• A graph showing the transmission of a bandpass filter with a central wavelength of 420nm and a bandwidth of 30nm.
  • Blue bandpass filter with black rim on a white background
1 2

BP420-30 Bandpass Filter(CWL=420nm,FWHM=30nm)

BP420-30 Bandpass Filter(CWL=420nm,FWHM=30nm)

PartNumber:SO3010755

$50.00 USD
$50.00 USD
Sale Sold out
Shipping calculated at checkout.
Center Wavelength (CWL) // FWHM
Optical Density // Peak Transmission (Tpk)
Dimension

In Stock.

Ships within 5 working days of order.
  • Wavelength: 420nm center wavelength (CWL) for violet fluorescence imaging and DAPI applications
  • Spectral Features: 30nm FWHM bandwidth with high transmission and controlled edge slopes
  • Optical Density: OD4 blocking for superior out-of-band rejection
  • Filter Dimension Availability: Multiple mounting diameters available to fit standard optical systems

Request Raw Data

You can request the raw transmission data from us.

Copy the link of the product page and send email to shop@syronoptics.com, you will get reply within 1 working days.

Shipment & Delivery

  • Stocked products ship within 5 business days after order confirmation.
  • Custom-made products typically ship within 4–8 weeks.
  • Delivery times may be affected by holidays, customs clearance, or other unforeseen events.
  • Tracking information becomes available 3–5 days after dispatch when the parcel is handed to the local courier.
  • Some deliveries may require customer pickup. Please ensure your contact information is correct and respond promptly to courier communications.
  • General international parcel shipping cost: USD 35 (for reference).

Return & Refund

1. Eligible Products

Stocked (catalog) products with a unit price under USD 500 are eligible for return within 14 days after delivery.

Custom-made or non-stock items are not eligible for no-reason returns.

2. No-Reason Return (Buyer’s Remorse)

If you wish to return an item for reasons other than product defect or seller error:

  • Please email shop@syronoptics.com to request a return authorization and return address.
  • Buyer is responsible for all return shipping costs.
  • Items must be unused, in original condition, and with original packaging.
  • Refund will be issued after inspection of the returned item.

3. Seller’s Fault (Defective / Wrong / Damaged Item)

If the return is due to seller error (defective product, wrong item shipped, or damage during shipping):

Please provide clear evidence (photos or videos) showing the issue.

We will evaluate the case and either:

  • Provide a replacement, or
    Issue a refund (with or without requiring the item to be returned).
  • Return shipping cost will be covered by the seller in confirmed seller-fault cases.

4. Important Notes

  • Returned items are subject to inspection before refund approval.
  • Shipping fees, customs duties, and taxes are non-refundable unless the return is due to seller fault.
  • Unauthorized returns will not be accepted.

Custom Sizing

Custom sizing is available from 3 × 3 mm (or Ø5 mm) up to 60 × 60 mm. For custom cut sizes, please contact shop@syronoptics.com for a quotation.

Pricing is not significantly lower for small-size orders in low quantities due to operational costs.

Payment Terms

Payments can be made online using Credit Card, Apple Pay, Google Pay, WeChat Pay, and Alipay.

If you prefer to pay by bank transfer, please contact shop@syronoptics.com to request an invoice with our banking details.

If you require deferred payment terms, you may request NET 7 or NET 30 at the time of placing your order.

All requests for deferred payment are subject to approval and will be confirmed by SyronOptics via email.

View full details
  • BP420-30 Bandpass Filter - Biomedical & Chemical Analysis - Porphyrin Detection

    BP420-30 Bandpass Filter - Biomedical & Chemical Analysis - Porphyrin Detection

    Biomedical & Chemical Analysis - Porphyrin Detection

    • Porphyrin Excitation: Porphyrins absorb strongly in this region and fluoresce in the red (~600–700 nm). This filter can serve as an excitation filter to stimulate porphyrin fluorescence.

    Recommended Light Sources

    To maximize the efficiency of this filter, you should use light sources that have strong output in the 405–435 nm range: High-Power LEDs

    • 415 nm or 420 nm LEDs: These are the most efficient match. They emit a narrow spectrum that fits almost perfectly inside the filter's 30 nm bandwidth, resulting in very little wasted energy.
    • 405 nm LEDs: While common, 405 nm sits right on the edge of this filter's passband (405–435 nm). Depending on the steepness of the filter's slope, it might cut off some of the light. A 415/420 nm LED is a better fit.
  • BP420-30 Bandpass Filter - Machine Vision & Industrial Inspection - Surface Inspection

    BP420-30 Bandpass Filter - Machine Vision & Industrial Inspection - Surface Inspection

    Machine Vision & Industrial Inspection

    • Surface Inspection: Violet light (shorter wavelength) scatters more on rough surfaces than red light, helping to reveal fine surface scratches, dust, or texture defects that might be invisible under longer wavelengths.

    Recommended Light Sources

    • High-Intensity Violet LED: Violet light has a shorter wavelength (~420 nm) compared to red or green. This shorter wavelength scatters significantly more when it hits microscopic imperfections (like dust or fine scratches), making them appear bright against a dark background.

Fequently Asked Questions

Different Types of Filter Mountings

Unmounted:

  • a bare glass optical filter

Mounted:

  • Smooth Mount for protection of the optics. No thread is there on the mount.

Metric Mount:

  • Start with M as prefix, usually seens as M25.5x0.5mm. Mostly used as camera filters

Imperial Mount:

  • Start with SM as prefix, usually seen SM1, SM05 etc... Mostly used in Optical system. (You will have a SM external thread to connecting to other objects)

C-Mount:

  • Very frequently used mounting. C-Mount is 1‘’-32TPI. And it is not the same thing as SM1, or M25.5x0.5mm.

What are the Thickness of the Optical Filters?

For Unmounted Optics:

  • 0.5mm
  • 1.1mm
  • 2.0mm

*Most of our optics are coming with 1.1mm and 2.0mm

With Standard Mounting (Mounted, No Thread):

  • 3.5mm (Default)
  • 6mm (Upon Request)

Thread Mounted:

  • 6mm - 8mm

  • dia12.5mm(unmounted)

    Clear Aperture:

    >90%

    Mounting Thickness:

    n.a

    Internal/External Thread:

    n.a/n.a

  • dia12.5mm(mounted)

    Clear Aperture:

    dia9mm

    Mounting Thickness:

    3.5mm

    Internal/External Thread:

    n.a/n.a

  • dia25mm(mounted)

    Clear Aperture:

    dia21mm

    Mounting Thickness:

    3.5mm

    Internal/External Thread:

    n.a/n.a

  • dia25mm(unmounted)

    Clear Aperture:

    >90%

    Mounting Thickness:

    n.a

    Internal/External Thread:

    n.a/n.a

  • SM05(0.535″-40TPI)

    Clear Aperture:

    dia9mm

    Mounting Thickness:

    7.62mm

    Internal/External Thread:

    SM05/SM05

  • SM1(1.035″-40TPI)

    Clear Aperture:

    dia21mm

    Mounting Thickness:

    7.62mm

    Internal/External Thread:

    SM1/SM1

  • C-Mount(1″-32TPI)

    Clear Aperture:

    dia21mm

    Mounting Thickness:

    Internal/External Thread:

    C-Mount/C-Mount

  • M25.5x0.5mm(mounted)

    Clear Aperture:

    dia20.5mm

    Mounting Thickness:

    6.5mm

    Internal/External Thread:

    M25.5x0.5mm/M25.5x0.5mm

  • M27x0.5mm(mounted)

    Clear Aperture:

    dia22mm

    Mounting Thickness:

    6.5mm

    Internal/External Thread:

    M27x0.5mm/M27x0.5mm

  • M30.5x0.5mm(mounted)

    Clear Aperture:

    dia25.5mm

    Mounting Thickness:

    6.5mm

    Internal/External Thread:

    M30.5x0.5mm/M30.5x0.5mm

  • M34x0.5mm(mounted)

    Clear Aperture:

    dia29mm

    Mounting Thickness:

    6.5mm

    Internal/External Thread:

    M34x0.5mm/M34x0.5mm

  • M35.5x0.5mm(mounted)

    Clear Aperture:

    dia30.5mm

    Mounting Thickness:

    6.5mm

    Internal/External Thread:

    M35.5x0.5mm/M35.5x0.5mm

  • M37x0.5mm(mounted)

    Clear Aperture:

    dia32mm

    Mounting Thickness:

    6.5mm

    Internal/External Thread:

    M37x0.5mm/M37x0.5mm

  • M52x0.75mm(mounted)

    Clear Aperture:

    dia47mm

    Mounting Thickness:

    6.5mm

    Internal/External Thread:

    M52x0.75mm/M52x0.75mm

  • M55x0.75mm(mounted)

    Clear Aperture:

    dia50mm

    Mounting Thickness:

    6.5mm

    Internal/External Thread:

    M55x0.75mm/M55x0.75mm

  • dia27mm(unmounted)

    Clear Aperture:

    >90%

    Mounting Thickness:

    n.a

    Internal/External Thread:

    n.a/n.a

  • dia34mm(unmounted)

    Clear Aperture:

    >90%

    Mounting Thickness:

    n.a

    Internal/External Thread:

    n.a/n.a

Need any help?