SuiheiBATCH PHOTO STRAIGHTENING FOR MAC
Suihei brings angle suggestions, manual rotation, cropping, and batch review into one Mac app. Use it after Lightroom or your usual editor to straighten a large set without overwriting the originals.
BEFORE +9.4°AFTER 0.0°Automatic suggestions, manual control
After loading a set, choose the built-in AI or Vision to apply automatic correction. Review the results, then focus on photos marked for review and any deliberately tilted compositions you want to keep.
Manual control, built into the batch
Weak horizons, competing lines, and intentionally tilted frames can still call for judgment. When Suihei finds a possible angle but will not apply it automatically, you can preview the suggestion, confirm it, or dismiss it. A ruler, 0.1° rotation, crop positioning, and undo stay close at hand.
Results vary with the imageSome sets may need little intervention, while others deserve a closer pass. Review the suggestions and adjust only the photos that do not match your intent.
The filmstrip separates corrected photos, photos that need no correction, and results that are unreviewed or need attention.
When the image has competing cues, drag the ruler along the horizon or edge that should be level.
Zoom or pan with the mouse, adjust in 0.1° steps, check the crop, then move straight to the next photo.
The UI examples below use generated demo photos. They are not customer photos or measured correction results.
Built for the final check
Angle and crop preview
Whether you keep a suggested angle or adjust it yourself, Suihei shows the rotated image and crop together. Move the crop if needed, then export when the composition looks right.
The UI examples below use generated demo photos. They are not customer photos or measured correction results.
Suihei analyzes each image separately when you run AI or Vision correction. It does not apply one setting to the entire shoot. A detected tilt of 0.2° or less is left unrotated and marked as needing no correction.
One decision per photoReview a low-confidence suggestion in a temporary preview, then confirm or dismiss it. If the result still misses your intent, trace a level line with the ruler or rotate in 0.1° steps.
Preview + ruler + fine rotationRotating a photo creates empty corners. Suihei finds the largest clean rectangle that fits inside the image and crops automatically.
Auto crop after rotationSuihei reads JPEG, HEIC, and PNG files without changing them. Corrected photos are saved as JPEGs in a separate folder with supported EXIF metadata; photos without corrections keep their source format.
Originals untouched · corrected JPEG outputSet JPEG quality from 50% to 100%, or ask Suihei to prefer the detected quality of the source JPEG. Photos without corrections are copied without re-encoding.
Quality control for re-encoded photosAfter Lightroom. Before delivery.
Export from Lightroom or your usual editor, then open a folder or select JPEG, HEIC, and PNG files.
Loading does not rotate the photos. Choose an automatic method for the set, inspect unreviewed and review-needed results, and use the ruler or fine rotation for the exceptions.
Choose an output folder and JPEG quality. Suihei saves corrected copies there and leaves the files you opened unchanged.
Keyboard shortcuts for repeated work
Use shortcuts to apply automatic correction, rotate in small increments, move the crop, select, undo, and export. Zoom and pan with a mouse or trackpad. You can remap every shortcut to match your setup.
Your photos stay on your Mac
The built-in AI runs on your Mac. Suihei never uploads your photos, and neither your photos nor your editing activity is used to train a model. Core image processing works offline. A connection may be needed to buy or restore a purchase.
After editing. Before delivery.
Export from Lightroom or your usual editor, then run the finished set through Suihei. Leave color and exposure to your main editor; use Suihei for the final straightening and cropping.
$39.99
One-time purchase · no subscription
Prices vary by App Store region. The price shown by the App Store at purchase applies.
The first 100 photos you successfully export are free. After that, you can export up to 10 photos per local calendar day. Viewing and editing stay available after today's allowance is used. A one-time purchase of Unlock Exports removes the export limit.
Requires macOS 26.4 or later and Apple silicon.
View on the Mac App StoreWhat to know before you start
Suihei is designed for the final check on a large set. It keeps per-photo suggestions, review states, manual controls, and export in one place. The finished set is saved as new files.
Not every photo. Some sets need little adjustment, but photos with weak horizons, competing lines, or intentional tilts may need a closer look. Suihei marks those photos for review and gives you a ruler and 0.1° rotation controls when you want to adjust the result.
No. Suihei corrects side-to-side tilt and automatically crops out the blank corners created by rotation. Use your main editor for color, exposure, retouching, and perspective correction.
No. All angle detection runs on your Mac. Suihei does not upload your photos, and neither your photos nor your editing activity is used to train a model.
No. Suihei reads source files without changing them and saves corrected copies in a folder you choose. Backups are still recommended for any professional workflow.
No. Unlock Exports is a one-time purchase with no recurring charge or automatic renewal. It removes the export limit in Suihei Version 1. It costs $39.99. Prices vary by App Store region, and the price shown at purchase applies. If you have already purchased Unlock Exports, you owe nothing further. Without a purchase, the first 100 photos are free to export, followed by up to 10 photos per local calendar day.
For press and reviewers
Suihei is a photo utility for Mac, developed by Marginal Gains, Inc. in Osaka, Japan. Contact us for product details, press assets, or interviews. The app is a free download and the first 100 exports are free, so it is fully reviewable without a code.
Request press informationSpend less time checking horizons.
Suihei for Mac is available now for $39.99. App Store prices vary by region.
