Photoshop CS6 will have a new Iris Blur tool that lets you quickly add blur to an image that fakes a shallow depth of field. It’s a one tool-process that eschews the traditional methods of using masks, layers or depth maps.
Posts Tagged ‘depthoffield’
You probably know that stopping down (i.e. increasing your f-stop number) can increase the sharpness of your subject, but how much should you stop down to boost resolution without losing that nice, creamy bokeh? Roger Cicala did some research on this question and writes:
For those lenses that do benefit, stopping down just to f/2.0 provides the majority of resolution improvement. The difference between wide open and f/2.0 is generally much greater than the difference between f/2.0 and the maximum resolution.
Getting the edges and corners sharp requires stopping down to at least f/4 for most wide-aperture primes, and some really need f/5.6. Stopping down to f/2.8 may maximize center sharpness but often makes only a slight difference in the corners, at least on a full-frame camera.
None of the lenses performed any better after f/5.6 (for the center) or f/8 for the corners. Most were clearly getting softer at f/11.
If you’re using a wide-aperture lens, stopping down to just f/2.0 will reap big gains in sharpness while still keeping the depth-of-field narrow. Furthermore, for some lenses you don’t really even need to worry about stopping down for sharpness, since it hasn’t a relatively negligible effect on the outcome.
Stop It Down. Just A Bit. [LensRentals]
Google scientist Sam Hasinoff has come up with a technique called “light-efficient photography” that uses focus-stacking to reduce the amount of time exposures require. In traditional photography, increasing the depth of field in a scene requires reducing the size of the aperture, which reduces the amount of light hitting the sensor and increases the amount of time required to properly expose the photo. This can cause a problem in some situations, such as when a longer exposure would lead to motion blur in the scene.
Hasinoff’s technique allows a camera to capture a photo of equal exposure and equivalent depth of field in a much shorter amount of time. He proposes using a wide aperture to capture as much light as possible, and using software to compensate for the shallow depth of field by stacking multiple exposures. In the example shown above, the camera captures an identical photograph twice as fast by simply stacking two photos taken with larger apertures.
Cell phone cameras have pretty poor image quality when compared with point-and-shoot cameras due to their small sensors, but one advantage they have over compact cameras is a naturally deep depth of field. That was particularly useful for this YouTube user in capturing some sharp video of his new motorcycle — something that would have been much more difficult using a standard point-and-shoot.
A compact camera probably isn’t the first thing someone would grab when looking to make a photo with an extremely shallow depth-of-field, since the small aperture and small sensor limit it in this regard. That might soon be different: a recently published patent application by Samsung shows that the company is looking into producing achieving shallow depth of fields with compact cameras by using a second lens to create a depth map for each photo.
Learning how to control depth of field with your camera isn’t too difficult, but do you know the science behind how it works? This uber-educational 20-minute video lesson gives a thorough explanation of depth of field and the different factors that affect it. It was made by artist Justin Snodgrass, and is also available for download (and in parts) over on his website.
(via Petrucci Francesco)
The Frazier Ultimate lens is like the universe’s anti-matter to the Canon 50mm f/1.0 that we shared yesterday. Rather than have a tiny depth of field and tons of bokeh, the Frazier lens is one that has massive depth of field, allowing both the foreground and background of the image to be in focus at the same time. It’s widely used in Hollywood and in wildlife documentaries, and the video above shows some of the visual tricks you can do when having infinite DoF.
DOF Calculator is an app for Android phones that helps you easily calculate depth of field and hyperfocal distances. Simply tell it your camera, lens, and aperture setting, and it’ll spit out the numbers you need for optimally sharp landscape photographs. You can download it for free by searching for “DOF Calculator” in the Android Market.
For a quick video tutorial on how hyperfocal distance works, check out this post.
The concept of hyperfocal distance is used in landscape photography to achieve the greatest depth of field and acceptable sharpness for both near and far objects. In the two minute tutorial above, wildlife photographer Chris Weston walks through some hyperfocal distance focusing techniques. You can also find a couple informative tutorials at DOFMaster and Cambridge in Colour.
Researchers at the University of Toronto have come up with a new video camera that can achieve infinite depth of field even when objects are immediately in front of the camera. What they did was stuff an array of video cameras into a single camera, with each camera focused at a different distance. Software then calculates the distance of each object in the scene, and selects the individual pixel that has the object in focus. The resulting image is one in which every object, both near and far, is in focus.
Maybe in the future consumer cameras will also have an array of cameras, allowing us to have much more control over the photo (or video) in post-processing.
Image credit: Photo and illustration by the University of Toronto