Discussion on cameras and lenses for UV

[nfoto]

Looks like the Cine lens you refer to has gone through the roof in terms of asking price.....

 

Do note that using this or any other lens without a CPU on a V1 is fraught with difficulties. This whether or not the camera is modified. You have no means of activating the focusing magnifier thus unlikely to get precise focus.

 

The Panasonic GH-2 with the Coastal 60 APO is compact enough for me when it comes to a field kit for UV. This setup further has the benefit of using rear-mounted filter so in principle any F-mount lens can be tested and tried for its UV performance.

[igoriginal]

Looks like the Cine lens you refer to has gone through the roof in terms of asking price.....

 

Oh, it's been around that price range for years (averaging $250 to $325), even BEFORE I discovered its UV-transmission abilities.

 

Although I have been fortunate to pick up one copy of the lens for $89 USD (I have three copies). The other two, I payed $125 and $289 for. The $289 was justified, because that final purchase was of one that was in MINT (new old stock) condition. Unused, and in original box / case. No cosmetic imperfections, no scratches on the body, no dents, no tarnishing, not a single indication of use. Looks like it came off of the assembly line, just yesterday. ;)

 

(I do, however, feel that anything over $150 is a bit inflated, UNLESS it is mint / near mint. I don't know, maybe this is some kind of special glass or something, because I cannot understand otherwise why it would be so high in price. It really IS a surprisingly good lens, though. Contrasty, and sharp, for a simple, uncoated triplet. I believe that part of the reason that flare is controlled so well, is because the front element is so deeply recessed into a hood-like front).

 

I also wanted to mention that there is an F/1.9 version of the Wollensak Velostigmat 1" (25mm) Cine lens, as well. Practically identical body and build (chrome body, with the dark copper-colored hood-like brass front section). I have one copy of this variant, as well. And, although I have not tested its UV transmission yet, I have reasons to suspect that it very likely DOES have the same UV transmission as the F/1.5 variant. My assumption from this has to do with the fact that I have disassembled and then reassembled both variants - the F/1.5 and the F/1.9 - and they BOTH seem to have what looks like identical glass / element configurations (a triplet design, I believe ... with no discernible cementing, and absolutely no coatings / bare glass). But don't take my word on that, until I test the F/1.9 variant in my possession, first.

 

(I see an F/1.9 right now on an open Ebay auction, with just two bidders for the time being, and so far it is $15 USD. http://www.ebay.com/...5-/201040309025 ). However, like I said before, I *HAVE NOT* tested the F/1.9 variant for its UV transmission, yet. But I plan to. I suspect that it WILL have similar UV transmission, but I cannot promise it until confirmation.

 

 

Do note that using this or any other lens without a CPU on a V1 is fraught with difficulties. This whether or not the camera is modified. You have no means of activating the focusing magnifier thus unlikely to get precise focus.

 

Ahhh. I didn't know that the 'Nikon 1' systems didn't have a focus-magnification / focus-assist function for manual-focus (no electrical communication) lenses. Bummer.

 

So, I suppose that I should just stick to my Micro-4/3 systems (Panasonic / Olympus), for UV-only work, as far as compact cameras go?

 

NOTE: Keep in mind, though, that because the Wollensak Velistigmat F/1.5 (and F/1.9) have such a LARGE maximum aperture ratio, it is MUCH easier to focus than most other lenses with smaller maximum starting apertures. The images are VERY bright at F/1.5 (and even F/1.9), even with a dark UV glass on the lens.

 

So, this is another advantage of this lens: First, focus with the aperture wide open (F/1.5 or F/1.9), then stop down to F/8 and shoot. No problems! BRIGHT glass (FAST aperture) makes a HUGE difference in aiding with pre-focusing of a manual lens, before stopping down.

 

(The aperture is also "clickless." No click stops, just smooth all the way through.)

 

Also, the one EXTRA good function on my full-spectrum-converted mirrorless Pentax K-01 that I have in my UV-photography arsenal, is that it ALSO has a function called "focus peaking", which is IMMENSELY useful when implementing manual-focus lenses. Are you familiar with this relatively novel new function? It's VERY useful for attaining perfect focus, especially with DARK uv-based photography! I believe that some Sony mirrorless models are also employing "focus peaking", for assistance with manual-focus lenses. But I am not sure which other models have already adopted this wonderfully useful utility. Perhaps others?

 

It's a PERFECT tool, for UV work!

[igoriginal]

This video is an EXCELLENT example of the "focus peaking" utility now being used for helping with focusing manually.

 

This is a WONDERFUL tool, especially for UV photographers! Because it will help you manually focus in darker scenes.

 

http://www.youtube.com/watch?v=yWHDEOLREGk

[colinbm]

Thanks Iggy

I need all the help I can get with focus.

Just got to wait for Sigma to catch up

Col

[igoriginal]

Absolutely, Col! You're welcome.

 

Actually, I'm reading that Canon is also now starting to phase in the "focus-peaking" technology! Exciting news! Shouldn't be long, until this very useful feature makes its way into more camera systems.

 

One more video. Here is how my Pentax-K01 does focus peaking. Especially pay attention to the part where the guy is using "focus-peaking" for the flowers (which will apply to us UV photographers). This is just SO USEFUL! And it will be THAT much more useful, for UV work!

 

 

http://www.youtube.com/watch?v=YKnGzd1RLr8

[nfoto]

No focus peaking system can be more precise and accurate than what the underlying AF module(s) delivers.

 

With a smaller format one actually requires even higher focusing precision just to keep up the performance compared to the larger formats. This has been well understood since the days of large-format film cameras and the relationships don't change this basic fact.

[nfoto]

This topic is established as a placeholder for the various technically orientated post in the Felicia thread here http://www.ultravioletphotography.com/content/index.php?/topic/702-felicia-amelloides-visible-and-uv-a/.

 

To achieve a continuity in the thread, I've taken the liberty of copying the second and third post in that thread into this one.

[Alex H]

Thanks Bjørn, for separating this discussion from the original post. I missed it.

 

Answering one of the questions posted here:

 

My current main UV camera is full-spectrum modified Sony NEX-6, preceded by NEX-5N, NEX-3 and A100.

[nfoto]

I procrastinated in making the split, which only came back to myself as creating more work :D

[Andrea B.]

(Thanks, Bjørn, for separating this thread.)

 

Ah, yes, Alex - I knew/remembered there was someone "out there" who was making good use of the Sonys for UV. And it is you!! :D :D :D

 

I've been on the point of purchase of a NEX, or similar Sony, multiple times, but other purchases keep getting in the way, so-to-speak, as there is only so much discretionary cash for this little UV 'obsession' we all share. The "other purchases" being stuff like dentistry, car repair, etc.

 

My reason for looking around for other non-Nikon bodies is primarily to accomodate the various native flange focal distances (FFD) of some of my UV capable lenses in order to achieve infinity focus. To that end, I converted a Pentax K5 for my little collection of Asahi/Pentax lenses. The K5 is a very nice camera for UV/IR work as our member Dave O can attest. Back when I still had the Tech job and could afford such things, I managed to snag an Asahi Ultra-Achromatic-Takumar 85/4.0. Now it finally has a home camera to be useful on.

[Andrea B.]

Being the odd man out as always, I don't seem to be that fond of focus peaking so far. It kinda "gets in the way" to me. Can it be turned off on those cams which have it? I haven't totally made up my mind on it however as more experience is needed.

[Andrea B.]

BTW, as long as we are having a 'chatty' thread :D I want to let everyone know that I'm in process of updating the Sticky Lens List. It is taking a while to gather up all the references from the threads over on Nikongear, but I'm getting there.

So Igor - your nifty Wollensak find will get on the list soon!!!!

 

Question about that Wollensak, how are the corners? Some cine lenses have a kind of "swirl" in the corners. (Is there a technical term for that?)

[igoriginal]

No focus peaking system can be more precise and accurate than what the underlying AF module(s) delivers.

 

Auto-focusing is definitely FASTER than any human can manually focus.

 

Nevertheless, why are we even comparing AF to Focus-peaking? Focus-peaking was specifically designed to assist with focusing lenses that DO NOT have AF communications. And many UV-capable lenses are only MANUAL lenses, right? So why even the comparison? This was never a battle of AF versus manual-focusing. This is me explaining HOW HELPFUL focus-peaking can be, when there is no way to auto-focus.

 

I procrastinated in making the split, which only came back to myself as creating more work :D

 

I apologize for giving you that extra work. :D But I am grateful that you made the split, so that we may have better organization of topics / subjects on this site. You are truly a COMMITTED administrator, and I THANK you for that!

[igoriginal]

My reason for looking around for other non-Nikon bodies is primarily to accommodate the various native flange focal distances (FFD) of some of my UV capable lenses in order to achieve infinity focus. To that end, I converted a Pentax K5 for my little collection of Asahi/Pentax lenses. The K5 is a very nice camera for UV/IR work as our member Dave O can attest. Back when I still had the Tech job and could afford such things, I managed to snag an Asahi Ultra-Achromatic-Takumar 85/4.0. Now it finally has a home camera to be useful on.

 

Which reminds me of one OTHER reason why I love the Micro-4/3 system so much: It's native flange distance is so short, that virtually almost ANY non-native lens can be adapted to it, and STILL keep infinity focus. This saves a lot of money. In other words, instead of buying a camera for ever native flange / register distance, a SINGLE camera with a very short native flange / register distance can accept lenses from all other systems with LARGER flange / register distances, and STILL keep infinity focus for all of the non-native lenses. Of course, that's for people who are left with no choice but to economize. It's certainly not the ONLY way, as you so clearly pointed out. But it's the most COST-EFFECTIVE route, though.

 

(The Sony NEX / mirrorless systems also have a relative short flange / register, although a bit larger than the Micro-4/3 system).

 

Speaking of the Pentax K-5, were you aware that the Pentax K-01 camera is essentially a K-5 (on the inside), but adapted to a mirrorless body? In other words, the Pentax-01 is actually a K-5, internally. It is built on the same system, the same sensor, the same parts, and the same processing engine. This is one of the reasons why so many photographers "in the know" snapped up all of the Pentax K-01 stocks like candy, back when it was introduced and most consumers had no clue that at was an actual K-5 in disguise, but at 1/3 the price! The only difference is that it was a mirrorless version of the K-5.

 

(However, once more people became aware of this fact ... the price of Pentax K-01's jumped up, even HIGHER than their initial MSRP / launch prices! Today, the Pentax K-01 is actually selling for nearly DOUBLE the price of its official RELEASE / LAUNCH price!!! Averaging between $389 and $449, instead of the $249 that I bought mine fore! Crazy, huh? That doesn't happen very often ... but there was clearly a BARGAIN LOOPHOLE, and when people caught wind that the Pentax K-01 was a K-5 in disguise, then prices shot up.)

 

So, for these reasons, is why I had my Pentax K-01 converted to full-spectrum, instead of my K-5: I get the SAME image quality, capabilities and performance of the K-5, but with full-time live-view and in-camera UV white-balancing. Bottom line is: Whatever the Pentax K-5 can do with UV work, the Pentax K-01 can do, and better. For these reasons, I kept my K-5 unconverted, and saved it for my PAID work instead.

 

Even so, at the hiked-up prices, I STILL consider the Pentax K-01 one of the BIGGEST BANGS FOR THE BUCK, especially for UV work! But that's just my opinion.

 

Being the odd man out as always, I don't seem to be that fond of focus peaking so far. It kinda "gets in the way" to me. Can it be turned off on those cams which have it? I haven't totally made up my mind on it however as more experience is needed.

 

I had the same reservations, at first. Was wary of it. Now, my concerns have been laid to rest, and replaced with gratitude for this very useful tool.

 

Yes, focus-peaking can be turned on / off, at will. Easily. Just as any other function.

 

However, IF and WHEN I need it most (to help me focus in particularly DARK scenes that are hard to assess by eyesight alone, especially with dark UV glass in front of the lens), I cannot ever say that it "gets in the way" any more than the dark UV glass does. :D Quite the opposite, the focus-peaking has SAVED my photos, in many times where I probably would have missed the mark, or would have taken longer (tedious trial and error) to finally nail the right focus.

 

Thus, have no fears! It's a selectable option that can be turned off, at worst ... and a VERY USEFUL TOOL at best.

[igoriginal]

BTW, as long as we are having a 'chatty' thread :D I want to let everyone know that I'm in process of updating the Sticky Lens List. It is taking a while to gather up all the references from the threads over on Nikongear, but I'm getting there.

So Igor - your nifty Wollensak find will get on the list soon!!!!

 

Question about that Wollensak, how are the corners? Some cine lenses have a kind of "swirl" in the corners. (Is there a technical term for that?)

 

Thank you so much for all you do! Much, much appreciated!

 

As for the question about certain cine lens, and the "swirl" phenomenon which you refer to:

 

The phenomenon is commonly referred to as the "Petzval effect", named after the Hungarian scientist, optician, mathematician and inventor Joseph Petzval, who first introduced the "double-doublet" optical formula (4 elements, in 2 groups), back in the mid 1800's.

 

And it is true, many double-doublet optical designs made well into the 1930's and early 40's continued to exhibit this "swirly bokeh" phenomenon, which is actually seen as a more POSITIVE (artistic) attribute, rather than a negative issue. In fact, it is now a highly-sought effect, for portraiture in particular.

 

This is because there is actually no distortion of the actual subject in the FOREGROUND (which depth-of-field that one focuses on). The "swirl" is only created with the much more distant, O-O-F (out-of-focus) objects in the BACKGROUND. And then, this requires the aperture to be WIDE OPEN, particularly if it's a very BRIGHT aperture (under F/2.8). But once one stops down, the "swirly bokeh" background is negated.

 

Even so, in order to obtain this usually pleasing, aesthetic and often desirable bokeh / background swirl ... the background has to contain much overlapping textural structure (such as dense tree branches), and other thick, high-contrast and complex patterns. So, the "bokeh swirl" only occurs under certain conditions.

 

Again, this is NOT actual "corner distortion" of IN-FOCUS subjects, but rather the BACKGROUND swirl of OUT-OF-FOCUS objects. The actual subject in the foreground that is IN-FOCUS remains sharp and distortion free.

 

So, what causes this: The PRECISE mechanisms are still heavily debated and contended, but the general consensus is that it is a combination several dynamics combined:

 

1. A highly CURVED-FIELD of view (as opposed to FLAT-FIELD lenses).

 

2. The placement of the aperture in the center of the body, in between the two doublet groups.

 

3. The resulting "partial / incomplete astigmatic correction" phenomenon referred to as "THIRD-ORDER ASTIGMATISM" that is inherent to a double DOUBLET optical design.

 

However, if that's the case, then other variables must be at play, because I believe I have seen some "swirly bokeh" present in some TRIPLET optical formulas, as well. But I could likely be wrong, and what I assume to be air-spaced triplets are actually double-doublets, too.

 

In short, do the Wollensak Velostigmat 1" (25") F/1.5 and F/1.9 variants generate "swirly bokeh" out-of-focus patterned backgrounds? Yes, they do. And they do it beautifully, as far as I am concerned.

 

And while I agree that this optical "effect" is not for EVERY scene (which is why I also carry OTHER uv-capable lenses), it is nevertheless yet ANOTHER artistic expression in photography, among many.

 

Here is an example of this "Petzval effect" occurring with my Wollensak, when I took VISIBLE and UV-A photographs of a flower against a dense patch of grass in the out-of-focus background:

 

(The UV-only photo was taken HAND-HELD, at 1/10 sec, with aperture at F/1.5 ... which is ANOTHER advantage of a FAST lens: No long exposure or tripod necessary.)

[colinbm]

Wow, that is very striking Iggy.

It is like a whirlpool :D

Col

[nfoto]

Auto-focusing is definitely FASTER than any human can manually focus.

 

Nevertheless, why are we even comparing AF to Focus-peaking? Focus-peaking was specifically designed to assist with focusing lenses that DO NOT have AF communications. And many UV-capable lenses are only MANUAL lenses, right? So why even the comparison? This was never a battle of AF versus manual-focusing. This is me explaining HOW HELPFUL focus-peaking can be, when there is no way to auto-focus.

 

 

Focus peaking is not a rabbit pulled out of a hat by magical means. It is based upon AF technology incorporated in the camera. Hence my comment.

[igoriginal]

Wow, that is very striking Iggy.

It is like a whirlpool :D

Col

 

Col, that's a perfect description! You've got a way with words. Excellent! Maybe it should be called "whirlpool bokeh", and not "swirly bokeh", simply because a "swirl" can still be asymmetric and off-axis ... whereas a "whirlpool" suggests an on-axial / centralized, symmetrical circular pattern, which is what is going on, here.

 

Good call!

[igoriginal]

Focus peaking is not a rabbit pulled out of a hat by magical means. It is based upon AF technology incorporated in the camera. Hence my comment.

 

Well, yes. It's based on contrast detect auto-focusing algorithms ... and the "focus peaking" simply is a manually-operated and visual projection of this focusing algorithm unto the live-view / mirror lock-up screen mode (or alternatively, an EVF-based / mirrorless system).

 

I get it. :-)

 

But, I never implied that this was some voodoo or magic. I simply state that it has been proven to be USEFUL. That's all. And that's not just my opinion. This function has been praised by many others as a "game changing" feature, when adapting old (legacy) manual-focusing lenses ... especially for videography, where the pre-set / clickless apertures of vintage lenses are choice (generating no internal noise, from aperture changes, unlike the "click" apertures of more modern lenses) ... or worse, no external aperture rings at all (in some of the newest lenses), which brings down production costs of lenses, but is not desirable for certain videography projects.

 

Nevertheless, it's an ingenious idea ... even if based upon existing technology. And it should also prove to be a game-changer especially for UV photographers, given the difficulty of focusing with darker filters. I know for certain that it has made a dramatic difference in my focusing success rate, when adapting manual-focus lenses for UV work.

 

But, I get what you are saying. Thanks!

[igoriginal]

By the way, speaking of the very unique "Petzval Effect" produced by the double-doublet design (with aperture located midway in the body, in between the two doublet groups), I just learned that a company obtained patent rights in reproducing the original Petzval formula, in Nikon and Canon mount cameras, for professional portraiture work!

 

This means that now there is a larger image-circle version of this cine lines, that should cover the larger image circles of APS-C and FF cameras! Wonderful!

 

So, I am wondering if this Petzval lens has a UV-capable transmission, even though it is a modern "spin" on it? Hmmm. :D

 

(I am guessing that it will all be dependent on the type of lens adhesives that are employed in the cementing together of the front and rear doublets. We all know that cementing will make or break a lens's UV transmission capabilities.)

 

Nevertheless, a link below, to the site which is offering this Petzval authentic re-issue:

 

http://microsites.lo...m/petzval-lens/

[igoriginal]

Well ... I just read the "technical information" section of the site that is selling the Petzval authentic re-issue.

 

It states:

 

• Are the Petzval Lenses coated and is the lens waterproof/weatherproof?
   
  All Petzval lens elements are multi-coated in a special formula to protect them. However, we cannot disclose the full details of the materials due to industry standards.
  Like most manual lenses, the Petzval is not weather/waterproof. However, to prevent dust particles getting into the aperture slots, there is a lining material to cover the Waterhouse aperture slots. The Lens also comes with a special ‘blank’ aperture ring which can be inserted to cover the aperture slot when the lens is not in use.
  The lens can also be taken apart to clean inside if any dust happens to get in; however, we recommend that this type of lens cleaning is only done by a qualified lens technician to avoid damage to your wonderful lens.
  

 

So, it looks as though UV-transmission capability will not likely be there, given the "multi-coating" application. :D I definitely won't fork out a whole wad of cash, just to gamble on that slim chance.

 

However, if I ever buy a FF-format camera, I will invest in this lens for portraiture work, since there is no other Petzval-effect lens designed for a full-frame sensor that I know of. And from what I can gather, this particular Petzval release is especially optimized for FF format.

 

(I do wonder, though. Perhaps the company is willing to fill a special order, and have it leave out the lens coatings for a customer? I could call, and find out, if it ever comes to that.)

[Alex H]

By the way, speaking of the very unique "Petzval Effect" produced by the double-doublet design (with aperture located midway in the body, in between the two elements groups), I just learned that a company obtained patent rights in reproducing the original Petzval formula, in Nikon and Canon mount cameras, for professional portraiture work!

 

This means that now there is a larger image-circle version of this cine lines, that should cover the larger image circles of APS-C and FF cameras! Wonderful!

 

So, I am wondering if this Petzval lens has a UV-capable transmission, even though it is a modern "spin" on it? Hmmm. :D

 

(I am guessing that it will all be dependent on the type of lens adhesives that are employed in the cementing together of the front and rear doublets. We all know that cementing will make or break a lens's UV transmission capabilities.)

 

Nevertheless, a link below, to the site which is offering this Petzval authentic re-issue:

 

http://microsites.lo...m/petzval-lens/

 

The Petzval effect is something not very well defined in the internet discussion fora, and, in my humble opinion, is highly overrated. The "swirl" or, as you now say, "whirlpool", OOF rendering is not exclusive to Petzval-based lens designs. In fact, I have a high quality Petzval lens that does not show that effect at all. On the other hand, please look at the Zeiss Biotar / KMZ Helios lenses, many of which have "swirly" OOF rendering - their optical design is very different from typical Petzval formula. And you just said yourself that your Wollensak is "Contrasty, and sharp, for a simple, uncoated triplet." So, Petzval effect has very little to do with number and arrangement of glass elements in the lens.

 

Now, as far as the Lomography Petzval lens goes, they did not need to obtain any patent rights from 1840. I will not be surprised that the company just cashed in on their users and are basically remaking one of the old GOI designs, for example OP-5-2 85mm F/2 lens for cinema projection, which is based on petzval design. I would love to be proved wrong. Please consider this particular paragraph as my own speculations that has no factual proof to back it up.

 

I do not know how the new Lomography Petzval lens performs in UV. All I know is there is no reason to generalize lens performance based on limited knowledge of its design. We only know it is three elements in four groups. We do not know the optical properties of the glass used to make it, and the properties of lens cement used for the front doublet. And we do not know what type of coating they use.

 

I do have something to say about the UV transmission of lenses, which design is similar to the original "Petzval Portrait Lens". I have one lens with the similar optical construction and it does transmit down to at least 325nm. Though, I would not expect other lenses with similar optical construction to perform in the same way.

 

It would be very good if we, in this particular forum, will avoid any generalization, and just speak from our own personal experience supported by some factual information. This forum is very specialized. Publications in this forum, at least in some of its sections, are to be considered as close to "peer-reviewer publication" as possible, so I think it will be for the benefit for all of us to avoid speculations as much as possible.

 

EDIT - wrong grammar and misprints were corrected.

[igoriginal]

The Petzval effect is something not very well defined in the internet discussion fora, and, in my humble opinion, is highly overrated. The "swirl" or, as you now say, "whirlpool", OOF rendering is not exclusive to Petzval-based lens designs. In fact, I have a high quality Petzval lens that does not show that effect at all. On the other hand, please look at the Zeiss Biotar / KMZ Helios lenses, many of which have "swirly" OOF rendering - their optical design is very different from typical Petzval formula. And you just said yourself that your Wollensak is "Contrasty, and sharp, for a simple, uncoated triplet." So, Petzval effect has very little to do with number and arrangement of glass elements in the lens.

 

Indeed, my Wollensak does *appear* like an air-spaced triplet. But, I could be wrong. Given the very small size of the glass, it is difficult to analyze based on my abilities for testing at the moment. I may, in fact, have a small doublet involved in the optical formula, rather than a simple, air-spaced triplet.

 

Nevertheless, this is why I stated that the "cause" of this effect is still "heavily contended and debated."

 

I did, however, mention that it could be due to a severe curved field, and not necessarily only a partially-corrected (but incomplete) astigmatism. It could be many variables, coming together, indeed. I agree.

[igoriginal]

Now, as far as the Lomography Petzval lens goes, they did not need to obtain any patent rights from 1840. I will not be surprised that the company just cashed in on their users and are basically remaking one of the old GOI designs, for example OP-5-2 85mm F/2 lens for cinema projection, which is based on petzval design. I would love to be proved wrong. Please consider this particular paragraph as my own speculations that has no factual proof to back it up.

 

 

What I mean by obtaining "patent rights", is not in the optical formula itself, but the actual design authentication (mimicry) of an original Petzval lens BODY / CASE appearance, as well as the extrusion points and decorational / ornamental shaping of the metal. And also, one of the original "Petzval" stamp designs on the barrel, as was once stamped on the original release of this lens design.

 

 

It would be very good if we, in this particular forum, will avoid any generalization, and just speak from our own personal experience supported by some factual information. This forum is very specialized. Publications in this forum, at least in some of its sections, are to be considered as close to "peer-reviewer publication" as possible, so I think it will be for the benefit for all of us to avoid speculations as much as possible.

 

Ahhh, but do scientists not first commence a process of obtaining additional knowledge, by first gathering incidental / observational / circumstantial evidence (hypotheses)?

 

I am not saying that I am going to go on and on in this direction without additional testing ... but at the same time, how are we to even discover additional UV-capable lenses, it we just remain complacent?

 

Does not a very specialize field deserve additional data / discoveries, if they are there? What exactly is a forum for, if we just sit on our collective arses and languish with what is simply already known, rather than constantly push boundaries and propose new ideas? :D

 

After all, this thread topic has just been changed to "Discussion on cameras and lenses for UV", so this is what I am doing: Considering new / undiscovered possibilities. How is that a bad thing? :D

 

I don't know about the rest of you, but I plan to find things that remain undiscovered, for the benefit of others. And all new / undiscovered things always START with "speculation." My discovery of the Wollensak Velostigmat 1" 25mm F/1.5 as being UV-capable all started with "speculation", based on prior experience with similar lens designs.

 

(Knowledge doesn't fall on someone's lap, already complete.)

[igoriginal]

I do have something to say about the UV transmission of lenses, which design is similar to the original "Petzval Portrait Lens". I have one lens with the similar optical construction and it does transmit down to at least 325nm. Though, I would not expect other lenses with similar optical construction to perform in the same way.

 

Ahhh, precisely. And if one "suspects" that a lens might turn out to be UV-capable, then shouldn't it be considered? That consideration starts with "speculation", followed by obtaining, then testing.

 

I plan to be a person who speculates, obtains, and then tests ... so that others may continue to benefit from what we find. :D

 

(And yes, I greatly welcome peer review from individuals like yourself. Which is why I am grateful that you chimed in, and added in additional considerations. Thank you so much! This helps a lot, on my journey / exploration!)

 

My next goal, is to test the Wollensak Velostigmat *F/1.9 aperture* variant of the F/1.5 version, and see if its UV-transmission properties are similar and / or identical.

 

I also hope to soon acquire a spectrometer of my own, as I have been saving for a good one for a while, now.