Oxford School of Photography

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Tag Archives: Focus (optics)

Macro Flower Photography: A Tutorial in Focus Stacking

This tutorial by Harold Davis explains how you can use Photoshop to achieve crisp focus throught a macro image.

“The closer you get in macro flower photography, the fussier focus gets. Since “fussy” is not a technical term, let me explain. Because focus is inherently shallower as you get closer to your subject, slight variations of distance between camera and subject throw you out of focus very quickly, and even fully-stopped down you may not have enough depth-of-field for your entire photo to be in focus.

Certainly, stopping your lens down to its smallest aperture, observing whether you have the in-focus areas you want, and seeing if there is any way to position the camera to improve the amount that is in-focus is a good way to start. But bear in mind that stopping down a lens comes with some downsides: optically your lens may not perform best at its smallest aperture, and when the aperture is small you can’t use a shutter speed fast enough to stop motion.

An approach that often can surmount these obstacles is to use focus stacking: shooting at a number of different focal points and combining the images in Photoshop to create a hyper-focal image that has an extended area that is in focus.”…MORE

Understanding depth of field and showing some self control

This is a really useful article from Jim Harmer at Improve Photography. Regularly in the classes I teach I find people who are so absorbed by shallow depth of field that they fail to see that some of the most important parts of their image are out of focus.

“I get it.  Depth of field is fun to play with and makes our pictures look amazing, but I’m here to say that more of a good thing is not always better.

Look at the image featured on this page of my beautiful wife, Emily.  The depth-of-field adds to this image to make her stand off the page; however, this image suffers from too shallow depth of field.  The depth of field was only about two inches in this picture because I used an aperture of f/1.8, a 50mm lens, and I was only two or three feet away from the subject.  You can see that part of her face is out of the plane of focus, and that is a bit distracting.  What I really wanted was to make her completely in focus and just blur out the background.  You might not be able to tell this on the small preview of the image, but it’s obvious if you click to make it big.  This post is for those of you who always crank the aperture down to the lowest number available.”…interested?...more

Too shallow depth of field – Jim Harmer’s mistake