In-depth Technical Articles

These articles cover detailed technical analysis of camera sensor and lens performance.

Our policy is that articles published within the last 24 months are only accessible to BirdLife Photography members, who must be logged in to see them.

  • Reach and Cropped Sensor Myths
    Hits: 441

    Ian Wilson - October 2020

    Ian explains the meaning of the photography term ‘reach’and debunks some myths regarding cropped sensor cameras and their full-frame equivalents. The idea of full-frame equivalence is widely misunderstood and can lead to poor gear choices by novices and the unwary.

     

  • A Guide to DxO Numbers for Bird Photographers
    Hits: 411

    Ian Wilson - August 2016

    This article explains the scoring system used by DxO Labs for camera lenses and bodies, and which are the most useful metrics for bird photographers.

     

  • High Megapixel DSLR Lens Limitations
    Hits: 390

    Ian Wilson - April 2014

    This article discusses the relationship between the resolving ability of the lens, and the size and number of pixels on the sensor. It demonstrates the challenges in developing a lens which can fully take advantage of the resolving power and detail of high megapixel sensors.

     

  • High Megapixel DSLR Opto-mechanical Limitations
    Hits: 343

    Ian Wilson - April 2014

    Ian discusses the impact of the opto-mechanical systems in cameras (particularly DSLRs) including the mirror and shutter drive, the lens autofocus movement, and the aperture mechanism. All of these systems involve physical movement and introduce vibrations into the camera, affecting image quality to some extent, with these impacts being amplified in high-megapixel cameras.

     

  • Sharpness Explained
    Hits: 395

    Ian Wilson - April 2013

    A detailed technical discussion about the sharpness of lenses.

     

  • Bird Photography Using Focal Length Multipliers
    Hits: 381

    Ian Wilson - February 2013

    A second article by Ian on the use of focal length extenders in bird photography with test charts and real world pictures.

     

  • Performance of Canon MkIII focal length extenders
    Hits: 355

    Ian Wilson - August 2012

    Ian provides a detailed analysis of the optical performance of focal length extenders (1.4x and 2x) on different Canon bodies and Canon prime lenses. See also Ian’s article “Bird Photography Using Focal Length Multipliers”.

     

  • Close Encounters with a Telephoto
    Hits: 409

    Ian Wilson - June 2012

    A discussion of telephoto photography - lens resolution and the optimal aperture for best resolution, depth of field, and the trade off in real life between aperture, shutter speed and ISO.  Examples use Canon equipment.