Under-exposing – when, why and how

Table of Contents

I often under-expose my images, and you may have found yourself wondering why, or what you should do about those crazy highlights in your image that are all blown out, or maybe you’re thinking that getting a “deep dark forest” image begins with a deep dark photo (hint: it doesn’t).


One important thing to keep in mind as you work through this lesson and the subsequent action task, is that:

We don’t WANT to underexpose… but we may have to in order to keep detail in the highlights… so we ONLY do it as much as is necessary.

I see many students going a bit “overboard” when they start underexposing more often (I did too!!) so just keep the above in your head, check the histogram, and only underexpose WHEN, IF and AS MUCH as it is necessary

Learning Journey

This is a fairly advanced concept and lesson, probably best if you’re in stage 3 or later! Feel free to come back to this one, and we will be exploring the concept in future lessons!

What is Under-Exposing an Image?

Under-exposing is the process of purposefully taking your photo at a particular exposure which renders the subject darker than it “should” be. Eg., the subject (and probably the rest of the scene!) is under-exposed. 

Below are some examples of before & after images – first of some relatively “normally” exposed images – the dog’s face is reasonably light, almost “perfectly” exposed…. then progressively getting darker and darker. 

Can you guess why some of these images are much more under-exposed than others? Why do you think even the lighter ones are still slightly dark? What is the purpose to making them darker? (hint: it isn’t because we love editing so much)

Why under-expose?

It’s pretty simple – I (generally) expose for the highlights in an image. Which is to say, the brightest parts of an image. 
The reason for this? If we “blow out” or clip the highlights, and lose the data in them, they turn into white blobs with no detail. Can you see the highlights in each of the images above? Each image with bokeh has retained the shape and colour of that bokeh. 

Let’s have a look at some blown out, vs., non-blown out bokeh. 

Blown Out Highlights

In the image below,  I more or less exposed for Journey, though he’s still slightly dark! 

The image on the right is zoomed in, with the exposure almost totally lowered. 

Can you see how the bokeh looks? No matter how much I would edit this photo, there is no data in these highlights. I have some tricks to “fix” them, but it’s never perfect and is always a bit of a process! 

Under-exposed for Highlights

The image below was taken at the same place and time, except that I under-exposed – A LOT!! As seen by the photo on the left. The photo on the right is completely edited, with highlights lowered and so on. But I never had to “fix” any white blobs that had lost data. You can see how soft the bokeh is.

Unedited/Straight out of Camera

Edited. Note the Bokeh.

There’s more to this than just bokeh! You might be thinking, ok, but I never shoot backlight, so it doesn’t apply to me. Well… it does. As you can see in the examples above, any time I had any kind of highlight in my image, I was paying attention to it. Maybe that’s the wide open sky, and you need to under-expose to capture the dramatic clouds, or to preserve the colours of a rainbow.


Or, maybe you have a dog with a white stripe, white chest, white face. These white areas are highlights too!

As our student Jamie recently discovered when photographing her brown dog with a large white stripe on his face, having a bit of stronger light on that stripe very quickly blows it out. She came up with the catch-phrase: “Just right is too bright”! Meaning that probably, because of his white stripe, if her dog looks “just right” in terms of exposure, he’s probably sliiiiiiightly too bright and heading into dangerous territory!

This image of Loki I intentionally over-exposed for this lesson, blowing out the highlights on his chest and snout.

If I tried to edit that now, and bring back the fur detail, there would be none there. He’s just a white blob. It is VERY easy to blow out the highlights on the brighter side of a white snout, so be aware, pay attention to the highlights!

This is ESPECIALLY important when you’re shooting in any kind of patchy sun. This is where I’ve seen people run into the most trouble. They have the exposure set for the majority of the scene, not taking into account the one tiny patch of sun hitting the dog’s snout or shoulder, or top of their head and suddenly they’re left with an area of their dog that is intensely white, with no detail! 

How to Under-expose Your Images

It’s not as easy as just changing some exposure settings and deciding the image is probably dark enough! There are 5 important factors to consider when it comes to whether you underexpose, and how much:

  1. How dark does it need to be to save the highlights?
    1. Eg., if I’m shooting with the sun in the frame, I CANNOT underexpose for the sun. The whole photo could be black and the sun will probably still be the sun.
    2. If the sun is strongly filtered through trees, and I’m in a bright, open space, I will not need to underexpose so much.  You can learn more about this in the Backlight lesson.
  2. How much darkness can your camera handle? (in regards to noise). What colour/shade is your subject? How good is it at retaining detail in shadows?
  3. What ISO are you already using?
  4. How much skill/effort/energy do you want to put in to fixing/editing an underexposed image?

On the last point. If you have NO IDEA how to edit an underexposed image – that’s ok! But it may mean you just don’t under expose. I know plenty of pet photographers who don’t. There’s no point underexposing if you can’t then make the photo useable.


How dark does it need to be to save the highlights?

Just dark enough that they aren’t blowing out..  

How can I tell if my highlights are blown out while I’m shooting?

Most cameras have 3 different options. 

1. Zebra stripes. These show up as stripey lines over clipped areas when you preview the image. I don’t use them.

2. “Highlight warning” – when looking at images you’ve already taken, an area of black will flash on and off to warn you that those areas have been clipped and you might want to change your settings going forward. Also not my absolute favourite method as I find it tends to flash a warning even if the highlights are actually alright, just that they’re highlights and they’re bright?

3. Histogram. You can have the histogram on screen while you shoot (with some cameras) so that as you adjust your settings you can see if there’s any spikes toward the right hand side (Highlights end) and fix it accordingly. This is what I use! It’s not fool-proof because a small area of blown-out highlights (eg., the snout) won’t necessarily cause a large spike. So you need to keep an eye on any data creeping up toward the right hand side. There’s a whole Histogram lesson you can check out too.

The images below show the histogram from Lightroom, but it’s the same as the one in-camera (but with the colour elements too. Just ignore those). Click on the images to enlarge.


Two other things to note (and this is covered more in the backlight lessons) are that: the amount of ambient light on the dog’s face will directly affect how much you need to underexpose. Think of it as a seesaw that you need to keep in balance. Strong light from behind needs LOTS of ambient sky light on the dog’s face. Otherwise, to combat this, you have to make the dog practically black, due to a lot of light behind, and no light on the dog. Softer, more filtered light from behind NEEDS less ambient light on the dog, but you will definitely benefit from still having a good amount on it. Again – this is all covered in the Light topic! 

Also… if you have big, wide gaps between the trees in the background, that go to nothing but pure white sky… these areas will likely end up as pure white blobs. There’s nothing to create texture when there’s no branches, leaves, etc to create texture.

How much darkness can my camera handle?

Honestly, this depends on the camera and its dynamic range. 

Some cameras can under-expose a lot and retain detail. Others get very grainy as soon as you begin to raise shadows or to try and lighten the dark areas (which can be dependent on ISO as well of course!). The only way to answer this question is to get out there and experiment and learn your camera. 

Here’s what I learnt from hours and hours with my camera:

I can under-expose quite comfortably until about ISO 800. The photos in the first part of this lesson are a good example of what my “normal” amount of under-exposing would be. There’s still clear detail in the fur even before editing (for the most part). 

If I need to under-expose to the extreme (like the twilight snow photos), and REALLY raise the shadows, then even ISO 200 will result in a lot of grain/noise. So clearly that level of bright/dark, and under-exposing Loki in particular, was really right at the very edge of what my camera could handle. 

But my camera has an excellent dynamic range! If you have a different camera, you may only be able to slightly underexpose at ISO320 before you start to run into grain issues when lightening the image in editing. 

There is a lot more information about this in the ISO lesson

Get your camera, head outside. Take TONS of photos. Purposefully under-expose, medium-expose, and over-expose some. See what gives you the best effects. Find out how dark you can make a photo before you can’t brighten it any more. What is your camera’s limit? What happens if you underexpose at ISO 200 vs. ISO 1000? What happens if you underexpose only a little bit at ISO 1000 but quite a lot at ISO 200?

The Dynamic Range of Your Camera

It is worth noting that you CAN “blow out” the blacks on your image. This is when the dark/black/shadows areas become so dark that the camera was just unable to obtain any information for what was supposed to be in there. Imagine being put in a windowless room, and being told to describe what’s on the walls. If there’s not enough light, you can’t do it. If, in that windowless room, there is a very small single fairy-light on one wall, lighting up a painting – you would be able to describe that, but not any of the paintings on any of the other walls – the light just wouldn’t go that far for you to be able to physically see what’s there.

Depending on your camera and its sensor, it may be able to handle a lot of very dark areas before it “clips the blacks”, or it might not. Again, the only way to find out is to read the manual, and to experiment!

Here is an image I took recently. Although I would never brighten it up to such an extreme level, it does show how some lost detail in the blacks might look. See the circled areas are staying stubbornly black? If I continue to lighten them up, they’ll just become more and more noisy.

You may have experienced this in your own photos – have you ever tried to lighten something up and it suddenly became sort of… hazy? Maybe flat and grey with no details in the fur or shape of the face? Yep, there’s no more data there. 

Just for fun, here are two more images. I took this one with the intention of it being a silhouette but obviously hadn’t noticed how much the sky had darkened since I last changed my settings so even for a silhouette it’s dark!

I increased the exposure all the way, and raised shadows a bit too. It’s noisy as hell and of course there’s no fur detail etc, but it’s amazing to see how much data the camera HAS managed to retain.

This was f/4.0 and ISO 800, by the way. 

Creating a Dark & Moody Mood

Underexposing your images is NOT the best way to achieve this (in fact, if you’re having to under-expose, you probably won’t be achieving the dark forest/dark & moody photo anyway, as it means there is a lot of light/highlights somewhere, which goes against the dark & moody atmosphere). If you want to go dark & moody, it’s much better to expose as correctly as possible (depending on the highlights) and then DARKEN in editing. You won’t lose image quality from darkening. You will lose image quality from lightening. 

Editing Underexposed Images

This is certainly more of a challenge, but it’s totally doable. Mostly, you need to gradually build up the lightening effects on the face and body, so it still looks natural. Try raising whites, maybe shadows, maybe exposure. Selective edits are going to be more successful than global adjustments where you raise the exposure/whites of the entire image, as this will blow out your highlights in editing.

There are plenty of under-exposed images within the Learning Community. I may upload a tutorial here dealing with backlight/dark dogs too.