How to use Program Mode to set Your ISO


When I’m teaching my photography classes, the students and I are often neck deep into discussions of the exposure triangle; shutter speed, aperture size and sensor sensitivity (ISO). You can find great discussions and explanations of the triangle here on the dPS. I’d like to dissect the ISO corner of the issue, and give you a simple technique you can use to set the ISO to the best value for the situation. Understanding ISO is one thing but setting it correctly on the fly is another.

Exposure triangle

An equilateral triangle represents a well-exposed image. If any corner is too long, (slower shutter speed for example) the image would be brighter. If the corner is short, the image would be darker.

First a definition of ISO:

ISO is an acronym for International Organization for Standardization. It is a group that sets all sorts of standards for science and industry, but the meaning of ISO for photographers with digital cameras, is that it places a numerical value on the sensitivity of the camera’s imaging component, the sensor. Often compared to the film sensitivity rating called ASA (originally developed by the American Standards Association).

ISO is often seen as numbers ranging from 100 to 6400 and higher. The lowest number your camera presents is the lowest sensitivity setting; the highest number is the most sensitive. So, you can use the ISO settings to help you shoot in a variety of situations; bright and dark. Often you are taught to boost the ISO when conditions get dark but the opposite might be true depending upon your intent.

You are also told that high ISO settings degrade the quality of the image in the form of digital noise. Noise is a visual distortion of specks of light. Some is colored, and some just looks grainy. It is a similar look to the grain we would see in film negatives of higher ASA’s. Noise is worse in the shadows and appears more with higher ISO settings. This is true but the degradation of the image is gradual, and you can sometimes use ISO numbers that are quite high and get great, usable images.

ISO setting in menu

Select ISO sensitivity in the menu, via the Info screen, or sometimes with a dedicated button.

You probably came to understand the concept of ISO as part of the exposure triangle, and then immediately asked, “What ISO should I set?” Hmmm, something is missing in the explanation!

Here are some tips for setting ISO:

First for tripod shooting, set your ISO to the lowest (thus highest quality) setting. There won’t be any camera shake if you practice good technique and your images will have the highest quality. This will hold true unless you need a shorter shutter speed for other reasons. If that is true, keep reading and use the handheld technique.

When shooting handheld, you need to balance the quality you are getting with the ISO setting versus the shutter speed that you can use to get a sharp shot, with no camera movement. For example, if you have your ISO at 100 and you need 1/10th of a second to expose the shot properly, you are going to have some camera movement, and your image will not be sharp.

Follow these steps:

  1. Make sure your camera is not set to Auto ISO.
  2. Set your camera’s exposure mode to Program (not Auto). Even if you need Shutter or Aperture Priority, set it to Program first.
  3. Next, note your present ISO setting.
  4. Now half press the shutter button to wake it up and point it around your shooting environment. Try several different directions. Maybe you are in a restaurant; point it at the tables, at a group of people, down the bar, etc.
  5. All the while, watch your camera’s information display. You can look through the viewfinder for the information, or turn on your INFO display on the back LCD display. As the camera’s meter evaluates all the different shots it will adjust the shutter speed. Program tries to keep both aperture and shutter settings in the normal ranges. Take mental note of those shutter speeds.
    ISO on Info screen

    Here the shutter speed is showing 1/3rd of a second. This is way too slow for handheld photography.

    Shutter apeture in viewfinder

    1/2 of a second shutter time as seen through the viewfinder.

  6. Your camera will go sleep in a few seconds if you don’t wake it up occasionally by half-pressing the shutter button. Let it focus, as that will give you a more accurate reading.
  7. If you are seeing shutter speeds that are slower than 1/60th or 1/80th of a second, then the ISO needs to be bumped to a higher number. Most people cannot hand hold a camera, and obtain sharp photos, at longer than 1/60th of a second. You need good solid technique to do hand hold at those speeds. NOTE: 1/60th is being used here as a typical situation that includes a lens with up to 55mm of zoom. If you are going to zoom further, see the note below on focal lengths.
  8. If your shutter speeds are really fast, (1/1000th or 1/2000th) then you can safely drop the ISO to a higher quality setting (lower ISO number).
  9. Keep repeating the above steps until you see shutter speeds that you are comfortable with using, for the image you intend to make. Now you have your ISO set correctly for handheld photography in your current location, lighting conditions, and focal length.
Camera shake example

An example of camera shake. Note the exposure information. This was taken with the lens zoomed to 62mm (93mm equivalent on a cropped sensor). 1/160th of a second would have been better, which I could have gotten with an ISO of 400 rather than 200.

Focal length makes a difference

The focal length of your lens makes a difference as well. The directions above assume you are using a lens that is typical to entry-level DSLR setups. For example the typical kit lens is a 18-55mm zoom. If you are using a longer zoom, say 200mm, then the slowest shutter speed you can hand hold is much shorter. The widely accepted rule states: one over the focal length (so 1/200th of a second in the above mentioned situation) is the longest shutter speed that you can hand hold for a sharp, no-shake image.

However, this is an old rule that was based on 35mm film (and it applies to full frame digital sensor cameras). Many digital cameras have a crop factor, or multiplier effect, for focal length because their sensor is smaller. Yours might be 1.5x, 1.6x or even 2.0x – check your camera’s manual to be sure. Assuming a 1.5x multiplier for a 200mm zoom shot, you would need 1.5 x 200 = 300, so 1/300th of a second is your slowest shutter speed for an image that has no camera shake blur.

What about Shutter and Aperture Priority?

At this point you may be thinking that you actually need Shutter or Aperture priority – that is fine. But now you know the ISO range that will work. Perhaps ISO 400 was where you ended up, and the meter was telling you that the shutter speed of 1/200 was going to work. Now you can switch to the mode you want. Let’s say you need Shutter priority to stop some subject movement. Set your camera to Shutter priority, let’s say a shutter speed of 1/400th of a second, and repeat the process of aiming at some possible compositions. If your camera starts blinking the aperture, you will know your setting is out of range. It is telling you the aperture cannot be opened any wider, so you’ll know you need to increase the ISO to use that shutter speed.

For Aperture priority, set the aperture you need for a desired depth of field and use the camera’s meter to evaluate the scenes as described above. If the shutter speed starts goes below your maximum for the lens you’ll know your settings are out of range. Then you will need to bump up the ISO.

What about Vibration Reduction?

Sometimes called Image Stabilization, this is technology that might be built into your lens or camera. It can allow you to shoot at speeds longer than normally recommended, since it counteracts the movement you introduce into the camera. Take the marketing information about how many stops longer you can shoot with a grain of salt. Do your own tests with your equipment, with your best steady technique. I find that most people can learn to get two extra stops of shutter speed latitude. So, in our scenarios above you could shoot at 1/15th and 1/50th of a second respectively.

VR button

Vibration Reduction switch on a Nikon lens.

Try this process for a while with the Program mode to get comfortable, then you can use all of the exposure modes to set your ISO quickly and correctly. As your experience grows you will set your ISO quickly with intelligent estimates. You will never have to guess about your ISO again.

No camera shake

A higher ISO (3200) made little difference in quality here. The shutter speed of 1/250th assured a no-shake image and was fast enough to stop any subject motion.

Read more from our Tips & Tutorials category

Steve Gandy is a life-long photographer, educator, trainer, and technology support professional. Steve has introduced the ins-and-outs of digital photography to students, young and old, since 1995 and has been involved in education since 1978. His photography is varied but he focuses on fine art natural scenes. He also shoots commercially. He owns Steve Gandy Photography, TeachTech Inc. and has a group in the Denver/Boulder area. You can also see his work on Instragram.

  • Spoonie

    Given your camera has logic built into it to apply the 1/focal length shutter speed rule when using auto ISO and there hasn’t been a camera made in the last 10 years that didn’t have auto ISO built in (not to mention most caneras now allow you to set the lowest shutter speed so you can either bump this up or go lower if you have VR), why wouldn’t you just use auto ISO rather than mess around in program mode to guess the ISO??

    Using auto ISO is basically applying the steps you have gone through above. So:

    1. If you are using aperture priority the camera will chose the lowest ISO to give you a shutter speed of 1/focal length or higher.

    2. If you are using shutter priority it will chose the lowest ISO and then work through the lowest apertures to achieve correct exposure.

    3. If you are in manual mode it will give you the right ISO for the selected shutter and aperture settings (if possible).

    This post seems to be way overcomplicating a problem I don’t think anyone has. Even if I was the newest camera owner in the planet I wouldn’t fiddle around in program mode to guess the right ISO and then switch to shutter/aperture priority, I’d just start in shutter/aperture priority, it’s the same light meter doing the work applying the same rules you have discussed above (only, you know, waaaaaaaay faster)…

  • Doc Pixel

    +1 – Ditto your entire reply, especially this: “…his post seems to be way overcomplicating a problem I don’t think anyone has.”

  • Spoonie

    And can we once and for stop referring to digital noise as “grain”… Digital noise is always the size of a pixel, regardless of the ISO setting. The size of the grains in the film varies depending on the film sensitivity and emulsion used. The more sensitive the film, the larger the grains.

    Film grain is colour neutral, as it consist mostly of luminance noise. Digital noise consists of both luminance and chroma noise.

  • Right, but you are not a beginner anymore, obviously. This technique works well with new photographers that are trying to understand _all_ of the controls and settings at once. They need the processes broken down.

    Auto ISO will also give you varying levels of quality in a given shoot and location in that the camera evaluates for every shot. In my instruction, I always start things from a stance of producing the highest quality images possible in the situation. It is a good starting point for photography classes.

    Your suggestions are a terrific next step to the process, thanks!

  • You are right, that’s why I described it as “…a visual distortion of specks of light” and “… looks grainy”.

  • Doc Pixel

    IMO AutoISO on Manual Mode is an easy and great way to start, because you take the ISO control out of the triangle equation for the moment. Later when viewing or culling with Info on, the beginner can see what ISO settings can be set with predictable results in the future.

    Also… in the not too distant future, and some would argue even today, ISO settings are not as crucial as they once were due to incredible camera sensors.

    It is far better… and even easier… to wrangle ISO into a usable state, than throw away half of a shoot due to blurry or vastly under-exposed images.

    Quality in my book starts with a sharp and properly exposed image.

    This is not only personal opinion, but a number of well respected sites (DXO and DPReview I believe) have technical articles that point out why this is for the last couple of generations of cameras.

  • Choo Chiaw Ting

    What ISO, Aperture and f-number suitable for this case?? Very limited space…

  • Doc Pixel

    I still think that it obfuscates that ISO is “not grain”, or a good thing aesthetically as it relates to the terms used in art and the true-grain aspects of film processing.

    ISO NOISE should (must?) be dealt with BEFORE “digital grain” is added back in to achieve a desired film look. IMO.

  • In your classes I’m sure you will proceed in your instruction as you layout. In mine I start from the other direction. comme ci comme ça, eh? I think you have assumed that this is the only instruction I would give to a new photographer on ISO. That isn’t the case. This is just one technique that can be used. I don’t think DPS would let me publish a whole book on the Introduction to Digital Photography 😉 but maybe I should ask!

    In either scenario, (and there are certainly plenty of other scope and sequence lesson plans out there on the subject) the student learns the ins and outs of ISO/exposure/quality/noise in a hands-on the camera environment. And that is what is important, IMO.

    You should write up your ideas and submit it. I notice that DPS has lots of views/techniques/tips on every possible photographic detail.

  • You didn’t include the shooting info so I’m just going to give some general thoughts.

    In this case I would say use Aperture priority mode, and choose the aperture that will keep the whole group in acceptable sharpness. You have faces at 3 or 4 distances from the camera so you need a smallish aperture for a depth of field that will cover the whole group. It looks like the girl in the back is just a bit soft so stop down a bit more.

    Then, check the shutter speeds that the camera gives you…are they too slow for the subject? And/or for your handheld skill? If so, boost the ISO just high enough to give you the aperture and the shutter speed you need.

    Also, if you can move them farther away from the background, it will be less focused and less distracting.

  • Spoonie

    I get where you are trying to go with this, but I don’t think anyone learned anything from waiving thier camera around on program mode to learn what different ISO’s do.

    Yes, different ISO’s will give you different image quality, but they will also give you sharp images if you are hand holding your camera or you have moving subjects. A sharp noisy image will trump a blurry low noise image in pretty much everyone’s books.

    You state you start from the stance of producing the highest quality images possible, does that mean you select an ISO that won’t give you a suitable shutter speed when you are hand holding your camera or you have a moving subject? I doubt it.

    The issue with your workflow is its backwards. You state you set your ISO then check your shutter speed and then adjust your ISO accordingly.

    But you already know some of the parameters, you know you want a shutter speed of 1/focal length at least. So, if that’s the case, set that first. Then check the auto ISO setting. The camera will choose the lowest setting (in your terms highest quality) for you. You’re now 2 steps ahead of the workflow of choosing ISO First.

    It really then just becomes a question of is the ISO too high, if it is and you’re going to get some sort of noisefest, you know you need to do something else (move your subject, use a flash, a tripod find more light).

    Why mess with guessing your ISO to get a shutter speed within a range that you already know, when you can select the shutter speed you want and the camera will select the best ISO using the logic you would have used automatically.

  • Doc Pixel

    “SO/exposure/quality/noise in a hands-on the camera environment. And that is what is important, IMO.”

    I guess that’s where we’re different. Because as a “technologist” and a traditionally trained artist/designer, I use tech to it’s fullest so that I can get down to creating aesthetically pleasing photos and explore my creativity, rather than always worrying about the technical side.

    Some would equate that to setting it on Auto mode and be done with it… but “aesthetics” are attained by understanding the tech and what you’re trying to achieve. If the tech available enables a certain amount of trust… then “capturing and framing the moment” becomes the concern and concentration. Knowing that the tech is available to correct or enhance those frames, is even more power to explore and experiment.

    I think a budding or amateur photographer will be more successful and happier with the results to continue learning (a never ending process), rather than becoming flummoxed by the tech and less than optimal images and eventually giving up.

    An article this morning at SLR Lounge, wrapping up the recent Photoshop World (which I didn’t attend) noted that, “…A theme I heard expressed repeatedly throughout the conference was the
    importance of developing one’s own style, of pursuing the specific type
    of photography that makes your heart sing. In his The Designing Photographer session Corey Barker emphasized the importance of experimenting, playing and just trying things to see how they work.”

    I agree with that mission statement 100%.

  • Carlos Martins

    Hi all! 🙂 Despite all critics I really beieve this is the way to go! Call me old schoold but I really prefer knowing the theory and the basics rather then justo follow what a CP says 🙂 But that´s me! The problem of not knowing the basics is that when you go to a different situation you don’t know what to sort it out. Learn the basic! This triangle is the most important thins in photography. You can have a D4S but if you don’t know this triangle you might just spend you money elsewhere! 🙂

  • Amen, and nicely put, Carlos!

  • Bostonhiker

    Isn’t some of this information incorrect? I thought 62 mm on a full frame camera yielded a lower equivalent with a crop sensor, more like 1.5 times X = 62 mm. Also, if you say Most people cannot hand hold a camera, and obtain sharp photos, at longer than 1/60th of a second, isn’t that supposed to be less than 1/60th? Please correct me if I am wrong. This is confusing.

  • DuLaurence Duke Miller

    This post starts with, “Understanding ISO is one thing but setting it correctly on the fly is another.” Exuuuuse me! Your solution is the most un-on-the-fly method there is. When, and only when I have my camera set to the Normal (point and shoot) custom setting, it is programmed to automatically up the ISO when shutter speeds below 1/60 are required. Then, whether in P, A, or S, I don’t worry about anything…except trying to get a decent capture. Isn’t that what all this technology is supposed to enable?

  • Lisa Moyer

    Thanks for giving me my next exercise…. and a really enjoyed the pics of the lab too!

  • Hi DuLaurence, Thanks for commenting.

    Of course, you can use Auto ISO. There is nothing wrong with that… My technique is for those want to begin to set their ISO manually. By doing so, and understanding how to use (and set) the exposure triangle they can become Manual mode shooters if they wish. Not everyone wants or needs this. But they can gain a visceral understanding of how ISO affects the shutter speeds and aperture settings. This is just one technique used in some of my photography classes. If you can use it, great. If not, that’s fine too.

  • Hi Bostonhiker, Thanks for commenting.

    I think you might have misread…I said, “The widely accepted rule states: one over the focal length..” So, in your example 62mm x 1.5 is 93. Thus, you’d need 1/90th or 1/100th of a second to ensure a steady handheld shot. So, 1/100th of a second is less time than 1/60th.

  • I appreciate the comment, Lisa! That’s our new baby, Koa, in the pictures.

  • ireribonita .

    Hi Steve, thank you. I’m a total beginner and this I was having trouble with understanding. I love this site as I am learning from different people that are so nice to give us their tips. I’m also taking courses aside, but you guys help me so much to understand more and put in practice what I learn. I appreciate so much what you and others have posted to keep (us) me at least, still very interested in Photography and not get frustrated. Please never stop helping us newbies. Thank you. 🙂

  • Thanks for your interest in the site and my article!

  • J Public

    Nice try Steve, but I still get Palpitations trying to understand “P” Mode! I sort of thought that you could use it to set Aperture & Shutter and then it would automatically give you the lowest ISO the metering method allows – but couldn’t achieve this so just gave up.

  • J Public

    Yes that makes sense, and also maybe it’s a bit like learning to drive or play an instrument – you need to be instinctive. So perhaps for new digital photographers the answer is exercises, like playing within the scales. You could send the learners out into a forest for an hour and say they can only use f2.8 and see what happens.

  • Hi, J, thanks for your interest. Yes, I agree when you are a beginner it helps to do some “guided practice”.

  • Reread the the paragraph on “What about shutter and aperture priority?” and try the technique there. If you want 1/500 of a second for example and your aperture is blinking or the camera is otherwise showing you it can’t do it, then boost the ISO one stop at a time until you get it in range.

  • wiz

    It is always wise to build knowledge on a firm foundation. Knowing how you got from A – B is important to the development of one’s skills. Steve made it clear that this was a starting point and not the end all. It is a link in the chain so to speak. Good job Steve.

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