Exposure Triangle - Not just about more/less light

Exposure Triangle – Not just about more/less light

So we probably all know about the exposure triangle by now. Pretty basic stuff you learn when you’re first getting into manual. And if you’re just learning, you may be wondering what the point is in obsessing over your ISO, aperture and shutter speed. So indulge me as I explain the triangle sub-headings:

{Aperture – Depth of Field} When I learned that there were lenses that were ‘faster’ than others (meaning the aperture can open widely), and that this was required for good photos in low-light situations, I thought ‘great! problem solved!’ Well…problem NOT solved. Why? Because opening your 50mm f/1.4 right up to 1.4 now causes issues with very shallow DOF (depth of field). So if you’re shooting a wedding, perhaps, and your plan is to just open your aperture up, you better have a plan B. Because at some point, the groom will be a smidge in front of the bride or the bride will be holding her boquet in front of her and the focus will fall on the wrong thing. So simply opening your aperture isn’t going to be enough to leave you other settings as they are. Point? When adjusting aperture, don’t just think ‘more light’, also think ‘depth of field’.

{Shutter Speed – Sharpness} When first learning about the exposure triangle, every setting was explained to me in terms of how it dealt with light: aperture lets in more or less light, shutter speed lets it in longer or shorter, and ISO is how sensitive the sensor is to light. But like in the example above, there are other factors when considering your settings. With shutter speed, it isn’t only the length of time the shutter is open that you have to think about. Particularly in low-light situations, using a too-slow shutter can cause camera shake from your shaky hands or motion blur from moving subjects. And this all leads to blurry photos, soft edges and no sharpness in sight. Inside, use as fast a shutter as possible while still being slow enough to fit into your triangle. And if you can, invest in lenses with IS (image stabilising) because this helps you to create sharper photos when shooting at slower shutter speeds or long focal lengths (far zoom) when your hands may be shaking. The short of it? Shutter speed = sharpness.

{ISO – Grain} ISO can be your best friend or your worst enemy. It’s the setting I compromise on last and not if I can help it. I really hate noise. I’m learning not to pixel peep and LR3 is so much better at handling noise than LR2 ever was. That said, just know that ISO isn’t a magic triangle-balancing number. You can’t just whack it up to 3000 and forget about the rest. You should know that higher ISO equals increasingly more noise/grain. And some photographers add grain on purpose, particularly when shooting or editing in B&W. Basically? High ISO = grain

Hopefully, expounding upon these other factors to think about when choosing your manual settings will help you make more informed choices and better photographs.

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Elizabeth Halford is a photographer and advertising creative producer in Orlando, FL. She wrote her first article for dPS in 2010. Her most popular one racked up over 100k shares!

Some Older Comments

  • keef March 20, 2011 08:14 pm

    Hold it right there...don't get too hung up on the semantics. Grain, noise, bokeh, fuzz..blur, shake. The biggest mistake you can make is to have a moment pass or walk away...just because someone says 'its what not I read'. I am often asked 'whats the best camera' ? the one you have with you. I see a lot of newbies drowning in technology and terminology. Learn and understand the magic three and make your own judgements. Nothing wrong with making up your own language and set of rules.

  • Nevalee February 18, 2011 10:46 am

    Here is a great site I recently discovered that has lots of exposure triangle charts:www.fredparker.com Photography is a field with much to learn and I always feel like I'm a newbie.

  • Jatin October 16, 2010 05:37 am

    Amazing article, especially when my head was spinning looking at those three terms being used almost interchangeably in my camera manual.

  • Jackie August 22, 2010 01:08 am

    excellent synopsis!

  • Matt P August 21, 2010 07:02 pm

    Good article, really helps to highlight the three main areas to watch when getting started. I must say that some of the comments are uncalled for and are really nitpicking when it comes to prduxing good photos. To carry on with the car analogy, we are drivers who enjoy riding our cars and we just need to know enough to make that happen, we are not training to become repair engineers. Most people who come to DPS are probably of the 'driver' than the 'engineer' category.

  • JAWAD HUSSAIN August 21, 2010 09:36 am

    thanks alot for the lesson ....actually the iso if u but highe number the photo come so noicy.

  • Melody Mainville August 21, 2010 03:45 am

    GREAT ARTICLE!!! I'm not to new at this.. but I need more education!! and this really helped...

  • adam August 21, 2010 02:49 am

    I'm a beginner and new to photography. I think this is the 4th or 5th article I've read on the exposure triangle and I wondered why some of my night time shots were grainy or why certain shots were not as sharp as I would have liked. The depth of field bit I figured out not too long ago, but I've been struggling with sharpness and noise.

    ISO= Grain and Shutter Speed= Sharpness

    Seems so simple now. I'm sure it'll only take a lifetime to master, but at least I now know what to focus on. No pun intended.


  • Guess the Lighting August 21, 2010 12:50 am

    Great way to talk about the building blocks of any photograph. If you're interested in also seeing how famous photographers light their images, take a peek at GuessTheLighting.com

  • Sue August 20, 2010 10:19 pm

    @Colleen: that made me laugh out loud.

    I found this article useful - always good to have reminders of what we should be thinking about.

  • jpatt August 20, 2010 09:00 pm

    This is the third article that I have read on this site today where several of the following comments have been disparaging of the article writer.

    This is at best inconsiderate at worst downright rude and a practice I suspect that the individuals concerned would probably have not indulged in had they been in a face to face discussion with the article writer!.

    I am all for the correct use of terms but would venture that the in the case of noise/grain that these terms are used interchangeably where dslr's are concerned.

    I also agree with @Matt Needham that in the days of analogue film 'grain' was at best tolerated for B+W and hated in colour emulsion film. The nostalgia (rose tinted spectacles syndrome) that grain is now looked upon with is totally misplaced in my view.

  • Prashant August 20, 2010 02:16 pm


    Does any body know what needs to be set right to take continues photos in Fuji Finepix HS10 camera as this is a bridge camera takes more than 3-5 seconds to save an image after clicking. I want continues shooting option in order to capture the actions.

    Right guidance is need of the hour, Please guide. Mail - prashantgy@gmail.com



  • Colleen August 20, 2010 01:37 pm

    I recently accompanied my brother on a camera-shopping trip. As the salesman showed him the camera, I made a comment about high ISO and noise. My brother confided later that he was thinking I must really be a pro if I was concerned about how much noise the camera would make--after all, he'd be shooting outside and who would hear it? Needless to say, he was relieved he hadn't said anything at the time. ;-)

  • Will August 20, 2010 11:55 am

    "Shutter speed = sharpness" is not true. If anything aperture controls the sharpness of your lens more than shutter speed does.

  • TheLiberalThug August 19, 2010 11:59 pm

    I have to agree with B - it's important to get these terms right, or else it just gets very confusing further down the line.

    It reminds me of when my mother keeps on talking about 'downloading the pictures to the memory'...

  • SNK August 19, 2010 04:30 am

    I appreciate how you wrote about the triangle... and then challenged the very thinking that I've had not too long ago. I once wondered why you would ever shoot at any aperture other than wide-open... until I discovered the importance of DOF. Thanks for articulating these points, as it's a good reminder about how to get the basics right. :)

  • fauxtog August 19, 2010 02:56 am

    Unless I'm deliberately trying to capture motion blur, I'll actually compromise on ISO first (opposite of your feelings on the matter). I'm not a studio photographer, and mostly try to work with whatever light the shot's environment provides me with. This often leads to a ratcheting up of ISO, either by me manually, or by the camera's automatic ISO function. I agree with you that LR3 is phenomenal at managing noise, which has only emboldened me further, with respect to how liberally I'm willing to crank up ISO.

    Long story short, for me, in most cases, I'll take sharper focus over lower noise, if need be; and, as it turns out, my need often be.

  • Sarah August 19, 2010 02:55 am

    Thank you for this article. I'm just starting out and moving away from auto mode. Articles like these a a huge benefit for readers like myself. Keep it up!

  • Shokinen August 19, 2010 02:25 am

    Great way to "expose" (hehehe) the downside of each part of the triangle.

  • Arun August 19, 2010 12:12 am

    Nice one, barring that one thing on Shutter Speed = Sharpness and I think there's been enuf people on that already. So I ain't gonna add my two cents there...

    As far as the aperture goes, I always used to wonder why fast lenses are such a big fuss amidst the Pros! - when I can't really get to utilize the wide open aperture due to various reasons!
    But like already stated, it still helps in shooting 2 stops lower to get tact sharp photographs.

    Yet, I still don't understand why a lens being fast matters so much as compared to the picture rendition quality or sharpness of the lens at various apertures or distortions at end of the focal range! I know variable apertures are a problem, but why exactly 'fast' lens - God only knows!

    As far as ISO is concerned, yeah, I used to have similar mindset as you do - never touch it if you can help it! The result - I was never able to nail exposure! (very important when you've got only one shot, and a jpeg to add to it!) With experience, I can tell you, if your camera can handle noise anywhere near decent, I don't mind a 400 or a 800!!! ISO affects sharpness, but there are situations that benefit from such a setting.

    My two cents:
    Well, although you've talked about the triangle to be different from just a change in exposure setting, to me I still look at it as a control over exposure.
    Ideally, if you're in a situation where you don't have external lights. The ambient light is also insufficient. And yet you'll have to make do with what you've got.
    I'd say, open up fully, use suitable shutter, and suitable ISO, and... THIS IS IMPORTANT.. compose such that you have your subjects where you want so you don't lose the story. More than anything else, this matters most.
    Tell me that you can never get a good shot of the bride & the groom with a 2.8, and I'd be surprised!!! Yes you can.. and I'll leave that to you to figure out how.

    Still, nice post, as I sync with a few thoughts, and it's got me thinking again after a long time...

  • Georgino August 19, 2010 12:04 am

    Excellent, article. It is hard to find proper words for newbies. Trick is not to be much technical and you just hit the nail on the head.
    Elizabeth you are right with Grain / Noise is not Car / Buss but belong to category vehicle. For newbie it is exactly same thing and maybe will be for ever. Also shutter in their case = sharpness. Because if they are getting blurry images and you have 5 second to tell them what to do – You will tell them increase your shutter. You will not give them ½ lecture of every possibility and internal construction of the lens ;-)
    Good work

  • B August 18, 2010 10:54 pm

    "Distinguishing grain from noise is really picking at nits because the end result is the same."

    I think this has been shown false by the various comments here contrasting film grain vs. digital noise.

    Anyway, my comments may sound like quibbles, but it's important to get your terms right. A bus and a car are very similar, but if you're taking a bus and telling someone you're in a car, it's confusing (and wrong). To use a photography example, overexposure leads to a brighter image and underexposure to a darker one, but exposure and brightness are two very different concepts. Telling someone you adjusted your brightness when you mean you adjusted your exposure is just inaccurate, and it's worth getting this stuff right. Especially if you're ostensibly educating others.

    I almost brought up Eric's qualm about motion blur vs. sharpness too, because it's the same issue; using "sharpness" (or rather, the lack thereof) to refer to motion blur would mean that the blur from subject movement is also considered a lack of sharpness, which just isn't true. It's like calling any hoofed quadrupedal mammal a pony (or in this case a unicorn). Camera shake is a form of motion blur which is different than sharpness. I think the least we can ask from someone trying to teach others is that they get their terms right, no matter what audience they're writing for.

  • pangolin August 18, 2010 09:14 pm

    Aperture means DOF, but on the very closed ones it also means star bursts effect. If you have the sun or any small and strong light sources in the composition, you may decide that rendering it as a bursting sun (or sparkling X-mas lights fo exemple) is the one thing you really want to emphasise. In this scenario you stop down your lens, not having DOF in mind. Loss of sharpness is the price to pay when using this creative tool, as general softness is for wide open selective focus.

    So with aperture, you may think DOF but also bursting lightsources.

  • Umair August 18, 2010 08:37 pm

    Hey, great article... i am a newbie and it helped a lot. But now i want more, is there a combinations chart of some sort for the three settings of the triangle?
    Obviously there would be no fixed settings for each shot, but a general range as to what settings complement each other?
    I know like too much of a newbie, but i am really interested to find out more... help!

  • Alexander Kiselev August 18, 2010 08:05 pm

    Oh ! Very nice article !

  • dogwatcher August 18, 2010 05:16 pm

    Will McA wrote:
    >> "..but digital noise has no aesthetic quality whatsoever"

    ..well depends. There are some cameras out there with a kind of luminance noise and absence of chroma noise at some ISO-settings, that has something to it.. of course, it all depends on personal taste.

    The Pentax K-7 is such a case, it may be noisier than it's competitors, but some people thing that it's a kind of noise which sometimes can turn out quite nice... Not like the Pentax K10D, which produced noise which hardly had anything aesthetic to it above ISO800 or ISO1000.

    But as I said, it's all a matter of taste.

  • Biswajit Dey August 18, 2010 04:06 pm

    Oh! That's a very good explanation of the topic! The aperture, shutterspeed and iso are so closely related that you cannot afford to ignore them if you are into photography. And this article clearly tells the side-effects of changing all these three.. :)

  • Philippe August 18, 2010 03:54 pm

    Great post. For someone who just started to shoot and knows pretty much nothing about all the technical stuff, this is really helpful. Understanding the basics and how they are related to each other is a must and it's motivating to learn more. Cheers.

  • oliverignacio August 18, 2010 12:58 pm

    good post.. it is appreciated. Thanks!

  • KyleHase August 18, 2010 12:15 pm

    Great writeup.

    Recent improvements in CCD/CMOS sensors have reduced the grain/noise at higher ISO which extends the possibilities for photographers. Also, some of the latest cameras include backlit sensors which are supposed to help in low light situations.

    I'm wondering if similar improvements can be made in lenses to increase the amount of light passed (wider aperture) without affecting the depth of field. It may take a completely new design though, like compound eyes as opposed to simple eyes.

  • Matt Needham August 18, 2010 10:33 am

    I think it's funny how film grain is looked back on with affection and nostalgia. Before digital very few people found it particularly attractive. That's why some of us spent all that effort hauling medium and large format cameras around. We found grain to be nasty, ugly stuff. Now people talk about it fondly. I think it's more of a case of absence makes the heart grow fonder. It didn't look very good, and compared to the Canon DSLRs I've been using for the last 6 years ISO 1600-3200 print film just looks atrocious.

    Sure, go with the lowest ISO possible, but learn how to process (IMO where most of the objectionable qualities of digital noise are created) and take advantage of what today's DSLRs have to offer at high ISOs. Since switching to digital my concept of how much light I need to get decent image quality has changed radically.

  • Will McA August 18, 2010 09:57 am

    Excellent article. I'm with you on ISO. It was different in the days of film when grainy photos had an aesthetic quality, but digital noise has no aesthetic quality whatsoever, so it's the absolute last thing I compromise.

    Having said that the result tends to be I forget about it completely, and am on the verge of giving up on a photo opportunity before realising, 'hey I could try a higher ISO'.

    I do find it somehow fitting that increasing sensitivity of a CCD has a similar effect to increasing sensitivity of film, but for completely different reasons.

  • McGuireuk August 18, 2010 09:33 am

    Good article. Its not often thought about like this. Many beginners can be told the importance of understanding the exposure triangle and learn the importance of DOF, noise and camera shake seperatly but this adds them together quite nicel i think.

    Well thought out. Very good. Well done.

  • Geoff August 18, 2010 09:17 am

    Even though I'm very familiar with the exposure triangle, this was a great refresher. Thanks for the article!

  • Sime August 18, 2010 09:10 am

    Hey Liz, good post!! Thanks..


  • Karen Stuebing August 18, 2010 08:55 am

    Lots of good info. However, both eric and b make good points. Beginners should also be given accurate information. I'm with you. I hate noise.. It is not like film grain which can actually look kind of cool, IMHO.

  • Lynda August 18, 2010 08:42 am

    Awesome! I knew about ISO = Grain and Aperture = DOF, but Shutter Speed = Sharpness is a revelation! I usually shoot in AP, but now I think I'll start using AE at least to experiment.

    Thank you!

  • Jim poor August 18, 2010 08:05 am

    Nice, brief and to the point.

    Distinguishing grain from noise is really picking at nits because the end result is the same.

    That said, one can get away with a lot more in terms of high ISO settings than we are typically led to believe. Noise, unless it is really, REALLY bad doesn't show up in prints all that much due to ink spread, so if prints are the goal do some experimenting and find the limits for your specific situation. I live at ISO settings in the 6400-12,800 range and don't worry about noise unless the final presentation is to be a large digital image.

  • Matt Thomson August 18, 2010 08:01 am

    @ B - Same goes for you. Elizabeth has used language that the lay person might more easily understand. The point is made, merely by the fact that you were able to see that grain referred to noise...etc etc.

    Dont get me wrong, I am all for constructive criticism. I just think that it should be warranted, after first considering the context with which the article was written.


  • Matt Thomson August 18, 2010 07:48 am

    @Elizabeth - nicely written

    @ Eric - With respect to your criticism about sharpness/motion blur; I think it is a case of she say potato, you says potado


  • Elizabeth Halford August 18, 2010 07:12 am

    Hey y'all thanks for reading! Before you tear my post to shreds please remember that it was written for newbies. :)

  • Valorie August 18, 2010 06:56 am

    Nice reminders...ISO is the one I always forget! I had great reminders this past weekend trying to shoot wildflowers in the breeze. If I had just raised the ISO, I could have stopped the motion.

  • Zoe August 18, 2010 06:50 am

    Love your write up! I just took a beginner's class and still get my basics mixed up. This really helps, especially the idea that maybe i should have parallel thoughts about sharpness, graininess, and depth of field instead of just the pure science of light distribution.

  • B August 18, 2010 06:40 am

    Digital cameras do not have grain. They have noise. Grain specifically refers to a quality of film due to the presence of silver halide. While noise behaves like grain in some ways -- notably being more prominent when the sensing media is more sensitive to light (high ISO or ASA speeds) -- they're not the same thing, much in the same way that gluing a carrot to a horse doesn't make it a unicorn.

    Note that aperture almost always affects sharpness as well; most lenses are not as sharp as possible wide open, and are sharpest two to three stops narrower than wide open (some, like Canon's 70-200mm f/4L lenses, show less of a difference than others). And this disappears again at very narrow apertures, because the nature of digital sensors and lens optics cause diffraction. Most DSLRs reach their diffraction limit between f/8-f/11 or so, though real hits to sharpness due ot diffraction aren't apparent until even smaller apertures than that.

  • eric August 18, 2010 06:31 am

    Shutter speed controls motion blur, not sharpness. That's a property of the lens.

  • ajsuk August 18, 2010 06:24 am

    Great write-up. It's all stuff I feel I have a good grasp of already, but still worth a re-read! Also I love those sum-up shorts, why don't all writers do this? It just what the lazy skimmer ordered! :P