Why I Purposely Underexpose All My Raw Images

Why I Purposely Underexpose All My Raw Images

By now it’s common knowledge that when shooting film, it’s important to not underexpose to hold on to shadows, and for digital it’s key to save the highlights. I’m going to advocate, however, that with modern digital sensors, it’s prudent to shoot underexposed all the time.

You’ll hear many people argue that there are certain situations where underexposing has its benefits, but not all the time. While it may sound counter-intuitive to the folks arguing to “get it right in the camera” all the time, there’s a method to my madness.

The first major reason to underexpose is to get a faster shutter speed. Sports photographers know that if they’re in a tough environment (for instance, a night college soccer game) then underexposing will give them the precious extra stop or two of shutter speed. The difference between 1/250 and 1/500 could mean the difference between getting a blurry mess or a sharp shot. The penalty comes on the back end, where you have to process that photo out so that it’s properly exposed, but with modern software, batch processing a large amount of files to the same exposure isn’t challenging.

But beyond the faster shutter speeds that are possible, there’s the practical benefit of protecting the highlights. Even dialing in a third of a stop or two thirds can give you the leeway to prevent a sky from blowing out, or a white shirt from blending into a white background.

I first started doing this mostly by accident more than a decade ago, when screens on digital cameras were so poor that I thought I was overexposing all of the time when I set the meter to 0. Instead, I found that things looked just fine on the computer, and I was just being fooled by chimping on the camera. But I still gained that exposure latitude, and the practice just stuck.

The original file from above in its underexposed state, shot this way to get a faster shutter speed of 1/500. It was easy to bring it back to proper exposure in Photoshop.

Of course this only applies for raw files. If you’re shooting JPG, you don’t have the editing headroom. Don’t do it!

What do you think? Is underexposing all of the time crazy? Do you do it too? Leave your thoughts in the comments below.

Wasim Ahmad's picture

Wasim Ahmad is an assistant teaching professor teaching journalism at Quinnipiac University. He's worked at newspapers in Minnesota, Florida and upstate New York, and has previously taught multimedia journalism at Stony Brook University and Syracuse University. He's also worked as a technical specialist at Canon USA for Still/Cinema EOS cameras.

Log in or register to post comments
92 Comments

I do same at times, especially when shooting with flash so as to compensate. Getting it too low risk messing up the picture as usual

I too, do this all the time. My main reason is to preserve highlights when using flash, which is the majority of the time.

My wheel is on EV -0.7 all the time.

same here. i'm usually on a tripod shooting landscapes but i generally expose -2/3 to -1 EV in daylight. i'm going to post process all of my images anyways, so bumping up the exposure a stop in post is nothing and worth protecting the highlights. digital *generally* preserves shadows better than highlights at base ISO, so the benefits of the headroom outweighs any potential drawbacks.

It all depends on end use. Are they going to be printed large? I personally wouldn't but I understand what you are doing.
There are times to do it and times not. Wouldn't you want to up the ISO one stop as well? You'll have noise to fix both way.
Processing should never be an issue and NEVER WAS. We did that with film, digital is the same way. Processing shy is wrong in my opinion. There is capture and processing and I believe that people who avoid the processing part are not getting the full understanding of what photography is.
Getting it right in camera has no meaning. Getting it right in camera with the intention ahead of processing for a specific need has value. And that is what you do when you decide ahead on how you will process the images. We used to pull and push chromes with the same intention and alter very slightly the first bath for the same reason. I've seen it done on 8x10 film. NEVER listen to others if your process works fine for your need especially after 10 years of practice.

I know I do this is in high contrast situations. Some people have said different raw files respond differently when I’ve said this. I do this with Nikon raw, but some Canon folks have cautioned against this. Maybe that’s changed now though.

From what I have seen, Canon and Sony have a lot more wiggle room in highlights, where as nikon blows highlights really easily - but handles shadow recovery really well. As a canon shooter I shoot to the right much more aggressively than I think would be wise for Nikon shooters.

Canon tends to underexpose by roughly a third of a stop compared to Nikon and without EC one is generally better exposing to the right to capture the most information though there are times for bracketing and situations to do what the author describes. The more difficult question is balancing the optimal Tv, ISO, DR, etc. against noise, motion artifact, etc. in real time.

In my experience Canon looses details shadows very easily... also some contrasty lens they have, so its better to overexpose just a little bit to get details in shadows. Highlights is not a problem with 1 or 2 stops this days. But I just finished teaching my assistant retouching who uses Canon we compared few shots in studio in same conditions with Nikon, and again Canon looked like it looses shadows details almost immediately if underexposed, Nikon has no such problems. but than again there is a factor of lenses... so the general advice is to get the exposure right. Over-exposing or under-exposing is a myth for some reason persistent in the internet...

I found this to be true for previous generations of Canons, but 5D4/1DX2 and newer seem to hold the shadows much better than they did in the past, at least for me.

When I shot d800 years ago I would crank up shutter speed in exteme low-light situations to capture action and was able to crank up the exposure back in Lightroom or Capture One due to the dynamic range of that sensor. I preferred to have an "underexposed" image than to have a properly exposed image that has way too much motion blur due to low shutter speed.

I haven't used Lightroom since about 2012 but back then I felt LR did a better job than C1 in bringing back images that were pretty underexposed this way.

Dani Diamond had a post about underexposing for portraits.

I have been doing this for about 6 years as well. Originally, it was mostly to just get faster shutter speeds when shooting bands that play in very low light at local bars. In those low-light conditions, ninety percent of the time my aperture is always wide open (f/1.4-2.8 depending on lens), shutter at a minimum of 1/200th, and ISO adjusted to whatever I need to make up the difference… but it’s almost always 1 to 2 stops under-exposed so I can keep my ISO lower as well.

Of course it’s possible to underexpose too much, but within reason, as long as you don’t try and dig too deeply, the details you dig out of the shadows in post will look great. If you’re not afraid to let your darkest shadows to go black - and you shouldn’t be - you may begin to see more film-like textures to your photos without trying to manufacture that look in post. Different cameras and different megapixel counts vary in look, so you have to find out what setting combos look best with your specific camera.

I grew up appreciating and EXPECTING to see grain in low light concert photos shot on film. Some of the most iconic photos are super-grainy compared to today’s standards. Don’t be afraid of grain! Be afraid of bad-looking grain. Not all grain is created equally. The grain produced naturally by modern-sensors is very film-like, but over-exposing makes it look trashy.

Learning nuance in your exposure/post-processing settings can help get a more aesthetically pleasing result in your final images.

Same here. My Fuji deals with shadows really well but highlights easily blow out.

I agree. Underexposing gives much more leeway in post processing of the RAW images. Would much rather be under rather than over-exposed. Ideally, perfect in-camera exposure would be ideal, but good luck getting that every time. -2/3 to -1 usually does a nice job.

This is camera relative. Some cameras lie in positive some in negative EV. Histogram is made from JPEG!! 1st use RawDigger to examine exactly where your camera/meter clips. I found on my Pentax K5ii than I am losing 2 f-stops of DR just because jpeg profiles were made bright. I tunes one jpeg profile to push development exposure down, so it matches raw when I open files. I can use spot meter on brightest sky, dial +3 EV compensation, lock exposure and everything will be just perfect from ETTR stand point, so I maximize DR. That way I can push ISO at least one f-stop further to previous. Previously images were noisy just because they were underexposed by 2-fstops even than where was plenty of light. Now I know. For night event photography, where spot light are concerned, there is mostly so great DR it will never do anything than silhouettes if spot light is exposed. It is trade off. So I make test shot than decide. I leave 1/2 f-stop lower than maximum, to be safe.

Some cameras are very prone to processing noise. Canon. But Sony sensor cameras are OK. You will not harm image by underexposing. Still I rather bump ISO. It is always more beneficial. At least I can review photos better at he back of the camera.

I always try to get as much light as possible while still freezing as much action as I need to, while not clipping highlights. So yes, sometimes increase the speed while ISO and aperture remain the same and then bring it up in post; helps that my sensor is ISO invariant for the most part. But other times it's not action I want, but DOF and a smaller aperture, so same thing. But as a default I'll make it bright right up to the limit, even if the JPEG in the window looks hideous, so that I maximize the amount of light info I'm gathering.

I spot meter off the important highlights and add + 3EV of EC https://www.fastrawviewer.com/blog/spot-meter-exposure

I went to the comment sections to see if there was at least one person to use the proper technique. THANKS!
I learned this recently and I am still 'experiencing' but it funny how much I was taught wrong by internet.

Yep, I'm typically underexposed to perverse...err.. preserve the highlights on the sky, but most importantly on the skin. I try to keep the histogram slightly stretched to about -2/3 stop. Varies depends on how harsh the sun is.

Interesting to see that just about everybody else in the comments does this, too. Add me to the list!

Interesting to see that just about everybody else in the comments does this, too. Add me to the list!

I just recently started that myself. Especially as most images are seen on a bright screen so it always looks better.

Yes, the difference between self-illumination and other-illumination, the difference between a back-lig self-glowing display presentation, and a front-lit reflective print presentation.
.

First off relating shutter speed as a reason to under expose is fine if you need too. However it compromises your image.

“Always” is the key point. Obviously the contrast, color latitude, their relationship to how the image is exposed is lost in this post.

You don’t need to under expose to hold highlights. You do need to properly expose however.
If you want to loose information in the blacks for an artistic purpose go for it.

Agreed, if your shooting on auto for sports it’s a good protective technique. But for others exposure is and has been one of the fundamental crafts of photography since film.

It’s almost as ridiculous as mis-spelling the word ridiculous.

And I think you are blowing your response way out of proportion. Under exposing a shot slightly (in relation to the cameras light meter) as many others are saying allows you to protect highlights, shadows can be lifted far easier than highlights recovered.

I shoot a lot at sunset, if I ‘correctly’ expose my shot as per the meter the sky will be blown out so I notch it down to compensate.

Thank you for correcting my spelling, it was late. However adjusting exposure also effects the
contrast and color latitude. I don't mean to be in a contest here. When I used to shoot 16mm I would rate the film 1/4 lower. The Kodak iso (asa) gave us very little room for error. So what the article is saying is that you have a little more room for error. However, if you are in a controlled environment its always best to define your look. I only have an issue with the "always" part.

The spelling correction was a more a joke than being a pedant tbh.

Yes it’s not ‘always’ the correct thing to do but I assume the author is working on the assumption that the majority of photographers are working contrasty environments 99% of the time, which is kind of true (at least from what I’ve seen).

The only true way of retaining details in both without noise/blowouts is to use filters or bracket, otherwise it’s a case of exposing for the highlights (which often reads as under on the meter) then dealing with shadows in post, which I think is the original point.

I usually shoot with my exposure comp at -.5 or -1. I wouldn't call this underexposing, but preserving highlights. It seems cameras like to overexpose.

Too many do not understand what is going on here. Several things they do not understand.

First, this is nothing more than push-processing. This has the same advantages and disadvantages as it had in the film days, (and done for the same reasons).

Second, “grain” is a direct result of not saturating the film, be it emulsion or silicon. It is not really “grain,” which truly did exist with emulsion, but photon noise, which is independent of the film, and only dependent on the amount of light hitting any given part of the film, due to the Poisson distribution.

In a properly exposed scene, there is “grain” —more properly, noise— in the shadows. As the scene is underexposed, more noise appears in the shadows, and some start to show in the mid-tones. As the underexposure increases, the noise in the shadow and mid-tones increase, and start the appear in the highlights.

This is true whether the underexposure is as a result of setting the exposure index to any ISO value above the base sensitivity,† setting the exposure compensation to a negative value, or simply adjusting the exposure time lower, or the f-number higher.

Third, preserving the highlight is not as important as preserving the detail where one wants detail. That is the basic difference between high-key, (expose for Shadow detail), and low-key, (expose for highlight detail), photography. Sometimes one needs to let the highlights get blown-out, and sometimes one needs to let the shadows get crushed.

†If you think raising your EI in camera does not produce more noise, it is because your camera is doing high-ISO noise reduction. This comes at a price; less detail.

Sounds good in theory. With modern sensors (sensors produced in the past five years) you have several stops you can pull up your shadows and not worry about detail loss. Doesn't matter if it's better sensors, processors or algorithms, you've got plenty to play with.

The noise of which I speak, photon noise, is absolutely unavoidable with any film technology, be it the latest chemistry emulsion, or the latest CMOS technology.

Furthermore, no matter what kind of these one gets, be it photon noise, electrical noise, or heat noise, all automated noise reduction techniques reduce detail. Nothing comes from nothing. Nothing ever will.

Also, noise reduction generally has nothing to do with the sensor, except the new “dual read” technologies, which merely puts hardware noise reduction into the sensor, (as opposed to software algorithms), and, yes, it does reduce detail.

Thank you for the information. Practically speaking, if you're shooting digital and have an upscale camera produced in the past five years, you will have plenty of detail in the shadows with very little to worry about in terms of noise. Often several stops before noise becomes an issue. But this is just practically speaking.

True. I actually do not have a problem with noise at all. I hear people keep saying that such-and-such a camera is unusable above such-and-such EI value, but I have shot great pics with high EI settings, with noise, and no one ever said, “Man, look at all that noise!” They just see a great image.

One of my best images, was accidentally taken at ISO 12,800/42⁰. Very noisy, as far as I am concerned, but the noise is not so distracting that I thought it ruined the image, and no one who has seen it thinks so either.

That being said, it is still true that noise cannot be mitigated without reducing detail, but slightly reduced detail on a 6Mpx Bayer raw image, and slightly reduced detail on a 36Mpx PixelShift raw image are two different things, especially when neither image will be seen on anything better than a 4k monitor, or at more than 2Mpx output, anyway, including “digital picture frames”.

Anything that measures something, will have a signal to noise ratio and is subjective to what qualities are being measured and by what observer is measuring them and with what instrument.

All true, but I do not understand the relevance to what I posted. (Honestly, not being a troll or anything).

Don't listen to this guy, he blathers on endlessly, creating complicated word salads, but his logic is flawed and too simplistic and he doesn't even understand basic photographic concepts.

Lol, yep, pretty much.

Don't listen to this guy. He cannot follow logic and ends discussions by insulting people.

I saw the title and was immediately transported to the 90's with a brick of Velvia in my hand.

The concept of underexposing Raw files works well but should be done with caution with older sensors that tend to show more noise in the shadows than newer sensors when the image is lightened.

For the use case mentioned in the article, one rarely wants to raise the deep shadows. It is far more likely one wants to crush them to make what's going on in the stands or outside the end of the stadium less distracting.

If you're only referring to the "use case" of sports in a stadium then yes, you're absolutely right. I was taking the article and title in more general terms. And based on some of the heated comments going on around us it seems others did too. :)

I do this even in more general situations, not just sports, though that's the example I chose to feature up there. Daniel is correct though - I wouldn't do this in the past with older cameras because of shadow noise (and even to some extent with Micro Four Thirds cameras) but newer APS-C and Full Frame cameras are much better.

I'd be interested in seeing before and after.

I used to do that on M mode and since I started experimenting with Av - I set it to -1/3 or -2/3 in contrasted scenes.

Yes. Protect your highlights. Simple.

Ditto. Underexpose, and bring it back in LR.

Indoor theater / dance with poor lighting, a busy background that may contain glaring highlights and fast movement in the foreground.

The standard option would be to use a high ISO. This may incur unacceptable high noise, blown out highlights, and less than perfect motion capture because noise reduces definition. The non-standard option would be to choose a much lower ISO (250-320) and shoot with a faster shutter (because you expect someone to be jumping center stage.)
Be prepared to constantly adjust ISO as the stage lights change.
The pictures in-camera may appear black, except for the highlights in the background which will not be blown out. In Capture One, all detail can be restored in the shadows. How many stops difference? I leave that up to each situation. I would say at least 3 full stops underexposure. 4 stops can bring you down from 6000 to 400 ISO.

The real difference is there is little or no noise, highlight detail preserved, and a pure black. If you use a fast enough shutter, good movement capture now possible. This goes against all sense but it works for this type of environment. The difference is huge in a larger print.

It can be summed up by learning to be sensitive to ISO as a changing variable in poor lighting because, like me, you really dislike excessive noise in a larger print.

It is frequently a tradeoff between blown highlights and noisy shadows. Noisy shadow may be recoverable but blown highlights are not. I, too, purposely under expose if the primary subject highlights are important.

I don't under-expose or over-expose on purpose (yes, it can happen by mistake), I just expose how it should be exposed.
Sometimes some subjects need to be under-exposed and others over-exposed, but that doesn't mean that I under-expose all my photos "for security".
In fact it also depends on the final use of the image, where and how the image will be used, on which medium (web, print, press) and in which size

I do as well. My only concern is for snow. I don't really do landscapes or anything like that. It's pretty much all street photography but I live in Canada so my winter street has a lot of snow. I overexpose to compensate for the white snow so it doesn't look grey but the negative side of that is that it can easily blowout the highlights. Not sure what to do with that one.

More comments