Do-It-Yourself Spectrometer

[Alaun]

Colour vs wavelength => look at a spectrum (just for fun)

 

Beside my trials with CDs and DVDs (with reflective grids) it happens I also have some transparent grids.

After reading some stuff John had linked here, I tried to convert my kitchen into spectrometer, so here is the set-up (works thanks to a letter size foil grid with 1000 lines per mm)

 

 

 

 

And here comes a composite, taken with a Panasonic GH3-UVIR, the UV-Nikkor, and with different filter sets

• no filter
  
• with 2mm S8162,
  
• with S8162 & BaaderU, and
  
• with 2mm S8162 and U340 (uviroptics).
  

First just demosaic-ed (just nothing clicked on in PN, maybe PN still uses the camera WB setting?). The camera WB setting was for IR (works quite good for UV by the way). Pictures put together with PS.

 

 

And second version is the same picture, within PS with all the sub pictures applied the camera raw filter on the dark part of the Baader U sub picture:

 

[baffe]

Parts of uv band appear as yellow and green while other parts seem to be overexposed.

 

Does yellow and green change colour or even disapear if you shorten the times while using Baader U and combo filter?

 

(do I tell nonsense again?)

[Andrea B.]

Admin Note: I have given Werner's DIY Spectrometer its own thread. Thanks, Werner, for a great experiment !!

 

My observation is that the BaaderU + S8612 appears broader banded than the U340 + S8612. We know this from the specs, but now we can see it with the "spectrometer". :D Cool!

[Alaun]

A little continuation:

 

First, a picture of the setup taken with Panasonic GH3 uvvisir

and Olympus E.Zuiko Auto-W 1:4 25mm out of cam WB (created for IR)

 

 

 

And now, same camera and lens, moved a bit closer and different filters

 

a)without b)with S8162 2mm to block out IR and c as b & Baader U and then d = c e = b and f = a but last three -4EV

 

Processed in PN with all options clicked off, then taken into PS and cropped to one picture.

 

 

Compared to the UV-Nikkor, the little bit of green is now missing with the Zuiko

 

@Baffe: if you take a closer look at the pictures with the Nikon above, you can see a second "reflection" in the lower part of the images, which has gotten less light

[rfcurry]

Excellent!

This refutes the notion that UV photographers use everything but the kitchen sink! ;)

[JCDowdy]

I am wondering about the light source. Tungsten, but what envelope, glass or quartz? Fixtures that have UV transmitting quartz enveloped bi-pin bulbs usually incorporate some kind of tempered glass UV blocking filter. This is common in puck style under cabinet down lights. If this is what you have then you might want to remove the UV cut filter and see what you see then. But, be careful of the heat from the bare bulb.