# GravLens3 vs ExpiWell

The clearest difference is rating: ExpiWell at 4.6 against GravLens3's 3.7. ExpiWell also leads on update cadence (every 5 days vs every 17 months) and ratings volume (1.5K vs 6). GravLens3's advantage is review sentiment (80% vs 39%) and iOS requirement (6.1 vs 15.0). On price, ads, in-app purchases and monetization model there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

ExpiWell holds the better App Store score, 4.6 against 3.7. That said, the two scores are not equally well evidenced: ExpiWell has 1.5K ratings behind it against 6, so its average is the more settled of the two. Written reviews complicate that: 80% of GravLens3's written reviews are positive against 39% of ExpiWell's, so the app with the better star average is not the one people write more warmly about.

GravLens3 ships an update every 17 months, ExpiWell every 5 days. The most recent releases landed on October 23, 2026 and November 1, 2026 respectively.

## The numbers

| Metric | GravLens3 | ExpiWell |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.7 (6 ratings)](https://appshunter.io/ios/app/gravlens3/id318275930/reviews) | **[4.6 (1.5K ratings)](https://appshunter.io/ios/app/expiwell/id1070733440/reviews)** |
| Number of ratings | 6 | **1.5K** |
| Positive reviews | **80.0% of reviews** | 39.3% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 17 months | **Every 5 days** |
| Monetization | Free | Free |
| Size | 4 MB | 36 MB |
| Requires iOS | **6.1** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Eli Rykoff](https://appshunter.io/developer/318275933) | [Expiwell, Inc.](https://appshunter.io/developer/1070733439) |

## What reviewers say

### GravLens3

[App page](https://appshunter.io/ios/app/gravlens3/id318275930)

Simulate the effects of gravitational lensing on your iPhone or iPad. Adjust lens parameters and apply distortions to your photos or live camera feed. Share your creations or project them for educational purposes.

**Highlights:** Simulate Hubble Space Telescope images, Adjust lens size and ellipticity, Distort photos from library or camera, Live real-time lensing view, AirPlay and external monitor support, Save and share distorted images

**Features:** macOS Compatibility

**In-app purchases:** none


### ExpiWell

[App page](https://appshunter.io/ios/app/expiwell/id1070733440)

This app facilitates experience sampling and ecological momentary assessment for research. It allows users to share opinions and experiences through surveys and daily diaries, ensuring data privacy. Researchers can collect valuable insights through this platform.

**Highlights:** Experience sampling method (ESM), Ecological momentary assessment (EMA), Surveys and mood tracking, Daily diary entries, Just-in-time adaptive interventions (JITAI), Digital ethnography

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

**In-app purchases:** none

**What reviewers like**

- 👍 Straightforward experience
- 🚀 Clean and easy to use
- 💡 Fascinating app

**What reviewers complain about**

- 🐛 Keeps signing users out
- 🐛 App shuts down
- 🐛 Slow performance
- 🐛 Frequent updates

**Reported bugs**

- Login issues
- Incompatibility with certain devices
- Crashing during surveys

**Requested features**

- Better notification system
- More seamless interface


## Frequently asked questions

### Is GravLens3 free?

GravLens3 is free to download, with no in-app purchases.

### Is ExpiWell free?

ExpiWell is free to download, with no in-app purchases.

### Which has better reviews, GravLens3 or ExpiWell?

ExpiWell is rated higher. GravLens3 averages 3.7 out of 5 from 6 ratings, while ExpiWell averages 4.6 from 1.5K ratings.

### Do GravLens3 or ExpiWell have ads?

Neither GravLens3 nor ExpiWell shows ads.

### Which is updated more often, GravLens3 or ExpiWell?

GravLens3 ships an update every 17 months, and ExpiWell every 5 days. Most recently, GravLens3 was updated on October 23, 2026 and ExpiWell on November 1, 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.*