• Ultraviolet Photography

[Filter Test SEU Gen2 #12] Summary

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#1 Andrea B.

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Posted 28 July 2018 - 17:21

[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

Summary of SEU Gen2 Tests

Thank you to vendor-member Reed Curry of UVR Optics for offering the new SEU Gen2 dichroic UV-pass filter to me for review. I like the filter. I'm going to buy my test copy. B) Speaking of which, there is a temporary discount on the SEU Gen2 which I want to mention to you as part of UVP's permitted one-time-announcement of a new product. Scroll down on that SEU Gen2 link I just gave you to find the price.

Required Boilerplate: Ultravioletphotography.com (UVP) is an independent website which has no affiliation with any vendor of photographic gear. We are a non-monetized website.

Thank you to Jonathan Crowther (JMC) for contributing Test #6 and to Ulf Wilhelmson (UlfW) for contributing Test #7. Your efforts are much appreciated.

I hope all the UVP members and readers have enjoyed reading the 11 or so SEU Gen2 tests. I would like to thank you all for your comments and for your interest. I did try to provide some variety of subject matter and some different lighting conditions, but we still need a SEU Gen2 portrait. So now it is your turn, OK? :lol:
  • Exposures times under the SEU Gen2 are faster than with other well-known UV-pass filters, all other factors being equal, because the filter's highest transmission rate, between 60-73%, is in the 370-400 nm range where sunlight provides the most UVA. This aids outdoor UV captures under hazy or overcast conditions when there is less UV reaching ground level.
  • The SEU Gen2's 70-73% transmission between 380-400 nm is very useful for non-specialist, UV-capable lenses many of which do not reach past 370 nm or so.
  • The SEU Gen2 nicely preserves the sharpness and detail offered by the lens in use. It is impressive on a lens like the UV-Nikkor 105/4.5 (rig on tripod, remote shutter triggering). I was not able to fully explore monochrome comparisons, but I really liked the Black & White conversions from the SEU Gen2.
  • There is no Visible or IR leakage in photos made under a UV-cutting longpass filter (420 nm) stacked over the SEU Gen2 and given the same exposure as the UV-only frame. There is a very good transmitance chart on the product page showing the out-of-band blocking.
  • 31 October 2018 This comment has been corrected. The word "potential" has been added in two places.
    The SEU Gen2's potential small passage of violet light (.2% between 400-406 nm) does not affect the UV capture. We already know this from using other UV-pass filters having a potential minor passage of violet light. Light around both sides of 400nm, say approximately 390-410 nm, is recorded similarly by our cameras.
  • The SEU Gen2 is well made. Protective screw-on caps are included in the purchase and should be used for storage to protect the mirrored surfaces.
  • The D610-mod white-balanced false colour in a finished SEU Gen2 landscape photo is a very pleasant mix of false-blue and false-green. False-yellow may also show up in some photos. As with any other UV-pass filter, the SEU Gen2 false colours are dependent on subject distance, white balance algorithms and converter used in addition to the camera and lens used.
  • The higher transmission peak of the SEU Gen2 at 392nm and high transmission between 380-400 nm may - for some subjects - offer a slightly different UV view than what is captured by a filter such as the BaaderU with a peak at 350 nm. This will be fun to explore further for an amateur botanist like me.
  • Like all other dichroic UV-pass filters, the SEU Gen2 can cause concentric discoloration when used over a wide-angle lens. Interestingly, this discoloration can sometimes be mitigated in a finished photograph by converting the photo to monochrome or split-tone and perhaps also applying vignetting tools. So the SEU Gen2 is certainly not precluded from use on wide-angle lens. Any concentric dichroic effect is significantly reduced when using a lens with longer focal length such as the UV-Nikkor 105/4.5. The photographer might also consider framing the subject so that some cropping could be applied.
  • I did not find any consistent veiling flare with the SEU Gen2 such as occurs with the hard-coated Edmund 340/10 at all apertures and at all illumination angles. However, using a lens hood, always good practice, is mandatory with a dichroic filter such as the SEU Gen2. The photographer should also have a willingness to reframe the subject to avoid confronting direct sunlight (unless flare is wanted as an artistic enhancement!).
  • Any dichroic, mirrored filter can produce the occasional wacky outlier result. With the dichroic BaaderU, I get the occasional ring reflections of an inner lens barrel. The SEU Gen2 and EL-Nikkor 80/5.6 (old metal version) sometimes produced a doubling of a portion of a very UV-bright subject photographed against a UV-dark background. I don't know why that EL-Nikkor does that.

Andrea G. Blum
Often found hanging out with flowers & bees.

#2 Andrea B.

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Posted 28 July 2018 - 18:55

[Done 2018.07.28 14:55 EDT] Please let me know of any errors, typos or confusing statements I might have written. Thanks !! :D
Andrea G. Blum
Often found hanging out with flowers & bees.