In my last post I wrote about my attempts to measure vignetting in the lenses I use with my DSLR camera. Another lens problem that the camera can correct (but only for Canon lenses) is lateral chromatic aberration. To determine the amount of correction my lenses need I printed out a simple test chart and … Read more
A few years ago I wrote about some experiments I’d done with measuring and correcting vignetting in digital photographs. (Some cameras have such correction built in, called “peripheral illumination correction” or similar.) I recently purchased a second-hand 10-18 mm wide angle lens for my DSLR. Measuring its vignetting using my previous method is difficult as … Read more
Long focal length lenses for SLR cameras are mostly one of two types – refractors (true lenses) or “mirror” lenses (actually Cassegrain telescopes). Large aperture long lenses are big, heavy, and expensive, but they can perform really well. Mirror lenses are much smaller, lighter, and usually a lot cheaper. However they are fixed aperture, usually … Read more
In a previous post (21st Century Photosniper) I described various additions I made to a “Stedi Stock” shoulder brace camera mount. These include a remote shutter release cable to allow the camera to be operated while holding the shoulder brace by its handle. The commercial cable release I used contains a single switch, so there … Read more
I bought my first “proper” camera, a Zenith E, in the late 1970s. At that time I would gaze enviously at adverts for the KMZ Photosniper outfit, a long lensed SLR mounted on a rifle-like shoulder brace. Photograph ©Patrick Stacey I recently happened across the Stedi Stock shoulder brace, designed for use with cameras, telescopes … Read more
In a previous blog post I outlined how I correct vignetting in digital photographs. In this post I will describe in more detail the software I’ve written to do this. The corrector is part of my Pyctools project and you can download example scripts that use it from my Pyctools-demo project. The picture below shows … Read more
I recently purchased a budget telephoto lens for my Canon EOS 100D DSLR camera. It’s a 500mm f/6.3 mirror lens, essentially a small Cassegrain telescope. Like many budget lenses it suffers from “vignetting”, i.e. the edges of a photograph are darker than the centre. The EOS 100D camera has built in vignette correction (called peripheral … Read more
…they could help owners of copyright in images track down their “orphaned” works. A hot news story in the UK in recent days has been the passing of a law to allow photographs to be published without the copyright owner’s consent, provided a “diligent search” has been undertaken to find the owner. See http://www.bbc.co.uk/news/technology-22337406 Many … Read more
A much neglected task for any photographer is labelling one’s photographs. In the old days one could write on the back of a print, but as I always preferred slide film this wasn’t an option. So I created a database in which I stored a simple title and description of each slide. However, as it … Read more
I’m not an avid photographer, but have still managed to accumulate over 2800 35mm slides before I bought my first digital camera in September 2003. These have been sitting in a couple of shoe boxes, slowly decaying, for up to 30 years. A few weeks ago I decided to bite the bullet and transfer them … Read more