OM SYSTEM Olympus OM-3 Silver Micro Four Thirds vs Sony ILCE7SM3/B Alpha 7S III FullFrame ILC Camera
Updated August 2026 — OM SYSTEM Olympus OM-3 Silver Micro Four Thirds wins on design, Sony ILCE7SM3/B Alpha 7S III FullFrame ILC Camera wins on video and price.
The OM SYSTEM Olympus OM-3 offers a great balance of features and price for still photography, while the Sony Alpha 7S III excels in video capabilities and low-light performance.
Why OM SYSTEM Olympus OM-3 Silver Micro Four Thirds is better
Price
OM-3 is significantly cheaper at $1,699.99.
Design
OM-3 has a vintage-styled, rugged design.
Resolution
OM-3 has a higher resolution sensor at 20 MP.
Why Sony ILCE7SM3/B Alpha 7S III FullFrame ILC Camera is better
Video
Alpha 7S III records 4K video at up to 120p.
Low-light
Alpha 7S III has an ISO range up to 409,600.
Autofocus
Alpha 7S III features 759 phase detection AF points.
Overall score
Specifications
| Spec | OM SYSTEM Olympus OM-3 Silver Micro Four Thirds | Sony ILCE7SM3/B Alpha 7S III FullFrame ILC Camera |
|---|---|---|
| Sensor MP | 20 MP | 12.1 MP |
| ISO Range | 200-6400 | 80-409600 |
| Video 4K | No | Yes |
| AF Points | Not specified | 759 |
| Processor | TruePic X | BIONZ XR |
Dimension comparison
Overview
In the realm of mirrorless cameras, the OM SYSTEM Olympus OM-3 and the Sony ILCE7SM3/B Alpha 7S III stand out as two distinct offerings. The Olympus OM-3 is priced at $1,699.99, making it about 17% cheaper than the Sony Alpha 7S III, which retails for $3,698.00. Each camera caters to different needs and shooting styles, making a careful comparison essential for potential buyers.
Design and Build Quality
The OM SYSTEM Olympus OM-3 features a vintage-styled, premium metal body, which not only adds to its aesthetic appeal but also promises durability. With an IP53 rating, this camera is dustproof, splashproof, and freezeproof, making it suitable for various outdoor conditions. In contrast, the Sony Alpha 7S III, while also robust, focuses more on a sleek, modern design. It does not specify an IP rating, which may imply a lesser degree of weather sealing compared to the OM-3. For photographers who prioritize ruggedness and a nostalgic design, the OM-3 may be more appealing.
Image Quality
When it comes to image quality, the Sony Alpha 7S III showcases a 12.1MP Exmor R sensor optimized for 4K video, delivering exceptional low-light performance with an ISO range up to 409,600. This capability makes it a top choice for videographers and photographers working in challenging lighting conditions. The OM SYSTEM Olympus OM-3, on the other hand, sports a 20 MP Stacked BSI Live MOS Sensor, providing a higher resolution for still photography. While both cameras excel, the choice between them may hinge on whether you prioritize low-light video versatility or higher-resolution still images.
Performance
The performance specifications of the Sony Alpha 7S III are noteworthy, boasting a new BIONZ XR processing engine that delivers eight times more processing power than its predecessor. This allows for up to 120p 4K video capture with full pixel readout in all recording modes, which is a significant advantage for video creators. The OM SYSTEM Olympus OM-3’s TruePic X Processor also provides strong performance, supporting various computational photography features like Live ND and Focus Stacking. However, the advanced video capabilities of the Alpha 7S III position it as the choice for serious videographers seeking high-speed recording.
Autofocus System
The autofocus system in the Sony Alpha 7S III is particularly impressive, featuring 759 phase detection AF points that offer fast and accurate focus, even in dynamic conditions. This is a crucial feature for wildlife and event photography where timing is essential. The OM SYSTEM Olympus OM-3 does not specify the number of autofocus points but includes computational photography features that enhance focus control, such as Focus Stacking. While both systems are capable, the Alpha 7S III's advanced autofocus may appeal more to those who require rapid and reliable focusing.
Video Capabilities
For videographers, the Sony Alpha 7S III is a standout option with its ability to record 4K video at up to 120p, making it ideal for slow-motion capture. Additionally, it offers a S-Cinetone picture profile for professional-looking cinematic footage. The OM SYSTEM Olympus OM-3, while capable of video recording, does not emphasize its video features to the same extent and lacks specific high-frame-rate capabilities. For those prioritizing video performance, the Alpha 7S III is clearly the superior choice.
Usability and Features
The OM SYSTEM Olympus OM-3 offers a range of creative features, including a Creative Dial that allows for color profile control and various art filters, making it a versatile tool for artistic expression. Additionally, its computational photography features provide an edge for creative still photographers. The Sony Alpha 7S III, while also user-friendly, focuses more on performance metrics suitable for professional creators. Users looking for a camera that balances creative control with professional capabilities may find the OM-3 appealing, especially for still photography.
Price
The price difference between the two cameras is substantial. The OM SYSTEM Olympus OM-3 is priced at $1,699.99, while the Sony Alpha 7S III comes in at $3,698.00. This represents a price difference of nearly $2,000, making the OM-3 about 46% cheaper. This significant cost disparity could influence budget-conscious buyers or those new to photography who may not require the advanced features of the Alpha 7S III.
Which should you buy?
Choosing between the OM SYSTEM Olympus OM-3 and the Sony Alpha 7S III ultimately depends on your specific needs as a photographer or videographer. If you're seeking a well-rounded, creative camera for still photography with a robust design at a more accessible price, the OM-3 is an excellent option. However, if your focus is on high-end video production with exceptional low-light performance and fast autofocus capabilities, the Sony Alpha 7S III is worth the investment. Consider your priorities carefully to select the camera that best fits your creative vision.

