CONVERT
PEF → ICO
Fast, secure PEF to ICO conversion. No registration required.
DRAG. DROP. DONE.
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Setup: PEF is Pentax's RAW camera format. Goal: an interchangeable ICO. If you have ended up with a PEF and need a ICO, the mismatch is almost always about where the image is going next rather than the picture itself. Our server reads the PEF with ImageMagick, decodes each pixel, and re-writes it as a ICO using defaults tuned for fidelity first and file size second. Background. PEF is Pentax's RAW camera format. Destination side, ICO is the Windows icon container with multiple resolutions packed into one file.
Pentax RAW
Source formatPEF is the RAW image format used by Pentax DSLR cameras, containing full sensor data.
ICO Icon
Target formatICO is the icon file format used for favicons and Windows application icons. A single ICO file can contain multiple image sizes and color depths for different display contexts.
Why convert PEF to ICO
Both PEF and ICO describe a grid of pixels — the difference lies in how that grid is compressed, whether transparency is supported, and which software opens it natively. Moving from PEF to ICO is worth it when the ICO ecosystem is broader for your use case, or when ICO compresses photographs more efficiently than PEF.
HOW TO CONVERT
PEF → ICO
Drop the PEF file
Drag and drop or click to upload your PEF. The image is transferred securely over HTTPS and queued for conversion.
Re-encode with ImageMagick
ImageMagick decodes every pixel of the PEF and writes a matching ICO with sensible default quality settings.
Download the ICO
The converted ICO is ready to download as a single file; both files delete automatically within two hours.
Common Use Cases
Web publishing and CMSes
ICO uploads cleanly to WordPress, Ghost, Webflow and most blogging platforms; many CMSes silently transcode or reject PEF.
Email attachments
Email clients preview ICO inline while PEF may arrive as an unrecognised attachment on older Outlook or mobile apps.
Social media uploads
Platforms like Instagram, X and Facebook accept ICO natively; PEF is often rejected or silently converted with unpredictable results.
Design hand-off
Designers shipping assets to developers prefer ICO for faster pipeline imports and consistent display across build tools.
PEF vs ICO — Strengths and limitations
What each format does best, and where it falls short.
PEF Strengths
- Full Pentax sensor data with 14-bit or 12-bit depth.
- Rich Pentax makernotes for lens and filter metadata.
- DNG alternative available on body — user choice of archival openness.
- Every major raw processor supports PEF.
Limitations
- Proprietary with no public spec.
- Niche market share — Pentax DSLR sales are a fraction of Canon/Nikon/Sony.
- Lightroom profile coverage trails the Big Three.
ICO Strengths
- Multi-resolution: one file, many sizes, OS picks the right one.
- Universal favicon support in every browser since IE5.
- Supports transparency (1-bit since 1985, full alpha since XP).
- Tiny file size — an entire favicon pack typically fits in under 15 KB.
- No licensing or patent concerns — fully in the public domain spec-wise.
Limitations
- Cannot compress continuous-tone images efficiently — use PNG or WebP for photos.
- Format is essentially frozen in 1999 — no HDR, no wide gamut, no modern features.
- Maximum image dimension is 256×256 px (inside an ICO container).
PEF vs ICO — Technical specifications
Side-by-side comparison of the technical details.
| Specification | PEF | ICO |
|---|---|---|
| MIME type | image/x-pentax-pef | image/vnd.microsoft.icon |
| Extension | .pef | — |
| Container | TIFF/EP with Pentax MakerNote | — |
| Bit depth | 12 or 14-bit | — |
| Alternative | DNG (selectable in-camera on K-series) | — |
| Max resolutions per file | — | 65 535 images |
| Max single image size | — | 256×256 px |
| Color depths | — | 1, 4, 8, 24, 32 bits per pixel |
| Compression | — | Uncompressed bitmap or embedded PNG (Vista+) |
PEF vs ICO — Typical file sizes
Approximate file sizes for common scenarios.
PEF
- 24 MP PEF (K-3 Mark III) 30-40 MB
- 36 MP PEF (K-1 Mark II) 45-60 MB
ICO
- Classic favicon (16×16 only) < 2 KB
- Multi-size favicon pack (16/32/48/256) 5-15 KB
- Full Windows app icon set 20-100 KB
Quality & Compatibility
If ICO is a lossless format (PNG, TIFF, BMP) the output keeps every pixel of the decoded PEF exactly. If ICO is a lossy codec (JPEG, WebP, HEIC), the encoder re-compresses the image at the quality level you select — default 85 is transparent for photographs, quality 92+ for illustrations with hard edges.
Tips for Best Results
- Keep the original PEF alongside the ICO output — re-encoding already-lossy images accumulates detail loss on each round.
- If the ICO will be uploaded to a CMS, check whether the platform has a max dimension and downscale once on export rather than letting the CMS resize automatically.
- For thumbnails and avatars, export the ICO at exactly the display size; browsers will otherwise resample and the image may look soft.
Frequently Asked Questions
Frequently Asked Questions
It depends on the codecs involved. If both PEF and ICO are lossy, the pixels are re-encoded and a small amount of detail is discarded — invisible at default quality settings on photographs. If ICO is lossless (PNG, TIFF, BMP) the output keeps every pixel of the decoded PEF exactly, but cannot recover detail that PEF had already compressed away.
Often yes, especially when ICO is lossless. PEF tuned for efficient web delivery will usually produce smaller files than ICO's default settings. If file size matters, drop the quality in Advanced or pick a more compressed target format instead.
KaijuConverter uploads over HTTPS, processes the image in an isolated container and deletes both the source and the output within two hours. No account is required, file contents are never logged, and we do not use uploads to train any model. For confidential material, the paid plan includes a data-processing agreement.
Related comparisons
See these formats side by side to understand which fits your use case best.
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Read guideSecure & Private Conversion
Your files are encrypted during transfer, processed in isolated containers, and automatically deleted within 60 minutes. We never read, share, or store your data.