I Gilded the Lily

[dabateman]

Try Gimp it should work to stack as well

I follow the Bernard protocol with alignment using Hugin program and Gimp.

[colinbm]

Thanks everyone, looks like you have been having some fun while I was asleep.

The tri-colours look pretty good, but I think they are a bit complicated for my poor old brain to get a handle on.

Andy the #35 post looks fascinating, can this all be done in PhotoNinja ?

[Andy Perrin]

Colin, yeah, the number 35 can probably be done in PhotoNinja alone. I used Photoshop but I didn't have to.

[colinbm]

Colin, yeah, the number 35 can probably be done in PhotoNinja alone. I used Photoshop but I didn't have to.

 

It certainly put some life into such a narrow band.

[Stefano]

I should make a tutorial topic to show my method for doing TriColour. Bernard uses different programs, but the base concept is exactly the same.

 

---

Colin, there are two ways you can make your lighting more uniform: you can either place your LEDs as far away as possible to have something similar to a point source of light, or you can put them behind a diffuser. In both cases, they have to be placed in the exact same place and they have to stay still. They have to "appear the same" in order to be perfectly overlayed.

[colinbm]

Thanks Stefano

I'll pay more attention to the placements of the lights next time.

[Stefano]

If you have three UV bandpass filters you can fit on a lens, you can use sunlight or a flash and do it like Bernard did. The filters in the wheel you bought are small, but should fit some lenses. That way you just need to change them without moving your camera (and without moving your light source).

[colinbm]

Thanks Stefano, I have been trying to think along these lines......more thinking required....

[dabateman]

The 12mm filters should fit fine behind your fused silica element lens with its 3mm aperture. You will need to be careful to realign the lens after you unscrew it to add a different filter. The huge advantage that you may have with these filters is that since they are all from a filter wheel set, they might all have been adjusted to the exact same thickness. So you most likely will not need to refocus between filters.

 

If you can build something behind that lens to hold the wheel, then you could just rotate them for imaging. My wheel fit inside a 72mm aluminum cap set.

 

Now you have me wondering if I could do something similar with a small element in front and align the camera behind.

[colinbm]

I am giving it some thought, I have some other small UV filters too, including a UV sparticle.

They will all need a IR blocker like the S8612, & a strong UVA light source. This is one reason I am making these UVA LED lights as they don't have any IR & reasonable narrow band.

It is all swings & roundabouts in my head at the moment.....

[dabateman]

Yes but the same S8612 filter or stack of zwb1 can be screwed in front of the lens for IR blocking. Then the wavelength specific filters can be added behind the lens and dialled in when wanted. I may have to see if I can do this. I didn't have the fused silica elements when I disassembled my filter wheel. Now I will have to see if I can put it all back together. The single element also passes more light than a multi element lens, so the only 20% transmission isn't horrible.

[colinbm]

After a lot of thought, I can't see how I can do this with a flash light or sunlight.

The BaaderU as well as the S8612 are cutting the short end of the 340nm LED & doesn't need any filtering anyway.

The 365nm LED torches have their own filters of ZWB3, so they are fine as they are.

The 395nm LEDs I have filtered with some Hoya U360 that blocks above 405nm.

So these three photos are with the O D Industries 40mm enlarger lens that seems to pass most of the UVA spectrum & probably further then the camera can, without any filter.

Interestingly I took the visible light with the full spectrum camera without any filter too, & the room was lit with a cool white LED, that I set a CWB with.

Each photo was taken with a CWB & the PTFE target is included.

 

1/- with Cool White LED CWB, un-filtered.

 

 

 

2/- with 340nm LED CWB, un-filtered.

 

 

 

3/- with 365nm LED CWB, ZWB3 filter.

 

 

 

4/- with 395nm LED CWB, U360 filter, this one cuts off at 405nm.

 

[Stefano]

Shooting in UV with filtered light sources and an unfiltered camera is OK if the subject doesn't fluoresce a lot, so in this case the images are probably at least 99% UV.

[colinbm]

Thanks Stefano

I forgot about any fluorescence with the 340nm shot, I'll do it again with the U360 filter I have as it passes 300-405nm & will block any fluorescence.

[colinbm]

Sorry, I am a slow learner.

I think I have found what I want, to do this correctly.....

 

For your enjoyment I will take two photos of each of the three wavelengths of the LEDs, 340nm, 365nm & 395nm, one in UVA only & one in Visible only, to show the fluorescence.

For the UVA photos I will block each light with the a UVA pass filter & filter the sensor with a UVA pass only filter.

For Fluorescence photos I will block each light with the UVA pass filter & filter the sensor with a Visible light pass only filter.

 

For the 340nm LED UVA, I will use a Hoya U360 diffused filter that I have that passes UVA 300-405nm, & in the 40mm enlarger lens I will use a BaaderU that passes 330-380nm, with an in camera CWB.

And for 340nm LED Fluorescence, I will use a Hoya U360 diffused filter that I have that passes UVA 300-405nm, & in the 40mm enlarger lens I will use the original Sigma fp hot mirror, that passes 415-650nm, with an in camera CWB.

 

For the 365nm LED UVA, I will use a Hoya U360 diffused filter that I have that passes UVA 300-405nm, & in the 40mm enlarger lens I will use a SEU Gen3 that passes 350-400nm, with an in camera CWB.

And for 365nm LED Fluorescence, I will use a Hoya U360 diffused filter that I have that passes UVA 300-405nm, & in the 40mm enlarger lens I will use the original Sigma fp hot mirror, that passes 415-650nm, with an in camera CWB.

 

For the 395nm LED UVA, I will use a Hoya U360 diffused filter that I have that passes UVA 300-405nm, & in the 40mm enlarger lens I will use a SEU Gen3 that passes 350-400nm, with an in camera CWB.

And for 395nm LED Fluorescence, I will use a Hoya U360 diffused filter that I have that passes UVA 300-405nm, & in the 40mm enlarger lens I will use the original Sigma fp hot mirror, that passes 415-650nm, with an in camera CWB.

[ulf]

Sorry, I am a slow learner.

I think I have found what I want, to do this correctly.....

 

For the 395nm LED UVA, I will use a Hoya U360 diffused filter that I have that passes UVA 300-405nm,

And for 395nm LED Fluorescence, I will use a Hoya U360 diffused filter that I have that passes UVA 300-405nm,

 

The "Hoya U360 diffused filter that I have that passes UVA 300-405nm" sounds like a strange animal.

First of all I wonder how the diffusion function is done.

 

Then it would be interesting to know how much optical energy that finally reaches the motif for the three different LED wavelengths.

If you replace the flower with your fine spectral power measurement gadget and turn on each different LED type, illuminating the measurement sensor.

This is exactly such measurements that instrument was designed for.

 

Naturally the " Hoya U360 diffused filter that I have that passes UVA 300-405nm" must be in place during the measurement.

The information I am seeking is in the numbers the instrument presents.

I think the graph display is autoranging, to always show a big graph so you have to check what numbers are presented.

 

The official Hoya transmission data for U-360 do not pass much optical energy at 395nm.

As I do not know the thickness of your filter I just drew the curve for 2mm:

[colinbm]

Thanks Ulf, it is getting dark here & I will set-up the shoot & photograph in two hours, please let me know before if there any changes I should make Please.

 

Following are the spectrums of the three, 340nm, 365nm & 395nm LEDs filtered with Hoya LW U360.

 

395nmLED with Hoya LW U360.

 

 

 

365nmLED with Hoya LW U360.

 

 

 

340nmLED with Hoya LW U360.

 

[dabateman]

Colin you have two cameras correct, one full spectrum and one normal.

Just set them up side by side. Add the Baader venus filter on the full spectrum and add a uv blocking filter on the normal.

Then illuminated your subject with the U360 filtered light. You can then judt worry about changing the led lights. But keep the cameras still. Try to use similar focal length lenses or space the cameras to get the same field of view. The normal camera you will want closer to capture the fluorescence which will not be as strong.

[colinbm]

Thanks Dave, yes two Sigma fp, I will do as you suggest.

I don't think this set-up can be done in Sunlight, & not with flash, because we don't have the filters that transmit very well, nor block the visible or IR, this well ?

I think the S8612 would crop the 340nm LED a bit & still leak in visible, with the others ?

[ulf]

Thanks Colin,

 

The results are not what I expected, but then I assumed similar drive power levels for the three different LEDs and that the filter (U-360) is blocking the light with a mount that do not allow any light to pass around it.

The levels you see at 340nm is when compared to the 365nm-levels extremely high, less than 1/2 lower.

That is strange as 430nm LEDs normally has an efficiency of 1/10 or less compared to the 365nm LEDs.

 

Also I would expect a U-360 to attenuate the optical output from a 395nm LED to almost 1/10 of the optical power.

The toe of the peak into VIS is also strange as the filter's attenuation will increase rapidly further into the VIS.

 

The results are very confusing.

 

For the 395nm images they appear to be illuminated in a less beam like way that I like.

Could this partly be due to that some of the 395nm light escapes around the filter and hit the flower by bouncing elsewhere?

[colinbm]

Thanks Ulf

the largest diameter of the group of LEDs is the 395nm LEDs at 80mm & the LW U360 plate is 150mm square & is 3mm thick.

[colinbm]

I made too many mistakes & one camera froze, so I will go to beddie byes & continue tomorrow night.

[colinbm]

I have gone as far as I can with this at the moment until I find a better short pass filter say <405nm & add more 340nm LEDs to the light.

Then I have the question of, do I need to have a short pass filter on both the LEDs & Lens ?

[Stefano]

No, a shortpass filter on the lens is enough. A shortpass filter on the LEDs only is not enough as you can capture fluorescence too.

[colinbm]

I only put one on the lens as someone suggested I might have got some fluorescence ?

Anyway I am in a blackout as something has failed in my electricity box and I have to wait till tomorrow for it to be repaired.