Choosing a Verifire MST Interferometer: 4" vs 6"
By Zygo | Published: 2026-10-22
Category: Buying Guides
Compare the 4" and 6" Verifire MST interferometers to find the right aperture size for your optical testing needs.
Quick answer
Choose the 4" Verifire HD-MST for smaller optics and tighter budgets, or the 6" Verifire MST+ for larger parts and higher-resolution imaging.
Aperture size affects your testable part size
The aperture size determines the maximum diameter of the optical component you can test without a beam expander. A 4" aperture handles most standard optics, while a 6" aperture accommodates larger lenses, mirrors, and windows directly.
If you frequently test parts larger than 4", the 6" model saves you the cost and complexity of adding a beam expander. If your parts are mostly smaller, the 4" model is more practical and economical.
Camera resolution and imaging detail
The 4" Verifire HD-MST features a 2.3k x 2.3k camera, while the 6" Verifire MST+ has a 1.4k x 1.4k camera. Higher pixel count on the 4" model means more spatial resolution across the field of view, which is beneficial for detecting fine surface defects on smaller parts.
The 6" model's lower pixel count is still adequate for many production and lab applications, but if your work demands maximum detail, the 4" model's higher resolution is a key advantage.
Budget and value considerations
The 4" Verifire HD-MST is priced at USD 2.40 compared to the 6" Verifire MST+ at USD 41,926.50. The price difference is significant, so it's important to weigh the cost against the aperture and resolution needs.
If your testing requirements are within the 4" aperture and you need high-resolution imaging, the 4" model offers exceptional value. The 6" model is a larger investment but may be necessary for larger parts.
Decision rules for choosing your Verifire MST
- Part size: If your largest test part is 4" or smaller, choose the 4" Verifire HD-MST. If you need to test parts up to 6" without a beam expander, choose the 6" Verifire MST+. Measure your largest part before deciding.
- Resolution needs: If you need maximum spatial resolution for fine defect detection, the 4" model's 2.3k x 2.3k camera is the better choice. If resolution is less critical, the 6" model's 1.4k x 1.4k camera is sufficient. Review your defect size requirements to determine if higher resolution is essential.
- Budget: If budget is a primary constraint and your parts fit within 4", the 4" Verifire HD-MST offers a cost-effective solution. If you need the larger aperture, be prepared for a higher investment with the 6" Verifire MST+. Weigh the price difference against the cost of a beam expander if you expect to test larger parts later.
Product facts at a glance
- 4" Verifire Interferometer HD-MST: 4" Verifire HD-MST with 633 nm wavelength, 2.3k x 2.3k camera, coherent imaging system, 1X fixed magnification, and Ring of Fire coherent artifact reduction system. The higher-resolution camera captures finer surface detail on smaller optics, making it ideal for precision testing of components up to 4".
4" Verifire Interferometer HD-MST - 6" Verifire Interferometer MST+: 6" Verifire MST+ with 633 nm wavelength, 1.4k x 1.4k camera, coherent imaging system, 1x fixed magnification (with optional optical zoom), and Ring of Fire coherent artifact reduction system. The larger aperture directly accommodates bigger parts, and the optional optical zoom adds flexibility for varying magnification needs.
6" Verifire Interferometer MST+
Who should choose which?
Best for
- The 4" Verifire HD-MST is best for labs and production lines testing small to medium optics up to 4" with high-resolution imaging needs.
- The 6" Verifire MST+ is best for facilities that regularly test larger optical components and prefer a direct measurement without a beam expander.
Not for
- The 4" model is not for you if you need to test parts larger than 4" without investing in a beam expander.
- The 6" model is not for you if you primarily test small parts and need maximum resolution, or if your budget is limited.
