The focal length of your CO₂ laser lens dramatically affects how your machine engraves and cuts. If you’ve ever wondered whether you should use a 50 mm lens or upgrade to a 63.5 mm lens, this guide explains how they differ — and exactly which one is best for wood, acrylic, leather, MDF, rubber stamps, two-color plates, and more.
This is a practical, decision-making guide based on real cutting behavior and material performance.
✅ Best lens for each material & project
✅ Spot size, depth of focus & engraving clarity
✅ Buying recommendations + accessory CTA
The Quick Answer
If you need detail → choose 50 mm.
If you need cutting depth → choose 63.5 mm.
- 50 mm → smaller spot → finer engraving on thin materials
- 63.5 mm → deeper focus → better performance on thicker materials
Why Focal Length Matters
The focal length determines:
- Spot size (resolution)
- Depth of focus (stability at depth)
- Cutting penetration
- Engraving sharpness
Shorter lens → smaller spot → high resolution Longer lens → deeper focus → better material penetration
| Attribute | 50 mm | 63.5 mm |
|---|---|---|
| Spot size | ✅ Smaller | Larger |
| Depth of focus | Shallow | ✅ Deeper |
| Resolution | ✅ Higher | Good |
| Thick cutting | OK | ✅ Better |
| Engraving clarity | ✅ Excellent | Good |
Core Differences
50 mm Lens
- Smallest laser spot
- Best engraving quality
- Crisp text + clean edges
- Best for thin materials
63.5 mm Lens
- Deeper cutting stability
- Better for thicker materials
- Handles uneven surfaces better
- Larger kerf but cleaner penetration
Material Recommendations
Here are the best lenses for each common CO₂ laser material:
| Material | Best Lens | Why |
|---|---|---|
| Acrylic | 50 mm ≤6 mm 63.5 mm >6 mm |
Fine text vs deeper cutting |
| Wood | 63.5 mm | Better thick cutting |
| MDF | 63.5 mm | More stable penetration |
| Leather | 50 mm | Clean surface engraving |
| Two-color plate | 50 mm | Crisp engraving |
| Rubber (stamps) | 63.5 mm | Deeper relief |
| PVC* | 63.5 mm | Better control |
| Fabric | 50 mm | Fine detail |
Which Is Better for Engraving?
50 mm wins.
Because of its small spot size, a 50 mm lens produces:
- Sharper engraving
- Thinner lines
- Cleaner small text
- Better QR codes + logo details
Which Is Better for Cutting?
63.5 mm wins.
- Stronger penetration
- Better performance on thick hardwood / MDF / acrylic
- Less focus sensitivity
- More consistent edge
Use Case Guide
| Use Case | Best Lens | Why |
|---|---|---|
| Fine logos | 50 mm | Small spot |
| Signage (2-ply) | 50 mm | Shallow clean engraving |
| Rubber stamps | 63.5 mm | Deep relief |
| QR / barcode | 50 mm | Crisp detail |
| Deep acrylic cutting | 63.5 mm | Deeper focus |
| Thick wood decor | 63.5 mm | Stable penetration |
| Leather patches | 50 mm | Crisp surface |
Engraving vs Cutting Summary
| Process | Recommended Lens |
|---|---|
| Fine engraving | ✅ 50 mm |
| Deep engraving | ✅ 63.5 mm |
| Thin sheet cutting | 50 mm |
| Thick cutting | ✅ 63.5 mm |
What If I Only Buy One?
Buy 50 mm.
It handles the majority of engraving + general cutting well.
Example Material Performance
Even with identical machine power, focal length influences quality:
Acrylic 3 mm
- 50 mm → crisp edge
- 63.5 mm → slightly wider kerf
MDF 10 mm
- 50 mm → more charring
- 63.5 mm → cleaner penetration
Best Pairing Accessories
- Air-assist nozzle
- Honeycomb worktable
- Exhaust upgrade
FAQ
Q: Which lens is most versatile?
50 mm.
Q: Which lens gives the highest detail?
50 mm.
Q: Which is best for cutting thick wood?
63.5 mm.
Q: Can I use both lenses?
Yes — many users swap based on project.
Q: Do I need to adjust focus height?
Yes — set focus correctly for each lens.
Conclusion
The focal length you choose affects resolution, depth of focus, clarity, and cutting performance. For most users, the 50 mm lens provides the best balance of detail and versatility. If you frequently cut thicker material, adding a 63.5 mm lens will significantly improve cutting stability and edge quality.
In short:
- Engraving → 50 mm
- Thick cutting → 63.5 mm
- Best single choice → 50 mm