The Nikon D3200 is a digital single-lens reflex (DSLR) camera that was released in 2012. It features a 24.2-megapixel DX-format CMOS sensor, full HD video recording, and a 3-inch LCD display. The camera is designed for entry-level photographers and offers a range of manual and automatic shooting modes to accommodate different skill levels. The D3200 is known for its high image quality and user-friendly interface, making it a popular choice for beginners and enthusiasts. **

Yes, Sigma lenses are available in Nikon F-mount, which is compatible with the Nikon D3200. As long as you choose a Sigma lens with a Nikon F-mount, it will fit and work perfectly with your Nikon D3200 camera. Sigma offers a wide range of lenses in Nikon F-mount, so you have plenty of options to choose from for your photography needs. **

The Nikon D3200 is not specifically designed for live streaming as it lacks features such as clean HDMI output and continuous autofocus during video recording. While it is possible to use the D3200 for live streaming with the right setup and accessories, there are better options available that are more suited for this purpose. Cameras with features like clean HDMI output, continuous autofocus, and better low-light performance would be more suitable for live streaming applications. **

The Nikon D3200 is compatible with Nikon F-mount lenses, which includes a wide range of lenses from Nikon as well as third-party manufacturers such as Sigma, Tamron, and Tokina. The camera is also compatible with both DX and FX format lenses, although DX lenses are specifically designed for crop sensor cameras like the D3200. Additionally, the D3200 can also be used with older manual focus lenses with the appropriate adapter. **

The Nikon D3300 is generally considered the best option among the three cameras. It has a higher resolution sensor, better low-light performance, and improved battery life compared to the D3100 and D3200. Additionally, the D3300 has a higher ISO range, better autofocus system, and the ability to shoot 1080p video at 60 frames per second. Overall, the D3300 offers the best combination of image quality, performance, and features among the three cameras. **

The autofocus of the Nikon D3200 works by using contrast-detection autofocus technology. This technology allows the camera to analyze the contrast in the scene and adjust the focus to ensure that the subject is sharp and in focus. The D3200 also has 11 autofocus points that can be manually selected or set to automatic mode, allowing for flexibility in focusing on different subjects within the frame. Additionally, the D3200 has a 3D tracking mode that can automatically follow a moving subject to maintain focus. **

The Nikon D3200 is compatible with a variety of macro lenses, but a popular and suitable option is the Nikon AF-S DX Micro-NIKKOR 40mm f/2.8G. This lens is specifically designed for DX-format cameras like the D3200 and offers a 1:1 reproduction ratio for capturing close-up details. It also has a fast maximum aperture of f/2.8, allowing for good low-light performance and shallow depth of field. Additionally, its compact and lightweight design makes it a convenient choice for macro photography with the D3200. **

To change the settings on the Nikon D3200, first, turn on the camera and press the "Menu" button. From there, navigate through the menu using the multi-selector button to find the settings you want to change, such as image quality, ISO, white balance, or autofocus mode. Once you have selected the setting you want to change, use the multi-selector button to adjust the options. Finally, press the "OK" button to confirm your changes. **