# LensFactor vs Message Viewer Pro

The clearest difference is update cadence: Message Viewer Pro at monthly against LensFactor's every 24 months. LensFactor's advantage is price ($1.99 vs $3.99) and iOS requirement (11.0 vs 16.6). On rating, ratings volume, ads and in-app purchases there is nothing between them.

LensFactor costs $1.99 and Message Viewer Pro $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

On the App Store both sit at effectively the same score — 5.0 for LensFactor against 5.0 for Message Viewer Pro. Both are backed by a comparable volume of ratings — 2 and 1 respectively.

LensFactor ships an update every 24 months, Message Viewer Pro monthly. The most recent releases landed on September 21, 2026 and September 17, 2026 respectively.

## The numbers

| Metric | LensFactor | Message Viewer Pro |
| --- | --- | --- |
| Price | **$1.99** | $3.99 |
| Rating | [5.0 (2 ratings)](https://appshunter.io/ios/app/lensfactor/id370376269/reviews) | [5.0 (1 ratings)](https://appshunter.io/ios/app/message-viewer-pro/id6740704561/reviews) |
| Number of ratings | **2** | 1 |
| Positive reviews | 88.9% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 24 months | **Monthly** |
| Monetization | Paid | Paid |
| Size | 1 MB | 9 MB |
| Requires iOS | **11.0** | 16.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Bart van Stiphout](https://appshunter.io/developer/368100168) | [Matrix Logic Corporation](https://appshunter.io/developer/303074412) |

## What reviewers say

### LensFactor

[App page](https://appshunter.io/ios/app/lensfactor/id370376269)

This app helps calculate lens factors, screen sizes, and projector distances based on known variables. It's a utility for professionals or enthusiasts needing precise measurements for display setups.

**Highlights:** Calculate lens factor, Calculate screen size, Calculate projector distance, Input screen size and projector distance, Input lens factor and projector distance, Input lens factor and screen size

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Message Viewer Pro

[App page](https://appshunter.io/ios/app/message-viewer-pro/id6740704561)

Easily view EML and MSG email files, including attachments, directly on your iOS or macOS device. Share or print attachments, or compose new emails using the content of your saved messages.

**Highlights:** View EML and MSG files, Access attachments, Share attachments, Print attachments, Compose new emails from viewed messages

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is LensFactor free?

LensFactor costs $1.99, with no in-app purchases.

### Is Message Viewer Pro free?

Message Viewer Pro costs $3.99, with no in-app purchases.

### Which has better reviews, LensFactor or Message Viewer Pro?

LensFactor and Message Viewer Pro are both rated 5.0 out of 5 on the App Store, from 2 and 1 ratings respectively.

### Do LensFactor or Message Viewer Pro have ads?

Neither LensFactor nor Message Viewer Pro shows ads.

### Which is updated more often, LensFactor or Message Viewer Pro?

LensFactor ships an update every 24 months, and Message Viewer Pro monthly. Most recently, LensFactor was updated on September 21, 2026 and Message Viewer Pro on September 17, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*