From Photographer’s Blog we want to make your life (photographically speaking) easier. That is the goal of each of the articles we write. That is why I am going to dedicate today’s post to telling you what the crop factor or conversion factor is about, which you have surely heard of or if you have just landed it will not be long before you hear it, as well as terms such as Full Frame, APS -C, crop factor… All these strange and ugly names have an explanation and my purpose this time is for you to understand them in the simplest way possible.
A little history
To situate ourselves and understand what we are talking about, I have to go back to the analog era (it seems that we are talking about prehistory and it is not that far in time, or so I want to think that if I do not realize how old I am getting 😉 ). When there were only analog cameras, different films were used, but the most used was known as 35 mm, and in fact it is still sold (36x24mm).
When launching the first digital cameras, they respected this size when manufacturing the sensor, which is what is known as a Full Frame sensor, however, the objective of any company is to sell, so they managed to sell more cameras. How to achieve it? Easy, making them cheaper and more affordable to reach a much larger audience. To cut costs, they reduced the size of the sensor and this is where the well-known crop factor comes in. Well, what they did was exactly that, cut the sensor.
In this image from Nikon you can see how the image is projected with a larger sensor and a smaller one. The area on the left would be the part of the scene that is captured with each sensor. Notice how the figure above representing the Full Frame sensor (FX for Nikon) covers a larger area.
Next, you will see what area each sensor would cover. The same image taken with a full frame sensor and a cropped sensor (for Nikon FX and DX respectively).
More information about Nikon, cameras and lenses in the complete guide that we have prepared for you).
In reality, the difference is basically that the scene appears “cropped”, since the sensor records less part of the scene to be captured. Most cameras have a conversion factor of 1.5 or 1.6x, which is the ratio of the 35mm sensor. This is where the conversions with focal lengths come from, since a 50mm lens, for example, on a camera that is not full frame and has a crop factor of 1.5 x translates into a apparent focal length of 75 mm (result of the following multiplication: 50×1.5=75). Below is a table of equivalences so that you can calculate the apparent focal length that a lens can have depending on the crop factor of your camera, I insist, the focal length apparent Hey? 😉 :
And I say apparent because it is not really like that, since the properties of said focal length, such as distortions, are not modified at all. To make it easy for you to understand (an expert may throw his hands up) imagine that you have a photograph printed on paper and you cut the edges. The image is exactly the same, but it is “cropped”, part of the scene is lost.
So that you can see it more clearly, I leave you a video of different comparisons with different objectives:
And what is better?
Now comes the million dollar question, which is better? Do I buy a full frame camera or one with an APS-C sensor (the one that most DSLRs that are not full frame have)? Well, the key is not in the answer, but in the question. Let’s rephrase it: do you really need a full frame SLR camera?
Many times we think that the most expensive is the best, or that the more options or properties a gadget has, the better it will be, without taking into account what actually best suits our needs. To be honest, I’ve been using a cropped sensor camera for many years, in fact lately the photos I take that my people like the most are taken with the iPhone. By this I mean that if you are not a professional photographer, you may not need to spend a lot of money to cover most of the scene. Perhaps it is better to spend your financial resources on expanding your range of lenses, or even practice a lot to improve your results and begin to enjoy photography even more. Don’t obsess over numbers, terms, or teams if you really don’t need to. Enjoy photography, learn to move, to tell stories, to compose correctly, to highlight the center of interest; to focus, develop your photographic eye and forget about conversions. Look, feel and shoot. That is photography.
Do not entertain doubts
I hope that my explanation has been clear enough for you and that you have understood this conversion factor, which in the end is nothing more than a multiplication to see what the apparent focal length of a lens is on a camera that does not have a full frame sensor. I’ve left you a table, if you can’t find the value you’re looking for, you just have to multiply the focal length of your lens with the crop factor you have on your camera (1.5x, 1.6x…). If not, please, do not stay with the doubt and leave your question in the comments. We are here to help you 😉
Thank you and see you soon!
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