Use DSLR in macro photography
How to use DSLR in macro photography
Single lens reflex cameras are referred to as such because they have a mirror inside the camera body that reflects the light directly from the
lens to a prism at the top of the camera and into the viewfinder. The photographer sees exactly what the camera sees. When the photographer takes a picture, the mirror is quickly pulled up out of the way so that light falls on the camera’s film or digital sensor, which is why these cameras are referred to as reflex cameras. The main advantage of SLR cameras is that they can be relatively small yet permit the attachment of a wide range of lenses for different purposes. Also, the photographer sees exactly what the camera sees with no parallax error. The relatively compact nature of SLR cameras and the ability to attach a wide range of lenses is what makes them so popular.
Digital SLR cameras come in two basic forms, depending on their sensor size. A full frame digital camera has a larger sensor that is the same size as 35 mm film. When you attach a lens to this camera with a specific focal length e.g. , 100 mm, then that is the true focal length of the lens. There are also SLR cameras with slightly smaller sensors, sometime referred to as APS (Advanced Photo System). When you attach a lens on these cameras, the focal length is usually multiplied by about 1.5X such that a 100 mm lens becomes a 150 mm lens. The result is a slightly different angle of view and in the case of telephoto lenses, the result is greater magnification.
Some lenses are manufactured for use only with cameras with smaller sensors (Nikon Calls them DX lenses, Canon calls them EF-S, Pentax DA, Sony DT, Sigma DC, Samsung NX, Tamron Di II and Tokina DX). Lenses designed for use with the smaller SLR sensors are usually cheaper, but cannot be used on a full frame SLR camera without some vignetting or image cropping. Lenses designed for full size sensor SLR
cameras can be used on both types of digital camera; however the apparent focal length of the lens will be different e.g., 100 mm macro lens will become a 150 mm macro lens on an APS camera (some APS cameras multiply focal length by 1.3, 1.5 or 1.6X). The ideal solution, if you can afford it, is to own two camera bodies, one with the smaller APS sensor and another with the full frame sensor.
Not only is the number of pixels in a sensor important, but so is the size of the sensor and the size of the sensor pixels in determining picture quality. A large sensor with the same number of megapixels as a smaller sensor will result in better quality images because the individual pixels are bigger and more sensitive to light. Similarly in the past high ISO speed film e.g., 1600, was more sensitive to light because the silver halide crystals were bigger; however, this also resulted in images with more graininess. For this same reason, an SLR camera with the same number of megapixels as a compact camera will always have better quality images, as the sensor in compact cameras is usually smaller. Bigger pixels mean they have a larger area to capture photons of light, and the result is better signal to noise ratio, which simply means less grain and smoother tones, especially when using higher ISO speeds.
A normal 50 mm lens allows you to achieve about 0.25X magnification, which is fine for taking pictures of some flowers and groundscapes. To get even closer and higher magnifications there are a number of options:
- Attach close-up filters to a lens (also called supplementary filters in some books).
- Attach extension tubes between the lens and the camera.
- Attach variable extension tube or bellows for high magnification work .
- Use a reverse lens adapter or stack two lenses together, with the smaller front lens reversed.
- Purchase a macro lens.
- Attach your camera to a stereo microscope or light microscope.
- Attach your camera to a Scanning electron microscope