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[Filter Test SEU Gen2 #1] Introduction to the SEU Gen2


Andrea B.

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Last Update [2018.07.17::13.57.EDT. Added answer to test question.]

 

[Filter Test SEU Gen2 #1] Introduction to the SEU Gen2

[Filter Test SEU Gen2 #2] White Balance, Raw Histogram & Andrea's "White Signature"

[Filter Test SEU Gen2 #3] Filter Speed & A Windy Bull's-eye

[Filter Test SEU Gen2 #4] Dealing with the Usual Dichroic Effects

[Filter Test SEU Gen2 #5] Landscape Interlude

[Filter Test SEU Gen2 #6] Monochrome Museum Comparison

[Filter Test SEU Gen2 #7] Measured Filter Transmission

[Filter Test SEU Gen2 #8] Dichroic Reflection Detour

[Filter Test SEU Gen2 #9A] Longpass Stack Wandering Discussion. See #9B for results.

[Filter Test SEU Gen2 #9B] Longpass Stack Results

[Filter Test SEU Gen2 #10] What good is a filter test without a Rudbeckia?

[Filter Test SEU Gen2 #11] A Fascinating New Rudbeckian View

[Filter Test SEU Gen2 #12] Summary


 

Introduction to the SEU Gen2 392FWHM50

 

Nothing excites the UV-dark little heart of the passionate Ultraviolet Photographer like getting a new UV-pass filter to test. The SEU Gen2 UV-pass filter from UVR Optics, a subsidiary of UVR Defense Tech, recently arrived via the US Postal Service's General Delivery (I have no mail service at the summer house) and is now undergoing testing and review. I'm in 7th heaven planning tests and scouting good UV scene locations. I have more to do, but there's enough ready to begin sharing my results with the members of UVP and our other readers.

 

Reed Curry, owner of UVR Optics, was recently forced to discontinue the first generation StraightEdgeU because of the declining quality of materials from his supplier. Not an uncommon occurence these days, but worrisome because that first generation dichroic SEU was a good filter. It had no IR leak and was an excellent choice for the 360-400 nm range where many of our non-dedicated UV-capable lenses record well. The filter got its name from the almost vertical right-hand wall of its transmission curve.

 

The newly designed SEU Gen2 is described as a "hybrid UV bandpass filter consisting of an NIR-blocking ionic glass filter sandwiched between two proprietary dichroic filters". Formally, the filter is a 392fwhm50. I suspect that some folks might be wondering about that 392 nm peak, but the filter designation does not tell the whole story. The IR-blocking is reported as a minimum of OD 4.5 with an average of OD 6 between 405-1100 nm. There is some violet/blue pass as is common with so many UV-pass filters. I'll be looking at all these factors in the tests which follow.

 

My first question about the SEU Gen2 was, of course, did Reed keep that straight edge when he designed the second generation SEU? Yes, he did. :lol: Here's the linear transmittance chart for the SEU Gen2.

 

 

The SEU Gen2 has a straight edge for sure.

seug2Chart.jpg

 

 

Now, before I begin with the series of test results for the SEU Gen2, let me give you a teaser to show you what the filter is capable of providing. Then I'll discuss the filter's base color, its speed relative to two other commercial UV-pass filters, the discoloration problems encountered when using a dichroic filter over a wide-angle lens, and an interesting work-around to that. Other technical and non-technical posts will follow as I complete them. Along the way, your comments and suggestions are always welcomed. And please do let me know of any typos or misprints.

 

LANDSCAPE TEST: For each UV-pass filter, photograph a landscape.

This test will be revisited with complete results shown in a later post.

 

Question: How well do the filters perform for UV landscapes?

 

Answer: The SEU Gen2 is proving to be a very cool landscape filter. We will see more later.

 

Subject: The shore along Somes Sound in Southwest Harbor, Maine (USA).

 

Gear: D610 + Novoflex 35/3.5 Noflexar + SEU Gen2 UV-Pass Filter + Sunlight

 

Exposure: f/11 for 1/2" @ ISO-100

 

Conversion: Photo Ninja. Split tone processing, minor dodging/burning and sharpening was applied.

 

Shore Scene in Southwest Harbor, Mount Desert Island, Maine, USA

The photo may be clicked up to a 1200 pixel width in an expanded browser.

d610_novoflex_uvSeuGen2_sun_shoreScape_20180713swhME_11806pnSplitTone.jpg

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This will be interesting to read all of your reports. When you hinted at a new filter, I thought for sure it would be the SEUmk2. I will be interested in the IR leakage tests.

I recently got a manufacturer second. With similar spectral character to the new SEU, but mine dips down to only 377nm though, so not the same. In a quick test it had great IR blocking, but need to properly test with an IR filter. It is one to two stops faster than my Baader venus 2, for exposure times.

 

Was there any word on how many mk1 are still available or are they fully sold out?

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Manufacturer's second? I don't sell any seconds.

 

The SEU Gen2 has a silver mirror appearance on both sides of the filter. I will take some photos of the filter and put them on my website.

 

Thanks.

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Hello Reed,

No I am sorry. My description was wrong. I should have said I recently purchased a filter with similar spectral characteristics, from completely different supplier. I am sorry for the mistaken comment and I will see if I can strike it out above to avoid any other misunderstandings.

 

Follow up through, do you have any of the mk1 still available or are they all sold out?

Thank you,

David

 

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David, we are an independent, non-monetized website and our vendor members are not permitted to discuss business matters in a post. However, we do have the PM system, so you can PM Reed and ask him questions about the availability of UVR Optics filters.

Thank you for your understanding. :)

Andrea B.

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Thank you Andrea for the reminder. I knew that, but forgot the extent.

Sorry.

I will wait for your review, before making other quick comments. I need to think more.

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Last Update [2018.07.17::13.57.EDT. Added answer to test question.]
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