What is MOS?

Mamiya MOS (Leaf MOS) is a raw sensor data format from Mamiya/Leaf digital camera backs, used in professional studio photography.

What is ARW?

Sony Alpha Raw (ARW) is Sony's proprietary raw image format containing unprocessed sensor data from Sony Alpha and Cyber-shot cameras.

When Should You Use MOS vs ARW?

MOS vs ARW: Key Differences

• •The core technical difference: MOS relies on lossless compression whereas ARW uses lossless compression.
• •Both formats share lossless compression, so quality behavior is similar across the two — file size differences come from algorithm efficiency rather than compression philosophy.
• •How transparency is handled: ARW supports transparency, so alpha information is preserved during conversion.
• •Storage footprint: 30-70MB per image for MOS vs 20-40MB per photo for ARW.
• •Primary audience: MOS is built for mamiya camera raw processing scenarios, while ARW focuses on sony camera post-processing, professional editing — pick the format that matches your output requirement.

Advantages of MOS

• ✓MOS compresses data using lossless methods, keeping file sizes manageable for Mamiya camera raw processing.
• ✓Industry-wide support means MOS files open anywhere — from legacy systems to the latest devices.
• ✓Lossless quality makes MOS the gold standard for archival and master copies.
• ✓From professional software to open-source alternatives, MOS works out of the box.

Advantages of ARW

• ✓ARW applies lossless compression specifically calibrated for Sony camera post-processing, professional editing.
• ✓ARW enjoys broad native support across operating systems, browsers, and creative tools alike.
• ✓ARW guarantees every bit of the original data survives — no approximations, no shortcuts.
• ✓You will find ARW support built into virtually every tool that handles Sony camera post-processing, professional editing — no plugins or converters needed.

Common Use Cases for MOS to ARW Conversion

• Email marketing campaigns
• Presentation graphics
• Blog and article illustrations
• Mobile app UI assets
• Product photography for marketplaces
• Digital art portfolios

Industry Applications

Best Practices for MOS to ARW Conversion

• →Before converting MOS to ARW, decide whether you need maximum quality or smallest file size — this determines which format truly fits
• →Save a master copy in a lossless format before converting to ARW — you cannot recover detail lost during lossy compression
• →Check the color profile: MOS images may use a wider gamut than ARW supports, causing a visible shift after conversion
• →Resize images to the final display dimensions before converting — this avoids unnecessary processing of oversized files
• →Run a single test conversion first to verify quality meets your standards
• →Strip unnecessary metadata to reduce file size after conversion

Related Article

Troubleshooting MOS to ARW Conversion

• !Converting MOS to ARW gives blurry output → increase the quality setting before conversion
• !Colors look different in ARW than MOS → check color profile mismatch (sRGB vs Adobe RGB)
• !File size changed more than expected → ARW uses different compression, file size differences of 2-5x are normal
• !Transparent areas in MOS turned white in ARW → ARW may not support transparency

Related Image Converters

All Image Formats

More Image tools

Related Tools