Model Comparison

Flux 1 Schnell vs Flux 1.1 Pro Ultra

The ultimate trade-off: Schnell's sub-second generation versus Pro Ultra's stunning 4-megapixel output at 18x the cost. We analyze when paying the premium delivers images worth the price.

Comparison12 min read
Background

Speed Champion vs Resolution King

Black Forest Labs designed these models for opposite ends of the image generation spectrum. Flux 1 Schnell (German for "fast") is the speed-optimized workhorse of the Flux family, generating 1-megapixel images in about a second. Flux 1.1 Pro Ultra is the company's premium resolution champion, producing 4-megapixel images with native support for outputs up to 2048x2048 pixels and beyond.

The numbers define an extreme gap: Schnell finishes in roughly 1 second at minimal cost. Pro Ultra takes approximately 8 seconds and costs 18x more—a significant price difference with an 8x speed penalty. But Pro Ultra generates images with 4x the pixel count, which fundamentally changes what's possible in the final output.

Pro Ultra's "raw mode" is particularly notable. When enabled (it's on by default), the model produces images with more natural, less processed aesthetics—closer to what you'd expect from a DSLR camera than AI generation. This makes Pro Ultra especially compelling for professional photography applications where that authentic look matters.

These models don't compete directly—they serve different purposes. The question is whether your use case demands resolution and photorealism, or whether speed and cost efficiency take priority.

Note: Flux 1.1 Pro Ultra outputs 4-megapixel images natively. When you need print-ready resolution or large-format display, this eliminates the need for AI upscaling workflows entirely.

Side by Side

Visual Comparison

Compare outputs from both models using identical prompts. Note how Pro Ultra captures finer details and more natural skin tones, particularly visible in portrait and nature subjects.

PromptFlux 1 SchnellFlux 1.1 Pro Ultra
PortraitIntimate portrait of an elderly craftsman in his workshop, weathered hands holding tools, natural window light, documentary photography style, shallow depth of field
Flux 1 Schnell - Portrait
Model: flux-1-schnell
Intimate portrait of an elderly craftsman in his workshop, weathered hands holding tools, natural window light, documentary photography style, shallow depth of field
Flux 1.1 Pro Ultra - Portrait
Model: flux-1.1-pro-ultra
Intimate portrait of an elderly craftsman in his workshop, weathered hands holding tools, natural window light, documentary photography style, shallow depth of field
LandscapeDramatic Icelandic waterfall at golden hour, mist rising from the cascade, volcanic rock formations, long exposure effect, landscape photography masterpiece
Flux 1 Schnell - Landscape
Model: flux-1-schnell
Dramatic Icelandic waterfall at golden hour, mist rising from the cascade, volcanic rock formations, long exposure effect, landscape photography masterpiece
Flux 1.1 Pro Ultra - Landscape
Model: flux-1.1-pro-ultra
Dramatic Icelandic waterfall at golden hour, mist rising from the cascade, volcanic rock formations, long exposure effect, landscape photography masterpiece
ProductLuxury perfume bottle on a bed of fresh white roses, crystal-clear glass catching light, dewdrops on petals, high-end cosmetics advertising, studio photography
Flux 1 Schnell - Product
Model: flux-1-schnell
Luxury perfume bottle on a bed of fresh white roses, crystal-clear glass catching light, dewdrops on petals, high-end cosmetics advertising, studio photography
Flux 1.1 Pro Ultra - Product
Model: flux-1.1-pro-ultra
Luxury perfume bottle on a bed of fresh white roses, crystal-clear glass catching light, dewdrops on petals, high-end cosmetics advertising, studio photography
ArchitectureHistoric European cathedral interior, sunbeams through stained glass windows, dust particles visible in light shafts, reverent atmosphere, architectural photography
Flux 1 Schnell - Architecture
Model: flux-1-schnell
Historic European cathedral interior, sunbeams through stained glass windows, dust particles visible in light shafts, reverent atmosphere, architectural photography
Flux 1.1 Pro Ultra - Architecture
Model: flux-1.1-pro-ultra
Historic European cathedral interior, sunbeams through stained glass windows, dust particles visible in light shafts, reverent atmosphere, architectural photography
NatureMacro photograph of a hummingbird feeding from a hibiscus flower, iridescent feathers catching sunlight, frozen motion, wildlife photography
Flux 1 Schnell - Nature
Model: flux-1-schnell
Macro photograph of a hummingbird feeding from a hibiscus flower, iridescent feathers catching sunlight, frozen motion, wildlife photography
Flux 1.1 Pro Ultra - Nature
Model: flux-1.1-pro-ultra
Macro photograph of a hummingbird feeding from a hibiscus flower, iridescent feathers catching sunlight, frozen motion, wildlife photography

New to ImageGPT?

ImageGPT provides access to both Flux 1 Schnell and Flux 1.1 Pro Ultra through a single API. Use Schnell for rapid iteration, then switch to Pro Ultra for final high-resolution output—no provider switching required. Start with a 7-day free trial.

Recommendations

When to Use Each Model

Choose based on your output requirements, budget constraints, and whether resolution impacts your use case.

Flux 1 Schnell

  • Rapid prototyping and concept exploration
  • Thumbnails, social media, and web graphics
  • High-volume batch generation on budget
  • Real-time applications needing instant response
  • Any use case where 1MP resolution suffices

Flux 1.1 Pro Ultra

  • Print materials requiring high resolution
  • Hero images for large displays and billboards
  • Professional photography simulation
  • Stock photography and commercial licensing
  • Any use case demanding 4MP native output
Deep Dive

Resolution & Fine Detail

Examining how 4MP versus 1MP impacts detail rendering and overall image quality.

Flux 1 Schnell
"Close-up portrait of a snow leopard, piercing green eyes, in..."
Flux 1 Schnell result
Model: flux-1-schnell
Close-up portrait of a snow leopard, piercing green eyes, individual whiskers visible, fur texture showing each hair, wildlife photography, National Geographic quality
Flux 1.1 Pro Ultra
"Close-up portrait of a snow leopard, piercing green eyes, in..."
Flux 1.1 Pro Ultra result
Model: flux-1.1-pro-ultra
Close-up portrait of a snow leopard, piercing green eyes, individual whiskers visible, fur texture showing each hair, wildlife photography, National Geographic quality

This wildlife portrait prompt demands extreme detail: individual whiskers, the texture pattern in fur, and the complex reflections in a feline eye. These micro-details are exactly where resolution differences become most apparent.

In our testing, Pro Ultra's 4MP output revealed individual fur strands and more precise whisker placement. Schnell produced a convincing snow leopard, but fine textures tended to merge or simplify. When zoomed to 100%, the resolution gap was unmistakable— Pro Ultra held detail that Schnell approximated.

Tip: For images that will only be viewed at thumbnail or web sizes, Schnell's detail level is often indistinguishable from Pro Ultra—at 18x lower cost.

Deep Dive

Raw Mode Photorealism

Testing Pro Ultra's signature raw mode against Schnell's standard output.

Flux 1 Schnell
"Candid street photograph of a coffee shop in morning light, ..."
Flux 1 Schnell result
Model: flux-1-schnell
Candid street photograph of a coffee shop in morning light, steam rising from cups, natural window reflections, documentary style, unposed moment captured
Flux 1.1 Pro Ultra
"Candid street photograph of a coffee shop in morning light, ..."
Flux 1.1 Pro Ultra result
Model: flux-1.1-pro-ultra
Candid street photograph of a coffee shop in morning light, steam rising from cups, natural window reflections, documentary style, unposed moment captured

This candid scene tests photorealistic authenticity: natural lighting, atmospheric steam, realistic reflections, and the documentary feel of an unposed moment. It's the kind of image where viewers subconsciously judge whether something looks "real" or "generated."

Pro Ultra's raw mode showed clear advantages in atmospheric rendering. Steam gradients appeared more natural, lighting falloff was more realistic, and the overall image had a less processed quality. Schnell's output was recognizably similar but with slightly more saturated colors and a cleaner, more "digital" aesthetic that some viewers might find appealing but others might identify as AI-generated.

Deep Dive

Print-Ready Output

Evaluating whether each model can produce images suitable for print media.

Flux 1 Schnell
"Magazine cover photograph of a luxury watch, brushed steel c..."
Flux 1 Schnell result
Model: flux-1-schnell
Magazine cover photograph of a luxury watch, brushed steel case, sapphire crystal reflections, product photography, advertising quality, extreme detail on dial
Flux 1.1 Pro Ultra
"Magazine cover photograph of a luxury watch, brushed steel c..."
Flux 1.1 Pro Ultra result
Model: flux-1.1-pro-ultra
Magazine cover photograph of a luxury watch, brushed steel case, sapphire crystal reflections, product photography, advertising quality, extreme detail on dial

Magazine covers and print advertising demand resolution that holds up under scrutiny. This product photography prompt tests both models' ability to render fine mechanical details, reflective surfaces, and the precision expected in luxury brand imagery.

For print at 300 DPI, Schnell's 1MP output limits you to roughly 3.3 inches square—fine for a thumbnail but insufficient for a magazine spread. Pro Ultra's 4MP provides roughly 6.8 inches square at print resolution, suitable for half-page placements without upscaling. For full-page or poster prints, even Pro Ultra benefits from upscaling, but it starts from a much better baseline.

Note: At 300 DPI print resolution: Schnell = ~3.3" output, Pro Ultra = ~6.8" output. Plan your model choice based on final print dimensions.

Deep Dive

Atmospheric & Environmental

Comparing how each model handles complex environmental lighting and atmosphere.

Flux 1 Schnell
"Misty forest at dawn, sun rays filtering through ancient red..."
Flux 1 Schnell result
Model: flux-1-schnell
Misty forest at dawn, sun rays filtering through ancient redwood trees, ferns covered in morning dew, Pacific Northwest, ethereal atmosphere, fine art landscape
Flux 1.1 Pro Ultra
"Misty forest at dawn, sun rays filtering through ancient red..."
Flux 1.1 Pro Ultra result
Model: flux-1.1-pro-ultra
Misty forest at dawn, sun rays filtering through ancient redwood trees, ferns covered in morning dew, Pacific Northwest, ethereal atmosphere, fine art landscape

Atmospheric landscapes challenge models to render volumetric light, subtle gradients, and the interplay between mist and vegetation. These scenes separate models that approximate atmosphere from those that genuinely understand how light behaves in complex environments.

Pro Ultra's handling of light rays through mist was notably more sophisticated, with more natural falloff and interaction with the forest canopy. Individual fern fronds and bark textures remained distinct even in midground elements. Schnell captured the mood effectively but with less depth in the atmospheric layering—fog appeared more uniform rather than volumetric.

Deep Dive

Cost-Efficiency Analysis

When does the 18x premium justify itself?

Schnell (~1s)
"Professional headshot, neutral background, corporate portrai..."
Schnell (~1s) result
Model: flux-1-schnell
Professional headshot, neutral background, corporate portrait, business attire, confident expression, LinkedIn profile quality
Pro Ultra (~8s, 18x cost)
"Professional headshot, neutral background, corporate portrai..."
Pro Ultra (~8s, 18x cost) result
Model: flux-1.1-pro-ultra
Professional headshot, neutral background, corporate portrait, business attire, confident expression, LinkedIn profile quality

Consider a corporate headshot use case. For LinkedIn profiles displayed at 400x400 pixels, Schnell's 1MP output is more than sufficient—you could generate 18 variations to find the perfect composition for the cost of one Pro Ultra image.

But for that same headshot printed on a conference banner, business cards, or a company website hero section, Pro Ultra's resolution and raw mode photorealism becomes essential. The 18x cost difference is negligible compared to the impact of a low-quality image in high-visibility professional contexts.

Tip: Use Schnell for iteration and selection (18 images for the cost of one Pro Ultra). Use Pro Ultra once you've found the perfect prompt and composition.

Specifications

Feature Comparison

Technical specifications and capabilities for both models.

FeatureFlux 1 SchnellFlux 1.1 Pro Ultra
Release20242024
ArchitectureFLUX.1 (distilled)FLUX.1.1 Pro (premium 4MP)
Output resolution1MP standard4MP (2048x2048+)
Image qualityGoodExcellent
Fine detailsBasicExceptional
Generation speed~1s~8s
Cost per imageVery low18x higher
Text renderingBasicGood
Prompt adherenceGoodExcellent
Raw mode
PhotorealismGoodBest-in-class
Try It Yourself

Try Flux 1 Schnell

Try Flux 1 Schnell with your own prompts. Generate images and compare results. Experiment with portrait and landscape prompts to see how each model handles fine details.

Generated visual
https://demo.staging.imagegpt.host/image?prompt=Fashion+editorial+portrait+in+a+sun-drenched+conservatory%2C+golden+hour+light+streaming+through+glass+panels%2C+botanical+garden+backdrop%2C+Vogue+magazine+quality&model=flux-1-schnell

Frequently Asked Questions

Resolution or speed?
Match the model to the moment.