The problem you often encounter but can’t always understand-magnification
Hello everyone, I am Dashi, and today I bring you a new issue of “Speaking the Truth”. In the previous episodes of “Speaking of the Truth”, we talked about flange distance, back-illuminated sensors, and retouching displays. So what are we talking about in this episode?
Let me tell you a phenomenon first, that is, you will find that when many lens manufacturers introduce new macro lenses, they use a larger magnification as a promotional point, so some people want to shoot macro My classmates always think that the larger the magnification, the better the macro lens. In order to solve this doubt, let’s talk about the magnification of the lens.
Usually we will look at the parameters of the macro lens To a value is called the magnification. Like Canon’s 100 micro and Nikon’s 105 micro are macro lenses of 1:1 magnification, our common Tamron’s 90 micro and Sigma’s 70 micro are also 1:1 macro lenses.
At the same time, we may have seen many macro lenses that do not have a 1:1 magnification. For example, Laowa’s 60micron is a 2:1 magnification, so you want to understand the difference between magnifications We must first understand what magnification is.
The magnification is the performance parameter of the optical lens, which refers to the object passing through the lens The ratio of the imaging size on the focal plane to the actual size of the object.
In the camera lens, it is generally called “maximum magnification”, which means that the lens is in:
1. Maximum focal length;
2. The closest shooting distance for clear imaging;
magnification value under two conditions. The magnification value at this time is the maximum value of the lens magnification.
Do you not understand? It doesn’t matter, just give a small example.
For example, the nominal magnification of a 70-200mm focal length lens is 1/6.5, which means that when the lens is shot at the 200mm focal length and the shortest shooting distance that can be clearly imaged, the image on the focal plane is The ratio of the actual size of the subject is 1/6.5.
The magnification of most lenses is less than 1, which means that the imaging of most lenses is actually reduced, and the so-called 1:1 magnification is the real size of the image and the object. .
If you still don’t understand, I can give another example.
For example, use a 100mm focal length macro lens with a magnification ratio of 1:1 to shoot at the 100mm focal length and the shortest shooting distance for clear imaging. To shoot a 10mm object, 35mm film is full frame On the camera, the diagonal length of the full frame is 43.3mm. If the photo is finally printed as a photo with a diagonal length of 43.3mm, then this thing should be 10mm inside.
Similarly, if you use a 60mm focal length macro lens with a magnification ratio of 2:1 at 60mm focal length and the shortest shooting distance for clear imaging, you can shoot a 10mm thing on 35mm film That is to take a photo on a full-frame camera. If the photo is finally printed as a photo with a diagonal length of 43.3mm, then this thing should be 20mm in size, which is the meaning of the 2:1 magnification of this lens
So what’s the use of different magnifications? Let’s take a look at the picture below
The same butterfly, the butterfly itself The size of the camera remains the same, but if you use lenses with different magnifications, you will find that the photos taken are different. As the magnification increases, from the full-view shooting of the butterfly to the detail shooting on the butterfly wings, this is the most obvious application of magnification—detail shooting. Therefore, the smaller the details to be shot, the more you have to choose a lens with a high magnification. For example, in the photo below, you can guess what it was.
I don’t think many people can imagine that this is actually salt. It is the kind of refined salt that is usually used for cooking. Such a small thing is photographed one by one under 5X magnification. I think many people only know that each grain of salt is square, right? This is the charm of high-magnification shooting. Many super macro shots use lenses with higher magnification.
But if you look carefully at this photo, you will find that the high magnification can not only capture the details clearly, but also has a disadvantage, that is, the depth of field is relatively shallow. My aperture is very open for this salt photo. It is small, but the salt grains in front are still blurred. You can imagine the distance between the front and rear salt, how tiny it is. Let’s look at the photo of the butterfly just now again.
As the magnification increases, it is indeed more and more photographed The details of the butterfly, but can you still see that it is a butterfly at 5X magnification? Therefore, in the shooting of macro subjects, the most detailed part is usually not pursued. For example, if you take a photo of a unicorn, what you need is the state of the unicorn, not the full frame but the depth of field is very shallow. The head of a unicorn.
So the application of magnification in macro shooting is not Detail shooting, what is that? Let’s take a closer look at the photo of the butterfly above. From the whole picture to the details, it feels familiar, right? Does it feel like a scene shot?
Yes, you can use magnification in macro theme Think of it as the shooting size of the subject scene at the closest focusing distance. If we are shooting an ant, then the small magnification will be the panoramic or medium shot of the ant, and the high magnification will be the close-up or large shot of the ant. close up.
As we know, the macro lens is not the larger the magnification The better, unless you are shooting in detail, you still have to make a proper choice according to your ideal subject shooting scene. Alright, the truth of this issue is over here.
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