Turn a lens focal length and sensor size into the Perspective value you type into a Clip Studio Paint 3D layer, along with the horizontal, vertical, and diagonal field of view. It carries the framing you see in a photo reference straight into the way your 3D assets look on the canvas.

Basics

What this tool does

Enter a focal length, a reference sensor width, and your canvas size, and you immediately get the horizontal field of view alongside the Perspective value used by the Clip Studio Paint 3D camera. Focal length, horizontal FOV, and the CSP 3D camera Perspective value are three ways of describing the same lens, so editing any one of them updates the other two automatically. If you know the focal length used for a reference photo, you can read off the matching CSP Perspective value directly. Note that the Perspective value is driven by the vertical FOV, so the same focal length yields a different Perspective value on a canvas with a different aspect ratio.

CSP manual: Camera position and angle (Japanese) — Official reference; checked 2026-09-06

Where it fits in your workflow

Matching a 3D prop or background asset to the field of view of a photo reference you are drawing over.
Lining up the perspective baked into a 3D rough sketch with the vanishing points of a hand-drawn perspective grid.
Dialing in how much wide-angle exaggeration to add, by sweeping the Perspective value and eyeballing the result.

How to use it

Enter the pixel dimensions of the canvas you are actually going to draw on, in Canvas width and Canvas height.
In the Lens group, enter just one value: put the focal length in if you know it, or the horizontal FOV if you only know the reference photo's angle of view. The 24/35/50/85/135mm quick buttons apply a common prime-lens focal length in a single tap.
Leave the sensor preset on Full Frame if you are working from a 35mm-equivalent focal length. Change it only when you want to match a specific real camera body.
Give a frequently used combination of settings a name and save it under My presets so you can recall it instantly next time.
Read the "Estimated CSP 3D camera Perspective value" from the derivation steps in the Output panel.
In Clip Studio Paint, select a 3D layer, open the Tool Property panel, and set Perspective to that number.

What each input means

Focal length: The lens focal length in millimeters. On its own it does not determine the field of view — it only does so together with the reference sensor width.
Horizontal FOV: The angle, in degrees, spanned from the left edge to the right edge of the calculation frame. Only values that are meaningful for a perspective projection are accepted — greater than 0 and less than 180 degrees.
CSP 3D camera Perspective value: The value you type into the Perspective field of a Clip Studio Paint 3D layer. A larger number means a wider field of view; a smaller number means a narrower one. Measurements taken on CSP itself show that this value tracks the vertical field of view — the angle across the height of the canvas.
Reference sensor width: The reference value used to convert focal length into field of view. It is not part of any internal CSP sensor specification — it simply answers the question "what width of sensor should this focal length be treated as sitting on?"
Sensor fit: Chooses which side of the frame the sensor dimensions are applied to: horizontal, vertical, or auto. Auto applies the dimension to whichever side is the frame's long edge.
Specify the real camera sensor height: Normally the effective sensor height is derived from the aspect ratio of the calculation frame. Turn this on only when you want to match the sensor height of an actual camera body directly.
Set the calculation frame manually: Use this when the camera should only cover part of the canvas rather than the whole thing — for example, when you want the calculation to apply only within a single comic panel.

Reading the results & bringing them into Clip Studio Paint

Reading the results

The top of the Output panel holds three lines — base camera (focal length and effective sensor dimensions), field of view, then the Perspective value — so you can trace where the number handed to Clip Studio Paint came from. Below that sit the horizontal FOV, vertical FOV, diagonal FOV, effective sensor dimensions, calculation frame, pixel-equivalent focal lengths, and frame center.

The row labeled "Estimated CSP 3D camera Perspective value" is the number you carry into Clip Studio Paint.
The vertical FOV is what sets the Perspective value. Change the canvas aspect ratio and the vertical FOV changes, so the Perspective value changes with it.
The horizontal and vertical focal length in px figures are useful when matching a camera in other 3D software or photogrammetry tools.

Bringing it into Clip Studio Paint

Following the steps in Clip Studio Paint's own user guide, here is how the estimated Perspective value reaches a 3D asset on the canvas.

In the Material palette, select the 3D material you want to place — a drawing figure, a background, and so on — and drag and drop it onto the canvas. A new 3D layer is created at the same time the material loads.
Select that 3D material with the Object tool.
Open the Camera category, either in the Tool Property palette or in the Advanced Tool Settings palette (renamed from Sub Tool Detail in Ver. 5.0; opened from the detail icon at the bottom of Tool Property).
Confirm the Projection method is set to Perspective Projection, then type the "Estimated CSP 3D camera Perspective value" from this tool into the Perspective field.
Moving the camera changes the relative size and occlusion of nearby and distant objects. Perspective controls field of view; camera translation and rotation control viewpoint and orientation. Match the field of view first, then compare and adjust position and orientation.

Clip Studio Paint's own documentation describes Perspective as adding perspective to the 3D material: the larger the slider value, the wider the angle of view, and the smaller the value, the narrower it is — the same direction this tool's estimate follows.

How it works & limitations

How the calculation works

The field of view is computed as FOVx = 2 x atan(sensor width / (2 x focal length)). The vertical and diagonal FOV use an effective sensor height derived from the calculation frame's aspect ratio (sensor width x frame height / frame width). The pixel-equivalent focal length is frame width / (2 x tan(FOVx / 2)). The CSP Perspective value comes from the vertical FOV as Perspective = 17.636 x tan(FOVy / 2), and the reverse conversion uses FOVy = 2 x atan(Perspective / 17.636). Both the 17.636 coefficient and the fact that the vertical axis is the one that matters were measured on Clip Studio Paint 5.0.4 itself. All of the internal math runs in radians; conversion to degrees happens only for display.

Accuracy and what this tool does not cover

The focal length to field of view half of this tool is verified against Blender 3.6 itself. Six hundred combinations of focal length, sensor size, sensor fit and canvas ratio were checked against the projection Blender actually renders with, down to the pixel position of known points, and that comparison is locked in as a regression test. The Perspective conversion is likewise grounded in measurements taken from Clip Studio Paint 5.0.4 itself.

The conversion formula used for the Perspective value is not an official one, because Clip Studio Paint's own documentation only states that a larger Perspective value gives a wider field of view — it publishes no conversion formula for focal length or sensor size. So it was measured directly: a calibration cube was loaded as a 3D layer, exported at Perspective 5, 8, 12 and 20, and the real field of view of each export recovered from its vanishing points. A 1600x1600px square canvas pinned down the 17.636 coefficient (0.02% spread across the four points); re-measuring on 2400x1350 and 1350x2400 then showed the vertical FOV landing at 97.17-97.18 degrees on all three shapes, which is what identifies the vertical axis as the one the Perspective value follows.

The earlier formula, 10 x tan(FOVx / 2), came from a measurement-based community article on CLIP STUDIO TIPS. It agrees with the current formula only at an aspect ratio of 1.764 — which is very nearly 16:9 (1.778). In other words the old formula was not simply off by a constant; it had the wrong axis, and happened to be almost right on 16:9-ish canvases. This tool defaults to a 1920x1080 canvas, so anyone on the defaults saw only a tiny discrepancy. On square or portrait canvases it was far off: Perspective 5 on a 1600x1600 canvas really renders at 31.66 degrees, not 53.13. Always confirm the final look by placing your 3D asset in CSP itself.

Lens distortion (barrel or pincushion) is not modeled — the calculation assumes an ideal perspective projection.
This tool does not generate a perspective ruler for you. CSP's standard perspective rulers are built from eye level and vanishing points, not from a camera model, so that step is left to you.

How your data is handled

Calculations and automatic saving take place in your browser. Inputs are saved to localStorage and restored next time. Settings links contain parameter values, and opening a link sends its URL to the hosting server. Share only settings you want others to see. Clear this site’s site data in your browser to remove locally saved values.

FAQ

Where in Clip Studio Paint do I enter this value?

With a 3D layer selected, it is the Perspective field shown in the camera settings of the Tool Property panel.

Can I type in the focal length straight from a photo's Exif data?

Yes, as long as you set the sensor preset to match the sensor size of the camera that took the photo. If you are working from a 35mm-equivalent focal length, choose Full Frame.

Does changing the canvas size also change the Perspective value?

Yes. The Perspective value is derived from the vertical FOV, and the vertical FOV is derived from the effective sensor height, which comes from the aspect ratio of the calculation frame. At a fixed focal length, a wider canvas gives a smaller Perspective value and a taller canvas a larger one. Note too that a CSP 3D layer keeps the projection it was created with: resizing the canvas afterwards does not re-project the 3D view (confirmed on CSP itself), so create the 3D layer again after changing canvas size.

Can I work backwards from a CSP Perspective value to a focal length?

Yes. Type the Perspective value you are currently using into the Perspective field, and the tool derives the matching focal length and horizontal FOV for you. That reverse conversion also goes through the vertical FOV, so set the canvas size to match the one in CSP first.

Getting Clip Studio Paint

What Clip Studio Paint is

Clip Studio Paint is a painting application from CELSYS, built for illustration, comics and animation. What separates it from a general-purpose image editor is that the production features print work assumes — pressure settings tuned for inking, panel layout and speech balloons, screentones, 3D reference models and perspective rulers — are all there from the start. It runs on Windows, macOS, iPad, iPhone, Android and Chromebook.

The trial version and how it is sold

A free trial version is distributed on the official site, so you can judge how it draws and whether it has the features you need on your own machine first.
There are two grades, PRO and EX. The main dividing line is whether you need to handle a multi-page comic manuscript as a single project.
It is sold both as a one-time perpetual license and as a monthly or yearly plan. Which devices you can use it on, and how many, depends on the plan.
Prices, plan structure and supported devices are revised from time to time, so check the current terms on the official site.

How this tool relates to Clip Studio Paint

The tool on this page runs entirely in your browser, so the calculations and the exports work whether or not you own Clip Studio Paint. What you get here, though, is material meant to be carried into Clip Studio Paint: the estimated Perspective value only affects your artwork once it is typed into a Clip Studio Paint 3D layer. The reasoning transfers to other painting software, but the numbers and the exports are shaped around Clip Studio Paint.