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Hello UVP community!

10 replies to this topic

#1 Dmitry

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Posted 16 May 2018 - 12:53

Hello everybody!

I have many science oriented interests mainly to answer myself "how it works". Photo, optics and spectrum are some of them. I have micro4/3 photo gear, did full-spectrum conversion myself. Recently I made spectroscope add-on, myself of course.

Here are examples, I posted on other forum, but they more suitable here. More to come ;)

Solar full spectrum
Attached Image: P5028936.jpg

zwb3 filter applied to reveal more details in UV/IR parts
Attached Image: P5028939.jpg

#2 Andrea B.

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Posted 16 May 2018 - 14:28

Hello Dmitry and welcome to UVP. I look forward to your contributions. I know we would all enjoy seeing your spectroscope "add-on" with which you made the above spectra. Very interesting!

In particular, I was surprised by the abrupt transition from green to orange/red in the first spectrum. I know the yellow area is very narrow, but was surprised anyway. :)
Andrea G. Blum
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#3 nfoto

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Posted 16 May 2018 - 14:44

A nice introduction - welcome to our small, peaceful corner of the cyberspace. Looking forward to seeing more posts. Please elaborate technical details as you deem fit. Most readers here on UVP are eager to know more on such subjects.
Bjørn Birna Rørslett, Ph.D.
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#4 Dmitry

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Posted 16 May 2018 - 15:49

I tried UV photos few years ago, used different lenses and filters but had no much luck - photos was too blurry and nearly no UV marks. I can't just stop something not done, so learning cycle started. Long story skipped, and finally I found what my combo of lens+filter transmit more IR than UV. Its verified using spectroscope add-on :)

Above spectrum was taken on Lomo T-43 40/4 triplet. Pros - 3 tiny lenses, no lens cement, no UV illumination. Cons - it hard to adapt, have rare 27mm filter thread, so few photos made. Awaiting for step-up rings.

Here is another lens adapted myself. I had just lens block without any marks. Field of view is equal to 25mm and aperture is fixed at about f4. Here is assembled view:

Attached Image: P5108354.JPG

On top you can see jewelry spectroscope (china sellers have it for $30), handmade adapter itself fitted to 52mm filter frame and step-up rings to mount on lens to test.

Edit: wrong lens. It was Olympus 14-42ez

Edited by Dmitry, 16 May 2018 - 21:06.


#5 Dmitry

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Posted 16 May 2018 - 15:58

Oh, main purpose of this device is to check what part of spectrum can I see using exact gear. How its colored. How much UV Vis IR. How good is my light source.

Note about green-yellow-orange part. Other newer cameras have different colors. Its subject to more detailed topic.

Edited by Dmitry, 16 May 2018 - 16:03.


#6 Andy Perrin

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Posted 16 May 2018 - 16:19

What did you use as the replacement glass for the cut filter in your full spectrum conversion? It looks like you are not getting much UV past the 370nm or so based on past spectra I’ve seen on the board. Could be the lens or the replacement glass.

Edited by Andy Perrin, 16 May 2018 - 16:23.


#7 Dmitry

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Posted 16 May 2018 - 16:29

I used nothing for replacement :)

More details. Sensor assembly on e-pm1 adjusted using thin shims between case and assembly. Internal cut filter is about 2.6mm thick. Shims are 0.6mm on average. So without replacement glass I need to move sensor for about 0.7mm (or 0.9mm ?). I just not installed shims back and have just 0,1mm distance increase for rays of light. For native AF lenses its acceptable. For adapted lenses I use shortened adapter to get infinity.

Edit: cut filter was 2.6*17.3*22.3mm

Edited by Dmitry, 16 May 2018 - 16:36.


#8 nfoto

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Posted 16 May 2018 - 17:20

Consider moving the technical specs & discussion to a separate thread? I feel the introduction is moving away from its intended purpose at present.
Bjørn Birna Rørslett, Ph.D.
Just call me Birna

#9 Dmitry

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Posted 16 May 2018 - 17:36

Agree. Better to put technical discussion to proper place to make it easier to find later.
I have more to add to technical topics, but need some general guidelines about attaching large (ok, very wide) images.

#10 nfoto

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Posted 16 May 2018 - 17:59

In general, absolutely no need to post pictures larger than about 1200-1600 pix on the long side.
Bjørn Birna Rørslett, Ph.D.
Just call me Birna

#11 Dmitry

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Posted 16 May 2018 - 21:05

Ouch. Facepalm. Above spectrum was taken on kit pancake lens Olympus 14-42ez. Examined original RAW at home.