Back in the film days, ISO was used to measure how sensitive the film was to light. The higher the number, the more sensitive to light the film is. The same term is used today for digital cameras because they basically mean the same thing.
ISO is the measurement of how sensitive the camera sensor is to light. The higher the number, the more sensitive the camera is. That means with a higher ISO number, you will need less light to properly expose the image. With a high ISO, you can shoot a photo in a dark room and have a properly exposed image instead of just darkness.
The term ISO is not an acronym. many people believe ISO means “International Standards Organization.” This is not true. ISO means ISO. But there is an organization called the “International Standards Organization” that sets the standards that ISO is measured. Good thing this is not confusing at all :)
“The International Organization for Standardization is an international standard-setting body composed of representatives from various national standards organizations.” – Wikipedia
The lowest ISO setting on many digital cameras is usually around ISO 100. as you increase the ISO, it will change to 200, then 400, 800, 1600, 3200, 6400, and it keeps going up and up doubling every time. Every time the ISO doubles, you are reducing the light your photo requires by half.
For example, if you are taking a picture at f8, ISO 100, 50th of a second, and if you increased the ISO to 200, than your settings would be f8, ISO 200, 100th of a second. Just bumping the ISO up one step, made all the difference of getting a possibly blurry shot to a sharp image. The faster shutter speed reduces the odds of getting a blurry image.
ISO has come a long way in the last few years. Many digital cameras had a maximum of 800, 1600, and maybe 3200. But today, many some cameras are capable of increasing their ISO to incredible levels and can nearly see in the dark. The noise reduction technology has also come a long way in the last few years. I can only imagine how powerful they will become in just a few years.
Every digital camera has a “Native ISO.” The native ISO is where no amplification is added to the light because none is needed. As you increase the ISO, you are artificially boosting the light in camera to make everything brighter. There is not more light entering the camera, just the signal is being boosted in the camera. Shooting with the Native ISO will produce the best image quality because light is not being amplified in the camera. When the light is artificially amplified, the internal electronics of the camera can cause noise in the circuitry, and you will start to get noise in the photo. The higher the ISO goes, the more electrical interference you get, and the more noise your photo will have.
How to use a high ISO
When you are in a low light situation like a wedding, concert, a dark pub with friends, you will want to increase the ISO so you can capture those moments. The human eye can see in these dim situations no problem, but your camera does not see as well in the dark.
In order to get sharp photos in low light, you can either decrease the shutter speed, open up the aperture, or increase the ISO. All three options will enable you to get a properly exposed image, but they all will give you different results. Lowering the aperture will let more light in but you will be decreasing the depth of field. slowing the shutter speed will let in more light, but your image can quickly be come blurred or your subject will move causing a blur. Increasing the ISO will make your camera sensor more sensitive to light and you will have brighter photo. A higher ISO means you will have more noise in the final image, but sometimes its worth having a noisy picture if it means capturing the moment.
How high should I set my ISO.
Digital camera technology has come a long way in just the last few years. Modern digital cameras can have their ISO’s set incredibly and still deliver a sharp clean image. With every new generation of camera, the ISO capabilities get more advance. An ISO setting of 1600 or 3200 would have been unthinkable a couple years ago, but now you can set your ISO that high and not even think twice about it. Digital cameras have a maximum ISO that they can be set at, but some cameras also include an extended ISO range, This setting is sometimes indicated with the letter “H” for High. This pushes the ISO past the limits of an acceptable noise level. The image quality quickly deteriorates when you are in the Extended ISO range. You will have to enable the Extended ISO mode in your settings, it is not enabled by default.
How to use a low ISO
The ideal ISO you should set your camera to is the lowest possible ISO. On most cameras this is usually ISO 100. On other cameras this may be ISO 50. When you use a low ISO, you are going to get the best image quality because when you increase your ISO, you are amplifying the signal to get more light out of the scene. This causes noise in your final image. When you use the lowest ISO, you are allowing the camera to capture the highest quality image with the lowest amount of added noise. Some cameras have the ability to set their ISO even lower. This mode is sometimes indicated with the letter “L” for Low. The reason for this is so you can decrease the sensitivity of the sensor and capture less light in order to create a longer exposure in bright conditions. This is an alternative to using a neutral density filter to achieve long exposures during the day.
When To Use A Low ISO, and When To Use A High ISO
How to use ISO
To adjust your ISO, you first need to find the ISO button on your camera or in the settings. For most DSLR’s, there is a dedicated button on the on the camera that says ISO. Press that button and either turn the wheel on the back of my camera or press right to either increase or decrease the ISO.
Auto ISO
You may also be able to select Auto ISO and have your camera select the proper ISO to correctly expose the image. Using auto ISO is a good way to learn how to use the ISO. Auto ISO can be very helpful if you are walking around someplace moving in and out of the shadows and you don’t want to have to constantly adjust your settings. Auto ISO will raise and lower the ISO depending on if you are shooting in a dim area, or in direct sunlight. Because noise is an issue at higher ISO, your camera might support a maximum auto ISO. You set the highest level you want your auto ISO to go to, and it will not go beyond that point.
You can also enable a minimum shutter speed so you don’t end up with blurry photos when the auto ISO selected an ISO of 100 while in a dark room and decides to use a shutter speed of 1/2 second. With the minimum shutter speed, you can make sure the shutter speed wont drop below your desired speed when using auto ISO.
Auto ISO is not perfect, but it can come in handy when you are on the move or in a rush. It might choose the wrong ISO sometimes, but for the most part it gets it close.
Try it out
To better understand ISO and what your cameras maximum ISO is, go into a dark room and set your camera to ISO 100. Next put your camera into “P,” or Program Mode. Photograph the same subject while increasing the ISO every shot. Start at ISO 100, shoot, ISO 200, shoot. Keep going until you can not raise your ISO any more. Now is a good time to test out the Extended Range ISO to see how it looks. You may need to enable it in your camera settings. Next, open these photos on your computer, and zoom into it 100%. Look at how noisy the image quality gets before it becomes unacceptable. Remember this ISO, and know that this is the maximum ISO you can set your camera to and still get acceptable image quality.