Terms of Use — FocalMath

Acceptance of Terms

By using FocalMath, you agree to these terms. If you don't agree, please don't use the site. These terms apply to every page, calculator and reference entry on the site, including the paid product and donation pages.

The Calculators Are Estimates

Every number this site produces — depth of field, hyperfocal distance, exposure equivalence, astro shutter-speed limits, print size, crop-factor equivalence — is a computed estimate based on published photographic formulas and the inputs you provide. These are planning aids, not guarantees. Circle of confusion is a stated convention (diagonal/1500), not a fixed physical property of your specific lens or sensor, and real-world results depend on factors this site cannot know: your lens's actual resolving power, your focus accuracy, atmospheric conditions, your camera's specific firmware behavior, and more. Always confirm critical focus and exposure on your own camera before a shot that matters.

Reference Data

Camera and sensor specifications are drawn from manufacturer-published figures at the time of writing and are provided for reference only. Manufacturers occasionally revise published specifications, and we may not catch every revision immediately. If you spot a discrepancy, please tell us via the contact page.

Accounts

This site does not currently require an account to use any calculator or read any reference page. If that changes in the future, these terms will be updated accordingly, and any account-related terms (password security, account termination, and similar) will be added at that time rather than assumed in advance.

No Professional Advice

Nothing on this site is professional photographic, technical, or safety advice. You're responsible for your own equipment settings and for verifying results before relying on them for paid or otherwise consequential work.

Intellectual Property

The site's design, original written content, and calculator code are owned by FocalMath unless otherwise noted. You're welcome to link to any page. Reproducing substantial portions of the reference content elsewhere without permission isn't allowed.

Trademarks

Camera and brand names referenced on this site (Canon, Nikon, Sony, Fujifilm, Panasonic, OM System, Olympus, Leica, Pentax, DJI, GoPro, and others) are trademarks of their respective owners. FocalMath is an independent reference site and is not affiliated with, sponsored by, or endorsed by any camera manufacturer.

Paid Products and Donations

Paid products are fulfilled by email as described on their product pages, typically within 24 hours of purchase. If you don't receive your product within that window, check your spam folder first and then contact us — delivery issues are almost always a mail-filtering problem on the receiving end, and we're glad to resend. Donations are voluntary and non-refundable except where required by law. All payments are processed by Stripe, and we do not store your payment card details on our own systems at any point.

Acceptable Use

Don't use automated tools to scrape or bulk-download this site's reference content or calculator results in a way that degrades the service for other users. Don't attempt to circumvent, disable, or interfere with the site's security or functionality. Don't use the site for any unlawful purpose.

Third-Party Links and Services

This site links to sister sites and other third-party resources where genuinely relevant, and uses third-party services (Google Analytics, Google AdSense, Stripe, Brevo for email) to operate. We aren't responsible for the content, availability, or practices of any external site or service we link to or rely on — their own terms and policies govern your use of them.

Limitation of Liability

The site and its calculators are provided "as is" without warranty of any kind. To the fullest extent permitted by law, FocalMath is not liable for any loss or damage arising from your use of, or reliance on, the site's calculators or reference content.

Termination of Access

We reserve the right to restrict or block access to the site for anyone who violates these terms, particularly the acceptable-use section above, without prior notice.

Severability

If any part of these terms is found unenforceable, the remaining terms stay in effect.

Changes

We may update these terms from time to time. Continued use of the site after a change means you accept the updated terms. If you have questions about these terms, contact us through the address on the contact page and we'll do our best to clarify anything that's unclear.