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 VI - Lewisia differentials

I got this mentioned 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 good UV transmission which I have previously shown here. Now today some outdoor shots at f11, light source was overcast sky. Target was a Lewisia cotylodon flower. But this time a bit different images - Differentials, which shows the difference of two images.

[click on image gets you a larger image]

VIS image using UV/IR Cut filter:
 

UV image using Baader-U filter:
 

Simulated butterfly vision:
 

Simulated bee vision:
 

VIS - UV differential image:
 

VIS - UV differential image, color swap:
 

VIS - Simulated butterfly vision differential:
 

VIS - Simulated bee vision differential:
 


Lewisia has a visible UV pattern, its petal tips are UV bright around 385nm, its center is UV dark, so this gets quite nicely visible as differentials, also in simulated butterfly and bee vision using this astonishing lens.

I have written more about that flower HERE 

I have written about that used 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 V - Lewisia

I got this mentioned 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 good UV transmission which I have previously shown. Now today some outdoor shots at f11, light source was overcast sky. Target was a Lewisia cotylodon flower.

[click on image gets you a larger image]

VIS image using UV/IR Cut filter:
 

UV image using Baader-U filter:
 

Simulated butterfly vision:
 

Simulated bee vision:
 

Quadryptich of human vision, reflected UV, simulated bee and butterfly vision (left to right, top to bottom):
 


Lewisia has a visible UV pattern, its petal tips are UV bright around 385nm, its center is UV dark, so this gets quite nicely visible, also in simulated butterfly and bee vision using this astonishing lens.

I have written more about that flower HERE 

I have written about that used 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 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