Comparison

Thin Lens Equation Calc vs Pocket Printer

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Thin Lens Equation Calc

Features
Read full description

Thin Lens Calc. is the essential optics calculator for students, teachers, and engineers. Instantly solve the thin lens equation (1/f = 1/do + 1/di) for any unknown variable — focal length, object distance, or image distance — with real-time results and an interactive ray diagram. SOLVE ANY VARIABLE Select what you want to find, enter the two known values, and get the answer instantly. The app auto-calculates as you type or drag the slider, so you can explore how changing one parameter affects the others. INTERACTIVE RAY DIAGRAM Watch the ray diagram update live as you adjust values. See how light passes through converging and diverging lenses, where real and inverted images form, and how virtual images appear on the same side as the object. A visual way to build intuition for optics. STEP-BY-STEP SOLUTIONS Tap to reveal a full algebraic walkthrough of each calculation — from the starting equation through substitution, simplification, and unit conversion. Perfect for checking homework or learning the method. UNIT CONVERSION BUILT IN Switch freely between millimeters, centimeters, and meters for each field independently. The app handles all conversions internally so you never have to convert by hand. FEATURES • Solve for focal length (f), object distance (do), or image distance (di) • Live-updating ray diagram with object and image arrows • Step-by-step solution breakdown • Unit pickers (mm, cm, m, in, ft) per field • Adjustable decimal precision (0–10 digits) • Tap-to-copy results to clipboard • Save calculations to history (SwiftData) • Negative value support for virtual images and diverging lenses • Scientific notation for extreme values • No ads, no subscriptions, no internet required Built for physics students studying geometric optics, teachers preparing demonstrations, and anyone who needs a fast, reliable thin lens calculator on their iPhone or iPad. Thanks for your support, and please visit nitrio.com for more apps for your iOS devices.

About

Pocket Printer

Connect to your printer via Bluetooth to easily create and print various documents. Edit text, insert images, icons, and barcodes, or use built-in templates for notes and lists.

Highlights
  • Bluetooth printer connection
  • Customizable note editor
  • Image editing tools
  • Barcode and QR code generation
  • Pre-built templates (notes, lists)
Features
Read full description

This is a beautiful and convenient app, connected to the printer through Bluetooth, simple and practical operation, can print work, list that template, convenient life, a fun and easy to use app. 【Note editor】You can edit the content freely, set the artboard you want to print, insert text, pictures, ICONS, bar codes, QR codes, etc; 【Picture image】Image editing tools, you can freely crop, rotate, filter, insert text and so on; 【Templates】Sticky note、To do list、Decorative,Built-in rich templates; More functions and creative, welcome to use and explore.

Screenshots

Thin Lens Equation Calc4 screens
Pocket Printer4 screens

Verdict

The call

The clearest difference is price: Pocket Printer at Free against Thin Lens Equation Calc's $2.99. Pocket Printer also leads on update cadence (every 2 months vs every 27 months) and iOS requirement (13.0 vs 17.6). On ads, in-app purchases and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Pocket Printer is free to download; Thin Lens Equation Calc costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Thin Lens Equation Calc ships an update every 27 months, Pocket Printer every 2 months. The most recent releases landed on October 25, 2026 and October 30, 2026 respectively.

Scorecard3 real differences · 7 level
Thin Lens Equation Calc versus Pocket Printer: the parameters behind the verdict, then further details
ParameterThin Lens Equation CalcPocket Printer
Price$2.99Free — better
Rating—2.0 (5 ratings) — better
Positive reviews—40.0% of reviews
Number of ratings—5 — better
Update frequencyEvery 27 monthsEvery 2 months — better
AdsNoNo
In-app purchasesNoNo
Monetization—Free
DevicesiPhone, iPadiPhone, iPod
Requires iOS17.613.0 — better
Further details — not scored
Size1 MB240 MB
Age rating4+4+
DeveloperNitrioKarsten International B.V.

In-app purchases

None

Thin Lens Equation Calc

No in-app purchases

None

Pocket Printer

No in-app purchases

Questions

Is Thin Lens Equation Calc free?
Thin Lens Equation Calc costs $2.99, with no in-app purchases.
Is Pocket Printer free?
Pocket Printer is free to download, with no in-app purchases.
Do Thin Lens Equation Calc or Pocket Printer have ads?
Neither Thin Lens Equation Calc nor Pocket Printer shows ads.
Which is updated more often, Thin Lens Equation Calc or Pocket Printer?
Thin Lens Equation Calc ships an update every 27 months, and Pocket Printer every 2 months. Most recently, Thin Lens Equation Calc was updated on October 25, 2026 and Pocket Printer on October 30, 2026.

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