Information about the UV-Capable lenses formerly listed in the Lens Sticky is being revised. Transmittance Charts and results from Lens Test Charts are available in the following linked sections. More lenses will be added as time and money permit. The revised data is more informative and certainly more accurate.

Section 5. UV-Capable Lenses This section contains a brief summary of our UV LENS TECHNICAL DATA board and a list of possibly good lenses which have not yet been measured.

These equa­tions demon­strate that choos­ing the same f‑number on a lens of any focal length will result in the same amount of light pass­ing through the lens. They also explain the inverse rela­tion­ship between f‑numbers and expo­sure. For a giv­en focal length, as the aperture’s size increas­es, the ratio decreas­es, and vice ver­sa.

Sticky :: UV-Capable Lenses by Andrea G. Blum for UltravioletPhotography.com [Last Update :: 13 Nov 2023. Sticky formatting was cleaned up.]

The best way to address this is by start­ing with the basics. Inside every inter­change­able lens is a ring of over­lap­ping blades col­lec­tive­ly known as an iris diaphragm or iris. Expand­ing or con­tract­ing the blades adjusts the open­ing in the cen­tre of the iris, called the aper­ture.

About the UV Lens List For a lens to be on our UV Lens List, it must have at least one member or contributer who has either used it or tested it to confirm that the lens is UV-capable in some portion of the UV bandwidth. Our lists are by no means exhaustive, so please experiment and let us know of your discoveries. Please Note the following:

UV-Dedicated Lens :: Special Use :: Currently Manufactured Quartz lenses with deep UV transmission are currently manufactured for various industrial uses, but please be warned that many of these lenses may not be corrected over their transmission range and would therefore not be suitable for UV photography on a DSLR or mirrorless camera due to serious chromatic aberration. Such lenses, like their historical counterparts (see Asahi Pentax Quartz Takumar in the next table, for example), are intended for use with narrow bandpass filtration. Many of them may not fully cover a DX or FX sensor, although some can. We cannot provide an extensive list, but here are two manufacturers of such lenses and an example of their products. An internet search will provide other examples.

We express aper­ture val­ues using f‑numbers and not as the mea­sured size of the entrance pupil, such as its diam­e­ter, radius, or area, because it neglects the essen­tial role of focal length. This can be demon­strat­ed with a thought exer­cise.

[ultravioletPhotography.com does not endorse any specific products as a website. We simply offer reports, reviews and gear lists for your further investigation. Any opinions in such reports/reviews/lists belong solely to the poster writing them. UltravioletPhotography.com as a website is non-monetized and receives no compensation or income from any source.]

Last­ly, dou­bling the f‑number, such as chang­ing it from ƒ/2.8 to ƒ/5.6, reduces pic­ture bright­ness by one-quar­ter. And con­verse­ly, halv­ing the f‑number, such as adjust­ing from ƒ/8 to ƒ/4, increas­es pic­ture bright­ness four times.

Mount Type ? Many lenses on this list may need modification of the lens mount and the use of focusing helicoids and/or bellows for use on your particular camera body. Under such modification, the lens may not focus to infinity. Investigate before purchase!

A 50 mm lens set to ƒ/4 will have an entrance pupil diam­e­ter of 12.5 mm—because 50 divid­ed by 12.5 equals 4. A 24 mm lens set to ƒ/8 will have an entrance pupil diam­e­ter of 3 mm. Some lens­es can open to ƒ1.0, in which case the entrance pupil diam­e­ter and focal length are equal.

Most pho­tog­ra­phers sim­ply com­mit the stan­dard f‑number scale to mem­o­ry. How­ev­er, if you’re hav­ing trou­ble, a more straight­for­ward method is to remem­ber just the first two numbers—1 and 1.4—because the rest of the scale is an iter­a­tion of dou­bling each in alter­nat­ing order. The next f‑number is always dou­ble the pre­vi­ous one. So the num­ber after ƒ/1.4 is dou­ble of ƒ/1, which is ƒ2. Like­wise, the num­ber after ƒ/2 is dou­ble of ƒ/1.4, which is ƒ/2.8.  And on and on it goes.

UltravioletLens Glasses

Let’s pre­tend we have two lens­es attached to iden­ti­cal cam­eras: one lens is 50 mm and the oth­er is 100 mm, and both have entrance pupils with 25 mm diam­e­ters. Since their entrance pupils are iden­ti­cal in size, an equal amount of light enters each lens. How­ev­er, because the focal length of the 100 mm lens is twice that of the 50 mm lens, the light pass­ing through it has to trav­el twice the dis­tance to reach its camera’s image sen­sor, which pro­duces a dark­er image.

Please PM Andrea B. on UltravioletPhotography.com with any corrections, additions or suggestions. Or write to rudbeckia ultravioletphotography com.

Reduc­tion in bright­ness occurs because light has the prop­er­ty of spread­ing out as it recedes from its source, and from the per­spec­tive of your camera’s image sen­sor, this source is the point inside the lens from which focal length is mea­sured. This trait of light to dif­fuse out­wards is described by the Inverse Square Law, which states that inten­si­ty is inverse­ly pro­por­tion­al to the square of the dis­tance. In this exam­ple, the inverse square law informs us that the 100 mm lens expos­es its camera’s image sen­sor to 1/4 the light com­pared to the 50 mm lens because it’s twice as long. This occurs because one over two squared equals one-quar­ter.

Unfor­tu­nate­ly, the rela­tion­ship between f‑numbers, aper­ture size, and pic­ture bright­ness is not as imme­di­ate­ly intu­itive. Begin­ners are con­fused by the neg­a­tive (or inverse) rela­tion­ship between f‑numbers and aper­ture size. In addi­tion, they have a hard time under­stand­ing why big­ger f‑numbers rep­re­sent small­er aper­tures that reduce bright­ness, and small­er f‑numbers define larg­er aper­tures that increase bright­ness.

It is unlikely that any modern multi-coated, multi-element lens can be truly designated as a UV-capable lens. If the aim just is to detect flower patterns, such a lens might do adequate service in the 380 - 398 nm range. However, this in no way ensures the lens will render all there is of floral UV signatures or UV signatures of other subjects. For this reason alone using a UV-dedicated lens or a non-dedicated, but very UV-capable lens is advantageous. There's no predicting whether a given lens is UV-capable if it was not specifically designed for UV shooting. As noted, with a very long exposure an ordinary lens can often leak enough near-UV to produce an image, but it likely will not record the fine surface details that UV can reveal. What we can say generally about non-dedicated, UV-capable lenses is that they tend to have the following construction:

When you hold a lens up and look at the aper­ture, what you’re see­ing is tech­ni­cal­ly called the “entrance pupil.” The entrance pupil is the opti­cal image of the phys­i­cal aper­ture as seen through the front of the lens. This dis­tinc­tion mat­ters because when you look at the front of a lens, you see the aper­ture through mul­ti­ple lay­ers of glass that affect its mag­ni­fi­ca­tion and per­ceived loca­tion in space com­pared to the phys­i­cal open­ing in the iris. For the sake of sim­plic­i­ty, I’ll use “aper­ture” when refer­ring to both the set­ting and the phys­i­cal open­ing and “entrance pupil” in ref­er­ence to dimen­sions.

UV contactlenses

UV-Capability ? The amount of UV-capability of the lenses on this list varies. We have tried to list lenses that reach at least 350nm, but not all lenses have been formally tested. Investigate before purchase!

UV-Dedicated Lenses There are UV-dedicated, UV-capable lenses and ordinary lenses. A UV-dedicated lens is one which was designed and manufactured specifically for reflected UV photography. One of the most familiar UV-dedicated lenses is the UV-Nikkor 105/4.5. Others are discussed in later sections. Such lenses are very expensive and out-of-reach for most who want to try shooting UV. The next section will discuss the alternative: less expensive, non-UV-dedicated but UV-capable lenses.

The stan­dard f‑number scale is: 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32, and so on. The dif­fer­ence in expo­sure between adja­cent num­bers is one stop, which means that it either dou­bles or halves the amount of light pass­ing through the lens depend­ing on whether you’re open­ing or clos­ing the aper­ture. How­ev­er, the numer­ic sequence grows by a fac­tor of about 1.4 or shrinks by a fac­tor of about 0.7.

UV-Dedicated Lens :: Special Use :: Historical These lenses having excellent UV transmission are no longer manufactured and are rarely seen from dealers or on Ebay. On this list are industrial enlargers, microscope lenses and other special purpose lenses. Most require significant adaptions for use on a digital camera.

Birnian Rule of Thumb for UV-Capable Lenses from Birna Rørslett A decent UV-capable lens should require at most 3 stops more overall compared to the Nikon 105/4.5 UV-Nikkor or the Coastal Optics 60/4 APO. Measuring UV Transmission of a Lens I asked member Shane Elen what was needed to accurately measure the UV transmission of a given lens.  from Shane Elen Ideally you need a CCD spectrometer, or spectrophotometer (preferably in a dual beam configuration) with a monochromator, an integrating sphere, and a stable output UV-V-IR source. The integrating sphere helps ensure that the readings are independent of the incoming light ray angle. This will provide you with wavelength specific transmission response. To informally test UV lens transmission, it is possible to collect a set of narrow UV bandpass filters, mount them in some kind of holder and estimate a lens UV transmission by taking a UV photo of the mounted filters. Although the idea has been used before, Steve Smeed was the first in recent years to implement mounted UV bandpass filters in his clever Sparticle Board. Here is another example shown in an article by Enrico Savazzi: Filter Strip for Testing UV Lenses. See also Links to Informal Lens Transmission Tests.

Warning about Lens Scams The original UV-Nikkor 105/4.5 has become a very high-priced collectible. Prices have skyrocketed to the $4000-5000(US) range, maybe more. The lens has been seen offered at a much lower price in several lens scams across the internet. Do not fall for these scams! No one who is reputable will be selling the UV-Nikkor or any other rare UV-capable lens at a price under its current market value. Enlarger Lenses for UV An enlarger lens (EL) is used in a photographic enlarger for producing a print from a film negative. Some alternate photographic print processes require UV light to produce a contact print: cyanotype, platinum/palladium, gum, carbon, Kallitype and Van Dyke. So, most ELs pass some ultraviolet light between 370-400nm, some beyond that. But note that there is no generally accepted range of UV transmission for ELs. The range will vary by brand and lens construction. Enlarger lenses also, of course, magnify and have a flat-field construction. So ELs can be very useful for UV macro work when reversed. There are several enlarger lenses listed in the Lens Sticky, but it is not intended to be exhaustive. Use what is listed there for further explorations and experiments. Enlarger Lens References:

I hope this helped you under­stand the inverse numer­i­cal rela­tion­ship between f‑numbers and their effect on the aper­ture. If you have requests for future top­ics, let me know in the com­ments, and I’ll address them in future videos. In the mean­time, you can learn more about pho­tog­ra­phy on ExposureTherapy.ca. See you next time.

. UV-Capable Lenses from Birna Rørslett Here at UVP, we term a non-UV-dedicated lens as a UV-capable lens if the following criteria hold. The lens must:

Chang­ing the size of the aper­ture adjusts the inten­si­ty of light pass­ing through the lens. Increas­ing the aperture’s size allows more light to pass through the lens, increas­ing expo­sure and cre­at­ing a brighter pic­ture. Con­verse­ly, decreas­ing the aperture’s size reduces how much light pass­es through the lens, reduc­ing expo­sure and result­ing in a dark­er pho­to.

Opticallenses

Currently manufactured. Color corrected for 310-1100nm. Exceptionally sharp. No UV-Vis-IR focus shift. Transmission 290nm-1500nm. $5750(US). Hotspots at high magnification in this lens can be easily controlled via extension tubes or by a certain kind of lens shade.

UV-Dedicated Lens :: Photography :: Historical These photograpic lenses having excellent UV transmission are no longer manufactured. Most are rarely seen from dealers or on Ebay although the Carl Zeiss 60/4.0 UV-Objektiv and Nikon 105/4.5 UV-Nikkor may sometimes be found.

UniverseOptics.com a.k.a.Universe Kogaku America 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.

Under­stand­ing the rela­tion­ship between pic­ture bright­ness and both the shut­ter speed and ISO is straight­for­ward for stu­dents learn­ing the basics of pho­tog­ra­phy. Shut­ter speed is expressed numer­i­cal­ly in time units, with the most com­mon being frac­tions of a sec­ond; longer dura­tions result in brighter pic­tures, and short­er dura­tions result in dark­er pic­tures. ISO is also expressed numer­i­cal­ly; big­ger num­bers pro­duce brighter pho­tos, and small­er num­bers make dark­er pho­tos.

UV shooters such as Boon Tang, Vivek Iyer and Igor Butorsky have found other good UV-capable lenses outside the 35/3.5 category which are listed below. So let us keep up the search! We will continue to add some examples of non-dedicated, UV-capable here as they are brought to our attention.

35mm f/3.5 Lenses for UV - not the only category Any reader of the lens lists here in this Sticky will have noticed a predominance of non-dedicated, UV-capable lenses in the 35mm f/3.5 category. As has been remarked elsewhere, simply constructed lenses with minimal coatings and no UVIR-reflecting or fluorescing glues or other fluorescing or problematic inner parts, have been proven useful for UV imaging. Many of the older 35/3.5 lenses with manual apertures or preset apertures fall into that category. Read this post by Enrico Savazzi for a bit more insight into this: 35mm lenses for UV photography. With the research done by Klaus Schmitt, Enrico Savazzi and others and several nice 35/3.5 finds made by Oleksandr Holovachov, Steve Smeed and others, we have accumulated a good listing of UV-capable 35/3.5s. This, of course, has spurred others to look into this category where they discovered that there were quite a few UV-capable 35/3.5 designs produced by various non-mainstream lens manufacturers. And nice discoveries; were also made in the associated 105/3.5 and 135/3.5 categories and listed here. This is not to say, however, that there are no UV-capable lenses in other categories. There are indeed quite a few. Reed Curry, for example, has found many UV-capable lenses in Exakta mount which are not 35/3.5s: see Exackta Lens List (Partial) for more about Exackta lenses in general.

UV Focus Shift Focus shift between the Ultraviolet & Visible wavebands in a lens is a form of axial chromatic aberration that occurs because shorter, higher frequency UV wavelengths focus at a different distance along the longitudinal axis of a typical lens than do longer, lower frequency Visible wavelengths. Such wavelength-induced focus shift is a topic of particular interest in UV photography when using an external filter and a camera that has no Live View. First you must focus the lens in Visible light before mounting the dark UV-pass filter. After mounting the filter you might have to adjust your initial focus if the lens has not been designed to also bring the UV rays to the Visible plane of convergence. With a bit of trial and error you should be able to determine the proper correction at various apertures and note it for future reference. UV focus shift is less of a worry with an internal UV filter because during conversion the auto-focus can be adjusted a bit to compensate for UV for most lenses at most apertures.

UV Focus Shift ? Most of the lenses listed below have some degree of the UV focus shift discussed above. Lenses without such focus shift are noted. Consider converting a camera with Live View to avoid dealing with focus shift. Investigate before purchase!

This is pre­cise­ly why the f‑number is some­times called the f‑ratio. The f‑number express­es a ratio of the lens focal length to the diam­e­ter of the entrance pupil, and it’s defined by the equa­tion N=ƒ/D. Thus, the f‑number equals the focal length divid­ed by the entrance pupil diam­e­ter. It can also be mod­i­fied to solve for the entrance pupil diam­e­ter using the equa­tion D=ƒ/N. Thus, the entrance pupil diam­e­ter equals the focal length divid­ed by the f‑number.

Note from Editor: This Sticky began as a joint effort by the members of various forums who enjoy UV/IR photography. Thanks to everyone for their suggestions, comments, proofreading, lists, links, measurements, experiments and all round good fellowship.

Focus shift is not problem at all when using Live View if you have sufficient UV illumination. Attaining sufficient illumination to use Live View for focusing in the UV case is not always easy especially for UV between 300-350 nm.

UV LENS TECHNICAL DATA contains a detailed analysis of some of the best lenses for reflected UV photography. This board is produced and directed by our member Ulf Wilhelm. This board is briefly summarized in Section 5 of this topic.

ResolveOptics.com Resolve Optics is a UK company which makes the telescoping UV-forensic 60mm f/3.5 (228-000) lens and others. The UV-forensic lens transmits between 230nm-500nm and is corrected. No online technical information is available about this lens, but it is discussed briefly in this white paper: Ultraviolet Technology Aids Forensic Investigation. The UV-forensic lens 'images onto' the Horiba SceneScope RUVIS (a reflected UV imaging system).

UV lens camera

For­tu­nate­ly, pho­tog­ra­phers don’t need to per­form such cal­cu­la­tions to take pic­tures! That’s because hid­den with­in these num­bers is a straight­for­ward rela­tion­ship. For exam­ple, notice how the expo­sure pro­duced by the 50 mm lens with a 25 mm entrance pupil is iden­ti­cal to the 100 mm lens with a 50 mm entrance pupil. This is because in both cas­es, the ratio of the focal length to the entrance pupil diam­e­ter is 2:1.

Hi there, my name is Paul, and this is Expo­sure Ther­a­py. In this video, I’ll explain the rea­son for the inverse numer­i­cal rela­tion­ship between f‑numbers and the aper­ture. This rela­tion­ship is a wide­spread point of con­fu­sion for many begin­ner pho­tog­ra­phers, who regard it as irra­tional or need­less­ly com­plex. My goal is to dis­pel the mys­tery around f‑numbers and demon­strate why they’re a per­fect­ly rea­son­able method for express­ing how the aper­ture affects expo­sure.

In both cas­es, the rela­tion­ship between the set­ting and its effect on pic­ture bright­ness is easy to under­stand because there’s a pos­i­tive cor­re­la­tion, and they move in tan­dem. For exam­ple, when you dou­ble the expo­sure dura­tion, it dou­bles the bright­ness; when you halve the ISO, it halves the bright­ness. It’s a sim­ple rela­tion­ship that stu­dents in my pho­tog­ra­phy work­shops grasp with ease.

The 100 mm lens can pro­vide an expo­sure equal to its 50 mm coun­ter­part by open­ing its aper­ture to col­lect four times more light, assum­ing its aper­ture can open that much. Since aper­tures are rough­ly cir­cu­lar, we can deter­mine how big they should be by cal­cu­lat­ing the area of a cir­cle. An entrance pupil with a 25 mm diam­e­ter has an area of about 491 mm^2. The 100 mm lens would need an entrance pupil with an area of 1,964 mm^2, which is formed by a cir­cle with a 50 mm diam­e­ter. Sim­ple, right?

Diffraction In photography, diffraction is the interference of light waves with one another caused by their passage through a lens aperture. The narrower the aperture, the more the diffraction. The spreading light waves' interactions cause interference patterns around the Airy disk which is recorded on a digital sensor as a loss of sharpness in an image. In UVIR photography, a key fact to note is that longer IR wavelengths spread more at a given aperture than shorter Visible or UV wavelengths. Hence IR shots are more prone to the effects of diffraction and UV shots less so. Thus, for example, if you make a Visible light photo with a sensor & lens combo that begins to show diffraction blur past f/8, then you might have to open up your lens to f/5.6 (or larger) to shoot a sharp IR version of the same photo. On the UV side, you might be able to stop down to f/11 (or smaller) and still stay sharp. Opening up in IR to reduce diffraction must be balanced against the need for stopped-down depth of field. Some diffraction can be compensated for in the editor by various sharpening tools.