MOS to TIFF Converter

MOS vs TIF — Should You Convert, or Keep the RAW?

A .mos file is the untouched RAW capture from a Leaf Aptus medium-format digital back — high-bit-depth sensor data with full editing latitude, but a format almost nothing outside Capture One, Photoshop, or Lightroom will open. A .tif is a finished, rendered image: the natural print and archival master for studio work that was always destined for output. Convert to TIF when you need a stable, editor-friendly deliverable; keep the original .mos as your editable negative, because the conversion bakes in white balance and tone for good.

MOS vs TIF at a Glance

When to Keep the MOS

• You still want to grade the shot — RAW lets you recover blown highlights and re-set white balance long after capture; a rendered TIF cannot.
• It's your archival negative. Pro studios keep the .mos as the master of record and treat every export as disposable.
• You're staying inside Capture One, which replaced Leaf Capture as the processing software for all Aptus and Aptus-II backs.

When to Convert to TIF

• You need a deliverable a retoucher, layout artist, or print shop can open without a RAW processor — TIF is the long-standing print and prepress master.
• You want a lossless archival copy of the finished render: pick LZW or Deflate, not the lossy JPEG default.
• You're sending the image into a layered Photoshop workflow, since TIF carries layers and high-quality channels that JPEG cannot.

How to Convert MOS to TIF

1. Upload Your MOS File: Drag and drop your Leaf .mos onto the page or click "+ Add Files". You can queue several Aptus or Aptus-II captures at once, though each medium-format RAW can run from tens to over a hundred megabytes.
2. Set the Compression Type: Open Advanced Options — the "Compression Type" dropdown defaults to "JPEG", which is lossy. For a true archival master switch it to "LZW" (the long-standing TIFF default, read by virtually every TIFF tool) or "DEFLATE" for a slightly smaller lossless file; choose "NONE" for an uncompressed TIF.
3. Adjust Quality or Resolution (Optional): Use the "Quality Preset" ("Very High (Recommended)" by default) to govern the render, or downscale from the back's full pixel count under "Image resolution".
4. Convert and Download: Click "Convert" and download your TIF. No sign-up, no watermark.

Frequently Asked Questions

Will converting MOS to TIF lose the RAW editing latitude?

Yes. A MOS stores high-bit-depth linear sensor data, which is why you can recover highlights and re-set white balance long after the shot. To make a TIF the converter renders the RAW first — demosaicing the sensor data and baking in white balance, exposure, and tone — and once that render is written, the latitude is gone. A TIF is the right format for a finished, distributable master, but keep your original .mos as the editable negative for any future regrade.

LZW or Deflate — which TIFF compression should I pick for an archive?

Both are lossless, so neither touches image quality. LZW is the safe default for maximum compatibility — every TIFF reader since the early 1990s supports it. Deflate (also called ZIP) usually produces files a few percent smaller on photographic content, at the cost of slower encoding and slightly weaker support in some very old readers. For a long-term archival master where you want the widest compatibility, LZW is the conventional choice; if minimum file size matters more than reaching legacy software, pick Deflate. Avoid the "JPEG" option for archives — it is lossy.

Why does the converter default to JPEG compression for a TIF?

JPEG keeps the output small, which suits everyday use, but it is lossy — it discards image data the same way an ordinary .jpg does, just inside a TIFF container. That is fine for a working copy and wrong for an archival master. If your goal is a lossless deliverable from a medium-format RAW, change "Compression Type" to LZW or Deflate before converting; the page even notes that LZW is the standard for TIFF files.

Is there any quality difference between a .tif and a .tiff file?

None. .tif and .tiff are the same Tagged Image File Format — the three-letter extension is a holdover from older systems that capped extensions at three characters, while .tiff is the fuller spelling. The bytes inside are identical, so pick whichever your downstream software expects. If you specifically need the four-letter extension, use MOS to TIFF, which produces the same file with a .tiff name.

Does the TIF keep the resolution of a medium-format back?

It can. A Leaf Aptus back captures far more pixels than most deliverables need, and by default this converter keeps the original resolution, so the TIF holds the back's full pixel count — ideal for a print master. If you need a smaller working file you can downscale under "Image resolution" by preset or percentage, while the full-resolution master stays in the untouched .mos. Note that this converter writes 8-bit-per-channel TIFs rather than offering a 16-bit option, so for a 16-bit print pipeline you would export the TIF from Capture One instead.

My MOS file won't decode — what should I try?

MOS comes in uncompressed and compressed variants and support for the compressed form varies by RAW processor, so an odd file occasionally fails to read. The reliable fallback is to open the .mos in Capture One and export a TIFF, then feed that file through the Image Compressor if you need to resize it. Note that .mos is the Leaf Aptus format specifically — the later Leaf Credo backs write .iiq files instead, so if your file is actually an IIQ it needs the matching converter.

How are my files handled during conversion?

In our testing, an LZW-compressed TIF from a full-resolution Leaf MOS lands close to the size of the source RAW, since both are lossless — unlike a JPEG-compressed TIF, which comes out far smaller because it discards data. Your file is uploaded over an encrypted connection, rendered into a TIF on our servers, and deleted automatically a few hours after conversion — no sign-up, no watermark, never shared or made public. The main practical limit is upload size and time, since medium-format MOS files often run from tens to over a hundred megabytes each. If you instead need a small, shareable image, MOS to JPG or MOS to AVIF renders a web-ready copy.