Here's a question for you

[Cadmium]

True, some of those old longer focal length lenses have good UV transmission, but then who uses longer lenses for UV? Right? Seldom, if ever do I use a long lens for UV.

So then the question becomes, what typically used 'normal' focal length lenses have larger than 52mm filter thread size?

Older or newer. I have no experience or knowledge of any of the newer typical lenses that are being used with mirror-less cameras. Some are barely good for UV, from what I gather,

but I have no idea what filter thread they have, all smaller than 52mm I believe?

Just wondering if there are any lenses out there that people are actually using for UV that have larger than 52mm filter threads.

[dabateman]

Well the answer for me is not for UV. I typically use 25mm filters for UV.

 

Its IR that my typically filter size is 72mm.

[ulf]

The older Novoflex Noflexar 400mm and 600mm has two versions AFAIK. Mine are 77mm, but there were some 75mm too.

The more modern C-Griff and D-Griff types has internal slot mounted filters. I can check the thread of the adapter if you want to know.

[Cadmium]

Th reason I brought up the question is sometimes the question will be this:

"Are there UV filters for 82mm...?

My answer is something like this:

"I don't know of any good UV transmitting lenses that have larger filters threads. Are you sure your lens will work good for UV?"

In other words, select a UV capable lens first, and then you will know what filter size to look for. No need picking out a large filter size and paying twice as much money for something that is only going to work well on a lens with a smaller thread.

Of course, if you're going to be shooting with a 400mm lens with a larger thread size... then... but honestly, how many times have we done that?

It is usually more like a 35mm to 100mm lens, and many are smaller than 52mm, like the enlarger lenses even.

I will shut up now and let the topic return to norbal.

[ulf]

Some older wide (21mm?) lenses are at least marginally UV capable. Bushnell, Tokina...

To avoid vignetting a wide diameter filter is needed if you are using a full frame camera. Ideal would be a glued filter stack to keep ith as thin as possible instead of stacking several filters..

However the price would likely be rather high for such a filer and the market rather small.

[nfoto]

Some of these wide-angle lenses will allow rear filtration. That helps a lot as such filter can be much smaller and elaborate stacks are not out of the question.

 

I'm building a bespoke rear-filter unit for F-mount lenses on my modified Z6.

[dabateman]

The Pentagon 6 50mm f4 lens has an 86mm front filter thread. However both the single coated and multi coated versions are horrible for UV.

 

[Andrea B.]

Along with nfoto, I would recommend investigating rear filtration for any lens having an 82mm front diameter.

 

B+W used to make the 403 in large diameters. I think the one I have is 72 mm. Of course you would need to stack an IR blocker for the 403. I haven't looked recently to see what B+W has for sale.

[dabateman]

Cadmium,

An alternative for using large sizes may not be for the lens, but for a light. Don't some flashes have large filter threads?

A cheap alternative maybe to add a 77mm Zwb1 filter to a flash, then more expensive 52mm S8612 filter to your lens, for reflected UV. Someone maybe pricing the options.

[Timber]

the Spiratone 75/3.5

 

This one looks very similar to my Dixon Autocrat Deluxe 75mm f3.5. I compared it to the EL-Nikkor 80mm and seems to be on the same level for me. What is your experience with this lens?

 

And to be ontopic :)

My biggest filter size is 52 for UV with the Nikon Nikkor 24mm f2.8. All the other lenses with bigger filter thread are useless for UV.

 

For rear filtering I use a ULATA Canon-Sony Helicoid adapter to drop the filters in. The main issue with rear filtering is changing the optical formula and often the focus shifts way beyond infinity. For example the 8mm Samyang Fisheye was not able to focus to infinity, only beyond it, without the use of a Helicoid to move it about 2mm further the sensor. The ULATA adapter was the only one that works well with Full Frame lenses and can take 43mm filters easily, so no vignetting occurs (with 40.5mm filters I noticed lot of vignetting with the Samyang 14mm f2.8).

[Timber]

How about the old EL-Nikkor lenses such as f5.6/300 which has insane 95mm filter thread? :D Did anyone ever had a chance to try that in UV?

[ulf]

Along with nfoto, I would recommend investigating rear filtration for any lens having an 82mm front diameter.

 

B+W used to make the 403 in large diameters. I think the one I have is 72 mm. Of course you would need to stack an IR blocker for the 403. I haven't looked recently to see what B+W has for sale.

 

 

A thick rear filter will change the focal point for infinity, just as an incorrect thickness of the window, replacing the cameras original UV/IR-cut filter.

If the lens adapter can compensate for that there is no problem.

This effect is more pronounced for wide angle lenses as their focussing travel is shorter than for long lenses.

 

With some luck the lens's focus shift for UV might improve the situation.

[nfoto]

The Tamron 21/4.5 is such as case. Quite nice lens for UV in fact and it does infinity.

[bvf]

Just to add my tuppence-worth to the original question ....

 

Yes, the Sticky on UV-capable (or at least UV-friendly) lenses is very useful, and I always used it when looking for a UV lens.

 

BUT ... as has been mentioned already, having a binary yes/no as an answer is too simplistic. Almost any lens will pass some UV. We also need to know how fast the lens is in UV, and how deep it can dig into the spectrum - and other information like focus-shift would be useful.

 

I got my fingers burnt when I started out in UV and was looking for lenses with a range of focal lengths. Because of the Sticky I bought an old Biotar 58/1.8 and an Enna Tele-Ennalyt 135/3.5. These turned out to be very mediocre in UV. I subsequently proved this by putting together a prism-based device to compare UV capabilities of various lenses, and this made it clear how poor these lenses are compared with the acknowledged good guys, the Cassar S 20/2.8 and Kuri 35/3.5.

 

I would not ditch the Sticky, but would suggest starting a new one which is more discerning as to which lenses to include and provides supporting technical information.

 

BTW - attached are some of the results from my prism set-up. There are some variations in detail, but the general story is consistent. The Pupil is a lens made by Igor of these parts. The wavelength scale on one of the images is a computer simulation I wrote which computed what the spectrum should look like for various glass types in the prisms I was using (as I did not know what glass they were made of): the Schott Crown K7 seemed to closely match what I was actually seeing. Wavelength decreases to the left.

 

Camera was a full-spectrum Canon EOS M.

 

Either no filter was used or a S8612 was used to block IR.

 

The output seems to support the view that you can just about reach down to 320nm with Cassar S or Kuri.

 

 

 

 

 

[Cadmium]

Hmm... Bernard, interesting post. :-)

Yes, the Kuri (Kuribayashi 35mm f/3.5) reaches down to t 320nm, the plot taper has a fairly strong shoulder (as apposed to what I call a 'soft shoulder') this means it transmits lower UV stronger,

and it also has an amazingly small focal shift, if that is a concern in any application you are using it for.

I have a lot of lenses, most of which I have purchased to test for UV. The Kuri is my best.

I don't have any of the more specialized UV lenses, such as UV-Nikkor, Coastal Optics, etc., but then I don't feel I would be able to use much of the deeper reach of those lenses given sensor limits and usual UV-A filters.

Where did you find your Kuri? I don't see then on eBay at all anymore.

[bvf]

Hi, Cadmium.

 

Are you Europe-based - or an insomniac N American?

 

I bought the Kuri from Igor, whom you have exchanged messages with in other threads. He actually labelled it as a Kuri clone, so it may have been branded something else in its first life. But it performs well.

 

To be honest, I hardly ever use the Kuri. My normal UV lens is the Cassar S, and I recently acquired a metal El-Nikkor 105 which is my go-to lens for UV macro work.

 

I'll be starting a project later in September (when the filters have arrived) which will prove whether my kit really can make images round 320-325nm. I'm going to try making 3 colour-separation images in the 320-400nm range so that I can create full-colour UV images. At the short wavelength end I'll be using a 315BP25 filter. Long exposure times are expected! Hopefully the OD 6 blocking factor will be good enough to prevent any longer-wavelength leakage.

[dabateman]

Bernard, glad to see you around again.

Some of us USAers just never sleep.

Your 315bp15 sounds interesting. Are you going to just use sunlight or supplement with a UV bulb?

To hit that wavelength the ExoTerra UVB 200 bulbs are good. I use a 26W USA one, but you should be able to buy a 25W European one.

http://www.exo-terra.com/en/products/reptile_uvb200.php

 

There is a strong 313nm Mercury line that comes off these bulbs. They are standard E26/E27 screw base.

 

Make sure to wear amber protective glasses.

 

The Igor 35mm we have been refering to as igoriginal 35mm, as he bought a whole bunch of different 35mm f3.5 lenses, took them apart. Cleaned them, added seals and glued a step ring to 52mm on the front. Based on the pictures mine maybe a soligor lens. But they are all different and will not perform exactly as a regular off shelf lens as he modified them. I don't know how it would compare to a true Kuri. I don't know any one whom owns both.

 

Yes my go to lens seems to be the Pentax UAT, but I image mostly in a controlled room. If I ever go outside again the Nikor 80mm EL maybe my choice as its similar focal length that I seem to like.

 

[Andrea B.]

I would not ditch the Sticky, but would suggest starting a new one which is more discerning as to which lenses to include and provides supporting technical information.

 

Bernard, your point is well made, but I wanted to say something about "supporting technical information".

 

No UV photographer (emphasis on the photographer part) has the complete (very expensive) spectrometric setup for measuring the transmittance of a lens in UV or IR. There are a couple of professionals here in other areas who do have such gear (or most of it) and who do make use of UV photography. But these folks don't own the 100+ or so lenses listed in the Sticky. And they are, of course, quite busy with their actual jobs. They have provided some information for us of which we are greatly appreciative.

 

So, you see, the best we can do in the Lens Sticky is report what is reported to us. I do list this warning throughout the Lens Sticky:

NOTE: Transmission data is not guaranteed and may be only an estimate.

Also the range column is headed "Range Estimate". If we don't have any info, that entry is left blank.

 

The only solution to this I can think of is to hire someone to measure lenses for UVP. And then figure out how to get lenses to them to measure. (FedEx? Postal Service?)

 

I've often thought that I should perhaps get the measuring gear myself and get some proper instruction about how to use it. I've always been technically adept. (And seem to still be teachable! ) I could at least measure the 50 or so lenses I have. Maybe I can think more about doing this after I get relocated in the new house. (We are getting ready to move house here.)

---

 

Bernard, I think your project for 3-colour separation UV images will be fascinating. I hope you will provide us with a report and some examples! I did try this with 3 IR-bandpass filters, but it did not work out. I think that's because the filters were not narrow enough. I'd like to try again someday in either UV or IR.

 

May I ask, please, from where did you order your 315BP25 filter? I got a beautifully made 340BP10 from Edmund Optics. But it is hard-coated to achieve the narrow bandpass, and the hard coating caused such a bad reflection problem that the filter is useless for reflected UV photography.

[Andrea B.]

Off Topic

 

Are you Europe-based - or an insomniac N American?

 

Sometimes when I have stayed up late or gotten up early, I have seen UVP go around the world. It's cool! Although these days we have lost most members from Asia. I think they faced too many internet restrictions. And, of course, at any given time there are only a very small number of active members anyway. UV photography is not regularly practiced or explored by many people.

[bvf]

Hello again, David (it is David, isn't it?)

 

I've been part-time working in my retirement but now going back to full-time retirement, so ready to take on a new UV project. It will probably be the wrong time of year in terms of daylight quality.

 

I'm not sure yet what I'm going to do about lighting because I don't really have an idea of how how difficult it will be to get images down at 320nm - how long the exposures are going to be.

 

I was certainly intending to do some outdoor work. Are you saying that the Exo Terra bulbs are powerful enough to make a difference outdoors in daylight?

 

There are lots of Exo Terra bulbs on ebay - is this the type you're thinking of: https://www.ebay.co....zXsorGfjzZAhlbw

 

I also want to photgraph flowers, and that will have to be indoors. I was going to try my flashguns that I use for UV macro and close-up, but don't know yet whether they'll be powerful enough, even with a practicable number of multiple flashes per exposure. So a continuous UV source may be the way to go. (I alreadyhave a setup that can house 8 CF "black lights", but they probably won't deliver enough light at 320nm).

 

BTW - IIRC it was you that launched me on ths new project. I think you pointed me at BJOMEJAG on ebay as a source for interesting filters. I contacted the proprietor and explained the project, and he has put together 5 filters that should work. I've bought the 315BP25, 345BP20, and 380BP25. All offer OD 6, and the first two are also have an impressive peak transmission of 70+%. All I need now is enough sensor sensitivity and a strong enough light source at 320-325nm.

[bvf]

Hi, Andrea.

 

Yes, I understand the difficulty in getting formal measurements of lenses. But there is quite a lot of that data floating around the forum, and there will be lots of folk like me that can provide some anecdotal input - which is better than nothing. Listing a lens without giving any idea of its reach into the spectrum or how fast it is doesn't help very much - and it certainly cost me money when I dabbled with the Biotar and Tele-ennalyt.

 

So I realise you can't measure all the lenses, but I was thinking you could start a new Super-Sticky that had only the subset of lenses for which you had some data, and then thiw would grow over time. The most useful thing for me is the bar chart that lists 40 or so lenses and how far into the UV they reach - it's been bandied around the forum several times. This has far fewer entries than the sticky, but is more useful - and that's how I ended up with the Cassar S.

 

Re: from where did you order your 315BP25 filter?

My response to Dabateman discusses that - have a look at the "False Colour" entries at http://www.ebaystores.co.uk/BJOMEJAG-EBUYER-STORE/Ultra-Violet-Filters-/_i.html?_fsub=9&_sid=8343593&_trksid=p4634.c0.m322 . Mind you, I might have the same problem you experienced with the Edmund filter.

 

BTW - I was already thinking about trying this in IR as well, so I was interested to see that you'd tried but not succeeded. Can you outline what your results looked like and which filters you used? I would have thought you need a wide bandpass (say 700-800, 800-900, 900 -1000) rather than a narrow bandpass, similar to colour separation filters used for visible colour photography. My concern is that the IR filters I can find are too narrow, and I can't see one that covers the 700-800 range well.

[Andrea B.]

I used the 3 IR-bandpass filters offered by MaxMax.

https://maxmax.com/filters/bandpass-ir

The photographs from the 3 filters are so similar in tonality that when stacked you don't get much. MaxMax shows some examples. Mine didn't look quite like those. I'll look later for them and try to post.

---

 

Because of the Sticky I bought an old Biotar 58/1.8 and an Enna Tele-Ennalyt 135/3.5. These turned out to be very mediocre in UV.

 

I see a Zeiss Biotar 58/2.0 listed in the Lens Sticky. Is that the one you meant? You wrote above Biotar 58/1.8. Just curious.

 

Another difficulty I face as an editor is that one person will judge a lens as mediocre while another person will love the same lens and recommend it. Additionally, there is no way to know whether a particular lens model had changes in construction over its manufacturing life which might alter its capability in the UV wavebands.

---

 

A photograph made with a lens which has a range restricted to the Upper Quarter of 375-400 nm is a legitimate UV photograph. There seems to be a perception that a UV-capable lens should reach deeper than that. I don't quite understand that.

 

Of course, out of simple curiosity, we all want to try shooting below 350 nm. I do grant that. But nothing I've seen photographed below 350 nm so far in the last 10 years is all that different from what is photographed above 350 nm except for some false colours after white balancing. Of course, even though differences may be small, that doesn't mean that they are not scientifically meaningful. But anyone performing scientific or professional reflected UV-photography already owns a corrected UV-Nikkor/Rayfact or a Coastal Optics 60 or 105.

---

 

Nevertheless, I will try to made some alteration to the Lens Sticky to further warn that if a range estimate is not given, then the buyer should beware. By trying to provide UV-capable lens information, we do not want to mislead anyone.

[bvf]

Sorry, my error - should have been 58/2.0. (I'm just used to 50mm-ish lenses being 1.8 or larger these days.)

 

You are right that a lens limited to the Upper Quarter is legit - but my point is that to be useful the Sticky needs to provide this limitation so that the innocent/naive (like me) don't buy/use it expecting it to perform in the 2nd or 3rd Quarter. And again you're right - we shouldn't be using pejorative terms like "mediocre" which are down to opinion - we should be publishing facts. I also understand that warnings/caveats are necessary, but they don't help the reader in making use of the information apart from dissuading him/her from using it.

 

The spectra for the Maxmax filters look near ideal to me. But the price - over $500 for the set (plus postage and import taxes for the UK)! If I do try this as a hobbyist experiment I'll need to find cheaper alternatives. I'd love to see your results, including the 3 components.

[bvf]

Just another thought ...

 

Re.: "But nothing I've seen photographed below 350 nm so far in the last 10 years is all that different from what is photographed above 350 nm"

 

That may be because of the combination of low sensor sensitivity, low lens transmission, and low level of illumination at the shorter wavelengths, such that the image at the longer wavelengths is so much stronger that you can't see the effect of the shorter wavelengths. If that is the case and if the idea of UV colour separation images works, then this can be overcome because the short-wavelength image will get a lot more exposure than the longer wavelength image such that the images are of comparable intensity. So the colouring (whether it is the "natural" colouring the camera provides or whether it is a false RGB colouring) resulting from the shorter wavelength will be a lot more intense.

 

I just hope that theory can be turned into reality ...

[Andrea B.]

Yes, indeed, all those factors may also be in play in addition to the use of broadband filtration.

 

 

I just hope that theory can be turned into reality ...

 

Me too! We will all be looking forward to any results you obtain.

I had intended myself to explore some narrowband UV photography, but my initial narrowband filter was so expensive and *such* a disappointment that I put the experiment aside and have not yet returned to it (or to purchasing additional narrowband filters).