Jon Tarrant

Latest posts

How much does light bend?

Diagram showing refraction at different distances from the optical axis.

We have an explanation for why light bends when it moves across a boundary between two different media but is there any predictable pattern to the amount that any given ray of light bends?

Read full post

Why does light "bend"?

Line drawng showing simple odel of refraction

Having covered a couple of real-world observations of the behaviour of light it seems appropriate to look at some of the optics theory that explains how lenses are able to manipulate light to form images.

Read full post

Surface Curvature

Two panes of glass showing undistorted (flat glass) and distorted (rippled glass) images.

Most of the effect that a lens has on the light passing through it comes from the surface curvature of its elements. This curvature has to be both precise and very consistent as even the smallest deviations can introduce significant image distortion.

Read full post

Reflected Light

Why is some light transmitted and some light reflected at a glass surface? This is a surprisingly difficult question to answer because the nature of reflected light is not as simple as you might think.

Read full post


I've just been testing the new PZD version of Tamron's 18-270mm super-zoom and I've realised that when the review of the non-PZD 18-270mm was published last year it was accompanied by the wrong MTF graph! Here, therefore, is that review again - with the correct graph this time...

Read full post

Good books on The Science of Imaging are few and far between but Graham Saxby’s is one of the best. For that reason, and also because I’m honoured to be among some very high-calibre contributors whose photographs are included in the book, this ‘blog entry is an unashamed tribute to Saxby’s work.

Read full post

Page 4 of 10



Digital SLR Reviews

Latest posts