The Latest Information on the Hoya U 325C SW Filter

The following information is directly from Hoya Optics USA:

1. Will Hoya no longer be making the U 325C filter?

We are developing an alternative glass for the current U325C.

2. Hoya is trying to make that filter but at a different location (you told me that earlier). But the information says that Hoya is having problems producing that filter, is that true?

The company which has been melting U325C has decided to stop melting this glass. Hoya is trying to develop an alternative at a different location. Before the development is complete, we cannot say how different the alternative is compared to U325C.

3. Hoya will only be making the 6.5 inch square size of the U-325C filter not any larger sizes, is that true?

This is under our consideration, but not concluded yet.

4. Hoya will only make polished U-325C filters (I assume thinner than 4.5 mm), is that true?  If Hoya will be making that filter as molded what thickness will it be?

If Hoya will be making that filter as molded what thickness will it be?
This is under our consideration, but not concluded yet.

Some additional questions:

a. Is it expected that the price of the new Hoya U-325C filter will be more expensive than in the past?

Yes. The price will be more expensive.

b. Will the exact same formulation be used for the new U-325C filter?

The alternative of the exact same formulation is also under developing.

c. Will the solarization rate after exposure to 253.7 nm UV be the same for the new U-325C? Will Hoya conduct solarization tests on the new and old U-325C to compare the difference if any?

We don’t want to assume the solarization rate until the test is done. Hoya will consider conducting solarization test on the new alternative.

d. Additional I would like to know, if Hoya will be continue to make that filter when can orders be placed?

We are trying to launch it in Oct. 2019 as the earliest.