Category Archives: Technique

Expose To The Right (ETTR) Is Obsolete

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(Lake Moogerah — underexposed by two stops to save the highlights and exposure adjusted in Lightroom)

Expose to the right (ETTR) is a technique that became popular when digital photography started to pick up. I will not discuss the details of this technique but I’ll try to cover the basics. Before you continue make sure that you understand the concept of exposure. If you are a bit rusty on this topic then consider reading my previous article on understanding exposure.

The goal of ETTR is to maximise your sensor’s capacity to capture data. We know that every stop of exposure is equivalent to doubling the amount of captured light. So imagine if you have a glass that is half full of water, increasing the amount of water by a “stop” would mean filling the glass up to the brim. If we translate this into photography, say, using the zone system, this means that zone IX is practically half of the entire capacity of your sensel, zone VIII is a quarter, zone VII is an 1/8th and so on. That’s basically how camera sensors work. You would want to maximise the capacity of your sensels by forcing them to fill up with photons. It means that you would always want to have a zone IX otherwise you are wasting half of your data.

So why am I saying that this technique is obsolete? After all, digital capture is still digital capture. Sensels still respond linearly to incoming photons. What has changed?

Digital photography has advanced so much in the past five to eight years. In the early days, shooting beyond ISO 400 was a nightmare. I remember shooting with my Canon G10 and I would never dare shoot at ISO 400 unless I really had to. All my images at ISO 400 were just too noisy and were almost unusable. At present, point and shoot cameras can easily shoot at ISO 6400 with very acceptable results.

What does this mean? Recall that ISO has got nothing to do with exposure. Bumping up the ISO does not increase the amount of captured photons. In fact, bumping up the ISO forces your camera to underexpose. For example, if your camera has a base ISO of 100 and you are shooting in broad daylight, your exposure would go something like ISO 100, f/16, 1/125s (basic sunny 16 rule). If you increase your ISO to 200 then the exposure would go f/16 at 1/250s. At ISO 400 you have f/16 at 1/500s. Every time you bump your ISO you are forcing underexposure. That means your sensels would receive half the number of photons for every stop of increment in ISO. What I’m trying to say is that the fact that you can shoot at ISO 6400 is testament to the amazing ability of modern sensors to handle extreme underexposure. If any of these do not make any sense then please go back to that link I provided in the first paragraph. Read and understand the basic concepts of photographic exposure.

Again, every time you increase your ISO beyond the base ISO, you are forcing your camera to underexpose. Bumping up the ISO is the exact opposite of ETTR. It follows that ETTR only ever makes sense when shooting at base ISO. Performing ETTR at higher ISOs is stupid.

Let me explain that previous paragraph with examples and (stupid) counterexamples. Let’s consider shooting during an overcast day. A typical exposure at base ISO of 100 might go f/5.6 at 1/125s. Performing a stop of ETTR would mean shooting at f/5.6 at 1/60s or you can choose to maintain your shutter speed at 1/125s but shoot at f/4 instead. Look what happens when you bump the ISO to 200: the exposure would now read f/5.6 at 1/250s. If you perform a stop of ETTR at ISO 200 you get f/5.6 at 1/125s which is basically the original aperture and shutter speed combo at ISO 100. Your image might be brighter because of the increase in ISO but the truth is that you have NOT performed ETTR at all! It’s the same exposure of f/5.6 at 1/125s. If you want real ETTR at ISO 200 then you would have to shoot at f/5.6 at 1/60s (same as ISO 100 ETTR) but because of your ISO bump your final image loses dynamic range in the highlights! ETTR plus ISO bump is like taking a step forward and two steps backward. It’s stupid.

Again, with cameras capable of shooting natively at ISO 6400 and some of them even going as high as ISO 746123550123656128561249571243865 (looking at you Sony A7S) we know that modern sensors are now very very good at handling FORCED underexposure. But then the other side of the story is that modern sensors are still VERY BAD at handling OVERexposure. Once you clip your highlights there is no way you can recover that data. FACT!

Losing data is not the only problem of overexposure. When you overexpose by force, it is very difficult to judge the tones and colours just by looking at your LCD. When you ETTR, your blue skies will look bright grey, you lose the sunset colours, your shadows become dull. Of course you might be able to “fix it later in the computer” but you have practically deprived yourself the capability to properly judge how your image might look like and make decisions (i.e. adjust exposure) while you still can.

Again, let’s consider the facts:

  1. Cameras can shoot natively at high ISOs which means they can handle extreme underexposure.
  2. Cameras are very bad at handling overexposure.

Is ETTR really worth it? Shouldn’t you give your camera the best fighting chance by utilising its strengths instead of gambling with its weaknesses?

The ETTR ship has sailed. Move on.

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Easiest Way to Get a Good Shot

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Here is a very simple tip if you want to capture nice photos: find ONE subject and isolate it from everything else. That’s it.

Why do you think that shallow depth-of-field portrait shots look nice? It’s not just because of the creamy/blurry background but because shallow DoF isolates the subject from any background distraction. If the background is simple and non-distracting you do not need shallow DoF to get a good portrait shot. Studio shots, where the photographer has full control of the environment, are normally shot at f/5.6 or f/8 or even f/16 because the subject is already isolated.

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The main reason why n00bish shots look crap is because beginners tend to cram everything into the frame. This one goes especially to the n00b landscape photographers who would sell their kidneys just to get the widest lens possible. They want it ultra-mega-wide so they could include EVERYTHING in the frame. That’s the quickest way to get a crappy shot. STOP.

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Find a subject that you like and have a really good look at it then ask yourself: what is it with this subject that I really like? Is it the entire subject or just some parts of it? Is it because the subject is in a particular environment? If you can’t answer those simple questions then your shot will look crap.

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Once you find your subject, concentrate on it. Isolate it from everything. You may have to zoom in or get closer to your target. Do everything you can to single out the subject then take the shot. Now check your LCD and assess if you like your framing. If you think that it’s too empty or too simple then find something that will complement the subject. Zoom out or get into a different angle. Just make sure, when you do want to include more elements in the frame, that they will enhance the subject and NOT conflict with it.

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So again, the quickest way to get a nice shot is to pick ONE subject and make sure that nothing else is in the frame. Go out and try it. You’ll thank me.

Shooting the Moon

How could something so simple be so difficult to shoot? If anything, the photos I will be posting here are examples of my failure to get a moon shot that I’m happy with. Let this be a lesson of how NOT to shoot the moon LOL!

I mean if all you ever want to do is shoot the moon directly then it’s easy: Get your longest lens then use the sunny f/16 rule and overexpose by a stop. But that’s boring. Every photo of the moon that was captured in this manner looks exactly the same so what’s the point other than showing off your long lens? Let’s consider then something more challenging and exciting…

How about adding an interesting foreground? If this is what you want then timing is everything. You would want to shoot when the moon is rising while it’s not yet completely dark. Why is this? Remember that the moon is directly lit by the sun so the sunny f/16 rule applies. Depending on atmospheric conditions, you’d probably want to overexpose it by a stop or two so a good approximation is ISO 100, f/11, 1/125s. With these settings, your foreground will be severely underexposed when the sun is well below the horizon. If you expose for the foreground, you will overexpose the moon. This is what happens:

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One way of approaching this problem is by making two separate shots: one to expose for the foreground and another to expose for the moon. Careful though because you don’t want the sky to look too different. Since you’re doing composites anyway, you might as well zoom in at the moon. I think I shot the foreground too wide in this one so the moon looks unusually large. Note that the moon is also a bit overexposed because the correct exposure would have resulted in a darker sky and caused halos when superimposed over the foreground shot.

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Another thing you would have to consider is that when you include a foreground it will need to be very far otherwise it would fall outside the depth of field and look blurry. You can’t just use a small aperture because you will end up in a longer exposure and result in a blurry moon due to subject movement. The moon moves quite fast especially when using long lenses. A far foreground also means that it will have to be tall enough to cover your framing angle. So here’s what happens when your foreground isn’t far and tall enough:

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Note the grainy shots. This is what happens when it’s too dark. I had to push the ISO to freeze the blood moon and to expose the foreground properly.

Lastly, here’s my most recent attempt to shoot the August 10 supermoon:

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I made a stupid rookie mistake. I didn’t realise that my camera was set to auto ISO until much later. That’s ISO 800 with my Olympus E-M5. I do have low ISO shots but they were shot much later when it was already too dark and the magenta tint in the sky was already gone. They weren’t worth processing at all. It would have been the ideal time for a shoot because moonrise was just ten minutes after sunset. There was enough ambient light for my foreground rocks to balance the luminance of the moon. It was so frustrating.

Shooting the moon is my nemesis. If you guys have better tips then please share them below.

Pros and Wonky Exposures

Back when I was just starting to get serious with photography, I always checked the EXIF data of the photos that I found to be interesting. For me, the EXIF data was a learning tool. I thought that knowing what focal length and exposure to use to achieve a particular shot would give me a reference point in case I wanted to create a similar image later on.
 
 Fast forward a few years later, I realized that EXIF data is quite useless. I have learned that the images that I tend to appreciate have very little resemblance to the original shot that was captured on camera. Most photos that are above average are usually heavily post-processed. I do this to my own images as well. It is not uncommon for me to intentionally underexpose the shot in order to save the highlights and then push the shadows later in post. If a beginner was to follow my EXIF data, it would give him the wrong impression of the shot. Unless the viewer was at the scene of the shot, an EXIF data does not really tell how bright the ambient light was. You will have to rely on other external data such as the time it was taken, the location and the weather to make sense of it. It would be even worse if the final image was a composite of multiple bracketed exposures because the EXIF data would be totally misleading.
 
 I can’t help but notice that some photographers will include their exposure settings when describing their shots. Unless the images are totally unprocessed, I can’t find any relevance at all. In fact, there are times when I even question whether the photographer actually knew what he was doing. Consider this shot for example (taken from Australian Photography magazine)
 
 
 
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The exposure reads 1/320s, f/6.3, ISO 800, +3.3EV. If this was shot in aperture priority mode, why f/6.3? Why not something more exact like f/5.6 or f/8? If it was shot in shutter priority mode, why 1/320s? That is not even “flash friendly” (1/250s). The most confusing part is the +3.3EV exposure compensation. If you have to compensate this much then you might as well shoot in full manual mode. I’m not questioning the result but the exposure info is hardly useful. In fact, it is confusing even to an experienced photographer.
 
 This is not an isolated case. The winning photojournalism photos are littered with the same wonky exposures. One of them read 24mm, f/1.4, 1/8000, ISO 50!!! You can see that the photographer forced the shallow depth of field cliche of f/1.4 because it pushed the camera to its maximum shutter speed and the sensitivity was intentionally set to the wonky fake low ISO. Nevertheless, the shot was a winner. And this is where the problem lies. A beginner would think that this kind of circus act is proper photography. It’s not.
 
 Let this be a warning. Unless you are shown a completely unedited shot, do not take the EXIF data as gospel. Even in “true to life” photojournalistic shots, EXIF data should not be swallowed just like that. Think for yourself.

Understanding Exposure

This is a continuation of my previous post on where I used the analogy of a rain gauge (Rain Can Teach Us Photography) to understand photographic exposure. Here we dig deeper into understanding what photographic exposure really means in terms of real photography. 

You might have heard of the concept of exposure triangle. This concept explains the interplay between three independent aspects of photographic exposure namely:

1. f-stop

2. shutter speed

3. ISO sensitivity

Item #1 is more often incorrectly referred to as aperture. Although f-stop involves aperture, saying that f-stop is equivalent to aperture is photographically wrong because aperture alone totally ignores the effect of focal length in the intensity or amount of light that hits the sensor. I have covered this in detail in this post: Understanding Your Lens (Part 3). Please read that post if you have difficulty understanding this concept.

The main reason that I am discussing this supposedly understood-by-all-photographers concept is because it’s actually misunderstood by a lot of photographers – myself included until after reading and conducting experiments. Before I start, I would like to acknowledge a friend, Dan Bridges, for introducing and helping me understand this concept. It is not really a difficult concept to comprehend but it will surely change the way you think because we are accustomed to thinking in terms of the exposure triangle.

Let me start by saying that the exposure triangle is not entirely correct. Yes, you read that right. In fact, when you talk about exposure it’s really just the first two items: f-stop and shutter speed. ISO is not really a part of exposure and you will soon understand why … hopefully.

Begin by understanding that the amount of light in the scene that you are trying to capture is fairly constant throughout the entire exposure. Unless you are doing very long exposures in a disco bar or covering a concert gig, the ambient light is practically unchanging. Therefore whatever light that comes into the sensor chamber is basically controlled by your chosen f-stop and shutter speed.

Let me repeat that: the amount of light hitting the sensor is only affected by f-stop and shutter speed.

So why is ISO sensitivity not part of the equation? Because for a particular camera, ISO sensitivity is constant. You do NOT have any control of it. Surprised?

The immediate reaction is, “of course I can control my ISO”. Yes, cameras let you change the ISO but you are not really changing the ISO. It’s not real. You are lead into thinking that you are changing the ISO when in fact you are not. What you are changing is not the ISO sensitivity of your sensor but the brightness of the image. What you are changing is technically the gain.

The ISO sensitivity of any given camera is FIXED at manufacturing time. This is called the native or base ISO. It can not be modified at all. It is very important then that you know the base ISO of your camera. Read your camera’s manual. The Nikon D700 for example has a base ISO of 200 while the D800 has a base ISO of 100. We say that the D700’s sensor is more sensitive than the D800’s. If you think of sensors as water containers, differences in base ISO is like differences in the height of the containers. Same opening size but different heights. A sensor with higher base ISO is like a shallower container. It means that an ISO 200 container will fill up quicker than an ISO 100 container. Here’s an illustration:

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Allow me explain further. If you pour water at the same rate into two containers where the only thing different between the containers is their height, they will obviously have the same water level after any given time. Photographically speaking, same water level means same light level meaning same exposure. However, if you continue pouring water at the same rate, there will come a time when the shallower container will overflow and then water will start spilling for that container. As we have said, a higher ISO is like a shallower container. The sensor with higher base ISO will overexpose quicker compared to a sensor with lower base ISO. Water (light) will spill more quickly for the shallower container (higher base ISO). This means that if for a given ambient light, f5.6 at 1/125s is just enough to fill up an ISO 100 sensor to its brim, the same f5.6 at 1/125s will overexpose the ISO 200 sensor causing light to spill somewhere else (blown highlights).

As you can see, exposure is really NOT about the ISO but the amount of light that gets into the sensor. The base ISO is more of a warning label telling you not to overexpose your sensor or else light will start to spill. If a water container says it has a 100ml capacity, you would not want to pour 200ml of water into it. Makes sense?

Recall that base ISO is fixed and it can NOT be modified. It follows that the only way to control exposure is by f-stop (container opening) and shutter speed (total time that you are pouring water into the container).

Now let’s try to understand brightness. This is different from exposure. The definition of brightness is as camera-specific as that of base ISO. For the sake of simplicity, let’s say that an empty sensor produces a pure black image and a completely filled up sensor produces a pure white image. Since different sensors with different base ISOs fill up at different rates, it follows that they have different definitions of what is black or what is white.

Now here is an interesting outcome: Supposing that f5.6 at 1s is just enough to fill an ISO 200 sensor. It means that for that sensor, f5.6 at 1s produces a pure white image. That same f5.6 at 1s though is not enough to completely fill up an ISO 100 sensor. Therefore the same exposure will produce a slightly darker image for the ISO 100 sensor simply because the sensor is not completely full. Note that they have exactly the same amount of gathered light but they are producing totally different images. To produce the same pure white image, the ISO 100 sensor will have to be exposed longer at 2s for the same f-stop of f5.6.

Here’s another interesting fact: You can actually make the ISO 100 sensor in the example above produce a pure white image at the same f5.6 at 1s exposure. How? By artificially filling up the sensor until it’s full by adding “something”. If light in a sensor is like water in a container, you can make the water reach the top by boiling it. The amount of water will be the same but the act of boiling it has made it fill the container to its brim (and possibly spilling some of it). This “act of boiling water” is what happens when you increase the ISO in camera.

Increasing the ISO in camera does NOT add light to the sensor at all. It does not increase the exposure. It only artificially fills up the sensor with something. It boosts the signal. Unfortunately boosting the signal boosts everything including noise. The problem with increasing the ISO is not the act of boosting the signal itself. The main problem is that sensors have inherent noise in them already – signal or no signal. In darker areas where there is no light (signal), noise is still present. That is why if you boost the darker areas of an image, what you are boosting is just noise because there is no signal. Noise is more pronounced in darker areas of an image at high ISOs. This is why you do not test the high ISO performance of your camera in good light. That’s cheating. You should test high ISO in low light.

And now we finally arrive at an interesting consequence. Supposing that you are shooting in low light and you have chosen ISO 1600 so that you can hand hold your camera at a shutter speed of 1/125s at f5.6. Since exposure is only affected by f-stop and shutter speed, you can actually shoot at your base ISO, say, ISO 200 at the same 1/125s at f5.6 without affecting the final image. Of course when you look behind your camera’s LCD, the image will be very dark and you won’t probably see anything. However, when you get to your computer, you can use the exposure slider in Lightroom or Photoshop to boost the signal and arrive at the same image as the camera-boosted ISO 1600 image. The reason this is possible is because the exposure is the same. It’s still f5.6 at 1/125s. You either choose to boost the signal in camera by increasing the ISO or shoot at base ISO and boost the signal later in the computer. The advantage of doing this boosting in the computer is that modern software are smart enough not to boost highlights that are near clipping point. Your camera is not that smart and it will boost everything thus causing blown out highlights.

Disclaimer: that last paragraph is not always true. Some sensors behave differently. Sensors are actually more complicated than just a simple container so experiment with your camera.

This discussion won’t be complete without covering fake low ISOs that are in every camera. For example, the Nikon D700 has a base ISO of 200 but it also has Lo 1 which is equivalent to ISO 100. This lower fake ISO allows you to shoot at longer exposures. Since we know that the sensor ISO is fixed, fake low ISOs won’t actually gain you anything. The longer exposures will only cause areas of highlights to blow up. This is no different to applying the same ISO 100 exposure, say, f5.6 at 1/125s to an ISO 200 sensor. The ISO 200 sensor will be overexposed by a stop. So the same thing happens when you use a lower fake ISO and increase the exposure. Your sensor will be effectively overexposed.

To summarize everything:

1. Exposure is only affected by f-stop and shutter speed.

2. A camera’s base ISO is more of a warning label saying do not exceed your exposure beyond this point. It is a fixed value.

3. Increasing the ISO in camera only boosts the brightness of the resulting image. It does not increase the sensitivity of your sensor. With some cameras, you are better off boosting the image later using a photo editing program.

4. Fake low ISOs will do you no good. If you need a longer exposure then use a longer exposure using your base ISO. The consequences will be the same: blown highlights.

The Shallow Depth of Field Challenge

A common question thrown around by new photographers is whether they can get that professional-looking shots of people where the background is blurred using only their small cameras. Last night, I challenged myself to produce this shallow depth of field effect using only my m43 camera and kit lens. This challenge was brought about by proponents of full frame cameras who claim that the smallish sensors of m43 cameras are not good enough when it comes to achieving this creamy background blur.

And so I took some photos indoors using a toy as my subject. Is the m43 up for the challenge? Let’s find out:

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I think it’s more than good enough 🙂

Update: The “Impressionist” Challenge

Not really sure what that means but from the sample shots that have been provided to me it looks like make sure that “almost nothing is in focus” kind of shot.

So here it is completely unedited straight from the camera with a kit lens:

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Not sure if my shot makes sense here but I’m getting the “impression” that this is what impressionist means. 🙂

No,  I won’t even post that in my gallery. It’s just a sample of what can be done by a small camera and a kit lens.

Blood Moon 2014-04-15

I took my chance yesterday to capture the lunar eclipse. I went to my trusty spot at Wellington Point…along with a hundred other photographers who were already stationed there 😦
 
 I arrived late for the party and had problems finding a good vantage point. The location was packed. The moon did not show up until much later due to some low-lying clouds so I guess I was still lucky in some way.
 
 Here are two of what I think were my best attempts:
 
 

 Getting both the foreground and the moon in focus was very tricky. I didn’t want to shoot just the moon because that is boring and besides, the longest lens I have is an el cheapo Tamron 70-300 that I bought for less than $200 brand new.
 
 There will be a next time.