Photography camera classroom

"This camera has N times the length of the lens, and it is super easy to shoot cats! 」

"Those specifications are not important. Look at this camera ... Barabara. "

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Buying a camera is like buying a stereo. If you don't know what you want and what specifications you need, if you unfortunately meet an unscrupulous camera shop, you will often be regarded as a fat sheep. Maybe many people want to do some homework before buying online. Although there are countless camera specifications teaching online, how many people can really understand what "aperture" and "focal length" are? So today, I will try to introduce you to the three specifications most often mentioned by the store when buying a camera in a simpler and more straightforward way: film size, focal length and aperture. Although there are many points in buying a camera, according to my personal experience, these three camera specifications are usually the most frequently mentioned and the most easily confused. So today, we will introduce the meaning of these three specifications in a relatively easy-to-understand way, and how to choose the appropriate specifications according to our own needs. The following will be introduced according to the three specifications of "frame", "focal length" and "aperture", hoping to bring some help to all those who want to buy a camera!

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First, the key to determine the image quality and depth of field: the size of the film

Above: Remove the micro lens, and the green thing inside is the photosensitive element.

No matter whether you take photos with your mobile phone, or with a small camera, micro-monocular camera or monocular camera, as long as you use a "digital" camera, your camera will definitely have a "photosensitive component". The photosensitive element can be said to be the "negative" of a digital camera, which is responsible for recording all the image information. It can be said that it is the most important core of the camera body, and it is also one of the most important factors that determine the image quality besides the lens. So now the question comes: Is it true that the shop assistant said that "the size of the film is very important"?

First of all, we need to know "what is film size". Due to the consideration of cost and camera size, various manufacturers produce various photosensitive elements with different sizes. The so-called "film size" refers to the size of photosensitive elements. The following figure shows the size comparison of various photosensitive elements. The largest orange frame is the Quan Huafu FF photosensitive element used by professional monocells and Sony A7 series miniature monocells, which is equivalent to the size of traditional negatives. The next APS-C is a photosensitive element used by ordinary non-professional monocular, Sony or Fuji micro-single, and its area is smaller than the whole piece. As for M4/3, it is the size adopted by Olympus and Panasonic, and the next size is the size of photosensitive elements used by smart phones and consumer cameras!

As far as the current technology is concerned, the size of the film has the most direct and important influence on users: image quality details, depth of field, focusing speed and accuracy. In order to avoid it being difficult for everyone to understand these three items, here are the explanations!

1. Image quality details:

The bigger the film, the more light you can absorb, so you can have more details in the light and shadow color of the image, even the cat hair in the cat shop at first, than the small film. If you often look at big pictures and plan to engage in photography-related work, or if you are naturally too sensitive to image details and have a microphone, then a full-size model is definitely your best choice. If most of the photos you take are just shared online and you want to take photos more easily and simply, then the smaller APS-C and M4/3 systems are your good partners ~

2. Depth of field lens:

The larger the film, the shallower the depth of field under the same aperture. In other words, the scattered scenery outside your subject "will be more paste". If you like to take all kinds of shots to improve the texture, then you have to buy at least 1 inch photosensitive elements (such as Sony RX 100) or M4/3 camera to have the same beautiful shot as the cat picture at the beginning! Expensive, small-scale selfie artifact, you can never shoot that kind of beauty! !

3. Focusing speed and accuracy:

Is focusing speed important? If you often take pictures of dogs and kittens with your camera, it is a great test whether your camera can focus on the moving little guy smoothly. If you don't have a high budget to buy a camera, and you can't directly hit the high-order monocular, then the focusing speed and accuracy of M4/3 system will be better than that of APS-C monocular camera with the same budget within the budget of 20,000 to 30,000, and even some high-order Quan Huafu monocular cameras may not be better than M4/3 system! If you want to strike a balance between image quality, focus control and price, then M4/3 system is definitely your best choice!

In addition to the above three key points, the small-piece fuselage has a great advantage: small size. M4/3 system camera is much smaller and lighter than APS-C and all-film camera, so if you want to put a camera with good image quality in that beautiful small bag, then a small camera with M4/3 or 1 inch photosensitive element is definitely the best choice! As for the down in the smaller size? I think unless you don't have a smart phone, use that money to buy a bigger camera! Stop wasting money!

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The second is to watch it take a close shot: the focal length of the lens.

Before you begin, please remember the following information: Because the focal length of all lenses is based on the whole frame, the body of a small frame must be multiplied by different numbers to become the so-called "equivalent focal length". For example, the focal length of the lens on APS-C must be multiplied by 1.5, then? The 20mm lens will become 30mm on the APS-C fuselage, and instantly change from a "super" wide-angle lens to a wide-angle lens. The smaller M4/3 must be multiplied by 2, so that the 85mm portrait mirror will instantly become a 170mm telescope head! This is why the focal length of M4/3 fisheye wide-angle lens is only 8mm, not that M4/3 lens is super powerful, but that if it is not so short, multiplying by two will have no wide-angle effect!

The focal lengths I mentioned below are all based on Quan Huafu, so if you plan to buy an M4/3 camera, please divide my focal length by two and the APS-C camera by 1.5, so as to get the correct focal length you need! So you won't buy a camera by mistake!

"Look, the lens of this camera is 12 times ..." After solving the troublesome problem of film size, the second troublesome problem comes again: how much focal length does your camera need?

In fact, the magnification of the camera, whether the camera can see far or not, and whether it has a wide angle are all determined by the focal length (in mm) of the camera lens, so you can associate the three terms of magnification, telephoto and wide angle with the focal length, so that you can quickly understand what the focal length is used for.

The so-called wide-angle lens usually refers to the lens below 50mm, while the lens below 20mm is the so-called "super wide-angle lens". The characteristic of wide-angle lens is that even if you put the camera very close, you can shoot a wider perspective of "things are still far from you" Take the above picture as an example. The camera is so close to the cat. If it is a mobile phone, it will almost only capture a cat's head. But what is the effect of actually shooting a 20mm wide-angle lens?

This cat is too far away ! As can be seen from the above picture, if you have a wide-angle lens, then you can shoot cute little things at close range, such as the cat sitting on the leg like the picture below, or the food in front of you!

Image above: Wide-angle glasses are a good choice to avoid just patting the cat's head and want to pat the cat's whole body on its legs.

In fact, the general purpose of wide-angle lens is to shoot scenery, as shown in the above picture, but in fact it can shoot more scenes at close range, so it can be used to shoot more pictures in a narrow space, which can be said to be a very versatile lens choice.

Then there is the so-called "telescopic" lens! Usually when we buy a camera, the clerk will say "this is X times" camera. But what exactly does this x times mean? In fact, this multiple only refers to the difference multiple between the wide-angle end and the telephoto end of the camera. For example, the wide-angle end of a lens is 24mm, and the telephoto end is 120mm, with a difference of five times, which is a digital camera with "five times (5X) optical zoom". And the focal length above 80mm is also a telescope! This kind of long focal length lens allows you to shoot from a distance. However, if you want to shoot the cat on the roof, or the bird in the tree and other distant objects, then you need a lens above 150 mm, so now everyone knows that although the "multiple" of the camera can let you know whether the camera has the telescope function (usually more than 5X is the telescope), if you want to buy the camera or lens you want more accurately, it is absolutely very important to understand the meaning of "focal length".

Reciting formula: the smaller the focal length, the wider the lens, the larger the focal length and the farther the lens.

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Third, the key to decide whether you can shoot at night and whether there will be a fascinating scene: aperture.

Aperture is actually like a person's pupil, which can be used to determine the amount of light entering the lens. Generally, the numbers marked on the lens such as f 1.4, f 1.8, f2.8 and f4 (for example, 1.4 in the above picture, Nikon lens does not write "f") represent the "maximum aperture" of the lens, and the minimum aperture of the lens is usually not marked, so just pay attention to this maximum aperture.

Note 1: The larger the aperture, the smaller the number marked. So the aperture of 1.4 is larger than that of 4.

Note 2: The English code for aperture is lowercase "f", and the lens and camera are marked with f xx, and xx is the aperture value of the camera.

So what does maximum aperture mean? For the introduction of photography, we only need to remember two points: the first is to determine the maximum amount of light, and the second is to determine the degree of divergence of the scene. The so-called maximum light input is how much light can be input at the same shutter opening time. The larger the aperture (the smaller the number), the more light input the camera can get at the same time, so it can take darker images at a faster shutter speed, which can avoid problems such as hand shake and too dark images when taking pictures in dark places. For example, f2.8 can be compared with f6.3? A faster shutter can capture fast moving objects in dark places or avoid camera shake.

Another influence is the "divergence" of the lens. Due to the optical and physical characteristics, when the aperture is large (the aperture number is small), the photos will have a more dispersed shooting effect. For example, the photo of the cat (green background) in the above picture was taken with an aperture of f2.8, so all the shots except the cat are blurred. The above picture shows a cat photographed with aperture f8. You can see that the background is quite clear except for the cat itself. Simply put, the larger the aperture, the more mushy the background; The smaller the aperture, the clearer the binocular vision. However, it should be noted that large aperture shooting is only effective for large-size cameras (one inch, M4/3 or above), but not for small-size mobile phones and digital cameras (such as * * * artifacts)!

Back formula: a small number means a large aperture, and there will be scattered scenes; Large numbers are small apertures, with clear backgrounds, lights and stars in the sun.

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Seeing this, I believe everyone should have understood what the three important specifications of the camera represent respectively. In this way, you can easily master the camera specifications you need, and you won't be cheated by all kinds of strange marketing words! Just know the subject to shoot: for example, do you want to shoot far? Do you shoot things in a narrow space? Do you like taking pictures of scattered scenes? Do you often get excited about small things? As long as you know your own photography needs first, and then compare the above three specifications, you can list the camera specifications you need!

As for whether it is a single-eye, micro-monocular, quasi-monocular or digital camera? This is another question. Next week, I will introduce the characteristics and differences of various cameras, so that everyone can easily buy their own cameras! See you next week!

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Author: Chen Kun @ engadget