Fisheye Effect: Bulge a Photo Like a Wide Lens
Both axes are normalised by the same distance, so round things stay round on a wide photo instead of stretching into ovals. Includes the real rectilinear to fisheye projection alongside the usual barrel bulge.
Drop images here
or click to browse · or paste with Ctrl+V
JPG · PNG · WebP · GIF · BMP · AVIF
Distortion
The centre and the four corners stay exactly where they are at any strength.
Crops into the middle of the effect, which is useful when barrel distortion has pushed your subject too far out.
This adds distortion. It cannot correct an existing fisheye photo back to straight lines, because the pixels the lens never recorded are simply not there.
Presets
Your photos are never uploaded. The remapping and the export both run inside this browser tab.
People also use
Everything this tool does
Round things stay round
Both axes are normalised by half the diagonal rather than by width and height separately. On a two to one test image a circle came back at 91 by 91 pixels, a ratio of 1.000, against 1.41 for per-axis normalisation.
No empty corners, ever
The corners sit at a radius of exactly one and all three curves map one to one, so every output pixel has a real source pixel. No smeared borders and no blank wedges to hide.
A true fisheye projection
One mode uses the actual relation between a rectilinear lens and an equidistant fisheye, which curves harder near the edges than a generic bulge and reads as more convincingly optical.
Bilinear sampling
The remap reads between pixels almost everywhere, so sampling matters. Bilinear keeps curved edges smooth rather than stair-stepped.
Pincushion as well as barrel
The inverse curve pinches the middle inward, which at low strength is quietly flattering on portraits and is the correct starting point for imitating a longer lens.
Drag to compare
Before and after share one frame with a slider between them, which is the only reliable way to judge a warp this smooth.
Six purpose-built presets
Action camera, extreme fisheye, subtle bulge, true projection, gentle pinch and bulge and crop.
Batch with one ZIP
Apply identical distortion across a set and take everything as a single archive built in your browser.
Transparency preserved
The alpha channel is untouched for PNG and WebP output.
Nothing is uploaded
No server, no queue, nothing to delete afterwards. Close the tab and every trace of the image goes with it.
What each mode does
All three modes move pixels along the line from the centre outward, and they differ only in the curve they use. The centre and the corners are fixed points in every one of them.
| Mode | Curve | Try | Good for |
|---|---|---|---|
| Barrel | power curve, bulges outward | strength 30-60 | Action camera look |
| True fisheye | the rectilinear to fisheye relation | strength 50-90 | Convincing lens distortion |
| Pincushion | the inverse power curve | strength 20-50 | Pinched, telephoto feel |
| Strength 10-25 | subtle, almost plausible | any mode | Adding a little character |
| Strength 60-100 | extreme, obviously stylised | barrel or fisheye | Skate video, poster art |
| Zoom 100 | whole frame kept | any | Keeping the composition |
| Zoom 130-200 | crops into the middle | barrel | When the subject got pushed out |
3
distortion curves
0
empty areas ever
0
files uploaded
Fixed
centre and corners
ZIP
batch download
Free
no account needed
FlipMyFormat vs other fisheye tools
| Capability | FlipMyFormat | Typical free tool |
|---|---|---|
| Files stay in your browser | ||
| Circular distortion, round stays round | ||
| True rectilinear to fisheye projection | ||
| No empty corners at any strength | ||
| Pincushion as well as barrel | ||
| Batch ZIP download without paying | ||
| No watermark on the output |
How to use distortion deliberately
Distortion is one of the few effects where the subject decides almost everything. It works by moving every pixel along the line running from the centre of the frame outward, which means a pixel already at the centre does not move at all and a pixel at a corner barely does either. Everything interesting happens in the ring between. That has two practical consequences. The first is that whatever you want to distort should not be dead centre, because the centre is the one place the effect cannot reach. Put a face slightly off centre and it stretches; put it exactly in the middle and almost nothing happens to it. The second is that straight lines are what make the effect readable. A photograph of a lawn will bend and nobody will be able to tell; a photograph of a building, a doorway, a horizon or a road will bend visibly, because your eye knows those lines were straight. If your result looks like nothing happened, the odds are your photo simply has no straight lines in it. As for which mode, barrel is the familiar look and behaves predictably. True fisheye uses the actual mathematical relation between a straight lens and a fisheye one, which curves harder near the edges and reads as more convincingly optical at higher strengths. Pincushion is the reverse, pinching the middle inward, and it is worth trying at low strength on portraits because a gentle pinch can be quietly flattering.
- 1
Add a photo
Drag it in, click to browse, or paste with Ctrl+V. Photos with straight lines near the edges, such as buildings or horizons, show the effect most clearly.
- 2
Pick a mode and strength
Barrel is the familiar bulge, true fisheye uses the actual projection maths, and pincushion is the opposite. The centre and corners never move.
- 3
Zoom in if needed, then export
Barrel pushes your subject outward, so a little zoom brings it back. Save individually or take the batch as one ZIP.
The mistake that turns circles into ovals
One radius, not two
The natural way to write a radial effect is to divide the horizontal distance by half the width and the vertical distance by half the height, so both come out between zero and one. It is convenient and it silently makes the distortion elliptical, because on a wide photo one pixel of horizontal distance is worth less than one pixel of vertical distance. Round things then stretch into ovals, and the further the image is from square the worse it gets. This tool normalises both axes by the same figure, half the diagonal, so the distortion is genuinely circular whatever the shape of the frame. We tested it on a two to one image with a circle drawn in it: after a barrel distortion the circle measured 91 by 91 pixels, a ratio of 1.000, where per-axis normalisation gave a ratio of 1.41, which is an obvious oval.
Why there are never empty corners
Most distortion tools have to deal with the fact that pushing pixels outward leaves nothing behind at the edges, which is why so many of them either stretch the border pixels into smears or leave you with blank wedges in the corners and a zoom slider to hide them. Normalising by the half diagonal avoids the problem entirely, because it puts the corners of the frame at exactly a radius of one, and all three curves here map one to one. The corners are fixed points, the centre is a fixed point, and everything in between is pulled along the same line, so every output pixel has a real source pixel to read from. The zoom control is therefore optional rather than a repair: it exists because barrel distortion pushes your subject outward, not because there is a hole to cover up.
What people use it for
Action camera look
Barrel distortion is the signature of a wide sports camera, and adding it makes ordinary footage stills read as action.
Skate and BMX photography
The genre has used extreme wide lenses for decades, so the distortion is part of the visual language.
Music and event posters
Heavy fisheye on a portrait is instantly graphic and has a strong nineties association.
Architecture as art
Buildings bend the most, because their straight lines make the curve unmistakable.
Album artwork
A bulged portrait shot close up is a long-running cover convention.
Game and UI textures
Barrel distortion over a screenshot suggests a curved CRT screen or a helmet visor.
Gentle portrait pinch
Low strength pincushion narrows the edges of the frame slightly, which can be quietly flattering.
Making a photo feel wider
Mild barrel distortion imitates a shorter focal length without actually changing what is in the frame.
Six tips worth knowing
Keep your subject slightly off centre. The exact middle is the one place the effect cannot reach, because it is a fixed point.
Straight lines make the distortion readable. Buildings, doorways, horizons and roads bend visibly; grass and clouds do not.
True fisheye curves harder near the edges than barrel does, which reads as more optical at high strength.
Barrel pushes your subject outward, so a little zoom brings it back to a comfortable size without changing the distortion.
Pincushion at low strength is worth trying on portraits, where a gentle pinch is subtler than a bulge.
This adds distortion; it cannot remove it. Correcting a real fisheye photo needs pixels the lens never recorded.
Troubleshooting
It looks like nothing happened
Your photo probably has no straight lines, which is what makes the curve visible. Try an image with a building, a horizon or a doorway near the edge.
My subject got too small
Barrel distortion pushes things outward from the centre. Raise the zoom to crop back into the middle of the effect.
Round objects came out oval
They should not, since both axes are normalised by the same distance. If something looks oval, check whether it was already distorted in the source.
Can it undo a GoPro fisheye?
No. Pincushion moves pixels the other way, but the straight-line detail a fisheye lens compressed into the corners is not recoverable by remapping.
Frequently asked questions
What does a fisheye effect do to a photo?
It moves every pixel along the line from the centre of the frame outward, using a curve. Straight lines bend, the middle appears magnified, and the result imitates a very wide lens.
Why do round objects turn into ovals in some tools?
Because they divide horizontal distance by half the width and vertical distance by half the height. On a non-square photo those are different, so the distortion becomes elliptical.
How does this tool avoid that?
Both axes are normalised by half the diagonal, the same figure for each. On a two to one test image a circle came back at 91 by 91 pixels, a ratio of 1.000, where per-axis normalisation gave 1.41.
What is the difference between barrel and true fisheye?
Barrel uses a simple power curve and behaves predictably. True fisheye uses the actual relation between a rectilinear lens and an equidistant fisheye, which curves harder near the edges and looks more optical at high strength.
What does pincushion do?
The opposite of barrel. It pinches the middle inward, which is the distortion a long lens tends to produce. At low strength it can be quietly flattering on portraits.
Why does the centre of my photo barely change?
Because the centre is a fixed point. Every pixel moves along the line from the centre outward, so a pixel already at the centre has nowhere to go. Put your subject slightly off centre to see the effect on it.
Why do the corners not change either?
The normalisation puts the corners at a radius of exactly one, and all three curves map one to one. That is also why you never get empty wedges or smeared borders.
Can this fix a photo that already has fisheye distortion?
No. Pincushion moves pixels the other way, but a fisheye lens compressed a lot of detail into a few pixels near the edge, and that detail cannot be recreated by moving pixels around.
It looks like nothing happened to my photo
The effect is only visible where there were straight lines. A lawn or a cloudy sky bends without anyone being able to tell. Try a photo with a building, a doorway or a horizon.
What is the zoom control for?
Barrel distortion pushes your subject outward, so it can end up smaller than you wanted. Zoom crops into the middle of the effect to bring it back. It is not there to hide empty areas, because there are none.
Does the image change size?
No. The output keeps your original width and height. Only where each pixel reads its colour from changes.
Why does it need bilinear sampling?
Because a radial remap reads between pixels almost everywhere. Rounding to the nearest pixel would make every curved edge stair-step, and the error grows with distance from the centre.
Are my photos uploaded to a server?
No. The remapping and the export both run in your browser using the canvas API. Nothing is sent anywhere.
Which format should I export?
Either works. The warp is smooth, so JPEG at quality 85 or above is fine, and PNG is the safe choice if the photo has hard graphic edges.
Is transparency preserved?
Yes for PNG and WebP output. The alpha channel is untouched. JPG has no alpha, so transparent areas are filled with the background colour first.
Can I move the centre of the distortion?
Not at the moment. Keeping it at the frame centre is what guarantees the corners stay fixed and no empty area appears. A movable centre is a candidate for a future version.
Can I process a batch?
Yes. Add as many photos as you like and the same mode, strength and zoom are applied to each. Take the set as a single ZIP built in your browser.
Does it add a watermark or need an account?
No to both. No sign-up, no email wall, no daily limit and no watermark on the output.