Leitz glass transforms uv in to visible light

[frame-it]

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4 hours ago, dpitt said:

Older glass probably had a more limited bandwidth for UV wavelengths than the current glass.

when buying all my IR cameras, i did a lot of research on UV cameras as well, the choice of lenses is severely limited to very old~old lenses with very few elements and no coatings

OR the very expensive [and controlled supply] coastal optics dedicated UV lenses OR the nikon 105 UV lens

https://www.jenoptik.us/products/optical-systems/customized-and-standardized-objective-lenses/multispectral-objective-lenses

 

http://www.company7.com/nikon/lens/0105f4.5uv.html

 

Some Lens Coatings block UV light, and anyway the sensor blocks almost all

https://www.lenstip.com/113.15-article-UV_filters_test_Hoya_72_mm_HMC_UV-0.html

 

for film cameras + using certain older lenses, UV filters make sense.

https://kolarivision.com/uv-filter-effectiveness-article/

 

 

 

Edited November 20, 2023 by frame-it

[Mustafa Umut Sarac]

30 years ago , I got my IIIF and Summitar. Seller showed two options , one coated summitar , second uncoated ww2 summitar. I bought uncoated and took my best pictures. I havent seen such a quality anywhere in my life. UNBELIEVABLE.  After 30 years of research , reaching rare papers , chatgpt , I am sure that was the thorium glow to uv. Thorium glasses , later lanthanide glasses , % 90 fluor containg kodak ektar f: 111 f: 1.5 , all the same , extremelly long tonal grades at normal light but they go wild under filament bulb light at night. Do your best and buy one of these lenses

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[Anbaric]

I have a Summitar and it's certainly a very good lens, but this design doesn't have thorium glass, except for the very rare 'Summitar*', which is a prototype collapsible Summicron in disguise and looks different to a 'real' Summitar. The collapsible Summicron continued to use thorium in early production (these are the lenses where the glass yellows with age), but they switched to LaK9 lanthanum glass later and changed the design slightly. Whatever makes the Summitar unique, it isn't thorium.

[Mustafa Umut Sarac]

When compared to summilux price , summitar is peanuts. I was lucky , my first and second lens were summitars. Find a uncoated one from ww2 and buy for 500 dollars. You sell it later.

I think it was the best lens in history. You cant describe the lens , for every occasion , its best , better.

[frame-it]

17 minutes ago, Mustafa Umut Sarac said:

When compared to summilux price , summitar is peanuts. I was lucky , my first and second lens were summitars. Find a uncoated one from ww2 and buy for 500 dollars. You sell it later.

I think it was the best lens in history. You cant describe the lens , for every occasion , its best , better.

so which film are you shooting with your summitar?

[250swb]

3 hours ago, Mustafa Umut Sarac said:

When compared to summilux price , summitar is peanuts. I was lucky , my first and second lens were summitars. Find a uncoated one from ww2 and buy for 500 dollars. You sell it later.

I think it was the best lens in history. You cant describe the lens , for every occasion , its best , better.

I do have both an uncoated and coated Summitar and tbh I can only see a difference between them if shooting into the light or shooting lights and reflections. At that point the uncoated lens starts to glow turning into flare as it finally faces the light source. Which is what you'd expect from any uncoated lens. You could try using a lens hood, they can help to decontaminate a 'radioactive lens' of the stray light phenomena.

[pgk]

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8 hours ago, Mustafa Umut Sarac said:

30 years ago , I got my IIIF and Summitar. Seller showed two options , one coated summitar , second uncoated ww2 summitar. I bought uncoated and took my best pictures. I havent seen such a quality anywhere in my life. UNBELIEVABLE.  After 30 years of research , reaching rare papers , chatgpt , I am sure that was the thorium glow to uv. Thorium glasses , later lanthanide glasses , % 90 fluor containg kodak ektar f: 111 f: 1.5 , all the same , extremelly long tonal grades at normal light but they go wild under filament bulb light at night. Do your best and buy one of these lenses

Really? Its an old lens design with the usual mix of uncorrected aberrations, field curvature, lowering close-up performance typical of its era. You may well like the combination and the results these provide but the Summitar will not have a better tonal range (grade?) than more modern lenses. You might want to live in a fantasy world of the 'best' lenses being older but reality has a rather different take on things.

[willeica]

31 minutes ago, 250swb said:

I do have both an uncoated and coated Summitar and tbh I can only see a difference between them if shooting into the light or shooting lights and reflections. At that point the uncoated lens starts to glow turning into flare as it finally faces the light source. Which is what you'd expect from any uncoated lens. You could try using a lens hood, they can help to decontaminate a 'radioactive lens' of the stray light phenomena.

I actually like the de-saturated look from uncoated lenses. In some cases I have both coated and uncoated versions of the same lens and I like what I get from both. I have also used a brass lens from the 1870s on a bellows and I liked the look from that as well.  In fact it yields a saturated look which might be down to the yellowing of the lens with age possibly caused by balsam glue. I don't mind 'glow' either. Every lens has its own charms. Sometimes you can characterise what might be regarded as 'technical faults' as 'character'.

Going back to my earlier points we seem to be ignoring the properties of the plates or films that were used. This is not a problem today, unless we are using a deliberate old process, but many years ago this was more of an issue and lens manufacturers had to contend with this and design lenses with this in mind. The introduction of standard ratings for films/plates and apertures on lenses did a lot to resolve such issues, but that took many years to achieve - see the table from 1952 which I posted above. Once those issues were out of the way lenses could be tested against standard exposure criteria and solutions could be found. All that being said, the 'simple' 50mm Elmar is a remarkable lens which rarely flares and produces very consistent results. However, Barnack continued to insist that it was tested and improved for many years after it was introduced onto the market. There many changes to the lens, even before Barnack passed away in 1936, but most people would not notice them.

I'm still don't really know what Mustafa's point is. I have both coated and uncoated Summitars and while they are fine lenses they are probably not as good as my early (non radiocative , but yellowed) collapsible 5cm Summicron, but that in turn is not as good as later 5cm Rigid and DR lenses which I also have. I could go on, but these are all very fine lenses which are capable of providing good results even on a modern digital M camera. If Mustafa likes the look that the Summitar produces that is fine with me, but I struggle to see the connection with the Wet Plate paper as that does not cover all of the issues with early materials. 

William 

[pgk]

Looking through the photographic newspapers from the early days of photography makes it clear that vast amounts of experimentation were going on. Early plates were often coated by their users and later by one of the many firms which offered them. All claimed to have made improvements (and certainly 'sensitzers' are used to boost responsiveness and some may well have had an effect). Add in varying exposure, no standardisation of processing and so on and it is fairly obvious that comparing the results objectively (quantitatively) is nigh on impossible. A friend who studied when I did tried to recreate early film (he even made cellulose base until the lecturers put a stop to him doing so) and carry out sensitometric tests on it, but these were valide only for a modern recreation from refined modern materials whilst in the past even ingredients would have been variable in terms of theur purity and the impurities that they contained. To be honest I am in awe at how many early photographers succeeded the quality of results that they did. Carelton Watkins was apparently pleased to get two photos a day and carried a ton and a half of gear into Yosemite to do so. Today a 'phone will produce a phot which he would have been astounded by.

[frame-it]

4 minutes ago, pgk said:

(and certainly 'sensitzers' are used to boost responsiveness and some may well have had an effect).

you mean like: The emulsion is more sensitive to light in the blue (UV) end of the spectrum and render colours and skin differently from a digital sensor or film.

via

https://intrepidcamera.co.uk/blogs/guides/rikard-osterlunds-guide-to-wet-plate-collodion

[jaapv]

14 hours ago, frame-it said:

when buying all my IR cameras, i did a lot of research on UV cameras as well, the choice of lenses is severely limited to very old~old lenses with very few elements and no coatings

OR the very expensive [and controlled supply] coastal optics dedicated UV lenses OR the nikon 105 UV lens

https://www.jenoptik.us/products/optical-systems/customized-and-standardized-objective-lenses/multispectral-objective-lenses

 

http://www.company7.com/nikon/lens/0105f4.5uv.html

 

Some Lens Coatings block UV light, and anyway the sensor blocks almost all

https://www.lenstip.com/113.15-article-UV_filters_test_Hoya_72_mm_HMC_UV-0.html

 

for film cameras + using certain older lenses, UV filters make sense.

https://kolarivision.com/uv-filter-effectiveness-article/

 

 

 

If this were completely true, I wonder how I was able to do good UV photography using the M8 an Summarit 1.5 50. (coated)

[frame-it]

31 minutes ago, jaapv said:

If this were completely true, I wonder how I was able to do good UV photography using the M8 an Summarit 1.5 50. (coated)

dunno, but the m8 sensor probably let in a lot of UV?

[jaapv]

Possibly and the Summarit let it through ( no Absorban) 

[dpitt]

I thought the M8 is mostly too sensitive to IR light?
So it is extra  sensitive to UV also?

Of course the filters designed to use with it are UV/IR, but I always thought the UV cut off was mostly just a bonus on top of the IR cut.

[Mustafa Umut Sarac]

Dear Friends , we are not talking about how ultraviolet radiaton transit through lens. And when it comes to sensor , if the uv reaches to sensor , the answer will not be visible.

We are talking about different thing , when the uv hit to the radioactive , lanthanide , leaded glass or fluoro glass , I repeat when the uv hit these glasses , it makes a visible glow.

The film or digital sensor records it. Now you should find the amharic paper and my wet plate comparison paper IN THIS THREAD.You should read them carefully and learn what uv sensivity is and what compares with panchromatic film.

[pgk]

7 hours ago, frame-it said:

you mean like: The emulsion is more sensitive to light in the blue (UV) end of the spectrum and render colours and skin differently from a digital sensor or film.

No. Specific trace chemicals are used to increase film sensitivity. I can't remember the details but I think that some were contained in the gelatine used for later emulsions and were later used as additives in a more controlled and quantitative way.

[pgk]

6 minutes ago, Mustafa Umut Sarac said:

We are talking about different thing , when the uv hit to the radioactive , lanthanide , leaded glass or fluoro glass , I repeat when the uv hit these glasses , it makes a visible glow.

If you are talking about UV exceited visible light fluorescence then tat would simply make the glass itself glow and would fog the image reducing contrast. I can't imagine that this would be a desirable attribute and it would certainly not be beneficial in any way.

[Mustafa Umut Sarac]

15 minutes ago, pgk said:

If you are talking about UV exceited visible light fluorescence then tat would simply make the glass itself glow and would fog the image reducing contrast. I can't imagine that this would be a desirable attribute and it would certainly not be beneficial in any way.

Have you ever heard something like optical design ? 

[jankap]

vor 1 Stunde schrieb Mustafa Umut Sarac:

Have you ever heard something like optical design ? 

Could you underlay your opinion with pictures?  We talk here about non Apo lenses. That means, that light of a small band of wavelength produces a sharp picture. Outside this band, light of other wavelengths give unsharp pictures, if the lens would be transparent for it.

If UV light would interact with the glass somewhere in the lens, it would be emitted outside the optical design. Giving perhaps flare, diffuse light, light in undefined directions. 

This statement I don't understand: "Your subject should show her face muscles streched. Bulbs should be 4 meters far. " Do bulbs - incandescent light - emit UV light? 

Edited November 21, 2023 by jankap

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[250swb]

2 hours ago, Mustafa Umut Sarac said:

Have you ever heard something like optical design ? 

Have you? Your entire premise is based on the uncoated Summitar having radioactive glass as part of its optical design, but it doesn’t.