep canyon on a hike in southern Utah.

Cactus bloom at the bottom of a deep canyon on a hike in southern Utah.

But a big part of the reason I don’t mind (so much) when clouds are a no-show is that I still enjoy capturing images at these times.  True, there end up being fewer “Wow, stunning!” landscapes.  But I actually like photographing within limits, trying to come up with something good when conditions are unfavorable.  I think it forces creativity and makes me a better photographer in the long run.  Or this is what I tell myself.

There are two main ways to mitigate the effects of clear sunny weather when you’re traveling and photographing.  One is to shift focus to other subjects, and the other is to shoot in different ways.  In the 2nd and final part, I’ll cover some of the ways I get good pictures when the sky is cloudless and blue.  Have an awesome weekend!

To my delight, a few clouds moved in at sunset after a clear day at Great Sand Dunes National Park, Colorado.

To my delight, a few clouds moved in at sunset after a clear day at Great Sand Dunes National Park, Colorado.

 

Dynamic Range IV: Conclusions   11 comments

Central Oregon.  This type of scene requires a camera with good but not extreme dynamic range abilities.

Central Oregon. This type of scene requires a camera with good but not extreme dynamic range abilities.  Copyright MJF Images.  Please click on this image if you’re interested in it.

I know this hasn’t been the most straightforward of topics, but let’s try to end by putting dynamic range in proper context.  By the way, make sure to at least skim through Parts 1 – 3 first, then come back to this one. I started by pointing out the importance of dynamic range.  But then I proceeded to poke some holes in that idea.  To allay any confusion, let me tell you my current thinking on the subject:

      • Mostly it’s important to know the dynamic range capabilities of your camera.  Whether its dynamic range is high or more modest is not as important as knowing how much it has.  This will allow you to approach different lighting conditions with a good idea of whether you can successfully shoot in them.  And if so, whether you’ll need to employ graduated neutral density filters or other techniques.
      • Dynamic range is quickly becoming similar to megapixels.  That is, camera companies are exaggerating its importance in an effort to market newer models.  After all, their job is to make you upgrade your camera body before you really need to.
Sandy River, Oregon:  No great dynamic range required here!

Sandy River, Oregon: No great dynamic range required here!

Angkor Wat, Cambodia:  this is a high contrast thus tricky exposure, all about the details in the dark (not brightest) areas.  Copyright MJF Images.  Click on image if interested in it.

Angkor Wat, Cambodia: this is a high contrast thus tricky exposure, all about the details in the dark (not brightest) areas. Copyright MJF Images. Click on image if interested in it.

      • That said, the companies are really just responding to consumer demand.  The HDR trend that got going some years ago has had a real effect on how we capture and especially how we view images.  While (thankfully) the grungy, over-the-top HDR look has largely come and gone, a  push toward evening out tones is very widespread in nature photography today.
      • Combine the above point with our desire to photograph anything in any light and you have a recipe for the current trend toward cameras with ever-higher dynamic range.  I’m not sure this is all that healthy (see caveats below).
      • Now you tell me what you think about all this.  Do you like the HDRish imagery you see on the web?  Do you like some of it?  Do you think it’s overdone or natural?  Is the pendulum going to swing back or is this a trend destined to continue, driven by technological advances in sensor design and software capabilities?

 

The elephant tree of Mexico's Baja Peninsula.  Though it may not look like it, this is definitely a high dynamic range situation.  Copyright MJF Images.

The elephant tree of Mexico’s Baja Peninsula. Though it may not look like it, this is definitely a high dynamic range situation. Copyright MJF Images.

The Redwoods, California:  This is a fairly high dynamic range situation not because of the sun but because you need to retain detail in the bright spot in the ferns.  Copyright MJF Images.  Please click on image.

This redwood forest shot is a fairly high dynamic range situation not because of the sun but because you need to retain detail in deep shadows and in the bright ferns. Copyright MJF Images. Please click on image.

Caveats

There are many factors other than dynamic range that affect the ultimate range of brightness you can shoot in.  These combine with dynamic range to influence the variety of images you can capture.  If you know me at all, you know how important I think variety is in a portfolio.  But again, it’s not all about dynamic range:

      • The ability of post-processing software like Lightroom to compress or expand contrast just keeps getting better.  If you shoot in RAW (you are, aren’t you?) then you have much more control over dynamic range in post-processing than if you shoot in Jpeg.

As I explained in the 1st post in this series, your camera has a certain dynamic range capability.  If you avoid compressing that range (by turning the image into a Jpeg before it even leaves the camera) you then have some powerful software at your disposal, software that can go a long way toward bringing out shadow and highlight detail.

Navajo Arch, Utah:  I waited until the sunlight coming through the arch was filtered by clouds, so that the contrast wasn't too great.

Navajo Arch, Utah: I waited until the sunlight coming through the arch was filtered by clouds, so that the contrast wasn’t too great. Copyright MJF Images.

      • Tonal range is at least as important as dynamic range, maybe more so.  Tonal range is the number of different tones your camera uses to get through the dynamic range (which again is the total difference between brightest and darkest and still retaining some detail).

In other words, good tonal range makes for smooth transitions between dark and bright, while narrow tonal range can cause choppy, banded or otherwise unnatural looking transitions.  This is yet another criticism film shooters level at digital.

Lake Powell area, Arizona.  Copyright MJF Images.  Please click on image if interested.

Lake Powell area, Arizona. Copyright MJF Images. Please click on image if interested.

      • High dynamic range capabilities may make you a lazier photographer.  A narrower range can force you to adapt and limit yourself to shooting in suitable light.  Recall I’ve already pointed out that high dynamic range gives you more options during post-processing.  Sounds good right?  We want to be able to take pictures in all sorts of conditions and produce beautiful images.  That’s why camera makers are busy expanding dynamic range in their new models.

But is this a good thing?  Isn’t it better to learn how to look for better light, a better angle to avoid that over-bright spot, etc.  It’s like all learning in life.  Doesn’t it help to work around limitations, to meet and beat challenges?  It’s probably the better path toward becoming a good photographer, better than having everything under the sun available to you.  I’m not fully on board with this critique of high dynamic range (I like shooting in high contrast situations), but I can see the point.

This image on the Oklahoma prairie I captured with my point and shoot so there was no way to avoid letting the foreground go dark.

This image on the Oklahoma prairie I captured with my point and shoot so there was no way to avoid letting the foreground go dark.

      • The quality of light, like it does with most everything in photography, trumps dynamic range.  And good light tends to be soft, to have a narrow range (see above point).  The idea is that you don’t need very high dynamic range capability since good light tends to be low in contrast.

There are exceptions to this of course.  And it’s much more important in landscape than other types of photography.  But looked at in an admittedly skeptical way, high dynamic range just allows you to capture all of that ugly high-contrast light instead of just part of it.

Olympic Mountains Sunrise:  Anytime you're shooting into the sun (and aren't doing silhouettes) dynamic range is pretty important.  Copyright MJF Images.

Olympic Mountains Sunrise: Anytime you’re shooting into the sun (and aren’t doing silhouettes) dynamic range is pretty important. Copyright MJF Images.

      • Dynamic Range may not be as important for you as it is for other photographers.  As implied in the point above, the type of photography you’re doing and the the way your images will be displayed/used have a lot to do with how much dynamic range you need in a camera.

In fact, many pros want camera makers to make adjustable dynamic range a feature of new models.  You would adjust it like you do shutter speed, aperture and ISO.  And there are hints this is coming down the pike.  Sony’s new compact mirrorless camera, the A7s, supposedly has a sensor which adjusts its dynamic range depending on light conditions.  Not the same as user-controlled but going in that direction.

I hope you enjoyed this series.  Feel free to reblog, and make sure to comment below if you have anything to add, or even if you have questions.  I’m glad to respond to anything.  Click on one of the images to go to my main gallery page.  Contact me if you are interested in any of the images as a download or print.  Thanks for reading and have a great weekend!

An image at Death Valley that will appear in a magazine soon!  Copyright MJF Images.

An image at Death Valley that will appear in a magazine soon! Copyright MJF Images.

 

Friday Foto Talk: Dynamic Range III – The Histogram   7 comments

Elowah Creek, Columbia River Gorge, Oregon.

Elowah Creek, Columbia River Gorge, Oregon.

This is the third of four parts on Dynamic Range.  Check out the first two parts.  Part I is an introductory look, including what dynamic range actually is.  Part II goes into how your eyes and your camera see things differently.  Today we’ll look at a key tool you should be using and how it help you both understand and control dynamic range.

Beacon Rock, Washington side of the Columbia River Gorge.

Beacon Rock is a landmark on theWashington side of the Columbia River Gorge.

The Histogram & LiveView

With most any digital camera, when you capture an image the camera builds one or more histograms, which are attached to the image file.  Histograms are simply graphs with horizontal and vertical axes.  Most used (and useful) is the histogram that depicts tones (See Figure 1 below).  These show tone on the horizontal axis and the amount of pixels for that tone on the vertical axis.  On the far left is pure black (0, the black point); on the far right is pure white (255, the white point).

histogram_labeled

Fig. 1: Please click this image (which is not mine) to go to the source, a nice introductory blog post on histograms.

With most DSLRs, you can capture the image in LiveView.  In other words, you can use it like a camera phone, viewing the scene on the LCD instead of through the viewfinder.  This allows you to see a representation of what your final image will look like.  Unlike most camera phones, it also allows you to see a very accurate, live-action histogram of the scene before you.  This way you can see what the tonal distribution actually is before you fire the shutter.  For example a live histogram will show exactly how much of the scene is overexposed or underexposed (see Figure 2 below).  When I use LiveView I’m usually on a tripod.  I’ll frame up my composition by looking through the viewfinder.  Then I turn on LiveView to see how things look on the histogram.

Figure 2. The histogram on the left is of an image with a small area of underexposure.  The one on the right has a small area of overexposure.  Click on image to go to the source website.

Fig. 2. The histogram on the left is of an image with a small area of underexposure. The one on the right has a small area of overexposure. Click on image to go to the source website.

 

Dynamic Range & Your Histogram

When you capture an image with a lot of inherent contrast (a sun-dappled forest or the side of a sunlit barn with the door open), your histogram will show a curve that spans across the entire width of the graph.  And it will probably climb up the sides (see Figure 3 below).  For scenes with low overall contrast, the histogram of a properly exposed image will sit somewhere near the center of the graph with the curve dropping down to the bottom before it reaches the far left or right (see Figure 4).

 

Figure 2. The image would have a small amount of pure black (far left).  A little more of it is overexposed highlights (far right).  Click image to go to the source website for this.

Fig. 3. This high-contrast image would have a small amount of pure black (far left) plus an area of overexposed highlights (far right). Click image to go to the source website for this.

A casual shot in a city park at sunset.  This image has both clipped shadows and blown out highlights (the sun, which is okay!).  Thus its histogram is similar to Figure 3.

A casual shot in a city park at sunset. This image has both clipped shadows and blown out highlights (the sun, which is okay!). Thus its histogram is similar to Figure 3.

Figure 3. Three low-contrast histograms. Dark on left, bright on right.  Click image to go to the source website this.

Figure 4. Three low-contrast histograms. Dark on left, bright on right. Click image to go to the source website this.

This black and white image of a stormy Columbia River Gorge is mostly shadow and mid-tones, with modest contrast.

This black and white image of a stormy Columbia River Gorge is mostly shadow and mid-tones, with modest contrast.  Its histogram would be similar to the one on the left in Figure 4.

 

These two situations, low contrast and high contrast, are of course extremes in a continuum.  And one situation is no better than another.  But when faced with a scene that has a lot of overall contrast, a camera with good dynamic range will expose so that the histogram (again, of a properly exposed picture) comes close to but does not climb up either the left or right edges (see Figure 5 below).

Fig. 5. Histogram of a high-contrast scene.  Click image to go to the source website.

Fig. 5. Histogram of a high-contrast but properly exposed scene. Click image to go to the source website.

Garden of the Gods, Colorado.  This image has fairly high contrast, and so a histogram very similar to Figure 2.

Garden of the Gods, Colorado. This image has fairly high contrast, and so a histogram very similar to Figure 5.

When the curve of your histogram climbs up the edges, that means you are not properly exposing parts of the image.  You’re losing data and will wind up with either blocked (too dark) or blown-out (too bright) areas (see Figure 2 above).  The higher up the sides the histogram goes, the bigger are those areas, and the more likely they are to negatively impact the final image.  Of course if you want to do this then it’s probably fine.  And if something like the sun is overexposed, then it is more than fine, it’s natural.

A camera with good dynamic range helps with this problem of shadow or highlight clipping.  It allows you greater latitude to bring out details in very bright or very dark parts of your images.  It allows you to capture images with a great variety of overall contrast levels.

Pink bleeding hearts bloom in the forests of the Pacific Northwest during spring.

Pink bleeding hearts bloom in the forests of the Pacific Northwest during spring.

A Caveat

I would like to throw in a big caveat to this benefit.  Don’t think you always need to even out tones HDR-style.  How much brightening of shadows and darkening of highlights you do on the computer is, after all, up to you.  You can even go the opposite direction by letting things go to pure black.  Or you can purposefully allow bright areas to be blown out.

It’s probably best to not think so much about how much contrast you can squeeze from the scene without blowing out highlights or clipping shadows.  Instead, think about the mood of the scene, the emotions you wish to elicit, the story you want to tell.  Let that be your guide, not the ability of your camera to manipulate a wide range of tones.  It’s yet another case of “just because you can doesn’t mean you should”.  Okay, end of rant, and end of post!  See you next Friday, when I’ll wrap up dynamic range.

This shot of Oregon's Mount Hood was framed so as to show some of the surrounding forest.

This shot of Oregon’s Mount Hood was framed so as to show some of the surrounding forest.

Dynamic Range II: The Eye vs. The Camera   13 comments

Abandoned oilfield in western Oklahoma now blooming with flowers and a magnet for birds and coyotes.

Abandoned oilfield in western Oklahoma now blooming with flowers and a magnet for birds and coyotes.

Last week I posted an introductory article on dynamic range.  I want to start diving down into the subject a little more this week, starting with the best visual capture device I know:  the human eye.  The images here are both from my point and shoot here on the plains where I’m working, and also some from the archive.

Dynamic range, though technically expressed as a ratio, is more simply expressed in terms of stops, as in stops of light.  If you hold shutter speed (and ISO) constant and open your aperture from f/11 to f/8 you have brightened the image by 1 stop.  You’ve allowed twice the amount of light to enter the camera and be detected by your sensor or film.  For every one stop you either double or halve the amount of light.

Small waterfall along Oregon's Sandy River.

Small waterfall along Oregon’s Sandy River.

Our Amazing Eyes

So let’s start with your eyes.  Although the internet has a wide variety of answers to the question, most agree your eyes have a dynamic range of about 20 stops from darkest to brightest.  That means you can detect at least some detail in the darkest and brightest parts of that enormous range at the same time.  We don’t usually need to deploy all this range at once of course.  Instead we shift and adapt (very quickly!), using different parts of our dynamic range under varying conditions.  If you allow for pupil dilation our range increases to 24 stops!

We do have our visual limitations.  Our eyes start to fail us in very bright or very dark lighting conditions.  We nevertheless can detect enough detail for recognition of threats when either looking into deep shadows at dusk or the rising sun at dawn.  Remember each stop of light is accompanied by a doubling or halving of the amount of light.  So despite the fact that some other animals put us to shame in other visual abilities, it’s quite the impressive dynamic range we’ve got.

Given the above, you probably are not surprised that cameras, even the best, cannot match the human eye’s abilities in the dynamic range department.  At least when it comes to “normal” daylight exposures.  At night you can leave the camera aperture open for extended periods and collect the scattered light photons that, while our eyes may detect them, simply don’t end up translating into good clear images in our brains.  Our cones (color receptors) are especially lazy at night.  It’s the reason we are so amazed when objects in the night sky are rendered in stupendous color.

So unless the future sees us evolve into nocturnal creatures, our eye-brain visual system will remain limited at night.  Of course our brains have used our hands to invent devices to extend our vision into the nighttime realm.  So enjoy those images of space you see, both the deep-sky telescope images and the star-scapes that have become such popular fare on the web.

Violent storms pass (that included funnel clouds) pass away from Oklahoma farmland.

Violent storms (that included funnel clouds) pass away from Oklahoma farmland at sunset.

Wahclella Falls, Columbia Gorge, Oregon.  This is a very low-contrast image requiring virtually no dynamic range.

Wahclella Falls, Columbia Gorge, Oregon. This is a very low-contrast image requiring virtually no dynamic range.

Dynamic Range of Cameras

So let’s get to the question that sparked my interest in this subject in the first place: what can cameras see, and does it matter?  If you look into this on the internet, you’ll come across all sorts of over-complicated camera test results, graphs and data until it’s coming out your ears!  It may come as a surprise that film (at least negative film) can generally capture more dynamic range than digital sensors can.  This is debated (of course) on the internet, but it’s pretty much true.

The reason I say “generally” and “pretty much” is that firstly, comparing film and digital in terms of dynamic range is a little like comparing apples and oranges.  Film handles tonal variation differently (see Caveats below), and is nonlinear.  Digital sensors are linear.  In fact, in this way film is closer in behavior to your eyes than digital sensors are.  Secondly, film is noticeably better at handling highlight dynamic range (bright end of the scale), whereas digital has advantages on the shadow (dark) side of things.  Your eyes can also see more detail in shadow than in highlights.  Digital cameras mimic your eyes in this way, but as any film enthusiast will tell you, they don’t do quite so well with highlights (they would describe it less kindly).

It is very hot where I am right now, so here's a shot of Oregon's Faery Falls in winter freeze.

It is very hot where I am right now, so here’s a shot of Oregon’s Faery Falls in winter freeze.

All that said, digital camera makers have been working hard on increasing dynamic range, while film is not receiving that much attention.  So you can expect all this to be a moot point in the near future.  Currently, the best digital cameras for dynamic range, the Nikon D800 and other high end DSLRs, and (especially) the new digital video cameras, can supposedly record dynamic ranges of up to 14 stops.

But that’s at low ISOs.  Think about those starscapes I mentioned above, those images of an improbably colorful and bright Milky Way you see soaring over everything from mountains to farm tractors to the Eiffel Tower!  That is not really a demonstration of the camera’s dynamic range but its low-light capabilities.  When the photographer cranks up the ISO to create those images, she is cranking down on the camera’s dynamic range.

That’s enough for now.  This little miniseries on Dynamic Range will continue next week.  Thanks for reading!

The Lower Columbia River flows peacefully seaward at dusk.  Oregon's Mount Hood in the distance.

The Lower Columbia River flows peacefully seaward at dusk. Oregon’s Mount Hood in the distance.

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