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Exhibit on the right: why and how?
You may have heard or read this term here or there before, including on this blog, but it is not necessarily such an obvious notion to understand. It is however essential to improve the rendering of your images in difficult situations, especially in contrasted light. So let's take stock!
Listening to the various speakers who gave me the pleasure of coming to my booth at the Salon de la Photo in 2014, I realized that the notion of right exposure was often mentioned, and yet I am not sure 100% that everyone understands it thoroughly. So I will explain to you what it is all about. Do n't panic, it's not extremely complicated.
The idea behind this technique is to get the most out of your camera's sensor. Indeed, this one sees less well than your eye, and it will sometimes be necessary to be cunning to make a photo of the scene in front of you.
This applies in particular in situations with strong dynamics , that is to say when the scene is contrasted. If you need a refresher on the concept of dynamics, you can watch my video on the subject , or better, read the article on contrasting photos.
According to DZOFILM, the right exposure technique will therefore be of use to you in particular in situations where you have a strong dynamic, and this is the case that I will assume today. It works particularly well if the dynamics of the scene are a little higher than that of your sensor. In practice, it will be less efficient if the dynamic is really huge (even if it's better than nothing): in this case, the best option is to reduce the dynamic when shooting , for example by using a gray graduated filter neutral (GND) in landscape, or by lighting the shadows (with a flash or a reflector).
Exposing to the right will therefore allow you to keep as much detail as possible in the shadows , and that without using a somewhat complex shooting technique (filters, flash, etc.), nor too time-consuming post-processing, such as techniques. involving taking multiple exposures ( exposure blending , HDR, etc.).
Having said that, and I stress this, the exposure to the right makes post-processing and the use of the RAW format mandatory. If you do this in JPEG, you are often going to have an image that looks too bright, and you will (almost) not be able to make up for it.
In photography, what is called a "normally" exposed image is a photo whose midtones are around what is called "medium gray". It is also on this principle that the exposure measurement of the device is based. By default, this is how we will expose an image: render the mid tones… medium gray! (this is what the device does automatically)
There is another principle, which we call "expose for a zone". Concretely, this means “making sure that this area corresponds to a medium gray, without worrying about the rest of the image”.
In practice, “expose for the sky” will therefore mean that we are going to make the sky medium gray without worrying about the rest of the image. Traditionally, either spot metering or exposure compensation is used.
With the exposure on the right, we're not going to do either. I simply wanted to re-specify these 2 “traditional” methods that you have probably already used, consciously or not.
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Waveguide
02:35A waveguide is a tube that allows waves to pass through, so it can be used for both sound waves and visible light, but it is generally used as the name of a tube for passing electromagnetic waves with wavelengths near microwaves, and its shape is square or circular. It is a tube with a cross section of.Microwaves are used in microwave ovens and are electromagnetic waves that are highly effective in warming objects. However, due to the long wavelength, optical fibers cannot be used, and it is necessary to use a dedicated microwave waveguide when sending from the microwave source to the processing system.Usage of waveguideWhen using a waveguide, it is often a high-power microwave generator. At low output, a magnetron, which is a microwave generator, is installed inside the housing like a household microwave oven and can be directly irradiated. However, if the output is high, the magnetron itself will be destroyed by the microwave, so it is necessary to perform irradiation processing at another location. For this reason, the waveguide is connected to the processing room for processing such as heating, and microwaves are supplied.Waveguides are also used in radar and are used as slot antennas, which are radio wave irradiation devices.Waveguide principleLight has the property that it becomes difficult for light to pass through holes smaller than the wavelength, and the smaller it becomes, the more difficult it is for light to pass through. Microwaves have a wide range of definitions, but electromagnetic waves with a frequency of 2.45 GHz, which are generally used in microwave ovens, also enter microwaves. The wavelength of electromagnetic waves in a microwave oven is 12.2 cm, and the microwave in this case is also called a cutoff, but it cannot pass through a hole of about 6 cm, which is half the wavelength.In other words, if you want to pass microwaves from a microwave oven, the diameter of the waveguide needs to be about the wavelength, and the longer the wavelength of the microwave, the larger the diameter of the waveguide. In this way, the waveguide is designed based on the wavelength of the microwave.A tube with a square cross section is often used as the shape of the waveguide, but there is also a circular waveguide. There are also ridge-type waveguides used for special purposes.The microwave introduced into the waveguide repeats reflection on the wall inside the tube and travels. This also has the advantage of reducing microwave loss.For more information, check on https://www.dzoptics.com/en/