The final guide to the use of gradient lenses that photographers cannot use in landscape photography.

Now that we have good photographic equipment, all kinds of ND and GND, can we make a blockbuster movie? Not exactly, you just mastered the initial skills.

In practice, you will encounter various problems that will not appear in the tutorial. The essence of landscape photography is to think with the head behind the lens, see the tricks and take measures according to local conditions.

When many novices get their first cameras, everything in the world will be brand new to you. There are too many pictures to record and too many new knowledge to learn.

Many people think that it is possible to learn a few quick skills and the photos will change by leaps and bounds. In fact, many people ignore that photography, like other things, has a learning process. So please calm down and forget those shortcuts. Down-to-earth shooting is always more efficient than looking forward and backward.

Before you start your beautiful photography tour, you might as well take a look at these dry goods guides, which can really help you grow in your photography tour. I will explain the skills of using the gradient mirror in an illustrated way. Don't be too long, the fun is yet to come!

Since the invention of the camera, we have been trying to copy one of the greatest wonders of our body: the human eye. Unfortunately, although it has been over 100 years since humans first photographed light, we are still far from defeating nature. Why is this? Because your eyes are much better than your camera in the visible spectrum.

A, DYNAMIC RANGE (dynamic range)

Dynamic range is the ratio of the maximum value to the minimum value of a variable signal (such as sound or light). This basically defines the difference between the minimum and maximum brightness that a device (such as your eyes or camera sensor) can record. In the real world, dynamic range defines the camera's ability to see details in very dark areas and very clear (bright) scene areas.

If you want to know how much your eyes see, the answer is amazing. Your eyes can see and capture twice as much as a camera. ?

(1) Difference between tolerance and dynamic range:

So, this is why when you look at the beautiful sunset with your eyes, you can see all the details in the scene (in the sky and on land). But once you try to capture it with a camera, you will get an overexposed sky or an underexposed prospect. The dynamic range of the camera can only capture the details of an area, so it must be selected.

But even the best camera has only half the dynamic range of the human eye. So how can we hope to shoot a beautiful sunset or a wonderful sunrise and capture all the wonderful details?

There are different ways to overcome this problem, but my favorite is to use the medium density gradient grey mirror (GND).

(2) improve local contrast

Although the GND gradient mirror usually reduces the contrast of bright and dark parts, the contrast of each area actually increases, because the extreme tone is closer to the middle tone, which is where the contrast of the camera tone curve is the greatest (and where our eyes are most sensitive to the tone difference).

This is why many photographers often use GND filters, even though the dynamic range of the scene conforms to the normal function of the camera. Because it may provide more details to the clouds, more contrast to the ground, or make the picture more dramatic by darkening the sky.

In fact, for a professional landscape photographer like me, putting a set of high-quality filters in the camera bag is almost as important as a good tripod.

Second, what is a gradient mirror?

Gradient mirror, also known as GND filter, is one of the most important filters in photographic art creation. It can be divided into gradient mirror and gradient diffuser, and can be divided into soft gradient and hard gradient in gradient form. "Soft" means a large transition range, and vice versa, it means a small transition range, which should be chosen according to the creative characteristics.

GND is a filter composed of two different parts, a completely transparent area and a darker part. By setting the darkest part of the filter to correspond to the brightest part in the scene, the exposure difference (dynamic range) in the picture can be reduced. Reducing the exposure difference is to reduce the dynamic range of the scene, so that your camera can capture the details of the bright and dark areas of the scene at the same time.

GND was once a hidden secret of successful landscape photographers. Although 100 has been used for many years, many people may say that the gradient lens is out of date and post-processing is very popular now, but many photographers (including me) still like to "shoot correctly in the camera". In fact, the gradient lens can make up for the lack of CMOS native tolerance of the camera and solve the problems of overexposure in the bright part and blackening in the dark part in the early stage of shooting. Gradient lens is a filter often used in landscape photography, and it is also an indispensable tool for me.

Before sharing how to use the gradient mirror and the most suitable situation for it, let's introduce some basic knowledge.

Gradient lens is the most common landscape filter, and reverse gradient lens is now used by more and more people. The central gradient lens is also a special filter, which is of little practical use.

1, the type of gradient mirror.

GND is usually distinguished by the type of transition between the transparent area and the dark area of the filter. Therefore, we can determine three GND series.

(1) Hard Edge Gradient Filter:

It is characterized by a clear boundary between the transparent area and the dark area (obviously, a beginning and a beginning). Therefore, they can be used when the separation between bright and dark areas of the scene is very clear (such as the horizon on the sea).

(2) Soft edge gradient filter:

It is characterized by a soft transition (they gradually change from light to dark), so it is used when the transition between light and dark areas is not so clear. A typical example is shooting in the mountains.

(3) Inverse gradient filter:

The gray gradient lens of GND, commonly known as anti-gradient, is a special kind of lens. The darkest part of the gray is at the black-and-white junction of the lens, and the gray gradually decreases from the middle to the side (there will also be a small gradient down the middle, which can make the connection between heaven and earth more natural. )。 It is best to use this filter when the sun is close to sea level at sunrise and sunset.

When shooting scenery, our most common problem is that the light intensity of the sky and the ground is different, and it is impossible to balance the light ratio. If you measure the light in the sky, the ground will look gloomy. Ground-based exposure turned the sky pale. At this time, the medium gray gradient mirror can help you solve this problem. The medium gray gradient mirror is divided into different darkening intensities, and different filters can be selected according to different light to get the best exposure.

When is the reverse gradient mirror used?

Clouds in the sky are well-formed, with distinct layers and colorful at sunrise or sunset;

The best shooting time before sunrise is after sunset. After the sun goes down, the reflection on the water is even, showing a comfortable warm color.

If there is an object above sea level or horizon, the distance, shooting angle and shooting height of the object should be better, and the filter effect should be adjusted in time.

3. Style of gradient mirror

? Many people often ask me what size square filter I should buy to match the lens. Theoretically, square filters can be used on different filters through different filter rings, and most people want to use one set of filters for all lenses. The idea is beautiful, but the reality is not perfect.

Tip: Let's take a look at the common square filter sizes:

85mm square is suitable for lenses with aperture below 77mm and focal length greater than 18mm, and 85mm refers to the length of the short side of the filter. The 85mm filter was originally the standard size of the high-rise building, and it felt like it was eliminated. However, with the popularity of micro-single, the small filter system has found vitality again, but I would recommend 100mm instead.

100mm square is suitable for all lenses with aperture below 82mm and focal length greater than or equal to16 mm. Canon Nikon's 16-35mm can use 100mm filter, which is the most common and popular filter system and the first choice for beginners.

120mm square is only produced by a few manufacturers, which is not in the mainstream.

150mm square is suitable for large-aperture bubble lenses, such as Nikon 14-24mm, Longteng 15-30mm, Sigma 14mm f 1.8 and other mainstream super wide-angle lenses.

170mm square is an upgraded version of 150mm, which completely solves the problem of dark angle similar to Canon's 15438+0-24 mm lens, but the disadvantage is that it is too big and difficult to carry.

Three. Question and answer of gradient mirror use

Question 1: Why do squares have so many sizes?

Different sizes are mainly to solve the problems of light leakage and dark angle of super wide-angle lens. Light leakage is easy to understand. First of all, your filter must be larger than the lens to prevent light leakage. If you think about it for a long time, it can be inferred that small filters will also have dark corners when used at wide angles. Further extension, it can be considered that adding more filters is also prone to dark corners.

Therefore, it is well understood that the filter of 100mm cannot be applied to ultra-wide-angle bulb heads such as 14-24 and1-24. But is there a difference between 150mm and 170mm?

My practical experience is that the two filters on the 150mm filter bracket at the end of 14MM can basically have no dark angle, but most of the last three filters will have a little dark angle.

Question 2: Can 150mm replace 100mm filter?

The answer is yes. The technology of connecting the upper adapter ring and the card color 150mm to the 77mm or 82mm adapter ring is very mature. The gradient lens has been solved, and there is no problem with grey mirror and polarizer for small aperture lens. But in fact, I definitely won't use the 170mm filter on a small-caliber lens, because it feels like a big-headed doll, but it is still possible to do so occasionally in actual operation. Similarly, the 100mm filter can also replace the 85mm filter, which is one reason why the 85mm filter is rarely matched.

Question 3: Can I use a gradient lens for a medium telephoto lens?

As we all know, the focal length of a lens actually means different viewing angles. The wider the wide-angle viewing angle, the narrower the telephoto viewing angle. Imagine putting the filter near the lens. We can recognize the viewing angle scale of this picture as the correct scale, so I use three red boxes to represent the three most classic focal lengths: 17mm, 70mm and 200mm.

At first glance, I don't think the problem is big. It seems that the gradient is natural. Imagine that the picture is finally projected on the same CMOS, and the actual pixel size is the same, so I stretch the last two blocks to the same color block of 17mm to see.

It can be seen that at 17mm, the contrast between light and shade is 0.9, so the contrast between light and shade is only 0.3 at 70mm, and it is almost close to light and shade at 200mm. Of course, you can also use the following transitions by moving the gradient mirror, and the effect may be better, but the gear must be reduced a lot, and 200mm has almost become a grey mirror.

So I suggest that the limit of using gradient lens is 24-70mm lens. If the focal length exceeds 70mm, the gradient lens has no practical value, and so do grey mirror and polarizer.

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