Chinese filters - a positive experience

[ulf]

Sorry, how does one place an order for this filter? I do not see a link on the site at the moment.

This is a custom thing under discussion with Jason. It is not yet fully decided about the details.

He will eventually let us know where he put it up for ordering.

I think we should give it some more time for more members to see this and indicate that they want the filter-glass round.

 

Please observe that it is not a filter mounted in a filter ring, as it is so thick.

There are no such rings available for a normal type of retainer ring mounting.

The final assembly has to be made by yourself, but should be quite easy.

[Andy Perrin]

Yeah, does he need me to email him so he has a head count?

[ulf]

Yeah, does he need me to email him so he has a head count?

No, I have already informed him about the current six that are interested.

 

The final head count will be done during ordering when everyone commit to buy.

I will let everyone know when he tells me how we can order.

[Andy Perrin]

All right, I will wait for your “all ready.”

[StephanN]

I'm in as well, perhaps I'll get two, doesn't sound as if this is going to be available for longer, so in order to allow for me dropping one - even thick filters will break.

 

Is this the only filter which Jason will provide extra-thick?

[Andrea B.]

https://www.ebay.com...9IAAOSw63ZfRytv

 

Toni, you can buy BG25 = QB29 from Tangsinuo. Go to attached link.

Puoi acquistare BG25 = QB29 da Tangsinuo. Clicca il link.

[ulf]

Jason just told me that someone ordered a 8mm ZWB1.

No problem with that.

 

I guess that we should not wait much longer and asked him how he wanted us to order.

 

---

I am playing with the idea to eventually if possible get some more of these filter glass rounds to mount in a suitable ring system and resell.

If I do, I will measure the transmission for each one and supply the result with the complete filter.

The added parts and time to make them will naturally add to the price.

The glass round is just one component.

 

I do not know if this is against the forum's rules and must find out before I go ahead.

I also want to verify that my mounting ideas work on one or two filter rounds, before I invest in more material.

This will likely be a one time occasion and I will not become a merchant.

[Andrea B.]

We permit the following:

• A one-time announcement of a new product by a vendor or member/vendor where the product is sold elsewhere on another website or privately. Clear that with me first before making such an announcement.
  

• Non-profit sales of surplus materials sourced by a member. Of course, it is OK to add postage, etc. to the original cost.
  

• Group purchases where a collective of members decides to get together to buy something "in bulk" at a reduced price. I think the current discussion of purchases of 8mm thick filters from Jason Li fits into this category?
  

If you are selling something for a profit or mark-up, then you are a vendor and under strict restictions not to advertise here. We have to impose this kind of restriction in order for Birna and I and UVP to maintain a non-monetary, neutral strategy towards manufacturers because we do some occasional testing when requested. It is OK for Birna and I to have opinions, of course. But we will not take money to promote anything.

[dabateman]

What you can't be bought with swedish fish to recommend a bad product?

https://m.dpreview.com/videos/1505578032/dpreview-tv-sony-zv-e10-vlogging-camera-review

[Andy Perrin]

UlfW, have you heard anything new from Jason?

[ulf]

Hi Andy,

 

Today I finally got a response from Jason.

I asked him how you should place orders in a message 2021-07-29

 

The best way is if you contact him via email jason@tangsinuo.com to state your requests and let him know your delivery address.

He will then tell you the total and how to handle the payment.

 

I hoped there would be a group buy-benefit for us, but I assume that handling shipping for separate orders will make that difficult for them.

IMHO it is still a very interesting filter glass round for us to do experiments with.

[ulf]

I started to wonder what transmission the 8mm thick ZWB1 would have.

As I happen to have three ZWB1 3mm thick filter disks that I bought from Tangsinuo, last summer.

 

I decided to see what results I could get from such a stack and assembled the three glas rounds, for some experiments.

I used thin 3M magic tape at opposite sides of the flat filter surface, near edges to create some spacing and then taped together the rounds by the spaced sides.

First I took a measurement with that air-spaced stack.

 

To get a better view of what would be a massive glass round, I then added a few drops of glycerol at the edge not covered with tape and worked it in between the glass rounds.

The second measurement showed an improved transmission:

 

A comparison plot of the two stacking methods and a single 3mm filter.

Linear plot:

 

Log plot:

 

It looks like the stacked filters has an OD of just below 4.

The difference in thickness between 8mm and 9mm will not cause a dramatic difference of the OD.

 

The Schott calculator show a peak (T) transmission of around 2% of UG11, 3mm by the IR-peak while my measurement of ZWB1 3mm show around 4%.

 

A 8mm thick UG11 or U-340 would have a better UV rejection, but I think a ZWB1 8mm will perform reasonably well too.

[dabateman]

Yes its an incredible type of glass. You only loose 1 stop at 340nm, but gain little to no IR leakage.

Very usable outside with sunlight.

 

What I find interesting from your log plot is the 400 to 430nm bump. I didn't expect there to be that much signal in the 3mm. But the 8mm also wipes out that visible light.

[Stefano]

8 mm thick Hoya U-340 has significantly more transmission and OD 5 (10 times better than OD 4). I don't know if OD 4 will be enough. Still an interesting filter to play with.

[ulf]

Yes its an incredible type of glass. You only loose 1 stop at 340nm, but gain little to no IR leakage.

Very usable outside with sunlight.

 

What I find interesting from your log plot is the 400 to 430nm bump. I didn't expect there to be that much signal in the 3mm. But the 8mm also wipes out that visible light.

I'm not even sure that bump is real. It might be some crosstalk effect from the deuterium lamp part of the spectra.

The entire measurement was done with a full spectrum light source. This is not an advanced analysis, just a rather quick test for general transmission at the two peaks of the filter.

[ulf]

8 mm thick Hoya U-340 has significantly more transmission and OD 5 (10 times better than OD 4). I don't know if OD 4 will be enough. Still an interesting filter to play with.

I agree the U-340 is much better.

 

The problem is that AFAIK there are no 8 mm thick Hoya U-340 to buy anywhere.

You might ask ITOS to make one for you, but be prepared for a very high price if they accept to make it at all.

 

The best alternative would be if Cadmium produced more of his 4mm U-340. I bought two of them last year and likely will mostly use them stacked together.

If I remember correctly I paid 230 USD + shipping + 25% VAT for them.

 

It seams like filter-glass material costs increase all the time and I would not be surprised if he must charge even more for them now if he decided to make more.

[colinbm]

Thanks for the graphs ULF

[JMC]

Ordered mine today. Thanks for your work on it Ulf.

[Andy Perrin]

I ordered mine also. Jason said that Ulf is doing 49.6mm diameter, so I did the same.

[JMC]

I ordered mine also. Jason said that Ulf is doing 49.6mm diameter, so I did the same.

Yep, same for me.

[ulf]

I ordered mine also. Jason said that Ulf is doing 49.6mm diameter, so I did the same.

I found that few of the simple UV-filters I had in my "nice to have" collection, were using filter rings that had a bottom surface for the filter rounds with a diameter of 49.8mm.

 

To utilise the full depth of these rings I wanted a slight margin in the diameter of the 8mm filter glass rounds, hence the 49.6mm diameter.

I expect the rounds to also have a nice bevel just as the 3mm thick filter rounds have. The edges are not sharp on those.

[dabateman]

Yes I went with that size as well. I will figure out when it arrives if it works the way I want.

I have previously sandwiched thick glass with 52mm ring then 52-55mm step up ring, then 55mm ring and/or just 55mm-52mm step down.

Although I might just have some 52mm extension tubes from m43rds extension set that it might fit.

Will take a break from trying to program in python, to mounting this and finishing my 20mm lenses.

[diant]

A bit of a non-positive experience...

I've bought round ZWB1 (M52-mounted) filter at Tangsinuo Store and damage it in the very first day. I wiped it up only once with a cotton and had its surface totally damage.

ZWB1 as I see has so delicate surface that it seems like plasticine.

Tell me please, are U340 and UG11 (analogues of ZWB1) so delicate as ZWB1?

Did you clean it without damage of their surfaces?

[Andy Perrin]

I have rather brutally wiped my UG11 many times with no obvious signs of damage. 

[dabateman]

1 hour ago, diant said:

A bit of a non-positive experience...

I've bought round ZWB1 (M52-mounted) filter at Tangsinuo Store and damage it in the very first day. I wiped it up only once with a cotton and had its surface totally damage.

ZWB1 as I see has so delicate surface that it seems like plasticine.

Tell me please, are U340 and UG11 (analogues of ZWB1) so delicate as ZWB1?

Did you clean it without damage of their surfaces?

Buy some cesium oxide from Cadmium on ebay. Its white stuff in a bottle.  Add a couple drops to the glass, once its removed from the holder and polish it up again with a micro fiber cloth.  Then rinse with water and damp dry with microfiber cloth. 

That should bring it back to life.