Tag Archives: HDR

It’s Not Real

I have been asked so many times if my photographs were “real”. I hope that whatever triggered them to fire that (sometimes insulting) question was because my photos looked good.

Are they real?

No, they are not. The camera always lies. The photographer always lies.

A good photographer will hide the stuff he does not want you to see, while at the same time, emphasize and even exaggerate the stuff he wants you to see. They only show you their side of the story and make (or force) you believe in that story. That’s what every good frame of photograph does. There is nothing more to explain. The rest is up to the viewer whether he agrees or not.

Photography is actually the opposite of reality. Sure you can make good photos in good weather but it’s the worst of weathers that produce the best images. More often than not, the worst situations result in pulitzer shots. How I wish I could say the same for reality.

Some Thoughts on HDR

When I started doing serious photography around mid of 2009, HDR was kind of the latest craze. My reaction when I first saw HDR images was one of amazement. I never expected photographs to be so vibrant and detailed. HDR images looked surreal I just had to try making one myself.

Looking back, I have now understood why I was bewitched by those out-of-this-world photographs. There were several reasons I can think of:

1. I have never seen fine art photographs. Paintings, yes but never photographs. I blame my art subjects because they never discussed photography as an art form.

2. I was used to taking snapshots with film cameras. I did own several point-and-shoot digital cameras but they were there just to record personal experiences.

3. I have never attempted to retouch my photos. I thought that if my photos sucked then maybe I just don’t know how to capture them.

4. I didn’t understand the art of photography. I did not understand light and exposure. I didn’t think about composition.

I thank HDR for making me appreciate fine art photography. Without it, I probably would have continued being just a casual shooter.

Fast forward to the present, I can say that I have been exposed to all sorts of fine art photographs and have learned to appreciate most of them. I now have a bit of understanding on the role of light, even its absence, in creating pleasing photographs. I still struggle with composition and sometimes it is quite frustrating when I come back from a photoshoot with barely any keepers.

So what has this got to do with HDR?

I have realized that the best photographs are the simple ones. The lesser the clutter, the better they are. Most of the time.

So again, what has this got to do with HDR?

A photograph, ideally, must have a single subject. Everything in the frame must contribute to that single message. I once read in a book that before you click the shutter, SIMPLIFY first. You know that a photograph is finished when there is nothing more that you can remove from the frame.

Here lies the problem with a lot of HDR images: they show details all over the frame even in the shadow areas. The argument behind these HDR images is that the photographer wanted to recreate the dynamic range of human vision; there are details everywhere. No blown highlights, no black shadows. (Taken to the extreme, the resulting image becomes flat and lacks contrast. To counter this massive drop in overall contrast, some photographers mindlessly increase local contrast to create details. The result of which is the haloing effect.)

This, I believe, is a result of failing to understand how humans SEE. Humans have very narrow field of focus. If you stretch your arms out and spread your fingers, you could not focus on both your thumb and pinky. Your eyes actually roam around very quickly, gathering details along the way and the brain assembles all the separate data into a cohesive whole. There is no confusion.

Compare this to a frame of photograph where the eye is focused only on a relatively small area. If there are details all throughout the frame, the brain gets confused because the entire view is now crammed into such a small space. By presenting details in both highlights and shadow areas, the brain could no longer concentrate on one subject. This makes the photograph overly complicated and cluttered.

Basic rules of composition, if you believe that there is such a thing, tell you to arrange the elements in a frame in such a way that the main subject becomes the center of attention. Every other element in that frame must not contest the significance of the main subject. The brightest area of the frame catches the eye first so usually this is where you position your subject. By unnecessarily showing details in the shadow areas, you force the viewer to divert his attention away from the subject.

Another example is the basic composition technique of using frames: e.g. a tree in the foreground that frames a house which is the main subject. This “frame” is supposed to force the viewer to concentrate on the house. Improper use of HDR will show details on the tree thus diverting the eye from the house.

HDR is not a bad technique. Sometimes, it is even necessary. It is the improper use of HDR that makes weak photographs. I’m not referring to cartoonish HDRs (they are a completely different level of bad photos) but even “realistic” HDRs can be harmful to your art. Just be careful.

Choosing the Dark Side

Canon vs Nikon. They never end. Lucky Sony, Olympus, Pentax and other underdogs for not having to deal with the stupid arguments. But this post isn’t about brand wars.

Expose to the right (ETTR) is a common advice in digital photography. It simply means, try to make sure that you expose your shot with bias towards the right end of the histogram. Make it as bright as practically possible without blowing out the highlights. If you understand how digital photos are stored, this makes sense. You want to maximize every bit of those 12-14 bits.

There is danger in blindly following this advice since the linear profile of digital camera sensors is not very forgiving. Once you clip past a certain limit, no data is stored in the photograph. This is characterized by blown highlights. Unfortunately, it is a lot easier to blow the highlights than lose the shadows.
There is something I discovered just a few months ago that I would like to share with you: It is better to underexpose than expose to the right. Not just underexpose but severely underexpose especially if the dynamic range of the scene is too wide.
Have a look at this photo because I quite pushed the camera beyond its limits when I took the shot:


Very dark isn’t it? The exposure was ISO 400, f8, 30 seconds after +2.5 stops of exposure compensation from the metered reading. That’s pushing the sensor a bit too much. I could have opened up to f5.6 but my cheap lens is very soft at that aperture. Going ISO 800, on the other hand, will only introduce more noise.
Now have a look at the same photo after post processing:


That’s a world of difference! I just pushed the exposure by +1.35 stops and then pulled some of the shadows with fill light. I have managed to extract details in the shadows while preserving the highlights. There’s more: peep all you want but there is barely a trace of luminance or chroma noise even after brightening the shadows. Amazing!!!

The photo was captured with a Pentax K5. It’s really amazing how modern sensors have improved. I would expect the same performance in the Nikon D7000 and Sony A55 because all of them use the same Sony sensor (surprise?!!!).

This is not the only instance where I managed to salvage a seemingly hopeless exposure. I do a lot of HDR work when the scene is too contrasty and I normally bracket at -2,0,+2. Many times, I was able to scrap the HDR because I was able to extract enough information from the -2 frame. Single exposure shots are still way cleaner than HDR so I always try to pull the shadows if I can.

Experiment with your own camera and see how much you can extract from a severely underexposed image. Make sure you shoot RAW.

So who’s coming with me to the dark side?

Edit:
My new iPad blogging software ruined the original post. Lesson for me: sticking to one buggy software is sometimes better than switching software.

Nikon D700 vs Pentax K5

That’s not a typo. I’m not referring to Nikon’s crop sensor camera the D7000 but it’s professional full frame D700. Yes, I’m comparing a very good, very capable camera from Nikon vs Pentax’s crop sensor K5.

First things first. Both cameras are very good. If you decide to buy either of them, you can be assured of professional image quality output. If your photos are still junk then there’s no one else to blame but yourself.

I bought the D700 because it was on sale at an outrageous 40% off brand new from a legit (not grey) shop. Who could possibly resist that?! And besides, I have already invested in Nikon film cameras so it makes perfect sense to get a digital full frame that can share my existing lenses. Shifting from Canon to Nikon was a necessary evil I had to do but it wasn’t that bad since I haven’t invested in Canon lenses. All I had was the 17-85mm kit lens glued to my 40D. To be honest, I miss that camera. It was very capable, easy to use and infinitely customizable. Which brings us to my major gripes about this Nikon D700:

No memory for custom settings!!! What other modern DSLR camera can’t store your favorite settings aside from Nikon? You expect a camera as expensive as the D700 to be capable of storing user settings in dedicated memory banks. I shoot mostly landscape but I carry only very basic equipment: one camera, one lens and tripod. I never used filters (until recently) except for the default UV to protect my lens from salt spray and dust. If the scene is too contrasty, I bracket and use HDR technique. If you shoot at the proper lighting conditions, you don’t need filters because you could always do that in post. Which means, I expect my camera to do (reasonably) everything I ask it to do. Like bracketing 3 different exposures at 4EV wide, shooting at high speed using the built in timer to avoid camera shake. Unfortunately, the D700 can’t do that!!! To bracket at 4EV wide you need to shoot 5 frames, not 3. If you want high speed shooting, you can’t use the timer. How stupid is that?! And careful if you enabled bracketing mode because to shoot normally you will have to wrestle the darn camera like this: press that small button near the lens mount, turn the thumb wheel twice to cancel the bracket. If you want to bracket again, repeat the same procedure. Now if you are dead serious with HDR, you want at least 8EV wide brackets. That means 9 frames on the D700. As if Nikon RAW files are small. As if your shutter lives forever. Did you just shoot that cat at ISO 1600 in broad daylight? Ooops!!! It would be nice if you could easily reset your camera to your favorite settings to avoid the bloopers, yeah? And please don’t mind the exposure scale because going left is positive and going right is negative (yes, Nikon failed high school algebra). But there is a setting to invert that hidden somewhere deep in the stupid menu. You can read the very thick manual if you are unsure. But careful because that only changes the exposure scale. Everything else will still be in reverse. Seriously, WTF?!

Here comes Pentax K5. Fully weathersealed, built like a tank, in-body stabilization (which means all lenses including manual focus from the 80’s are image stabilized), lighter and way cheaper. And dig this: FIVE, as in five, custom settings memory banks!!! You can couple bracketing with timer. You can bracket 8EV wide with just 5 frames. There’s more: automatic mirror lockup in timer mode! How cool is that! The camera does not get in the way of shooting. It does what I want it to do. It’s the landscape photographer’s dream camera! Enough said. Anything I add here would only make the D700 look like it was crafted by amateurs.

Having said those harsh words against the D700, it still has a special spot in my photography. In controlled environments (e.g. portraiture) it’s still my camera of choice. And the fact that I have invested in quite a few Nikon mount lenses, it makes sense to keep it until it dies.

And that’s why my D700 is gathering dust while my K5 goes wherever I go.

HDR Tutorial Part 1: Introduction

HDR or High Dynamic Range, is probably one of the most hyped aspect of digital photography at present. It is also one of the most abused technique. If you are reading this then you probably already know something about HDR. This tutorial will be broken down into several parts and will attempt to provide techniques of proper HDR photography. If you expect wacky, cartoonish photos in this tutorial then sorry to disappoint you but you will have to look elsewhere. Please visit my Flickr HDR gallery for examples of my work. Some of them are my early HDR attempts so you will find wacky photos in there as well.

Why HDR? There are countless “reasons” as to why someone would want to use this technique. Here’s some of mine:

  1. No camera is good enough to record what our eyes can see. Our eyes are way better than any camera sensor in terms of capturing levels of light intensity. It can record about 40 stops while the best cameras can only do about 11 to 12 stops. So really, to capture a high contrast scene you would need at least 5 shots of different exposures with a bit of overlap.
  2. There are ways to overcome the limitations of #1 and that’s with the help of filters. A GND filter for example will allow you to properly expose the foreground and sky. GND filters though are good only if you have an unobstructed horizon. To be honest, I don’t use any filters except for the standard UV filter that I use to “protect” my cheap lens.
  3. I want to add some “punch” to my photos if the lighting condition is a bit flat.

When should you NOT use HDR? I always consider the following:

  1. If I can capture the entire dynamic range of a scene with a single shot then I won’t even bother with HDR, granting that my main subject is properly exposed. Beaches are easy subjects because the reflectance of sand is almost equal that of the bright sky. As long as the main subject isn’t under a shade then a single exposure might do the trick. I find single exposure shots so much cleaner than those made with HDR. I’m sure others would argue about this.
  2. Portrait shots. If the subject isn’t properly exposed then you have bigger problems. Learn to use flash or reflectors. This is the best site to read about proper lighting techniques: http://www.strobist.blogspot.com/.

So the basic goal of HDR is proper exposure of your subject. The goal may also extend to the proper exposure of the entire scene. The latter is usually what most people aim for. So we define what it means by correct exposure. In simple terms:

  1. The main subject has the correct color rendition. If it is white then it should appear white, if it is dark then it should appear dark. Simple as it seems, this is one of the most overlooked aspect of photography. White clouds or snow that look gray, a red flower that appears washed out and so on. Even with advanced matrix metering systems, correct exposure compensation is essential.
  2. There are no deep shadows or blown up highlights. This is very difficult to achieve in high contrast scenes and this problem will be our main focus in this tutorial.

Let’s talk about tools.

A good tripod is essential especially for landscape shots. Use the camera’s timer or cable to trigger the shutter release to minimze shake. If a tripod is not available make sure that your shutter speed is fast enough. Rule of thumb is 1/f, where f is the focal length. For example, if you are shooting wide at 28mm then shutter speed should be 1/30s or faster. For me, this shutter speed is still tricky for handheld shots even with image stabilized lenses.

A camera with auto exposure bracketing (AEB) would be very nice although not necessary. AEB will automatically take 3 or more shots with variable shutter speeds in succession in a single press of the shutter. I like how my Canon 40D allows me to couple AEB with the timer.

HDR software. My tool of choice is Photomatix. Another excellent tool is EasyHDR. There are others that you can download for free. I will list some of the tools at the end of this tutorial.

Photo editing software. Nothing beats Photoshop but it’s not the only tool. Paintshop Pro is very good. The free open source tool called GIMP is also very capable although it’s still limited to 8-bit colors.

Now we discuss the real stuff, HDR photography.

Just to illustrate how limited the dynamic range of a camera sensor is, go inside a house and take random shots but make sure that the entire frame includes an open window or door. Preview your shot in your camera’s LCD and you will probably notice that most of whatever is outside that window is just pure white (photo #1). If the image does show what’s outside the window, almost anything inside the house will probably be hidden in deep shadows (photo #2).  The issue is that the scene has high contrast. Outside the house is very bright compared to what’s inside. No known camera sensor could handle this at all. Normally, we would be throwing away both shots. This is the problem that HDR attempts to address.

With HDR, we could still salvage that scene by using both the same “useless” shots shown above. In HDR photography, multiple shots of different exposures are merged into one.

I would like to discuss this tutorial as scientifically as possible which means we need to understand how to read the histogram of our shots. A histogram is a graph of (light) intensity distribution as recorded in the image. Allow me to explain: the histogram has left and right borders. To the extreme left is pure black or dark or deep shadows. To the extreme right is pure white or blown up highlights. You guessed it, the middle is grey. This means a properly exposed shot of a white sheet of paper would show points to the extreme right of the graph and nothing on the left. A properly exposed shot of a black cloth would be the opposite. Photo #1, above, would therefore have a histogram that is biased to the right while photo #2 will have lots of points to the extreme left. Our goal is to make sure that NONE of the image “points” or pixels lie in either extreme left or right. Everything has to be within the middle of our graph. A scene that has good exposure would be represented by a histogram that approximates a bell-like curve. Therefore, we need to always check our histogram. Make sure that you understand this part as it is very crucial to proper HDR technique.

Now let’s concentrate on how to take the shots that we need for HDR. Set your camera to aperture priority mode or full manual mode. Select your desired aperture value. For landscape shots, this is usually set to f8, f11, or f16. Then, take multiple shots of different exposures by varying the shutter speed. The first shot is what we call our EV0. This is the normal shot that the camera meter sets the shutter speed into if you are in aperture priority mode. In manual mode, this is the shutter speed that best exposes the scene. Let’s say our EV0 is f11 at 1/125. Look at the histogram display of this image in your camera. The graph will probably have lots of points to the extreme right and/or extreme left. If it doesn’t, then you are lucky because life would be so much easier. For those unlucky souls, we would need to expose for the shadows and highlights. In aperture priority mode use exposure compensation to adjust the shutter speed. Depending on the scene, you would normally compensate at -1 and +1 or -2 and +2. The compensated shots are your EV-1, EV+1, or EV-2, EV+2, respectively. In full manual mode, you will have to set the shutter speed by halving or doubling the values. So we have, EV0 at 1/125, EV-1 at 1/250, EV-2 at 1/500, EV+1 at 1/60 and EV+2 at 1/30. By the way, always shoot with RAW image quality otherwise you will also have to manually set your white balance. RAW allows you to change the white balance later which you can not do easily with JPEG shots.

What we have done basically was to make sure that any deep shadows in EV0 are correctly exposed by the EV+ shots and any blown up highlights are correctly exposed by the EV- shots. In the photos shown above, photo #1 is EV+ and photo #2 is EV-.

The procedure above sounds complicated to some people. That is why if you are serious about HDR photography, you will need to invest in a camera that does AEB. With AEB you just set your aperture then click and hold your shutter once and the camera automatically captures EV0, EV- and EV+ for you. Easy.

Now imagine if we can choose specific parts of the EV- and EV+ shots so that we don’t have deep shadows and no blown up highlights in our final image. This process is called tone mapping. You can actually do this manually using layering techniques in Photoshop but it is very tedious. A better way is to use an HDR software which will automatically merge all shots and perform advanced tone mapping for us. This is what I will cover in part 2 of this tutorial. We will look into merging our photos using Photomatix. Stay tuned and happy shooting!