Technical Guide

Understanding Aspect Ratios and Camera Parameters in AI Image Generation

July 10, 2026 6 min read

Two of the most powerful levers you have when writing AI image prompts are aspect ratio and camera parameters. These technical details control the shape of your output, the perceived depth, the spatial relationship between subject and background, and the overall photographic quality of the image.

This guide covers everything you need to know about using aspect ratios and camera language in your prompts, whether you are using Midjourney, Stable Diffusion, DALL·E, ChatGPT, or Google Gemini.

Aspect Ratios: Choosing the Right Shape

The aspect ratio determines the width-to-height proportion of your generated image. Different platforms and use cases require different ratios.

1:1 Square — Instagram posts, profile pictures, app icons
4:5 Portrait — Instagram feed, editorial portraits, posters
3:4 Classic portrait — book covers, phone wallpapers
16:9 Widescreen — YouTube thumbnails, desktop wallpapers, cinematic scenes
9:16 Vertical — Instagram Stories, TikTok, Reels, phone wallpapers
21:9 Ultrawide — cinematic banners, website hero images, film stills

How to Specify Aspect Ratios

In Midjourney, add the --ar parameter at the end of your prompt:

cinematic landscape, golden hour, mountain lake, volumetric fog --ar 16:9

In DALL·E 3 and ChatGPT, describe the orientation in your prompt ("a vertical portrait-oriented image" or "a wide landscape shot"). In Stable Diffusion, set the width and height directly in the generation settings.

Focal Length: Controlling Depth and Perspective

Focal length is one of the most impactful photography terms you can add to an AI prompt. It controls how the AI renders depth, background blur, and subject proportions.

Example with focal length:

portrait of a young woman in a flower garden, soft natural light, shot on 85mm lens, shallow depth of field, bokeh background, warm golden tones, editorial photography --ar 3:4

Camera Angles: Controlling Viewer Perspective

The camera angle changes how the viewer perceives the subject. Each angle creates a different emotional response:

Depth of Field: Sharp vs Blurry Backgrounds

Depth of field (DoF) controls how much of the image is in sharp focus versus blurred. This is one of the most common parameters in AI prompts because it dramatically affects visual quality.

Shallow DoF example:

close-up portrait of a man with grey hair, shallow depth of field, f/1.8 aperture, soft background bokeh, natural window light, warm tones, photorealistic --ar 4:5

Shot Types: Distance from Subject

Combining Parameters for Maximum Impact

The most effective prompts combine aspect ratio, focal length, camera angle, and depth of field together. Here is a formula:

Formula:

[subject description], [lighting], [camera angle], shot on [focal length] lens, [depth of field], [mood/style] --ar [ratio]
Full example:

editorial portrait of a woman in a vintage bookstore, soft ambient window light, eye level shot, shot on 50mm lens, shallow depth of field, warm nostalgic tones, film grain, photorealistic --ar 4:5 --style raw

Quick Reference Cheat Sheet

Explore prompts with optimized camera parameters in the PromptGet Library.