UV8040BK2 - does it make sense?

[lukaszgryglicki]

Hi, I have an option to buy UV8040BK2 lens (https://www.universeoptics.com/product/uv8040bk2-ultraviolet-quartz-lens-assemblies/) with T mount to Nikon-F adapter.

But I cannot find *any* info about this lens, excluding https://www.ultravioletphotography.com/content/index.php/topic/1654-sticky-uv-capable-lenses/page__p__11071__hl__uv8040__fromsearch__1#entry11071

"

Universe Optics is a US company which makes the 78mm f/3.8 Quartz (UV8040) and the 105mm f/4.0 Quartz (UV1054B), both of which cover full frame but are not corrected. The lenses have a native C-mount with an underlying T-mount and are adaptable to the Nikon F-mount. Other more specialized UV lenses are also available.

"

 

What does it mean exactly? Uncorrected means a lot of chromatic aberrations? Everywhere? In visible range? In UV

Did anyone tested that lens on any camera and is able to provide any photos or details?

 

The lens is quite expensive and I would like to know anything more before attempting to buy it...

[Andy Perrin]

Yeah, I think several members have owned one but it does have aberration in UV. I don’t have an opinion but Mark said the aberrations are quite severe but he didn’t care since he used it mostly with a narrowband torch (he said UV had no color anyway, although we know that wavelength variations exist):

https://www.ultravioletphotography.com/content/index.php/topic/1856-uv-source-to-filter-or-not-to-filter/page__view__findpost__p__12773

 

Personally I would probably not buy one. We have many good glass options in UV-A.

[lukaszgryglicki]

OK, so I can assume it is useless if I try to make *any* image in full-spectrum and may even not work at all in visible or IR, right?

Even with UV say 300-400 there will be a lot of "chromatic" aberrations (if I can all them chromatic in UV). So the only usage will be with narrow band pass filters like 20 nm width etc.?

That's probably why seller don't want to send me sample images...

[Stefano]

Would a simple aspheric quartz/fused silica lens deliver similar quality images? That is also not corrected and sharp with monochromatic light.

[lukaszgryglicki]

Honestly, I have no idea, this is why I've created that post.

[Andy Perrin]

Stefano, I suspect this one probably has correction for some kinds of aberrations (like spherical) that the singlets probably do not. I remember mark made very nice sharp photos with his under torches. It’s not a useless lens just not good under wide spectrum sources.

 

I would think it would be functional but fringy in visible - unfortunately Mark removed all his photos so I can’t check.

 

In general people on this forum fixate too much on bandpass in selecting lenses. Especially new-to-UV people. It’s better to have a sharp lens with a moderate bandpass like EL-Nikkors than a blurry lens with a wider bandpass like a cheap quartz singlet.

 

Obviously best is to have a UV Nikkor which is both quartz/fluorite and corrected for all aberrations

[lukaszgryglicki]

OK I will check Nikkor 105/2.8 AF-D Micro & Nikkor 50/1.8 AF-D first (they're reported to be OK in some places). Currently, my best is Nikkor 50/1.4 but results are strange... like some places are in focus and some not but not in a way I would expect (like by the distance) - rather like tilted/shifted lens which is crazy... also photos are rather "dreamy" like a coma from wide open Nikkor 55/1.2 AI-s....

[diant]

This lens is designed and calculated for 250-266nm work and has image circle only 18mm.

[Andy Perrin]

Why don't you get an EL-Nikkor 80mm/5.6, old metal edition? That is known to be the sharpest lens with highest bandpass by our own spectroscopic tests (Ulf and others).

 

https://www.ultravioletphotography.com/content/index.php/topic/4279-nikon-80mm-f56-el-nikkor-old-metal-version/

[lukaszgryglicki]

Here is why (atm):

- I don't have any Macro lens, and just bought one in the weekend - so it wasn't at all for UV. I just read elsewhere that it's pretty good in UV - which is just a luck (if this is the case).

- Nikkor 50/1.8 AF-D is reported here: https://kolarivision...-compatibility/ (I'm not related to Kolari of course), bought one for less than $100 - so this is just to try it.

 

I wanted easy setup for a start and, actually I hope to be able to shoot UV (and record UV video) handheld with AF using live view (My D610 is full spectrum and debayered).I hope quite fast lens (1.8) and debayered/full spectrum camera will allow hand held photos and enough light to capture video in 30 fps without ISO going over 12800.

I just want to see if I like it or not, and then (only then) I'll consider EL lens which is a bit more painful to use, right?

[Stefano]

If you want macro, you can reverse-mount your lens (I don't know how much magnification you will get).

 

In bright sunlight, with a full-spectrum Canon EOS M (color sensor, not debayered), a Soligor 35 mm f/3.5 lens and a ZWB2 (2 mm) + Chinese BG39 (2 mm) filter, I can shoot UV videos at f/3.5, ISO 3200 and 1/30 s exposure. Pushing the ISO to 12800 (H), I can shoot noisy videos in the shade.

[lukaszgryglicki]

So (assuming Nikkor 50/1.8 works) I should be able to have maybe one stop more (from debayering) and 2 stops from lens speed (1.8 vs. 3.5) that gives, let's say 2.5 stops.

But I use Hoya U-340 4mm, so probably cancels out one stop from your setup (guesswork). Should be about +1.5 stop (maybe even more, who knows) - anyway - UV videos with about 1200 ISO at 30 fps - looks promising... will post my results of course.

[Andy Perrin]

(assuming Nikkor 50/1.8 works)

Almost any lens will work to some degree. Very few autofocus lenses have good bandpass, though. Our board tests are usually more reliable than Kolari's recs. In my opinion.

 

We do have some shots with that lens here:

https://www.ultravio...g-and-scorning/

 

UV video is not particularly difficult to do. Most setups can handle it. The eye is very forgiving of noise in videos.

[lukaszgryglicki]

Thanks for the links, I'm sure you're more reliable than *any* vendor.

I'm just saying that all my setup is collected long time ago, the *only* lens I've bought purely for UV is that 50/1.8 for about $95. I'm not (yet) buying any expensive stuff especially for UV - I was considering that dedicated UV8040BK2 but I'll skip it for now. I'll just test what I can do on this 50/1.8 and also new Micro 105/2.8 AF-D (buoght not for UV but just to have a micro lens). All other gear I already have for a long time, mostly for full-spectrum or IR.

[Andy Perrin]

Ok well you were starting to talk about debayered sensors, so forgive my confusion.

[lukaszgryglicki]

Yes, but I have that debayered sensor for years now.

[dabateman]

The Nikon 105mm AF-D works quite well for UV and AF was good.

Now that I have a viltrox nikon to m43rds autofocus adapter I should retest the UV AF with my better full spectrum camera.

 

I ask too about the UKA optics lenses when I first joined this board. John and Dave both owned them in the past. There comments were not very supportive of them.

The major problem is massive focus shift do to wavelengths change. So just like using a single element of quartz, you need to dramatically change the focus point between IR, visible and UV images. Completely useless for focus stacking and macro type imaging.

[lukaszgryglicki]

But in Live view, not in macro/micro distances it shoudl work pretty well, right? I'll see and post the results, same with 50/1.8 AF-D.

[dabateman]

I forgot the AF-D is screw drive AF. So will not work on the Nikon AF adapters to other camera mounts.

 

I am confused now what we are talking about.

 

My summary,

The UKA optics lenses are only good if you photograph one tight bandpass wavelengths and take one image. Not good for multiple wavelengths and merging. Not good for macro. Not good for broad UV, broad visible or broad IR wavelengths.

 

The Nikon 105mm f2.8 macro AF-D lens is good for UVA, with autofocus and for macro.

 

I haven't tested the Nikon 50mm. I don't own it. I also haven't tested the 60mm macro AF-D lens, but I do own one.

 

Your D610 is monochrome full spectrum, interesting. Expect two stops more UVA than a camera with color filter array.

[lukaszgryglicki]

So to avoid confusion, the exact lens names (no matter how they perform, I needed macro anyway and 50/1.8 is dirt cheap at $95 so doesn't matter at all)

- Macro Nikkor 105/2.8 AF-D (screw drive AF).

- Nikkor 50/1.8 AF-D (screw drive AF).

 

And a camera:

- Nikon D610 full-spectrum converted (no sensor IR/UV cut filter, replaced with clear glass, probably something passing from around 280 nm), debayered (RGGB CFA physically removed).

[lukaszgryglicki]

I'm still considering this lens UV8040BK2 - does anyone have any photos with it? Say I want to use it for a rather narrow band: Hoya U-340 4mm + S8612 2mm - this gives peak transmission around 340 nm, but also below.... no other lens (excluding UV kings here) will give a good transmission there, right? UV8040BK2 transmission chart says it is good even at 200nm... any thoughts?

[dabateman]

I don't know if it would go below the magic 235nm barrier. Depends how pure the glass is. But really that doesn't matter. Its too hard to image down there anyway.

 

I asked this exact same question when I first joined the board:

https://www.ultravioletphotography.com/content/index.php/topic/2762-opinions-on-the-uka-optics-quartz-lenses/page__p__21328__hl__+uka%20+78mm__fromsearch__1#entry21328

 

Unfortunately most of Marks images have been deleted. But the comments are about the same. You may still see chromatic aberrations and there is focus shifts between wavelengths.

[Andy Perrin]

Why don't you look into that Thorlabs quartz aspheric lens that Jonathan was playing with?

https://www.ultravioletphotography.com/content/index.php/topic/4594-thorlabs-79mm-uv-aspheric-lens-for-imaging/page__hl__quartz

[lukaszgryglicki]

OK focus shift and aberration, but when I focus via Live View and using U-340 4mm + S8612 2mm - then I have quite a narrow band, and if I have (in the far future) a diode emitting around 300nm and powerful enough - I can focus in live view? Or there is not enough light so live view will just show black?

[Andy Perrin]

If you have a diode, it won't be emitting any IR probably, so you don't need the S8612 IR blocker (which, by the way, would also block the 300nm light). The sensor is probably ok there if you have a debayered camera, so I bet you would be able to see in live view.