Surprising STEINHEIL f2.8/50mm lens for reflected UV photography VII - Focus Shift

This again is about this older 50mm lens, which was made decades ago by famous lens maker STEINHEIL which attracted me, since it showed some seemingly good UV transmission, which have already shown here. I have already shown that it performs quite well using the Baader-U filter, and using some even deeper reaching UV filters, using a 340nm shortpass and the IDAS 330nm filter (I have the 2" version, no longer made).

Now I wanted to show today how the focus shift of this, or any other lens can be easily made visible. All images shot at f8, using a modified Xenon flash.

[click on image gets you a larger image]

VIS image using UV/IR Cut filter:
 

UV image using Bader-U filter (approx. 320-390nm, peak 360nm):
 

UV image using IDAS UV filter (approx. 300-380nm, peak 330nm):
 

UV image using 340nm UV filter (approx. 320-340nm):
 

Now it is about to show how those images differ in size, using a method I call "differential", i.e. a subtraction of two images, one visible and one UV, where any focus shift will show as overlapping on the borders of the object. If you looks close you will see this around the object.

VIS-UV (Baader-U filter) differential image:
 

VIS-UV (IDAS UV filter) differential image:
 

VIS-UV (340nm UV filter) differential image:
 

It got quite obvious before, that this lens is also performing very well at even shorter wavelengths, making it a very useful lens for reflected UV down to 330-340nm at an optimal f8/f11 setting, especially since the image size deviation between visible and UV image is also only 1.3% , which can be easily seen (and measured) from those differential images.

I have written about that lens more HERE.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Surprising STEINHEIL f2.8/50mm lens for reflected UV photography IV

I had mentioned in my previous thread, that a few years ago I got an older lens, which was made decades ago by famous lens maker STEINHEIL . It is a possibly single coated, well made 2.8/50mm lens which attracted me, since it showed some seemingly good UV transmission when shining an 365nm UV LED beam through it. The surprise came when I had it under my spectrometer, revealing its high and deep reaching UV transmission.  I have already shown that it performs quite well using the Baader-U filter, and here now its performance using some even deeper reaching UV filters, using a 340nm shortpass and the IDAS 330nm filter.

[click on image gets you a larger image]

VIS image using UV/IR Cut filter:
 

UV image using IDAS UV filter (approx. 330-370nm) at f5.6:
 

UV image using IDAS UV filter (approx. 330-370nm) at f8:
 

UV image using IDAS UV filter (approx. 330-370nm) at f11:
 

UV image using IDAS UV filter (approx. 330-370nm) at f16:
 

UV image using 340nm UV filter (approx. 320-340nm) at f5.6:
 

UV image using 340nm UV filter (approx. 320-340nm) at f8:
 

UV image using 340nm UV filter (approx. 320-340nm) at f11:
 

UV image using 340nm UV filter (approx. 320-340nm) at f16:
 

VIS and UV (IDAS) image side-by-side both at f8:
 

VIS and UV (340nm) image side-by-side both at f8:
 

As I had mentioned before, it got pretty clear that this lens has a very high UV performance, as at 365nm it transmits around 75%. Its peak transmission with Baader-U filter attached is around 68% at 360nm. At shorter wavelengths it still has a very useful 56% transmission at 340nm and 22% at  320nm.

Before I had shown here, that stopping down has improved sharpness significantly, especially in reflected UV light using the Baader-U filter. Now it gets quite obvious, that this lens is also performing very well at even shorter wavelengths, making it a very useful lens for reflected UV down to 330-340nm at an optimal f8/f11 setting, especially since the image size deviation between visible and UV image is also only 1.3% there .

I have written about that lens more HERE.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Surprising STEINHEIL f2.8/50mm lens for reflected UV photography III

I had mentioned in my previous thread, that a few years ago I got an older lens, which was made decades ago by famous lens maker STEINHEIL . It is a possibly single coated, well made 2.8/50mm lens which attracted me, since it showed some seemingly good UV transmission when shining an 365nm UV LED beam through it. The surprise came when I had it under my spectrometer, revealing its high and deep reaching UV transmission, no other normal lens so far showed. But some outdoor images taken with it revealed, that it cannot be used fully open at f2.8 due to lacking sharpness and definition. So here now some indoor shots done in a controlled environment, using a modified Xenon flash for high UV output.

[click on image gets you a larger image]

VIS image using UV/IR Cut filter:
 

UV image using Baader-U filter (approx. 320-395nm) at f4:
 

UV image using Baader-U filter (approx. 320-395nm) at f5.6:
 

UV image using Baader-U filter (approx. 320-395nm) at f8:
 

UV image using Baader-U filter (approx. 320-395nm) at f11:
 

UV image using Baader-U filter (approx. 320-395nm) at f16:
 

VIS and UV image side-by-side both at f8:
 

As I had mentioned before, it got pretty clear that this lens has a very high UV performance, at 365nm it transmits around 75%, very close to the Kuribayashi 35mm which has 80%. Its peak transmission with Baader-U filter attached is around 68% at 360nm.

At f2.8 however the resulting images did not look as sharp as wished for, but stopping down has improved sharpness significantly, especially in reflected UV light, which by its shorter wavelength in theory resolves approx. 1.6x more. It gets quite obvious, that this lens is a clearly excellent and very useful lens for reflected UV at optimal f8/f11, especially since the image size deviation between visible and UV image is a bare 1.3% only.

I will in the next thread show the deep(er) UV performance of this lens...

I have written more about this lens HERE.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Surprising STEINHEIL f2.8/50mm lens for reflected UV photography II

I had previously mentioned that a few years ago I got an older lens, which was made decades ago by famous lens maker STEINHEIL. It is a possibly single coated, well made 2.8/50mm lens which attracted me, since it showed some seemingly good UV transmission when shining an 365nm UV LED through it. The surprise came when I had it in my spectrometer, revealing its high and deep reaching UV transmission, no other normal lens so far showed. Now some outdoor images taken with it, all at f2.8 to see if that lens speed could be used. Light was overcast sunlight.

[click on image gets you a larger image]

VIS image using UV/IR Cut filter:
 

UV image using Baader-U filter (approx. 320-395nm):
 

UV image using Baader-U filter (approx. 320-395nm) and 340nm shortpass filter stacked:
 

VIS image using UV/IR Cut filter:
 

UV image using Baader-U filter (approx. 320-395nm):
 

UV image using Baader-U filter (approx. 320-395nm) and 340nm shortpass filter stacked:
 

It got pretty clear that this lens has a very high UV performance, at 365nm it transmits around 75%, very close to the Kuribayashi 35mm which has 80%. Its peak transmission with Baader-U filter attached is around 68% at 360nm. Using that deeper 290-340nm UV filter which peaks at 334nm with 68% transmissing, it still has a 32% total transmission at its peak at 338nm.

At f2.8 however the resulting images do not look as sharp as wished for, so another test will have to reveal if stopping down will improve sharpness considerably.

I have written about this lens more HERE.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Surprising STEINHEIL f2.8/50mm lens for reflected UV photography I

Quite a few years ago I got an older lens, which was made many years ago by famous lens maker STEINHEIL. It is a possibly single coated, well made 2.8/50mm lens which attracted me, since it showed some seemingly good UV transmission when shining an 365nm UV LED through it. The surprise came when I had it under my spectrometer, revealing its high and deep reaching UV transmission, no other normal lens so far showed.

[click on image gets you a larger image]

Today now the spectrometric results as one of the best performing "normal" lenses for UV, slso showing the transmissing with the Baader-U filter, as well as a 290-340nm filter:



It gets pretty clear that this lens has a very high UV performance, at 365nm it transmits around 75%, very close to the Kuribayashi 35mm which has 80%. Its peak transmission with Baader-U filter attached is around 68% around 360nm. Using that deeper 290-340nm UV filter which peaks at 334nm with 68% transmission, it still has a 32% total transmission at its peak at 338nm.

 A very useful lens for reflected UV this seems to be, but photographic tests still needs to be done...

I have written about this lens more HERE.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Deep UV Ultraviolet Reflected Light Photography at UV-B and UV-C recording with candle light

Today another proof that reflected UV photography is doable at UV-B and UV-C using several special, up to NIR blocked, narrowband filters and a very different UV camera, an amplified 190-650nm MCP equipped video camera. Lens used was a CERCO f1.8/45mm quartz flourite lens. Light source was a candle flame.

[click on image to see a larger one]

This reveals, that the deeper one looks into UV, the area where the candle flame emits that UV moves from the top of the flame down to the sides of the flame. Pretty amazing how sensitive this type of camera is, as the needed amplification was still just in the lower 30% of the total available range.

I have a newer system HERE with a normal camera attached to the MCP amplification device.

I have previously written more about combustion and UV HERE.

Btw. Michael Faraday has in 1848 given six famous lectures about the chemical history of the candle, which may be read about HERE

Stay tuned, more will follow on that fascinating subject...

Deep UV Ultraviolet Reflected Light Photography at UV-B 313nm II

Today another proof that reflected UV photography is doable at UV-B using several special, up to NIR blocked, narrowband filters and a different than before UV camera. Lens used was my UV-Nikkor 105mm quartz flourite lens. All shots were done at f11. Light source was a gas torch flame.

[click on image to see a larger one]

Double hexaptych (top to bottom) of Visual light; emitted UV 320-390nm, 310-350nm, 290-340nm, 280-315nm, 304-322nm. Right side is morphological gradient filtering of left side:


This reveals, that the broadband UV image shows a much broader, but less detailed gas flame, the images shot with narrow(er) filters however, shows a much more detailed flame image and is useful to judge how efficient the gas combustion process is, 313nm being the emission peak wavelength of the OH radical.

I have previously written about that HERE.

Stay tuned, more will follow on that fascinating subject...

Deep UV Ultraviolet Reflected Light Photography at UV-B 313nm

Today a proof that reflected UV photography is doable at UV-B using a special, up to NIR blocked, peak 313nm, FWHM 9nm narrowband filter and my special UV camera. Lens used was my UV-Nikkor 105mm quartz flourite lens. All shots were done at f4.5.

[click on image to see a larger one]

313nm FWHM 9nm Filter transmission spectra:


Reflected UV-B image at 313nm, 0.8 sec exposure:


This was just a proof of concept that reflected UV imaging can be successfully done even at such deep UV-B wavelengths (OH* 313nm) showing the stainless steel combustion emission valves of a central heating system.

In case you were wondering how a flame of a gas torch would look like in UV...

Triptych (top to bottom) Visual light, emitted UV (320-390nm, Baader-U), emitted UV-B (313nm):


Triptych (top to bottom) Visual light, emitted UV (320-390nm, Baader-U), emitted UV-B (313nm) - morph. Gradient:


Diptych (black/white, top to bottom) emitted UV (320-390nm, Baader-U) vs emitted UV-B (313nm):


This reveals, that the broadband UV image shows a much broader, but less detailed gas flame, the 313nm image however, 313nm being the emission peak wavelength of the OH radical, shows a much more detailed flame image and is useful to judge how efficient the gas combustion process is.


Stay tuned, more will follow on that fascinating subject...

[UV] White Primrose (Primula) in deep ultraviolet light

When I passed by my friends' flower shop and saw he had some primroses (primulas), I wanted to see, if there would be some UV structure visible if shot in reflected ultraviolet light. This one is a bread form, all white and filled.

[click on image to see a larger one]

These UV images here also uses my standardized false UV color normal + high intensity palette:



Well and indeed there gets something visible...

VIS:

UV:


Now I was wondering about the contribution of the shorter wave, deeper UV sub-bands (as I call them). Here the results of using the plain Baader U2 filter (left) versus that same filter stacked with a filter that cuts all below 360nm, but passes all above (right)



It gets pretty obvious, that these shorter UV wavelengths are able to differentiate and make more structures visible. Here the red and especially green channel response play an important role.


Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos