Pushing Sat in UV Photo

[Andrea B.]

I made two photos of this Deciduous Azalea flower bunch - one with BaaderU and one with StraightEdgeU.

 

The usual rendering is shown for each together with a conversion in which I pushed the saturation hard. Differences between the two filters can be seen in both the low sat and hight sat versions. The differences are no doubt based on the different peaks - approx 350 nm for the BaaderU and 370-380 nm for the StraightEdgeU.

 

The range of exposure times today with the UV-Nikkor, f/11 and ISO-100 was 2-4 seconds for both filters. So there's nothing here to note about exp times.

 

D610 + UV-Nikkor 105/4.5 + Sunlight

Deciduous Azalea 'Tangerine Dream'

 

BaaderU with normal saturation: f/11 for 2.5" @ ISO-100

 

StraightEdgeU with normal saturation: f/11 for 3" @ ISO-100

 

BaaderU with pushed saturation

 

StraightEdgeU with pushed saturation

[GaryR]

Very nice work Andrea! I'm always intrigued by that gold tone, that you get from the BaaderU (in the first shot), but the 'blues' in that last shot is quite striking. The StraightEdgeU is on my wish list.

[Andrea B.]

The false dark yellow gives that "metallic" look in some photos.

And if you turn the color wheel a bit you can make it into other metallic colors. "-)

 

I like the StraightEdge especially for those non-dedicated UV lenses we all love from Ebay. Some of them tend not to reach too far, but with a UV-pass filter peaking in the 370-400 nm region like the SEU, we have a way to use those nice lenses well. UV photography in the 370 - 380nm range can take advantage of the higher amount of UV in sunlight in that region too.

 

For the record, my SEU is unclad. I'm not sure how UVR Optics is currently making this filter, so check first to see if they are using cladding or not. I don't like cladding myself as I feel it might cause reflection/flare problems or possible softness. There may be no basis to that -- this is really just a personal preference of mine that I got stuck in my head somehow. I'm not immune to that! :D

If you get an unclad filter then you would have to be alert to possible oxidation/corrosion. I keep an eye out for that on all my plain uncoated glass filters. When it begins to happen I sit down and have a filter cleaning session.

 

With the SEU I think a dramatic purple/pink look is possible too. I'll go look.

[ulf]

Thank you Andrea for this comparison.

 

The difference is naturally strongest with a lens that can transmit much UV and your lens is ideal for that.

If the same test was done with a lens that is marginally usable for UV I think the images would be more similar.

 

It would be interesting to see the same test with a flower with UV-patterns and UV-false-yellow like a buttercup or similar.

[Cadmium]

Next time, also try one with a U-360 2mm + S8612 1.5mm to 2mm stack, and I think you will find it is closer to the Baader U colors,

even with "a lens that is marginally usable for UV", like a Kuri 35mm of course...or the like.

[Andrea B.]

I was wanting something NOT like BaaderU of which I get tired sometimes. I was looking for those blue tints. But I didn't get much with a yellow flower different from BU.

[ulf]

Next time, also try one with a U-360 2mm + S8612 1.5mm to 2mm stack, and I think you will find it is closer to the Baader U colors,

even with "a lens that is marginally usable for UV", like a Kuri 35mm of course...or the like.

 

When I wrote "a lens that is marginally usable for UV" I ment a lens with a cutoff wavelength around 375nm or more.

The a Kuri 35mm is absolutely not marginally usable for UV, considering the sensitivity of sensors with a Bayer matrix present.

[Andrea B.]

Yes, I understood that. And I have some lenses like that! I'll try to shoot something as per your suggestion, Ulf.

 

Two Tests:

• If the same test was done with a lens that is marginally usable for UV I think the images would be more similar.
  
• It would be interesting to see the same test with a flower with UV-patterns and UV-false-yellow like a buttercup or similar.
  

[nfoto]

For me, the fact this flower cv is named "Tangerine Dream" suffices ...

 

Both the Baaader U renditions are pleasing.

[Andrea B.]

oh right!!!! I had totally forgotten that the name is coincidental. :D :D :D

 

For you youngsters out there: Tangerine Dream

This is one of Bjørn Birna's absolute favorite bands.

 

I don't think my azalea is sold anymore. It is about 30 years old. It has a heavenly scent.

[dabateman]

What I am amazed by is that over all the images I see on this forum the exposure values for the SEU filter is not significantly different than the Baader venus. Being centered at 380nm where cameras are more sensitive and lenses are more permissive, I would expect better exposure values. At most I see 1/3 of a stop. I am guessing this maybe due to the Baader curve being broader and the SEU being narrower. Thus similar total light. Also the SEU images seem to look similar to the UG1 1mm with S8612 2mm stack and the Baader look similar to the U360 2mm with S8612 2mm stack.

This makes my want the cheaper Ug1 1mm option.

 

[Andrea B.]

Yikes!!! I warned above that there was nothing to note about exposure times. When I say things like that I really do mean it!!

 

I was shooting in changing light and not at all attempting to make comparison shots between filters. I had exposure times for BOTH filters both above and below those selected for presentation. AND I was using a hand-held UV-flash for which I could vary the distance from the subject in such a way as to keep exposures all very similar.

 

If you look at some of the initial tests I did of the SEU for the manufacturer, then you can probably find something about properly set up experiments involving exposure times.

 

When I convert my photos for presentation here I apply white balance profiles and color profiles based on photographing standards in the same light as I'm shooting the flowers in. So if you want a comparison between the various stacks you mention, we have topics posted about that also.

 

In this topic UG1, BaaderU, U360 and some other filters are shown in Raw Composite form for visual comparison purposes.

http://www.ultraviol...h1-wb-raw-comp/

 

In this topic some U and UG filters used unstacked in their dual-bandpass mode are shown.

http://www.ultraviol...raw-composites/

 

Here is a comparison test between SEU, KolariU and BaaderU. The BaaderU is the fastest. The SEU and KolariU block the most IR. Now you begin to see the tradeoffs between speed and IR-blocking. There are other tradeoffs. "-) The day I made these shots it took a looooong exposure for f/11 and ISO-100 with no boost from additional UV-flash. Def not my preferred mode of shooting. But those shots do indirectly illustrate the benefits of using broad UV-flash even outdoors. "-)

http://www.ultraviol...-straightedgeu/

[dabateman]

Sorry Andrea, I know. I did read that and it did immediately remind me of the thought I wrote here. I should have indicated that I know this was uncontrolled. However in the controlled tests it still seems true, that is between the Baader and the SEU.

I only ment to mention the UG1, as you said you were looking for a different color. The 1mm UG1 does seem to have a similar SEU color. For you its a mute point as you already own the SEU. But may still be an option if your looking for something different or the newer Ug2a filter which seem to be similar to the ug1.

I directly wrote what I was thinking with out explaining why. And my frame of mind was between 4 projects. So my midday break posts may have been too off the cuff.

[Cadmium]

I believe the KU is probably a UG1 2mm stack, however, you would not use UG1 1mm unless you wanted a lot of visible blue, UG2A will give even more visible blue (UG2A 2mm = UG1 0.66mm).

U-360 2mm stacks have very little if any blue.

In my opinion, U-360 functions better for UV stacking than does UG1. U-360 has a more efficient higher UV peak amplitude using identical IR suppression, and has less visible blue leak at the same thickness.

[Andrea B.]

David, no apology necessary whatsoever !!

 

Sometimes I really dislike Internet communication because all nuance is lost. :(

 

As UVP's "Editor-in-Chief" in an attempt to be fair to all filter vendors and brands, I must try hard to ensure that readers don't get an incorrect impression about a filter based on *my* presentations. My posts shouldn't carry more weight than others members' posts, but sometimes it seems they do. However, the good membership here keeps me "honest", as they say. I get great support for making sure the factual information presented on UVP is correct and unbiased.

 

---

 

Both the BaaderU and the StraightEdgeU are dichroic. They have different peaks. They have different IR-blocking characteristics. Very generally speaking, the BaaderU is a little faster than most of the other UV-pass filters or stacks because it has approximately OD3.5 IR blocking. The SEU has better IR-blocking. I don't know the actual thicknesses of these two filters, but that too always plays a role in exposure times.

 

For these two filters and any other UV-pass filter stacks or brand UV-pass filters, exposure time differences are never so large that they can't be dealt with easily. You increase exposure time a bit or bump up ISO or simply hold your UV-flash a little closer.