This way, no out-of-focus bands will be visible in the final composite. The key is to ensure DoF overlaps in adjacent photos of the stack.
BEST FOCUS STACKER DEVICE SERIES
The starting point for focus stacking is a series of images focused at different planes, such that the circle of confusion on different areas in the image plane will be small enough and the final output will be considered as sharp. An additional asset of focus stacking is to remove sharpness falloff due to field curvature and lens misalignment. Moreover, focus stacking allows the generation of images that are physically impossible with normal imaging equipment, i.e., images with nonplanar focus regions or generation of out-of-focus areas (subject isolation) when using camera phones with a small image sensor, bokeh for the masses, so to say. 28 mm, f/8.Īlternatively, one may wish to freeze motion in one part of the image, but still preserve a large DoF in another. A scientific paper by Jeff Conrad on this subject (albeit aimed at the large-format shooter) can be downloaded here.Ĭampanile, Venice, Italy: Three-image stack composite. The theory and practice of obtaining maximum depth-of-field in a photograph is complex and would be a good subject for a future post, in particular when it comes to the medium format look. This happens relatively early (f/5.6) for high resolution full-frame cameras. These planes are always at right angles to the sensor plane unless we explore view cameras or use tilt/shift lenses on DSLRs.ĭepth of field can be increased by stopping down the aperture (larger f-number), but beyond a certain point, diffraction counteracts the benefit of reducing lens aberrations and of bringing the scene into focus. The acceptable sharpness between two planes on either side of the focal plane is known as the depth of field (DoF). The diameter of a sufficiently small blur spot is known as the acceptable circle of confusion. If this disk is sufficiently small for a given magnification and viewing distance, it will be indistinguishable from a point. Any point of a subject in another plane will be imaged as a disk, know as the blur spot. It is important to recall that for every single, non-stacked, image there is one (and only one) plane in the subject space at which the image points on the sensor are exactly sharp, that is, point like. This is often so in macro, landscape, and architectural work. This is particularly useful in situations where the scene has a large range of depths in the subject space compared to the shallow depth of field obtained for a given sensor size, focal length, and aperture combination. 85 mm, f/9.įocus stacking, also known as z stacking or depth of field blending, is a technique that combines multiple images focused at different planes, to obtain a greater depth of field. Toscana, Italy: Three stack composite along the horizontal lines of the fields.