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Techniques & Technology

Lenslock

The hated prism

The physical copy protection device that required players to decode on-screen codes through a plastic prism - universally despised for inconvenience and failure-prone design.

sinclair-zx-spectrumcommodore-64amstrad-cpc copy-protectionhardware1980s

Overview

Lenslock was a physical copy protection system used in the mid-1980s that required players to hold a plastic prism device against their television screen to decode a two-letter code. Intended to be uncopyable (you couldn’t photocopy a 3D optical device), it became universally loathed for being inconvenient, easy to lose, and prone to failure on different television sets.

Fast Facts

  • Era: 1985-1987
  • Developer: ASAP Developments
  • Platforms: Spectrum, C64, Amstrad, others
  • Method: Physical prism decoder
  • Games: Elite, TT Racer, others
  • Reception: Universally hated

How It Worked

StepAction
1Game displays scrambled code
2Player holds Lenslock to screen
3Prism reveals two-letter code
4Player types code
5Game proceeds (if correct)

Why It Failed

ProblemImpact
Easy to loseTiny plastic device
TV variationDifferent displays, different results
InconvenientEvery game start
FrustratingMisreads common
Damaged easilyScratched prisms useless

Notable Games

GamePlatformOutcome
EliteSpectrum/C64Player complaints
TT RacerSpectrumNegative reviews
OthersVariousSimilar reception

Player Reactions

The gaming press and players united in hatred:

  • Magazine reviews penalised Lenslock games
  • Players complained loudly
  • Publishers faced backlash
  • System abandoned quickly

Cracker Response

Ironically, Lenslock:

  • Was relatively easy to crack
  • All codes were in the program
  • Just required finding the lookup table
  • Cracked versions more convenient than originals

Legacy

Lenslock demonstrated that copy protection could be so annoying that it damaged legitimate sales. Players preferred cracked versions not because of price but because they were easier to use. The lesson—protection shouldn’t punish paying customers—took the industry decades to fully learn.

See Also