Jump to content
UltravioletPhotography

Intensity comparison between Canon 199A and Godox AD200


Recommended Posts

I have finally been able to do a proper measurement, comparing the the Canon Speedlite 199A with the Godox AD200 using the Flashlight head.

Both flashes are modified to improve UV emission by removing the plastic front fresnel parts.

The Godox flash still have the thick protective glas filter that cut UV-C and limits the UV-A and UV-B a bit.

 

The measurement is made against a matted PTFE sheet mounted directly in the flashes direction.

The intensity is monitored at a 45° angle via an UV-VIS fibre to the spectrometer.

The measurement intensity is limited by an iris, mounted at a distance, in front of the fibre, directed at the centre of the PTFE-sheet target area.

Otherwise the spectrometer would be overloaded.

 

The distance from the flash tube to the target affect the intensity very much.

Here are the results from the Canon 199A, with the flash tube at 10cm, 15cm and 20cm distance from the PTFE-sheet:

post-150-0-71326000-1556449715.png

 

The difference between Canon (blue) and Godox (red), at 20cm from the target:

post-150-0-90212500-1556449822.png

 

The front edge of both flashes extend ca 20mm in front of their xenon tubes, shortening the mechanical working distance that much.

 

---

A better alternative for the Godox flash might be using the bare bulb head together with the standard reflector and a suitable Quartz xenon tube.

This reflector has a more even and possibly a less wide angle light pattern.

 

The standard reflector is 120mm wide and extend ca 70mm in front of the focus point.

This might make the placement of the flash difficult to avoid obscuring the motif.

The emission spectra reach further into the UV.

 

Focal points 20cm from the PTFE-sheet:

post-150-0-17027100-1556451135.png

AD200 bare bulb head with quartz tube in the standard reflector. 2mm sun-bed grade perspex in front of the reflector. (Green)

Link to comment
Andy Perrin
The Canon has a smaller output, but a more even spectral distribution than the Godox? The Godox looks like it's going to strongly weight the longer wavelengths.
Link to comment

The Canon has a smaller output, but a more even spectral distribution than the Godox? The Godox looks like it's going to strongly weight the longer wavelengths.

I agree. Canon have a very nice spectrum more like sunlight.

My guess is that the Canon is something like a 40-50Ws flash, compared to the 200Ws the Godox have.

The intensity is also highly dependant of the light pattern from the reflector.

 

I think the spectral distribution of the Godox is caused by some coating of the reflector in combination with the transmission of the AR-coated protection filter.

 

The godox has more electrical energy to use, but with the modified speedlight flash head much is lost in the UV range.

There are still some advantages over the Canon.

Recycling time is 2s compared to tens of seconds.

It is radio controlled with a working TTL control, if full power is not needed.

 

With a custom quartz tube replacing the bare bulb-tube and using the standard reflector the result is quite nice.

Link to comment

Very interesting,

The 350nm turning point for the Canon I find intriguing. Also the 300nm signal your getting at 4 inches (10 cm).

I will have to test mine to see if I see anything at 300nm. With the Canon 199A you can manually fire them with a button press on the flash. The last time I tested that over a 2 minute exposure, I think I had the flash guns too far away. Using Alkaline, non-rechargeable batteries, you can fire the flashes quickly.

Link to comment

Very interesting,

The 350nm turning point for the Canon I find intriguing. Also the 300nm signal your getting at 4 inches (10 cm).

I will have to test mine to see if I see anything at 300nm. With the Canon 199A you can manually fire them with a button press on the flash. The last time I tested that over a 2 minute exposure, I think I had the flash guns too far away. Using Alkaline, non-rechargeable batteries, you can fire the flashes quickly.

 

The response is affected by differences in the fibre transmission and spectrometer sensitivity.

The setup is not calibrated for absolute power. I have not access to any calibration source for that.

 

However the emission patterns from different flash type vary a lot.

See here for some examples:http://www.ultravioletphotography.com/content/index.php/topic/2343-godox-ad200-electronic-flash-work-in-progress/page__view__findpost__p__16929

 

My 199A flashes, I have four, all need long time to reach full charge, as indicated with the indicator lamp blinking .

With fresh alkalines it takes ca 20s until the lamp starts blinking. It lights up after ca 10s.

It might be due to that the power-storage capacitors are old.

Link to comment

I tested my Canon 199A flashes today. Using Duracell alkaline batteries, one unit could flash every 6 seconds, my other unit could flash every 9 seconds. I was able between the two units to provide 15 flashes per minute.

Setting the flashes 2 inches away from a flower bare bulbs, using a 300bp10 filter on my UAT lens at f5.6 with ISO 1600, for just over 9 minutes. The image was basically black. If you try real hard you can maybe make out the outline of the leaf.

 

In contrast an image was obtained using my 2 UVb bulbs over similar time. My hot 125W mercury vapour lamp in just over 6 minutes had an interesting image. It has a line of light (hot spot) that you line up with the flower. So much different than the UVb bulbs.

 

So in practice not much at 300nm comes out of my 199A flashes.

 

I still haven't bought a dedicated 302nm light yet. But maybe one day. 313nm is similar and just really easy to image at.

Link to comment

Here are the 300nm test images.

 

The flower at 365nm captured using 330WB80 fitler:

post-188-0-07962900-1556601187.jpg

 

The flower using 2 Canon 199A flashes, exposure time was recorded as 543.72 seconds, F5.6 at ISO 1600. Flashes were 2 inches away:

post-188-0-53403300-1556601203.jpg

 

The flower using 1 Lucky herb 125W mercury vapor lamp about 7 inches away from the flower. Exposure was 390.76 Seconds, F5.6 at ISO 1600:

post-188-0-46875400-1556601216.jpg

 

The flower using 1 Exoterra 200 UVb bulb on the left and one Lucky herb 15.0 UVb bulb on the right. Exposure was recorded as 570.4 seconds, F 5.6 ISO 1600. However I start the image capture for about 15 seconds before the lamps come on, as only the first 15 minute warm up time of these lamps provided the 297/302 nm Hg bands. The lamps are 3 inches away from the flower.

post-188-0-83405500-1556601231.jpg

Link to comment
Andy Perrin
This all seems rather hard on that poor flower! I think the conclusion that the flash cannot be used at that wavelength is correct. Oh well.
Link to comment

Yep,

Don't use the Canon 199A for UVb type images. But it does work quite well for UVa.

It's been a while since I played with the mercury vapour lamp. It took 2 minutes to really come on, then I could see the line of light. So that 6 minutes and 30 second exposure, is really the first 2 minutes of not much. Then 2 minute of hitting the leaf, to find the line of light. Followed by 2 minutes on the flower area. It really is the best source for UVb from the lights I have. The problem is it gets really really hot.

For all of these tests I had on both my amber and orange Uvex glasses. When looking at the hard reflective light, you need saftey glasses. Leafs seem to reflect at 300nm where most flowers seem dark, so it helps to have a leaf to find the light.

Link to comment

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
×
×
  • Create New...