Research notes

Comparisons, measurements and technical reference material, documented so the working can be checked. Every page records when it was written and under what conditions.

Entries

Five so far

Sony A7C II kit: new versus used pricing

August 2026

A complete Sony A7C II kit priced twice over in Prague, new against secondhand. Twenty-two line items across five phases, and the finding that only three are worth buying used.

ThinkPad RAM socketing by generation, 2018–2026

August 2026

Socketed memory collapsed across the line around 2019 and came back in 2024. Which generations remain upgradeable, what they cost on the Czech used market, and which ones suspend properly under Fedora.

ThinkPad hardware floor: which SKUs clear 4C/8T and 8GB

August 2026

A four-core, eight-gigabyte minimum eliminates no ThinkPad line at all — only a short list of budget CPU trims. Sixty-seven models rated, the dual-core kill list, and the arithmetic showing 8GB is the wrong floor.

Sony FE lens comparator

Tool

The same 59 lenses, browsable. Weight compactness against sharpness against price and the ranking rearranges. Companion to the analysis above.

About

This archive holds research that outgrew a working note. Most entries begin as a buying decision or an unresolved technical question and end up long enough to be worth keeping.

Entries referenced in a video are linked from its description. Figures are first-hand unless stated otherwise, and measurement conditions are always recorded — where a page does not state how something was measured, the number should not be relied on.