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Mystery IR filter - transmission spectra and images

Infrared
128 replies to this topic

#41 Andrea B.

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Posted 13 September 2019 - 15:12

Addendum

provenance: place or source of origin.

Counterfeits are everywhere but especially found on Ebay or Amazon.
Compare your filters to the authentic product photos in online pages or brochures.
The labeling should be identical. The ring material should be the same.

If the price is too good to be true, then..........
Andrea G. Blum
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#42 JMC

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Posted 13 September 2019 - 15:27

Yes, is too early to start screaming FAKE just yet.

The Heliopan 715 and B+W 091 filters I have tested today were dealer bought and new.

The appearance of the Hoya R72, did not give me any reason to doubt its authenticity. Even the info online about the R72 transmission doesn't seem 100% consistent. However the reason for that is not clear yet, at least not to me.
Jonathan M. Crowther

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#43 Andrea B.

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Posted 13 September 2019 - 15:27

Kenko Global https://kenkoglobal.com/

It is as I suspected. Some 72s are bandpass, some are longpass.
Scratch that. As I continued looking, I came to a different conclusion.
See next post.

Under their own label Kenko sells 3 IR-pass filters having a "72" designation.
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#44 Andrea B.

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Posted 13 September 2019 - 15:59

Hoya makes 21 sharpcut longpass filter glasses amongst which is W-R715.
http://www.hoyaoptic...m/color/02.html

Hoya also makes 7 IR filter glass types amongst which is the IR-bandpass RT830
which is almost like the Schott RG9 IR-bandpass.
(I couldn't tell you why the W-R715 IR longpass is not in the following
IR filter glass section. Only Hoya knows.)
http://www.hoyaoptic...m/color/03.html

Now to me it would be odd if that IR longpass W-R715 would be labeled as R72.
So I am thinking now that all R72 filters are IR-bandpass??

And I think there are some idiots in marketing who don't know a longpass from a bandpass.
The same guys who mentioned stacking the IR filter with a visible yellow or red filter.
Andrea G. Blum
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#45 Andy Perrin

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Posted 13 September 2019 - 16:06

Argh. All I want to know is what the spectrum of the filter I own is. It makes a difference to me, especially with the TriWave since it records well past the bandpass for those R72s that seem to be bandpass.

#46 dabateman

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Posted 13 September 2019 - 16:14

Andy,
Well you may need to get some cheap 1000 line/mm film and check it using a hallogen bulb. If it cuts off compated to a known Lp filter. Then you will know.

Or buy a spectrometer.

I may need to test my IR filters.

#47 Andy Perrin

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Posted 13 September 2019 - 16:19

Or I will just buy some Schott from Cadmium.

What this effectively means is that I can’t use my R72 to test other filters with.

Edited by Andy Perrin, 13 September 2019 - 16:21.


#48 Cadmium

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Posted 14 September 2019 - 04:01

There are two possibilities:
1) Kenko is not making Hoya R72 filters out of Hoya R72 glass, and apparently neither is Heliopan.
2) Hoya is making some new bandpass type IR filter glass that they have yet to announce or show on any graphs, that they are replacing R72 with.
And if #2 is the case, then that would be rather problematic to be selling two types of glass under the same glass name. I don't think Hoya would do that,
that could cause big problems with customers.

It isn't a shiny side or coated or layered, it is just a different kind of glass, similar in idea to Schott RG9, which is a bandpass not just a longpass.
Hoya R72 is a longpass, practically identical to RG715, 5nm difference at 50%. Those are equivalent. RG9 is 720nm at 50%, but is bandpass.
Andrea, you have both RG9 and RG715, and R72 (assuming your R72 is the expected longpass type).
Frankly, I can't see any difference in photos between RG715 and RG9 (longpass vs bandpass), so the same is probably true between real longpass Hoya R72 and this non-Hoya bandpass R72.
Hoya doesn't make R72 bandpass, only longpass, and Hoya doesn't make camera filters, Hoya only makes filter glass.
Kenko has not replied to my inquiry. Hoya has, basically they said Hoya doesn't make camera filters, and suggested I ask Kenko, which I already had.
B+W makes their longpass filter out of Schott glass.

I think David said he thought Kenko owns Hoya, but no. I also read someone say that on DP review, but Hoya is not owned by Kenko. Kenko doesn't appear to be owned by anyone either.
Hoya doesn't make camera filters, just like Schott doesn't make camera filters. Hoya and Kenko are separate companies. Kenko buys filter glass from Hoya.

It is quite possible that Kenko is buying a lower cost IR filter glass which performs essentially and almost exactly the same in usual IR photographs (like I said), and using it to make the Hoya R72 filters, simply to save money.
It may even be a mutually agreed upon scenario.

You tell me if you can see any difference between RG715 and RG9 ? Maybe, but I would guess not.

These bandpass scans are not Hoya R72 filter glass, and not even Hoya glass, none that anyone knows about or that has been published.
Even two Kenko R72 pages have disagreeing graphs, one has the expected Hoya R72 graph, the other has the graph that Jonathan scanned.

Kenko page showing expected Hoya R72 graph (click on "specifications"):
https://hoyafilterus...a-r72-infrared/

Kenko page showing same as Jonathan's scan:
https://hoyafilter.c...t/r72_infrared/

I thought Heliopan 715 was made of Schott RG715 glass, but it could possibly be made from Hoya W-R715, but it is longpass, not bandpass.
Hoya W-R715 graph:
Posted Image

Hoya R72 graph:
Posted Image

More HOYA IR filter glass :
Posted Image

Schott longpass and longpass/bandpass (as the Schott catalog refers to RG9):
Attached Image: Schott_Longpass_23_box_insert.jpg

Edited by Cadmium, 14 September 2019 - 04:55.


#49 UlfW

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Posted 14 September 2019 - 04:51

View PostAndy Perrin, on 13 September 2019 - 16:19, said:

Or I will just buy some Schott from Cadmium.
Or even buy Zomei filters. They are longpass-filters.
Ulf Wilhelmson
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#50 Cadmium

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Posted 14 September 2019 - 05:02

PS: Andy, I didn't do the colors on those Hoya graphs. ;-)

#51 Andrea B.

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Posted 14 September 2019 - 05:46

https://shashinki.co...ke-hoya-filter/
That is an old link which discusses fake versus real Hoya filters. Quite interesting.


If you buy brand name (Hoya, B+W, Heliopan) filters from one of the big reputable sellers (such as B&H here in the US),
then you have a reasonable certainty of not getting a fake. Brand name filters sold on Ebay or Amazon
might be chancy.

I'm also thinking that for some products, different versions of the product are sold in different countries. Now whether that applies to brand name photographic filters, I do not know. But it is certainly possible that the R72 we are all trying to figure out is sold/marketed differently in US than in, say, Japan.

Cadmium, I hope you hear back from Kenko. :smile:
Andrea G. Blum
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#52 dabateman

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Posted 14 September 2019 - 05:49

So what have we learned?
The Real Hoya R72 and 715 filters are long pass, right. But Hoya nor Schott make camera filters you can screw on to a lens.

So some other company is licencing the Hoya name and stamping that on the filter ring.
So looks like if a company has a whole bunch of rings, you may get anything in that ring, bandpass or longpass.

I guess that make sense as I read that Quantaray CP filters were Hoya glass.

I guess what would matter is do we see a difference in the IR images taken with bandpass 720 vs long pass 720? That is with our normal cameras, not Andy's rare expensive IR camera.

#53 Andrea B.

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Posted 14 September 2019 - 05:57

The Real Hoya R72 and 715 filters are long pass

Do we actually know this yet? :smile:




The differences between RG9 bandpass and its nearest neighbors is minimal. It is too late tonight to go searching for examples. But I will look tomorrow.
Andrea G. Blum
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#54 dabateman

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Posted 14 September 2019 - 06:01

Andrea,
I now no longer believe those spot the fake type posts.
Hoya doesn't make filters. So that link may just be comparing a Tokina licensed Hoya glass to an other company that skimps on details but may in fact still have Hoya glass inside.
Some reputable seller on ebay that actually uses Hoya glass may just print a label and add it to a digital frame. That will still be genuine Hoya glass.

That is why this is a problem. The consumer really doesn't know unless they have a spectrometer.

#55 Cadmium

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Posted 14 September 2019 - 07:15

To answer both Andrea and David,
The graphs on the Hoya site, which I linked to in my last post above, are the actual transmissions for the Hoya filter glass types.
I would doubt strongly that those graphs are wrong for Hoya glass. You should not need a spectrometer if the glass is from Hoya.
They make tightly controlled standardized filter glass, used in many industrial and critical applications which require more precision and reliability than what we use filters for.

I don't get the impression here that this has anything to do with 'fake' filters. Not like some knock off type thing. Yet the glass is not Hoya R72, that is obvious, because Hoya R72 is longpass.
I don't know the history of Hoya camera filters, who made them, how many companies were making them, or if Hoya originally made them themselves or not.
I don't know if there are multiple companies making Hoya camera filters, other than Kenko.
It would seem that Kenko is the only company that makes the Hoya Branded camera filters, but I don't know that.
Nevertheless, it would seem that given Kenko's R72 graph is not R72 longpass, and that Jonathan's test of a randomly obtained R72 looks the same as the Kenko graph,
then this suggests that perhaps a large percentage of what people think are Hoya R72 longpass filters may not be actual Hoya R72 longpass filters at all,
but instead some other filter glass, which looks and works essentially the same as real Hoya R72 longpass filter glass when using it for usual IR photography.
For all I know, the 'fake' R72 glass may work even better for IR photography, by slightly muting the higher IR...
But I don't know, all I know is it is not Hoya R72 glass in that filter that Jonathan has. And now he has the Heliopan that looks the same also...
It's like ice-nine.

My guess, Kenko will not answer me, and Hoya probably wants to avoid the subject.
It would be a can of worms.

Hoya R72 data sheet:
http://www.hoyacande.../eo_pdf/R72.pdf

Edited by Cadmium, 14 September 2019 - 08:13.


#56 Andy Perrin

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Posted 14 September 2019 - 15:14

Cadmium, can you get real R72 glass from Hoya so I can buy a filter whose identity I’m sure of?

#57 bobfriedman

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Posted 14 September 2019 - 21:09

Chinese knock-offs - interesting business model, they figure no one would know the difference. deceptive advertising, I'd be blaming Kenko supply chain that supplies Hoya with their glass.

Edited by bobfriedman, 14 September 2019 - 21:18.


#58 Andy Perrin

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Posted 14 September 2019 - 22:15

I'm home at last and had an opportunity to take a closer look at my R72. Apparently mine is made by Tokina?! So if mine is a knockoff of anything, it would appear to be Japanese rather than Chinese.

#59 Cadmium

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Posted 14 September 2019 - 23:05

View PostAndy Perrin, on 14 September 2019 - 22:15, said:

I'm home at last and had an opportunity to take a closer look at my R72. Apparently mine is made by Tokina?! So if mine is a knockoff of anything, it would appear to be Japanese rather than Chinese.

Kenko is Japanese also. It is not about the manufacturer, it is about the glass used.
Unless your have a spectrometer, or do some pretty thought out fancy stacking with other filters, I think you will have a very hard time differentiating the real Hoya R72 filter glass from some bandpass fake,
that is the case between RG715 and RG9 also. Again, Hoya doesn't make the filter glass that is being used in the two filters that Jonathan has scanned.
Chinese glass, probably, but certainly not Hoya glass.

Edited by Cadmium, 14 September 2019 - 23:08.


#60 Cadmium

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Posted 14 September 2019 - 23:09

View PostAndy Perrin, on 14 September 2019 - 15:14, said:

Cadmium, can you get real R72 glass from Hoya so I can buy a filter whose identity I’m sure of?

Absolutely you can! I will get a sheet. It should still be tested, given all this, we need to make sure where the problem originates.

Edited by Cadmium, 15 September 2019 - 08:08.