Understanding the Exposure Triangle - Relation Between Aperture, Shutter and ISO

in our practical sessions for aperture ISO and shutter speed you must have noticed that I chose an f-stop or an ISO value and increase it gradually to demonstrate certain concepts I must admit when incrementing the values for aperture that is the F stops I didn't follow any logic I just incremented them randomly to help you understand the depth of field concept and to show you that aperture shutter and ISO are part of an exposure triangle and they work together it is important however that you know the logic behind these values and how they are related in your camera settings I am going to show you a chart in this lecture and with the help of a few examples we will learn how to adjust values in relation to one another here is a table of possible f-stops depending on your camera and lens starting from the top note that each f-stop lets twice the amount of light in as compared to the previous f-stop for example f/8 let's twice the amount of light as compared to f11 f11 let's twice the amount of light as compared to f-16 and so on as the aperture value increases the hole of the lens becomes small and less light comes in at f64 the lens will have its smaller aperture size what if you don't want to let twice the amount of light into your camera because of the scene in front of you well for that you can use values in between these numbers which can be halves for example you can use f 1.7 as a value in between F 1.4 and F 2.0 if that doesn't work you can use values which are available in thirds for example f 1.6 or f 1.8 here is a table of possible shutter speeds depending on your camera starting from the top each value allows the shutter to remain open twice the amount of time as compared to the previous value for example fifteenth of a second as compared to thirtieth of a second you can even go slower than one second for example two second three four and up to thirty seconds depending on your camera you can even go to halves and thirds just like f-stops here is a list of all ISO values depending on your cameras make starting from the top each value makes the sensor twice sensitive towards light as compared to the previous value for example is 100 makes the sensor twice sensitive as compared to ISO 50 depending on your camera you can also go in thirds for example ISO 253 2500 six forty one thousand one to 500 and so on and here is a combined table of shutter aperture and ISO these are whole values and not halves or thirds what do these values mean together let's look at an example and see how I adjusted values in manual mode to achieve the exposure just note that this is an example to show the relation between the values and the results you can obtain it is good to print this chart and keep it in case you need to make adjustments yourself have a look at this image which is straight out of the camera it was shot in manual mode the shutter speed was 15th of a second the f-stop was f11 and ISO was 100 I decided to change the ISO value from ISO 100 to ISO 200 this means that the sensitivity of the sensor was doubled here is the result you can see that the image on the right side is brighter because ISO was changed in my opinion the photo is a bit overexposed now to correct the overexposed photo I had to make a choice between changing the f-stop or the shutter speed I decided to adjust the f-stop because I increased the sensitivity by adjusting the ISO I had to bring the f-stop up to have a smaller aperture hole so that even less light comes in so I decided to increase the f-stop from f11 to f-16 this is exactly a one stop shift and as you can see the results despite different values both photos look the same now this is because I not only adjusted the ISO but also the f-stop to compensate for the ISO change I decided to change the ISO value again from 200 to ISO 400 this means that I double the sensitivity of the cameras sensor as you can see the image on the right is again a bit overexposed because of ISO 400 to compensate for ISO shifts from iso 200 to iso 400 I could either increase the F value or the f-stop by one stop that is from f-16 to f-22 or increase the shutter speed by one stop that is from fifteenth of a second to thirtieth of the second I decided to go with the option of increasing the shutter speed by one stop because I change the ISO by one stop although the values are different in these two images they look the same because ISO 400 make the right side image more sensitive to light but a fast shutter speed of 30th of a second balance the image and prevented it from getting overexposed if you look at these three images with totally different camera settings they are perfect exposures the difference between image 1 & 2 is of ISO and F value the difference between image 2 & 3 is that of ISO and shutter speed all these three images however have the same exposure the relationship of ISO aperture and shutter speed must be kept in mind while shooting as a change in one value affects the other's print a chart of stops and keep it with you as we advanced in the field of landscape photography you will come across situations where manual adjustments or an informed decision will be required on the values of shutter ISO and aperture for example when using graduated neutral density filters or nd 10 stock filters the settings are done manually when taking star trails or catching Milky Way at night decisions on the exposure triangle are required to be made for now practice with different values and see the results the more you practice the more it will be easy to deal with the situation in real-world scenario whether you are in aperture priority mode shutter mode or manual mode

Channel: Mujahid Ur Rehman

Views: 70,651

Rating: 4.8436608 out of 5

Keywords:

Id: F2tooh2xoNI

Length: 7min 49sec (469 seconds)

Published: Sun Aug 07 2016