WHAT IS ISO? HOW SHOULD USE ISO USE IN PHOTOGRAPHY?
Hello dear readers of fotografmania.com. From the shutter-aperture-ISO trio, I tried to explain the aperture in my first post and the shutter in my second post. Next is the third component ISO, which is very important in terms of photography. In this article, I will focus on what is iso in photo, what are the effects of iso on photography, how and where is iso used in photography.
What is ISO in Photography?
In the photograph, ISO refers to the sensitivity of a camera to light. In today’s photographic techniques, the most important feature directly related to the camera is ISO value. (what is the iso value: actually the word iso is used to mean ‘iso value’). For example, every camera has a shutter speed of 1/2000, but not every camera has 12800 iso, but the sensitivity of each camera to ISO 800 is not the same. Since ISO is one of the most important factors affecting the quality of photography, ISO performance will be one of the most important selection criteria when choosing a camera.
We said that ISO’s camera has sensitivity to light. In old film machines, these values were called ASA or DIN. ASA is an American origin standard and DIN is a German origin standard. The ASA, ie ISO features at that time, and the ISO features used in current digital machines are similar, but different in principle. Obviously, although the ASA feature used in film machines does not affect the photo quality much, the ISO feature that is currently used is a factor that directly affects photography on DSLR machines. ASA is related to the degree of exposure of the film. For example, a film of 800 ASA is designed to take photos in low light. Therefore, in low light environments, the film will be exposed chemically and the photograph will be taken with the correct exposure. There is no image loss. However, since ISO performance will cause what we call noise, the upgraded ISO in digital machines directly affects the image.
ISO stands for photography in ‘International Standard of Organization’. So ‘international standard organization’. What should be the answer to the question “What is ISO?
Factors Affecting ISO
We said that ISO success is the most important feature that should be looked for in a camera. There are several factors that affect ISO performance in our cameras. The most important of these is the processor of the machine. The better the processor of the camera, the more advanced technology it uses, the better the ISO value is expected. A second feature is related to the sensor of the machine. The larger the machine sensor, the better the iso performance. This is also a physical rule. ISO performance will be more successful as more light will fall on the larger area. Medium format cameras are expected to have higher ISO performance than any other machine. Full-frame (or 35mm) cameras’ ISO performance is expected to be better than cameras with crop sensors or smaller sensors.
Let’s clarify a situation that can be misunderstood while sharing this information: ‘‘ My camera has the highest 25600 ISO, but the full frame X camera has the highest iso 3200. Isn’t my camera’s ISO performance better? ” It is not exactly true. The sensor effect we mentioned is valid for the same ISO values. In other words, the image quality of the d5500 with 3200 ISO Nikon Crop sensor and the d850 with 3200 ISO Nikon Fill Frame Sensor will not be the same. Of course, since the d850 is full frame, ISO performance is expected to be better. Max iso performance and iso performance are not the same.
At the same time, the technological advances increase the ISO sensitivity of the cameras. For example, in models produced in 2008, while the ISO value is about 6400 at most, today (2018) models with 409600 ISO values can be produced. For example, Sony full frame mirrorless a7s ii model has max 409600 ISO.
ISO’s Effect on Photography
With the increase in ISO value, the noise rate in the photograph will increase. Noise directly affects quality. If noise is not desired, ISO is foreseen to be kept at the minimum value. In today’s cameras, the ISO values are expressed in sequential numbers, one of which is 2 times the other. When minimum ISO 50 is accepted, it progresses to 100, 200, 400, 800, 1600, 3200, 6400, 1280, 25600, 51200, 102400, 204800, 409600… respectively. These are the exact stops of the ISO values, and the next ISO value represents 2 times more light sensitivity than the previous ISO. In other words, the shutter value at 100 ISO and the shutter value at 200 ISO will be double. (at equal apertures). For example, if you want to take the photograph taken at 1.8 aperture, 1/50 shutter speed and 100 ISO, you should use 1.8 aperture but 1/100 shutter speed if you want to take 200 ISO.
Where And How To Use High Iso In Photo Shooting
“If the quality of the photo decreases when the ISO value is increased, why will we use high ISO”? The answer to this question is directly related to the shutter speed. While taking some photos, we see that our shutter speed is lower than desired. In order to reach the shutter speed we need, we need to raise the other ISO. In case of insufficiency in this type of shutter speed, especially ISO is used.
If we need to give an example; Let’s assume that we took photos with our kit lens in the evening. The kit will likely give f5.6 aperture when we zoom into the lens. It is not possible to give a lighter diaphragm. According to this diaphragm, the shutter speed required for taking pictures is about 1/80 – 1/100. Unfortunately, since we cannot get a shutter speed of 1/80 for f5.6 aperture in low light; it will probably be a speed of 1/5. In order to increase to 1/80 shutter speed, we will need to increase the ISO value. In this case, we need to adjust the other ISO to 1200 level. When we bring iSO to around 1000, we can have a snapshot value (about 1/80) that we can take pictures on hand. Therefore, while these changes mean that we waive the quality of the photo, it means that we can pose the photo correctly. Otherwise, it is impossible to take pictures at 100 ISO and 1/5. If the details of the camera will not be lost in ISO 1200, it is okay to increase the ISO value.
To what value can we raise the ISO? It is relative. It varies greatly from person to person, the type of photo, the light of the environment and the performance of the Camera.
To summarize:
* High ISO value is undesirable in the photo.
* I recommend that you force the minimum possible conditions in order not to raise ISO.
* The main reason for upgrading ISO is the lack of snaps. If you are going to shoot by hand, you can use a lens with vibration damping or you can choose camera models with vibration damping in the body. When I was using the sony a7ii, I could fall to 1/25 with a 100mm lens thanks to the vibration damper. This gave me 2 full stops of iso advantage.
* Another way to avoid high ISO value is to use a wide aperture lens, especially in low light environments. For example, with a 35mm f1.4, 1/30 snaps can be taken by hand. But if our aperture value was 4 instead of 1.4, we would have to make an iso increase of 2.5 stops for 1/30 shutter.
* You can interfere with ISO in all shooting modes except Auto modes.
* With RAW, you can intervene ISO better in photography
* If you are someone editing the photo, I recommend taking your photos RAW. In programs like PS, there are noticeable differences between editing the photo via JPEG output and editing it via RAW. RAW format is always more advantageous.
* If the subjects you are shooting do not contain moving items, use a tripod or stabilizer to keep the ISO value to a minimum. Thus, you can take the photo with the snapshot value you want.
* If you want to take noiseless photos in very closed or low light weather, you can try to fix yourself to objects such as walls, trees, poles to facilitate handheld shooting. Or have a monopod with you. You will see the benefits of these.
* If you need to increase the ISO value, increase it. After all, this feature is not in vain on machines.
* When making a camera preference, consider the sensor dimensions. Evaluate Full Frame cameras if you can afford it. See APSC sized machines that didn’t. ISO performance of m43 system machines with 2x multiplier is lower than the others. But they have extremely beautiful machines in terms of optical quality and ease of use.
* Some photos can be taken with high iso values. In such cases, it is also useful to use cameras with good ISO performance. For example, Milky Way photos are taken with high iso depending on the focal length of the lens. For example 2000 ISO (20 sec-f8 etc.). Some cameras take photos like mud, while others show masterpieces.
In this way, we complete ISO in photo with SHUTTER – APERTURE, which is the 3 components of the photo. You can click on the words for the other two values.
May your light be of good quality.
