Archivi categoria: Calibration

This is the Power of Sigma’s $60 Lens Dock for Fixing Focus

Sigma’s Art series of lenses are already praised for their image quality and sharpness, but you can hone that sharpness even more by adjusting the focus of your lens using Sigma’s USB Dock. Photographer Kyle Kozinski recently discovered just how much of a difference it can make.

Kozinski noticed that his $799 Sigma 18-35mm f/1.8 Art lens was slightly off in its focusing, so he shelled out $60 for a Sigma USB Dock.

“Everything up to close to infinity was front focusing and then at infinity it was back focusing,” Kozinski writes. After calibrating his lens’ focus with the USB Dock and Sigma Optimization Pro software, Kozinski saw a night and day difference.

Here are two 100% crops from photos shot with the lens before and after calibrating the focus:

As you can see, the lens now focuses correctly on the text found on the side of the drill driver instead of slightly toward the front or back. This tight, accurate focus is especially helpful for things like shooting portraits with a very shallow depth of field, when you want to ensure that your subject’s eyes are tack sharp.

Many modern digital cameras feature a AF Microadjustment feature for fixing similar focusing issues, but Sigma’s system goes a step beyond.

“The dock allows multiple adjustment values over different focal lengths and focusing ranges whereas the micro adjustment is the same value for everything,” Kozinski explains.

You can find more of Kozinski’s work on his website, Facebook, and Instagram.


Image credits: Comparison photos by Kyle Kozinski and used with permission

Video: A Primer on Color Spaces and Having a Color-Managed Photo Workflow

For some photographers, no term strikes more fear into one’s heart than “Color Spaces.” The idea that different devices, along with our eyes, perceive light differently can seem confusing. Anyone that has gone to print one of their photographs probably knows that it can take some know-how to ensure your images are correctly represented on paper.

If you’re new to the world of color theory, photographer Forrest Tanaka wants to help: in the 13-minute video above, he explains color spaces in an easy-to-understand way.

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Tanaka discusses the ideas behind the visible electromagnetic spectrum and how our eyes perceive the results. The discussion evolves into how color management modules function to try and ensure that color profiles match as closely as possible, and how we can improve their usage.

(via Forrest Tanaka via Reddit)