MOS to PDF Converter

How to Convert MOS to PDF Online

1. Upload Your MOS Files: Drag and drop, or click "Add Files" to select one or more .mos images shot on a Leaf Aptus or Mamiya digital back. Batch is supported, so you can drop a full shoot.
2. Pick Combine Mode and Paper Size: Choose Single PDF to merge every image into one multi-page document (default) or Individual PDFs for one PDF per file. Then set Paper size — A4 is the default; pick Original to match each image's native aspect ratio, Letter/Legal/Tabloid/Ledger for US print, A3/ISO B4/ISO B5 for European formats, or Executive/Arch A/Arch B/Screen size for portfolio sheets.
3. Set Page Layout, Margin, Placement, and Alignment (Optional): Switch Page layout between Portrait (default) and Landscape. Choose Margin — No margin (0"), Narrow 0.5" (default), Moderate 0.75×1", Normal 1", or Large 2×1". Pick Image placement — Cover fills the page edge-to-edge (may crop), Contained (default) fits within margins. Set Image alignment to Top, Center (default), or Bottom.
4. Tune Quality and Compression Type, then Download: Drag Image Quality (%) between 1 and 100 (default 75) to control the JPEG compression that DCRAW/LibRaw applies before embedding into PDF. Pick a Compression Type preset — Screen (Best) for smallest files (default), Ebook for tablets, Default for general use, Prepress for offset printing, or Printer for high-DPI output. Click Convert and download. Files process inside your xconvert session — no watermark, no sign-up.

Why Convert MOS to PDF?

MOS is a proprietary medium-format RAW image format created by Leaf and used on Leaf Aptus digital backs (Aptus 17/22/54s/65/75) and on Mamiya bodies that pair with a Leaf back. Each file holds the raw sensor mosaic — typically 16-bit linear data captured by 22-, 39-, 56-, or 80-megapixel CCD sensors — plus metadata and a JPEG preview. That means a single frame is roughly 30–120 MB, almost no general image viewer opens it, and emailing one to a client is rarely practical. Converting to PDF gives you a layout-aware, universally readable container for delivery, archiving, and review.

• Client proofs and contact sheets — Drop a day's shoot into Single PDF mode and send a paginated review document. Clients open it in any browser, Acrobat, or Preview without installing Capture One or a Leaf RAW plug-in.
• Print-ready layouts for medium-format work — Pick A3 or Tabloid with Cover placement and No-margin to deliver bleed-ready sheets for offset or large-format printing; pair with the Prepress preset to keep the embedded JPEG at maximum quality.
• Archival portfolios — Combine 20–50 hero frames at 75–85% quality, A4 portrait, into a single PDF that's a fraction of the original RAW size yet preserves the Leaf back's wide tonal range as a visual reference.
• Cross-software handoff — Studios mixing Leaf Aptus and Phase One IQ kits often need a viewer-agnostic deliverable. Per Adobe's community thread, Camera Raw does not support compressed Leaf MOS files, so a PDF render is the simplest universal artifact.
• Insurance and legal documentation — Architectural and product photographers shooting on Mamiya/Leaf systems can ship paginated PDFs with consistent margins and page sizes that hold up as evidence files where unprocessed RAW would be unviewable.
• Web/preview replacement for huge RAWs — A 90 MB MOS becomes a 4–8 MB PDF page at quality 75 with the Screen preset — small enough to attach to most email systems, where 25 MB is a typical cap.

MOS (Leaf/Mamiya RAW) vs PDF — Format Comparison

Paper Size and Compression Quick Guide

Frequently Asked Questions

Which cameras and digital backs produce MOS files?

MOS is produced by Leaf Aptus medium-format digital backs (Aptus 17, 22, 54s, 65, 75, and the Aptus-II line) and by Mamiya/Leaf systems that mate a Leaf back to a Mamiya body. Sensor counts on these backs run from 16 megapixels on the original Aptus 17 to 80 megapixels on the Aptus-II 12. After Phase One acquired Leaf in 2009, the line was unified under Mamiya Leaf and eventually folded into the Phase One Credo and IQ series, but legacy MOS files from the older bodies still circulate and need conversion.

Why won't my MOS file open in Photoshop or Lightroom?

Adobe Camera Raw and Lightroom support uncompressed MOS files from many Aptus models, but Adobe documentation and community threads confirm Camera Raw does not handle compressed Leaf MOS or IIQ files — you have to decompress them with Leaf Raw Converter or Capture One first. The Leaf Aptus 75, for example, opens fine in Camera Raw when uncompressed; the same image saved with Leaf's lossless compression won't. xconvert's MOS-to-PDF path bypasses this entirely because it renders through a RAW pipeline that handles both compressed and uncompressed Leaf files.

What's the difference between Cover and Contained placement?

Cover scales the image so it fills the entire page edge to edge — anything outside the page aspect ratio is cropped. Use it for full-bleed prints, magazine spreads, or tablet portfolios where you want zero whitespace. Contained scales the image so the entire frame fits within the page margins, preserving the full composition but leaving whitespace where the image and page aspect ratios don't match. Use Contained for client review PDFs and any context where you must show the full crop the photographer delivered.

Should I pick Screen, Ebook, Prepress, or Printer compression?

These presets correspond to Ghostscript-style PDF distill profiles. Screen (Best) targets ~72 DPI image embed — smallest files, ideal for email and web review. Ebook targets ~150 DPI — readable on tablets and laptops without obvious artifacting. Default uses general-purpose settings. Prepress keeps embedded images at ~300 DPI with color preserved for offset printing. Printer is similar but tuned for desktop high-DPI output. Pair Prepress or Printer with Image Quality 90+ for any deliverable a press will pull from.

How big will my output PDF be compared to the original MOS?

Expect roughly 5–15% of the source size at default settings. A 95 MB Aptus 75 MOS frame typically renders to a 5–9 MB PDF page at quality 75 with the Screen preset. Bumping to quality 95 with the Prepress preset can push that to 18–25 MB per page because the embedded JPEG holds more chroma and luma detail. Multiplying by a 30-image portfolio gives you roughly 150–700 MB total — still a fraction of the 2.8 GB those RAWs occupied.

Will my conversion preserve the wide dynamic range Leaf backs are known for?

Partially. The Leaf Aptus and Aptus-II backs were prized for ~12 stops of usable dynamic range from their 16-bit CCD pipelines. Embedding into PDF means the image is rendered to 8-bit JPEG before encapsulation, so the per-pixel tonal precision drops. However, the visible tonal range — the highlight and shadow detail you actually see on screen — is preserved because the conversion uses the camera-baked tone curve. If you need bit-accurate retention for further grading, work in Capture One on the raw MOS and only convert to PDF for final delivery.

What paper sizes does the converter support?

The Paper size dropdown includes Original (matches the image's pixel aspect), Letter, Legal, Tabloid, Ledger, Executive, Arch A, Arch B, A3, A4 (default), ISO B4, ISO B5, and Screen size. Architectural and product photographers shooting medium format usually pick A3, Tabloid, or Arch B for the bigger reproduction area. For mixed-region client decks, A4 plus Contained placement gives the most predictable layout across US Letter and European A4 printing.

Can I batch convert dozens of MOS files into one PDF?

Yes. Drop the entire folder onto the upload area, leave Combine set to Single PDF, and the converter paginates each frame onto its own page using your chosen Paper size, Layout, Margin, Placement, and Alignment. If you'd rather output one PDF per source — for individual delivery or per-image review — switch to Individual PDFs. For high-volume merging with explicit page ordering controls, see merge MOS to PDF or the broader merge image to PDF tool.

Is xconvert better than just rendering JPEGs from Capture One?

It depends on your downstream. Capture One gives you the most control over the RAW develop — exposure, white balance, sharpening, lens correction. If you need a paginated, layout-controlled deliverable, xconvert is faster: one upload, one click, no per-frame JPEG export plus separate PDF assembly. Many workflows do both — use Capture One for hero edits, then run the rest of the take through xconvert for the contact-sheet PDF. If you prefer non-PDF outputs, see MOS to JPG, MOS to TIFF, or MOS to PNG.