Until very recently I was not aware that optical glass filters can fluoresce when exposed to ultraviolet radiation. In this short post I use two filters from Heliopan that I own as examples of this. However, many other filters, and even the glass elements in some camera lenses can also fluoresce.
The light output of many types of lamps varies at twice the frequency of mains AC line frequency. Alternating power follows a sinusoidal shape, alternating between positive and negative half cycles. This causes the doubling of the frequency, for each half cycle in the power supply there is pulse in the light output.
This is the third of three instalments on the comparison of three sets of macro extension tubes for MFT cameras: Macro extension tubes (description), Macro extension tubes (glare), and Macro extension tubes (lens mount).
Focus stacking is a method for increasing depth-of-field in photographs, consisting in merging a set of photographs obtained using focus-bracketing. In this post I explain how it works, and why it is specially useful in macro photography.
[post revised on 2017-10-21] Definition and explanation Before describing different types of “image merging” workflows, I will explain some terms that I will be using in this blog. Today I will explain the meaning of bracketing. Bracketing consists in acquiring a series of images with different camera settings. The word bracketing comes from the idea that we have a target value for the setting, say exposure, and we acquire images …