A big role is played by the kind of lens you use for taking photos of a play in a theatre. The camera body matters, sure, but the choice of lens often matters even more because you can’t always take usable photos with the camera’s kit lens.
Use a Fast Lens
You should have a lens with a wide aperture. A wide aperture allows for more light to enter the camera sensor, hence brightening up the images and reducing the need to slow down the shutter speed or crank up the ISO. This is essential, as a slow shutter speed will cause your images to blur and a high ISO will add unwanted noise.
Use a Wide Lens
Wide angle lenses are made to capture more of a scene than a normal lens can. These can not only help you take some great photos of the actual theatre when it’s empty but also help you in capturing images of the whole stage if you cannot find a good spot away from it.
Use a Telephoto Lens
If you do manage to find a good spot away from the stage, and if it’s high enough that the audience’s heads don’t get in the way of your shots, consider using a fast telephoto lens. You can use the extra range that a telephoto lens brings to bring your subjects much closer to your camera sensor than they actually are.
Every kind of lens serves a different purpose, so take a good look at the different types available and then make a purchase decisions based on the tips mentioned here. Your theatre photographs will thank you for it.