Articles
Longer pieces on the two things this site keeps running into: the optics and exposure maths that decide what a photograph looks like, and the practical business of making camera hardware yourself. Each one is written to be read once and referred back to, and links out to the calculators and projects it relates to.
Technique
The optics and exposure maths behind the pictures, and where the usual rules of thumb quietly stop being true.
Crop factor and equivalence, without the arguments
Everyone agrees crop factor multiplies focal length. The argument starts one line later, at aperture, and it is mostly people answering different questions.
Technique4 August 202610 min readThe 500 rule is broken, and the NPF rule is why
A rule of thumb from the film era, applied to a 45 megapixel sensor, will reliably give you trailed stars and a confident explanation of why they are fine.
Technique4 August 20269 min readHyperfocal focusing in practice
The technique works. The way it is usually taught puts infinity right on the edge of acceptable, which is the one place you do not want it.
Technique4 August 20269 min readND filters and the arithmetic of long exposure
Three different labelling systems for the same piece of glass, and a conversion that is one line of arithmetic once you stop trying to memorise a table.
Technique4 August 20268 min readWhat EXIF actually contains, and what it gives away
Every photograph you take carries a few hundred fields of metadata. Some of it will diagnose a lens problem for you. Some of it will tell a stranger where you live.
Technique4 August 20269 min readWhy your depth of field calculator disagrees with your photographs
The calculator said the whole scene was sharp. At 100% on screen, half of it clearly is not. Both things are true, and the reason is a number nobody mentions.
Technique4 August 202610 min readThe diffraction limit is not a cliff
Diffraction gets talked about as a wall you hit at f/11. It is closer to a slope you have been walking down since f/4.
Technique4 August 20269 min readWhat shutter count tells you when buying a used camera
A number that gets treated as an odometer, quoted as a verdict, and misunderstood in both directions.
Technique4 August 20268 min read
Making
Designing, printing, and fitting your own camera hardware, including the failures worth knowing about in advance.
The threads and standards holding your camera together
Photography runs on about six standards, two of which are imperial threads from the nineteenth century and one of which is not really a standard at all.
Making4 August 202610 min readWhy cheap lens adapters lose infinity focus
One measurement decides whether a lens adapter can ever work properly, and it is not one that adapter listings tend to mention.
Making4 August 20269 min readChoosing filament for camera gear
PLA is the default for good reasons and the wrong answer for about a third of the parts on this site. Here is how to tell which third.
Making4 August 202610 min readPrinting threads that actually fit
A thread that binds and a thread that rattles usually have the same cause, and it is rarely the model file.
Making4 August 202611 min read