Quick answer

Choose the https://uqgopticser.com/products/schott-wg280-2-dbce8860d41805e22ec4a54c-1696615Schott N-WG280 if you need a larger 25 mm diameter filter for standard mounts and can accept a higher price. Choose the Schott N-WG320 if your setup uses a 12.5 mm mount and you want a lower-cost option. Both are 2 mm thick longpass filters that block UV and transmit visible light, so the deciding factors are size and budget, not optical performance.

Schott N-WG320

Schott N-WG320

What actually differs between N-WG280 and N-WG320

The N-WG280 and N-WG320 share the same basic construction: 2 mm thick Schott filter glass. The differences are in diameter and price. The N-WG280 comes in a Ø 25 mm size, while the N-WG320 is Ø 12.5 mm. That size gap matters more than any other specification because it determines which filter holders, lens barrels, or optical mounts you can use without adapters.

The N-WG280 is listed at USD 11.68 (catalog comparison price USD 16.00), and the N-WG320 is listed at USD 7.20 (catalog comparison price USD 12.00). If your mount accepts 25 mm optics, the N-WG280 gives you more glass area for the same 2 mm thickness. If you are working in a compact system with 12.5 mm mounts, the N-WG320 fits directly and costs less.

How to match the filter to your mount

Measure your existing filter holder or the clear aperture of your setup before ordering. A 25 mm filter will not fit a 12.5 mm mount without an adapter, and a 12.5 mm filter in a 25 mm holder leaves a gap that can cause stray light or alignment issues. The N-WG280 is the straightforward choice for standard 25 mm filter wheels and lens tubes. The N-WG320 suits compact cameras, miniature spectrometers, and small optical benches where space is tight.

Thickness is identical at 2 mm for both, so you do not need to worry about different optical path lengths or focus shifts between the two. If your system is already designed around 2 mm thick filters, either will drop in without changing your spacing.

Price and value: when the cheaper filter is the right one

The N-WG320 costs less, but that does not make it lower quality. Schott N-WG glass is a known family of longpass filter materials, and both filters use the same 2 mm thickness. The price difference reflects the smaller diameter and less material, not a different grade. If your application only needs a 12.5 mm aperture, paying more for the N-WG280 wastes money and space.

Conversely, if you need to cover a larger sensor or beam, the N-WG280 is the practical choice. Buying the smaller N-WG320 and trying to adapt it up usually costs more in adapters and alignment time than the price difference between the two filters.

Trade-offs at a glance

  • Size vs. compatibility: N-WG280 gives you a 25 mm aperture for standard mounts but will not fit 12.5 mm holders. N-WG320 fits 12.5 mm mounts but is too small for 25 mm filter wheels without an adapter. Match the diameter to your existing mount first; size is the hardest difference to work around.
  • Cost vs. coverage: N-WG320 costs less (USD 7.20 vs USD 11.68) but covers a smaller area. N-WG280 costs more but covers a larger beam or sensor. If your beam is narrow, the N-WG320 saves money. If you need full coverage, the N-WG280 avoids adapters and vignetting.
  • Same thickness, same handling: Both filters are 2 mm thick, so they share the same optical path length and similar handling needs. Neither is more fragile than the other based on thickness alone. You can switch between them without changing focus or spacing, as long as the diameter fits.

Product facts

  • Schott N-WG280: Schott N-WG280, 2 mm thick, Ø 25 mm, part numbers FWG28025, FWG-28025, FWG 28025. The 25 mm diameter fits standard filter mounts and larger optical systems, so you can use it without adapters in most benchtop setups.
  • Schott N-WG320: Schott N-WG320, 2 mm thick, Ø 12.5 mm, part numbers FWG32012, FWG-32012, FWG 32012. The 12.5 mm diameter suits compact mounts and small-diameter beams, and its lower price makes it a budget-friendly choice when the smaller size is sufficient.

Which filter fits your setup?

Best for

  • Users with 25 mm filter holders, lens tubes, or standard optical mounts who need UV blocking and visible light transmission.
  • Applications where a larger aperture reduces the risk of vignetting or beam clipping.

Not for

  • Compact systems with 12.5 mm mounts, where the N-WG280 will not fit without an adapter.
  • Budget-focused setups where a 12.5 mm aperture is sufficient and the lower cost of the N-WG320 is preferred.