New member's first attempts and questions

[montanawildlives]

Hello all, I'm a new member and have been trying my hand at UV photos. I wanted to post some of my early attempts and ask some very intro-level questions to help me get off the ground. Forgive me for a general "getting started" post rather than specific posts for each question.

 

All UV shots are with a Fujifilm X-t3 full spectrum conversion and a Kolarivision UV pass filter on the Fujifilm 27mm f/2.8 pancake or Fujifilm 60mm 2.4 lens.

 

1. I'm clueless about white balance for UV. I've read online that one should use a gray card and I've read the advice on the present site as well. Seems clear that the typical method I've used for IR photos (i.e., brightly lit green foliate for a custom WB) does not work too well. Auto WB also doesn't seem to work. First shot below is auto WB. Second shot is custom WB on green foliage. Third shot is a BW version. Ultimately, I think I will do mostly B&W UV, just as I have done lots of B&W IR (see fourth shot, just for fun).

 

I think from these shots I can conclude that the 27mm f2/8 Fuji pancake does ok with UV. This is the "correct" pattern for a dandelion, right? This would indicate little or no IR leak on the Kolarivision filter I think.

 

2. In full sun, f/2.8, ISO 160, does the 1.1 second exposure seem ok? From that would you say this lens is passing acceptable amounts of UV light, or would you say that this is too long of a shutter speed indicating that the amount of UV light being passed is problematically low? Of course I could raise the ISO (although, since the X-t3 is a crop camera, I would not want to go too high). I mostly do nature photography which typically means wind, so usually 1 second exposures are not fun.

 

3. I have several old Nikon AI-S lenses (55mm 3.5 macro; 28mm 3.5; 105mm 2.5; I also have the 50mm 1.8D). All 52mm filter threads. The only UV pass filter I have is the 39mm from Kolari (purchased because Kolari said that the 60mm 2.4 macro lens from Fuji is good for UV (and has a 39mm thread); I'm also using it on the 27mm f2/8 which also has a 39mm thread). I can still exchange the 39mm Kolari UV pass filter for a 52mm version, but would probably only do so if some of the AI-S (or the D) lenses work well for UV. I've seen lots of things that older, simpler lenses with less advanced coatings might work well with UV, but I haven't seen specific recommendations for these AI-S lenses. Any thoughts?

 

4. Kolarivision's website noted that the Fujifilm 60mm macro lens was good for UV, but I found it to be hotspotty--even wide open as the last picture shows (wide open it is more like vignetting, but stopped down the lighter center becomes more pronounced and well defined). Stopping down to 5.6 or 8 made it significantly worse. I am well versed in the hot spot issues with IR, do we usually have the same problems with UV? (and yes, that is the ghost of a man visiting a grave just to the right of center in the background). But....IT'S HIS OWN GRAVE!!! ;-)

 

Thanks everyone for any newbie advice you can offer.

 

John

[ulf]

The green and pale center of the dandelion is clearly an indication of leakage.

[Andy Perrin]

Hii! I like the pictures-as-art! My favorite is the 2nd from the bottom with the graves and lovely dark sky.

 

To the technical issues:

The dandelion pattern is correct but the center should be a lot darker than that. You probably have a great deal of infrared or visible contamination in that photo. Here is how my dandelions come out (pay attention to the brightness, not the color, and forgive the noise, this is a very old photo and my equipment and technique have since improved):

 

Your exposure time is pretty reasonable but I think you need to add an IR blocker filter like S8612 2mm. I have not been impressed with the Kolari's filter's IR blocking based on what I've seen members post to the board.

 

Typically it's rare to have a UV hotspot issue in the same sense as IR, but we do get dichroic artifacts (angle dependence of the false colors) and vignetting issues, and occasionally some haze artifacts from shiny objects or light sources pointed directly at the lens.

 

White balance should be done off of virgin PTFE or something like that (or Spectralon if you have money to burn). Cheap alternative is to click-white balance off anything magenta in the image using the RAW. You need a converter capable of setting a UV white balance properly, which excludes Lightroom and Photoshop's.

[dabateman]

The green looks like you got a Ug5 filter. That is what they kind of look like or a 2mm Zwb3 filter.

 

I don't know about the Nikon lenses. But Kolari lists the Nikon 50mm f1.8 D as good

https://kolarivision.com/uv-photography-lens-compatibility/

[montanawildlives]

The green and pale center of the dandelion is clearly an indication of leakage.

 

even with my completely random WB?

 

I've been looking for IR cut filters but maybe I also need visual cut. Three filters.

 

Is there not one filter that passes UV and blocks visible and IR in a screw on form?

 

I guess there is no reason to keep the Kolari filter. For $200 it should do what It says.

 

Thanks.

[montanawildlives]

Hii! I like the pictures-as-art! My favorite is the 2nd from the bottom with the graves and lovely dark sky.

 

To the technical issues:

The dandelion pattern is correct but the center should be a lot darker than that. You probably have a great deal of infrared or visible contamination in that photo. Here is how my dandelions come out (pay attention to the brightness, not the color, and forgive the noise, this is a very old photo and my equipment and technique have since improved):

 

Your exposure time is pretty reasonable but I think you need to add an IR blocker filter like S8612 2mm. I have not been impressed with the Kolari's filter's IR blocking based on what I've seen members post to the board.

 

Typically it's rare to have a UV hotspot issue in the same sense as IR, but we do get dichroic artifacts (angle dependence of the false colors) and vignetting issues, and occasionally some haze artifacts from shiny objects or light sources pointed directly at the lens.

 

White balance should be done off of virgin PTFE or something like that (or Spectralon if you have money to burn). Cheap alternative is to click-white balance off anything magenta in the image using the RAW. You need a converter capable of setting a UV white balance properly, which excludes Lightroom and Photoshop's.

 

Thanks. So even though the virgin PTFE looks white, it is needed for WB in UV versus just

some other thing that looks white? I see a bunch on ebay... do I just buy a piece, cut it

down to size and carry it around?

 

Thanks.

 

 

[montanawildlives]

The green looks like you got a Ug5 filter. That is what they kind of look like or a 2mm Zwb3 filter.

 

I don't know about the Nikon lenses. But Kolari lists the Nikon 50mm f1.8 D as good

https://kolarivision.com/uv-photography-lens-compatibility/

 

ok great, thanks!

[Andy Perrin]

Thanks. So even though the virgin PTFE looks white, it is needed for WB in UV versus just

some other thing that looks white? I see a bunch on ebay... do I just buy a piece, cut it

down to size and carry it around?

 

Thanks.

Yes, that would work! I have a piece that I carry around just like that. The key fact is that no matter what something looks like in visible light, it's NOT a good guide to what it will look like outside of visible light (neither in IR nor UV nor any other spectrum). The only way to know is to look up or measure the spectra for the material you are interested in. It happens that many materials that are white in visible light rapidly begin to absorb in UV. Sometimes this is because fluorescent materials have been added to deliberately make visible white look "whiter than white" by absorbing UV and reemitting it as blue — this is the case with most kinds of printer paper and fabric. Other times it is just an accidental fact of nature. PTFE is special in that it is white across a very wide region of spectrum from SWIR to UV. Similarly, salt (sodium chloride) is white from thermal infrared all the way to UV-A. Salt darkens in UV-B, so PTFE is better for our purposes, as well as easier to carry around.

[dabateman]

If you don't have PTFE or forgot it at home. An alternative is to custom white balance off asphalt, like a road or your driveway. But PTFE is best.

 

Yes if you just want UV filter without bug vision, than I would return or exchange that filter. That green look is sometimes referred to as bug vision, a guess of what the world might look like to a bee. You would need U340/Ug11 to cut out that visible leak. At which point you should just use that U340/ug11 with an IR blocking filter like S8612 or BG39 for better UV signal.

[Andrea B.]

In full sun, f/2.8, ISO 160, does the 1.1 second exposure seem ok?

 

I just ran a series today for some UV-pass filters. I set the UV-Nikkor lens to f/11 and the converted D610 to ISO-100. The 10 shots I made in full, strong sunlight ranged in exposure time from 1/15 sec to 1/3 sec. The KolariU shot was 1/5". So that is what might be achieved with a dedicated UV-lens in strong sunlight. See results here: Named UV-Pass Filter Shootout

 

With your lens wide open at f/2.8 and the camera set to ISO-160, it seems like your exposure time of 1.1 second might be telling you that your lens was not passing as much UV light as might be possible with other lenses.

 

Also note that the KolariU performs quite well in UV.

I'm not sure that your KolariU is the reason for your false green unless there is something wrong with it.

 

You might want to verify that your camera has no light leakage around the mount or through open ports or around LCD screens. (I have to tape the upper LCD on my D610 because it leaks some light.)

 

---

 

I'm clueless about white balance for UV. I've read online that one should use a gray card and I've read the advice on the present site as well.

 

This sticky tells you exactly what to get and why: https://www.ultravio...ir-photography/

 

---

 

We have found over the years that some hotspots can be mitigated by using a lens hood to cut some of the light entering the lens at an angle.

[Andrea B.]

John (montanawildlives), I was wanting to emphasize that I do think you should contact Kolari Vision about your KolariU. I wonder if you got one from a "bad batch" or something?

Would you be OK with uploading one of your raw files of the dandelion for me to look at?

 

Also I wanted to mention that the 4th photo is great!

And Octave Rivet is such an unusual name in English. Must be French? Is this cemetery in Montana?

[Andy Perrin]

Andrea, there have been so many “bad batches” of the Kolari UV filters that I’m starting to wonder if there are any good ones! We have seen person after person come to this board with leaky Kolaris. I wouldn’t recommend that filter to anyone unless they are prepared to keep returning it till they get a good one.

[nfoto]

#4 in the first post definitively is IR, not UV? UV will not give a dark sky, not at all.

[Andy Perrin]

#4 in the first post definitively is IR, not UV? UV will not give a dark sky, not at all.

 

Yeah, he said,

Ultimately, I think I will do mostly B&W UV, just as I have done lots of B&W IR (see fourth shot, just for fun).

[nfoto]

OK, I stand corrected. In a sense, that is.

 

The UV shots are badly troubled by a lens poor for UV thus IR leakage gets significant.

[Andy Perrin]

I think you are right on that issue. The solution is probably to find a better lens but I still think the Kolari filters are not all that good without extra blocking.

[montanawildlives]

Yes, that would work! I have a piece that I carry around just like that. The key fact is that no matter what something looks like in visible light, it's NOT a good guide to what it will look like outside of visible light (neither in IR nor UV nor any other spectrum). The only way to know is to look up or measure the spectra for the material you are interested in. It happens that many materials that are white in visible light rapidly begin to absorb in UV. Sometimes this is because fluorescent materials have been added to deliberately make visible white look "whiter than white" by absorbing UV and reemitting it as blue — this is the case with most kinds of printer paper and fabric. Other times it is just an accidental fact of nature. PTFE is special in that it is white across a very wide region of spectrum from SWIR to UV. Similarly, salt (sodium chloride) is white from thermal infrared all the way to UV-A. Salt darkens in UV-B, so PTFE is better for our purposes, as well as easier to carry around.

 

 

Great, I just ordered a piece off ebay for $10. Thanks!

[montanawildlives]

If you don't have PTFE or forgot it at home. An alternative is to custom white balance off asphalt, like a road or your driveway. But PTFE is best.

 

Yes if you just want UV filter without bug vision, than I would return or exchange that filter. That green look is sometimes referred to as bug vision, a guess of what the world might look like to a bee. You would need U340/Ug11 to cut out that visible leak. At which point you should just use that U340/ug11 with an IR blocking filter like S8612 or BG39 for better UV signal.

 

 

I tried asphalt today--I think it worked! See next posts...

 

Where does everyone buy their filters? I see lots of un-mounted filters but I'd much prefer threaded metal mounts. I see some people taking U-340 glass and mounting it inside 52mm threaded metal mounts on etsy, for example, fewer on ebay....is there some trusted source that you experts go to?

 

From another thread it seems that "the Hoya U-330 stacked with two S8612 IR-Blockers, 1.75 mm and 2.0 mm in thickness" might be the best option? Or not? Stacking three (threaded metal) filters has me a bit worried about vignetting too.

 

Thanks.

 

 

Thanks.

[montanawildlives]

In full sun, f/2.8, ISO 160, does the 1.1 second exposure seem ok?

 

I just ran a series today for some UV-pass filters. I set the UV-Nikkor lens to f/11 and the converted D610 to ISO-100. The 10 shots I made in full, strong sunlight ranged in exposure time from 1/15 sec to 1/3 sec. The KolariU shot was 1/5". So that is what might be achieved with a dedicated UV-lens in strong sunlight. See results here: Named UV-Pass Filter Shootout

 

With your lens wide open at f/2.8 and the camera set to ISO-160, it seems like your exposure time of 1.1 second might be telling you that your lens was not passing as much UV light as might be possible with other lenses.

 

Also note that the KolariU performs quite well in UV.

I'm not sure that your KolariU is the reason for your false green unless there is something wrong with it.

 

You might want to verify that your camera has no light leakage around the mount or through open ports or around LCD screens. (I have to tape the upper LCD on my D610 because it leaks some light.)

 

---

 

I'm clueless about white balance for UV. I've read online that one should use a gray card and I've read the advice on the present site as well.

 

This sticky tells you exactly what to get and why: https://www.ultravio...ir-photography/

 

---

 

We have found over the years that some hotspots can be mitigated by using a lens hood to cut some of the light entering the lens at an angle.

 

 

Thank you. I've been following that recent thread and just now skimmed through your "what to get and why" thread and...they are both so far over my head that it is going to take a lot of time and study to get up to speed. I did come to understand the virgin PTFD idea and have ordered a piece.

[colinbm]

Yep there is a guy on here that sells filter glass, but he chooses who he sells too & if you criticise anything he will stop selling to you, but he criticises other suppliers when he feels like it.

[montanawildlives]

OK, I stand corrected. In a sense, that is.

 

The UV shots are badly troubled by a lens poor for UV thus IR leakage gets significant.

 

Yes, sorry, the IR pic was a distraction, probably included because it was not as terrible as my UV shots.

 

I did some tests today to look at the hotspots again thinking that this would reveal the extent of the IR leak problem. Here is a test shot at f/2.4 and one at f/11. The hotspot gets significantly worse stopping down as I would expect with IR but not UV (so others have written) so I think this indicates significant IR leakage. (Fujifilm xt3 full spectrum with 60mm f/2.4 macro and kolarivision UV bandpass):

 

It's already terrible at f/2.4 of course, but this lens is never recommended for IR for this reason. It's the difference between f/2.4 and f/11 that I am looking at and considering evidence for lots of IR leak.

 

Thanks.

[montanawildlives]

John (montanawildlives), I was wanting to emphasize that I do think you should contact Kolari Vision about your KolariU. I wonder if you got one from a "bad batch" or something?

Would you be OK with uploading one of your raw files of the dandelion for me to look at?

 

Also I wanted to mention that the 4th photo is great!

And Octave Rivet is such an unusual name in English. Must be French? Is this cemetery in Montana?

 

I was more inclined to just return it, but maybe I will try contacting them instead.

 

Thanks about the fourth pic--someday maybe I'll be able to take a decent UV pic as well as IR. Yes, that is in Montana, at St. Mary's cemetery in the town of St. Ignatius in the Mission Valley (rural Montana is quite religious). I hadn't thought too much about the name, but yes I bet it is French, it was the Jesuits (founded in Paris) who started the mission after which the entire area valley is named. I do love IR cemetery pics though...

 

 

 

 

I wouldn't mind uploading a raw file at all, but it seems they are too big (50MB, way over the limit). I converted to a DNG which was under 30MB but...it seems that my quota of 30MB for the day is cumulative? I'm still figuring out how to negotiate this site.

[Andy Perrin]

Yeah, I think you should also find yourself a lens that passes UV better but also consider getting a new filter or a better one from Kolari. And buy some S8612 2mm. That will stop any IR dead.

[nfoto]

Do note 30MB 'quota' is *not* per day. It is the total for basic members.

[ulf]

John (montanawildlives), I was wanting to emphasize that I do think you should contact Kolari Vision about your KolariU. I wonder if you got one from a "bad batch" or something?

If this is the filter:

https://kolarivision...ss-lens-filter/

Then it might be well within Kolari's specs and still fail our more elevated demand for a high OD

In their production specification they say:

"Our filter has a 50% transmission peak at 365nm, and >25% transmission between 340-380 for high total light transmission.

Average out of band rejection is >OD 4.3 (0.005%), with a minimum rejection of>3.5OD (0.025%), meaning there is a high signal to noise ratio and no IR contamination."

 

>3.5OD might be OK for landscape-UV or showing freckles on portraits, but we know it is not good enough for all floral photography.

Especially not with lenses that are not as good in UV-transmission as the UV-Nikkor.

 

Average out of band rejection >OD 4.3 is totally uninteresting if there is an IR leakage with a worse OD.

It is just boasting with numbers.

 

As their OD specification is like I quoted above, I would not recommend buying the Kolari UV pass filter as it likely would not be good enough in all situations.