RAW File Size Calculator

Lossless RAW compression (Nikon's lossless compressed NEF, Canon's full RAW, Sony's uncompressed ARW) reduces file size by 30–50% using mathematically reversible compression. Every bit of the original sensor data is fully recoverable — identical to uncompressed. Lossy RAW compression (Canon C-RAW, Nikon small RAW, some Sony options) applies irreversible compression, further reducing file size by 40–60% but with a small quality reduction, primarily in highlight and shadow recovery latitude. For most photography, lossy RAW is acceptable; for critical commercial, fine-art, or heavy post-processing work, use lossless or uncompressed.

DNG (Digital Negative) is an open RAW format developed by Adobe as a universal standard, aiming to replace proprietary manufacturer formats. Benefits of DNG: self-contained metadata (no separate .XMP sidecar files needed), future-proof format maintained by an industry standard body, compatible with more software than proprietary formats. Drawbacks: conversion takes time, some manufacturer-specific features may not translate, and DNG compatibility isn't universal. For archival purposes, DNG is a strong choice; for workflow speed, proprietary RAW with XMP sidecars is faster.

In practice, the difference between 12-bit and 14-bit RAW is most visible in shadow recovery and subtle gradient smoothness. 14-bit RAW contains 4× more tonal levels (16,384 vs. 4,096) per channel, providing more headroom for aggressive shadow lifting and color grading without posterization (banding in gradients). For commercial and fine-art work where heavy adjustments are expected, 14-bit is worth the larger file sizes. For high-volume event and sports photography where speed is priority, 12-bit compressed RAW often delivers faster buffer clearance with negligible quality difference at normal processing.

Cameras offer multiple RAW formats to let users balance file size against quality and performance: higher compression = smaller files = more images on a card + faster buffer clearance, but with some quality reduction. Uncompressed = maximum quality but 2× larger files and slower buffer performance. Many photographers use compressed RAW for action, events, and high-volume shooting, switching to lossless for landscape, studio, or fine-art work. Some cameras also offer a 'Small RAW' that reduces the pixel output before writing — this is a true resolution reduction, not just compression.

Significantly. File size depends on compression algorithm, bit depth, and metadata included: Two 24 MP cameras may produce RAW files ranging from 20 MB (compressed) to 50 MB (uncompressed). Fujifilm's X-Trans sensor produces larger files than equivalent Bayer sensors due to X-Trans pattern complexity. Medium format cameras produce files 3–4× larger than full-frame at similar megapixel counts due to 16-bit capture and less aggressive compression. Always check real-world file sizes from user reports rather than calculated estimates.

For event photography requiring fast delivery (same-day highlights, news), JPEG is practical — smaller files, faster workflow, immediate sharing. For most professional work, RAW is recommended: provides crucial exposure recovery latitude (1–3 stops), allows white balance correction after the fact (important under mixed or difficult lighting), enables noise reduction on raw sensor data, and provides a permanent master file independent of any particular software version. Many photographers shoot RAW+JPEG: RAW as the archival master for editing, JPEG as the quick-share or proof file.

Images per card = Card capacity (MB) / Average RAW file size (MB). For a 256 GB card (262,144 MB) shooting 50 MB RAW files: 262,144 / 50 = 5,242 images. Note: always use 90% of capacity as the practical limit — never fill cards completely, as performance degrades and data corruption risk increases at near-full capacity. Manufacturers sometimes use '256 GB' to mean 256,000 MB (not 262,144 binary MB), so verify actual card capacity in MB from the manufacturer's specifications.