Megapixels are not the deciding measure
Character-level clarity matters more than megapixels, file size, or artificial upscaling.
Judge resolution at character level
Inspect
The original image viewed at full size, not only its pixel count.
Useful relationship
Readable character height matters more than a large canvas around tiny text.
Pass condition
Zoom into the smallest required character and inspect its separate strokes.
Judge the characters, not the file
Open the image at full size and inspect the smallest text you need. Letter strokes should be distinct, counters inside letters should remain open, and punctuation should not merge with neighboring characters. A high-megapixel photo taken from far away can still devote very few pixels to each letter.
File size is also an unreliable quality measure. A noisy or lightly compressed photo can be large without containing useful detail, while a clean screenshot can be small and extremely readable.
Avoid fake detail
Upscaling makes an image wider but cannot recreate missing strokes. Strong sharpening may invent bright and dark outlines that OCR mistakes for punctuation or extra character parts. Prefer recapture, optical zoom, or a closer camera position.
If recapture is impossible, test a tight crop and a mildly adjusted copy. Preserve the original and reject any edited reading that is not also supported by visible source pixels.
You can inspect dimensions alongside simple contrast and blur signals with the local OCR image readiness checker.
Match the capture to the object
For a flat page, fill the frame while keeping all four corners reasonably square. For packaging, photograph one curved section at a time. For screens, use the device screenshot function instead of photographing pixels through another camera sensor.
The practical target is not a universal dots-per-inch number. It is a source where every important character can be independently inspected and where compression, motion, or glare has not erased its distinguishing marks.
Understand why character size, focus, contrast, and compression matter more to OCR than a camera megapixel number alone. Continue with the photo quality and ocr guide collection for adjacent workflows.