In this page we discuss lens testing (actually, testing complete photographic systems) using the Koren 2003 lens test chart, which has continuously varying spatial frequency. You can download, print and assemble it yourself. This approach is primarily intended for film images, but Imatest Log frequency analyzes digitized images of the chart described further.


submitted: 5 years and 3691 days ago

What is the aperture of our cameras? What is the use of setting a large or small one?

Let’s dive into those mysterious numbers and find out what they mean. Think of the aperture as the opening of your lens. Light arrives and its photons are focused onto the sensor by the lens. The incoming analog signal gets then translated into digital numbers and written on the memory card.


submitted: 5 years and 3163 days ago

The first problem we need to look at is, how close the lens will focus. Lenses have a minimum focus distance which varies considerably from lens to lens, some longer zoom lenses have a 'macro' setting and will focus quite close but most lenses will not focus close enough to take the picture on the right.


submitted: 5 years and 3713 days ago

Tilt shift lenses enable photographers to transcend the normal restrictions of depth of field and perspective. Many of the optical tricks these lenses permit could not otherwise be reproduced digitally—making them a must for certain landscape, architectural and product photography. The first part of this tutorial addresses the shift feature, and focuses on its use for in digital SLR cameras for perspective control and panoramas. The second part focuses on using tilt shift lenses to control depth of field.


submitted: 5 years and 3713 days ago

Sigma makes some interesting lenses for digital SLR cameras. They also produce some of their own digital SLR bodies with a class-unto-itself new type of sensor. Sigma is mainly known as a third-party lens manufacturer, producing lenses in mounts compatible with the major brands: Canon, Nikon, Pentax, Sony, Olympus. They offer high-quality glass in many of the popular focal lengths which, in many cases, are at more affordable prices than the specific manufacturer’s offerings.
This article covers every current Sigma product.


submitted: 5 years and 3713 days ago

This review is mainly for DX camera users deciding between these two lenses. Comparison of the Nikon 14-24mm lens and the Nikon 10-24mm DX lens. Which one is right for you?


submitted: 5 years and 3690 days ago

This video tutorial shows you how to clean the front element of your camera (or video camcorder) lens properly with simple steps. Yes, this is how we do it. Enjoy!


submitted: 5 years and 3689 days ago

This video demonstrates you how to properly clean your lens filters to avoid loss of sharpness and image quality to deliver the maximum image quality and color rendering. Enjoy!


submitted: 5 years and 3689 days ago

A seven minute tour around Canon's super-zoom lens for EF-S compatible DSLRs.


submitted: 5 years and 3689 days ago

This is a short overview of the Canon EF 70-200mm f 4.0 USM. This tutorial will help anyone thinking about purchasing this lens.


submitted: 5 years and 3689 days ago