What parameters are used for shooting with a 420-800 ultra-telephoto zoom lens?

As an astronomy enthusiast, with the mentality of buying an "adult toy", I bought this telephoto lens modified from a monocular telescope with two lenses added. I almost watched it before buying it. All presentations and purchase reviews from one of the few online. The aperture of this lens is F8.3 at the 420mm end and F16 at the 800mm end. The aperture decreases with the focal length (the larger the value, the smaller the aperture). This lens is designed to have a smaller aperture and when the focal length is determined, the aperture Cannot be adjusted. Generally speaking, under the condition that the ambient light and camera parameters remain unchanged, the longer the focal length, the darker the picture. To take good photos with this lens, ambient light and SLR cameras are particularly important. This lens has the best image quality at the 420mm end.

Judging from the real-shot samples, the image quality and sharpness in the center area are obviously better than those at the edges, but the overall image quality is definitely lower than that of our commonly used brand lenses. Shooting in full manual mode (M mode) makes it easy to set various parameters to achieve the best picture based on this lens. It is recommended to use Sony’s high-sensitivity full-frame models, such as the A7 series. The reason for using the A7 series is that it has the purest high-sensitivity currently, which will be discussed in detail later.

Since the aperture of this telephoto lens is too small, if you want to take clear and bright pictures, it is recommended that the shutter speed be above 1/800, so that the picture can be clear enough by magnifying 100%. Because the focal length is too long, when the shutter speed is slow during use, even if I use a tripod + wireless shutter, the camera shake of the camera itself will cause blurry images, so the shutter speed needs to be very fast to get clear photos. To take beautiful photos with this lens, you need to use a high-speed shutter, and the aperture of the lens itself is very small, so you can only use bright light and the high sensitivity of the camera to determine the success or failure of the photo. Bright light can only depend on God ( Using this lens does not involve artificial lighting). In most cases, you still have to rely on the camera's CCD or CMOS and set a corresponding high ISO to capture high-sensitivity photos. This is why I recommend this lens for the A7 series. Finally, to use it on the A7 series, you also need to select "Allow shutter release without lens attached" in the settings.

To sum up, in order to take relatively good quality photos with this head, you need to set the focal length at 420mm on a sunny day, when the light is strongest at noon, the air is clear and haze-free. End, shoot the picture with the center composition as the main focus. I have seen starry skies shot by others using Canon 600mm/F4. The image quality is indeed great. Canon is also an official partner of NASA, but it costs tens of thousands to obtain images, and the lens is very heavy, so the tripod needs to be heavy-duty to be stable. Although the aperture of this lens is too small and the edge quality is very weak, it has the advantages of being cheap and lightweight. For amateurs, if they play well and play well with the equipment in their hands, they can take "beautiful pictures" to the maximum extent. This lens can be used with the A7 series to shoot most starry skies. PS: I am using Sony A7Rii, M mode, commonly used shutter settings are 1/1000, and sensitivity is between 100-12800. To quote a famous saying: “Whether the shot is good or not depends more on the head behind the camera.

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