When I’ve had a good experience with a supplier I like to try and mention them on my page, if nothing else as a bit of thank you. This brings me to Tangsinuo, a Chinese optical filter supplier. I recently found myself in need of some UV transmitting filters in larger sizes than I would normally be able to buy from Schott or other conventional suppliers. Big filters tend to command big (really) price tags even when they are available and this ruled out the more conventional suppliers for this work. ZWB glass is often seen advertised on ebay and other sites as being ‘equivalent’ UG1, UG11 and others, although some of the transmission graphs that come with the adverts have left me wondering how good they actually are.

One supplier – Tangsinuo – has been mentioned a few times on the UV photography forum which I’m member of, so I reached out to them to see if they could do large filters (200mm square) using the glasses I was interested in and was pleasantly surprised to find out that they could, and that they were very cost effective. In the end I placed an order for some 200mm square ZWB1 and ZWB3 glass, some 77mm diameter mounted filters in ZWB1 and 3, some 52mm filters in ZWB3 at different thicknesses, and also a load of fused silica 1mm thick microscope slides (75mm x 25mm) which are normally quite expensive items. All in all the price as extremely good even when I paid for expedited delivery – just over a week from China to the UK using tracked delivery.

So, how did they look? Transmission spectra of the filters, and the filter thicknesses, are given below (as measured using my Ocean Insight FX and STS spectrometers).

ZWB1 is said to be equivalent to Schott UG11, and it looks similar, although does leak a bit more IR than the Schott for an equivalent thickness. ZWB3 is said to be equivalent to Schott UG5, and again it looks similar. Overall, very impressive especially given the price.

I’ve not shared the transmission spectra of the fused silica microscope slides here, as well they are pretty much a flat line from 250nm to 1100nm and no where near as interesting as the filters.

My filters had a good surface finish (no surface striations which can sometimes be seen with some of these Chinese filters – I have a couple myself) and were chamfered at the edges.

So, thank you Tangsinuo. It should also be noted that they are open to working with customers on custom sizes and thicknesses too which is great to hear. Great prices and professional customer service are nice to experience, so please keep it up. If you’d like to know more about this or any other aspect of my work, you can reach me here.