[Filter Test] AndreaU Mk-I, AndreaU Mk-II, BaaderU, Hoya U360 Stack on a 35/3.5

[Andy Perrin]

Is that from doing "Save Settings..."? I don't think I've ever used that for anything, but I guess that would do it.

[Doug A]

@Andrea B. 3a definitely looks better with your editing. But, it takes a lot of adjustment to get there. If I already owned it, I would do the extra work. Don't see an advantage now. The Hoya U 360/ Schott S8612 has better color out of the camera, isn't dichroic, and is brighter than the AU2. If your AU2 is representive of current stock, the filter doesn't meet their claims of being brighter than the Baader U. 

 

Thanks for all the work,

 

Doug A

[Nate]

Thanks @Andrea B. for this test. My favorite turned out to be the Baader I own. The other ones really surprised me though, didn't call any of them. As a side note I have my S8612 now to test with some Chinese zwb 1 and 2's I have, and really liking what I got with the  ZWB1 2mm?/S8612 2mm. I know that ZWB1 filter might not be accurate, but pretty sure it lets less from the upper range through as there's way less purple than the Baader. I need to get out after cleaning both my Nikkor 80's to find the best one out of them.

@Andy Perrinfor preset LUT's, I use Affinity photo and it makes it really easy to make your own for any given color scene you encounter with different stacks/conditions. I'm sure the other editors do it too. 

[Andrea B.]

Doug wrote: 3a definitely looks better with your editing. But, it takes a lot of adjustment to get there.

 

I might not have made it clear that there were the same number of "steps" taken in Photo Ninja to convert all 4 of the UV-pass examples. The only difference between the initial conversion of the initial example of the 3A/AndreaU Mk-II and the second example was a change in one existing step! In the first conversion I set the PN saturation slider to Plain/60. In the second conversion I set the PN saturation slider to Plain/100. I don't want to give the impression that any of the conversions I presented are necessarily optimal and/or complete should one want to produce a finished product suitable for printing and framing. We always give printable files a bit more spit & polish, yes?

 

A general remark about reflected UV file conversions:  Hey, if I have to spend more than 2 minutes on the conversion part, then forget it! The core work of UV file conversion lies in getting a good white balance made* and then stored as a preset. After that it is just a few clicks on any file for which that prestored WB is usable.

 

HOWEVER, I do share the feeling with others that this current AndreaU Mk-II is a bit slow. And that the description of the AU-II on UVR Optics is not accurate, given the results we've just seen here. I just don't think the AU-II I used in these examples is quite like the one which I tested in 2016.

 

*WB on PTFE or Spectralon for each combo of camera + lens + filter + illumination.

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Nate wrote: I know that ZWB1 filter might not be accurate....

 

I've always tried to distinguish between UV artistic and UV documentary efforts. All the filters and stacks which we discuss and use here on UVP are giving you a reflected UV photo. There might be a greater or lesser degree of "contamination" with bits of violet or green or low IR from a given filter or stack, but the only place where purity of wavelength is a serious requirement would be in a scientific lab situation. So we should enjoy all the filters we use knowing that we have seen part-way into the Invisible realm. So cool!!

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[Doug A]

@Andrea B.thanks for the clarification. So the AU2 doesn't require more work - good to know. Losing one of its main advantages - speed, it is tough to find a reason to pick it over the others. One other thing that comes to mind is a single filter that is thin and less likely to vignette on wide angle lenses. Guess some people might consider less false color a plus.

Thanks,

Doug A

[Nate]

12 hours ago, Andrea B. said:

So we should enjoy all the filters we use

Very true, I may have been starting to get obsessed with perfect lens condition with the tear down and cleaning of my Nikkor 80's and wanting only below 400nm, when the Baader  brings the sharpest image, and is the fastest filter I've used. Less testing, more enjoying taking shots.

[Doug A]

The AU2 site talks about really robust blocking above 400nm. They say this helps when making long exposures on low UV or even rainy days! Is there any truth in this?

 

Thanks,

Doug A (yes, I'm still considering the AU2)

[nfoto]

Excellent blocking above 400nm indeed will assist in making cleaner long UV exposures.

[ulf]

6 hours ago, Doug A said:

The AU2 site talks about really robust blocking above 400nm. They say this helps when making long exposures on low UV or even rainy days! Is there any truth in this?

 

Thanks,

Doug A (yes, I'm still considering the AU2)

I think the statement about rainy days is about the SEU-filters that takes advantage of the sensor's higher sensitivity close to 400nm.

The AU2 is AFAIK a glued ionic stack of some kind recommended as a better alternative for wide angle lenses as it is not dichroic.

I did not see a very big exposure time improvement with my SEU-filter, But it gives an interesting tonality, especially with flowers that have bluish false colours.

 

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For the needed level of blocking I have my own ideas. 

I am not a strong believer in the holy 400nm border and that it must NEVER be passed to get reasonable UV images

The wavelengths at 400nm and even 380nm, at some places, are used scientifically to define where UV starts and VIS begins. That is undeniable.

 

However these lines are drawn in a gradual transition range where human vision tapers of. That change is not an abrupt change. 

It could be compared with some geographic state or nation borders that was defined using a ruler. Often the landscape on both sides is quite similar.

 

Blocking further into VIS, and especially into NIR is a completely different thing as bad blocking here can give contamination.

If possible I prefer OD5 or better as most flowerers are highly IR reflective and place high demands on the OD

 

Back to the UV-border. (400nm)

My view of the need for blocking there is defined by practical usage and more pragmatic.

 

If the images with a given filter or filter stack can deliver a pitch black UV-signature, and the stack can give images with normal UV-yellow flowers I see it as an OK UV-image.

I can accept a bit of overstep beyond the holy border.

One of the reasons is that I take pictures with many different filters and filter stacks, of the same motif,  to explore reflectance variations for different wavelengths in more detail.

 

I have a few alternatives to choose from for my "UV" images:

1. U-340 4mm 2x stacked. -- Eliminates the upper UV-A and have a good IR suppression. -- More difficult to WB
2. ZWB2 8mm -- Not tested yet. Eliminates the upper UV-A and have a reasonable IR suppression. slightly faster than 1. above. -- More difficult to WB
3. UG11, 2mm + S8612, 2mm. -- Typical UV stack with a slight skew to shorter UV-A range. -- OK to WB
4. U-360, 2mm + S8612, 2mm. -- Typical UV stack with a slight skew to longer UV-A range. -- OK to WB
5. Baader U -- transmission like a combination of 3. and 4. above, but slightly faster. -- has a tiny IR leakage and the typical dichroic potential problems. -- OK to WB
6. SEU3 -- Transmission that emphasises the wavelengths up to 400nm.  -- has the typical dichroic potential problems -- OK to WB
7. UG1, 1mm  + S8612, 2mm. -- Typical UV stack with  more skew to longer UV-A range, with a tiny overstep, (or not depending on what transmission is defined as OK at 400nm). -- OK to WB
8. UG2A, 2mm  + S8612, 2mm. -- Typical UV stack with even more skew to longer UV-A range, with an overstep at 400nm. -- OK to WB

 

 I have mostly been using 4. 6. 7. and 8. for my "UV" images.

All of them give pitch black normal UV-signatures for flowers that have such features.

They all give a proper UV-look with false yellow flowers.

The tonality of false blue flowers differ a lot from muted blue or purple to pale pastel blue.

 

1. and 2. are so new here that I here not yet much experience of them.

 

Stack #8. above is quite fast, way faster than Baader U or SEU-filters.