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Posted (edited)

I was primarily using the various apertures on the larger of the standard circular masks.  I just double checked the mounting module and I'm fairly sure its the correct one, it measures just under 43 mm from the front to the back of the bayonet component (see attached image).  I also found the box it came in that says "Mounting module (Retra Flash Prime/PRO)".  

I will set up some controlled bench tests for playing with things to see if the results are similar to what I was experiencing underwater.

 

retra.jpg

Edited by jonjake

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I ran some initial bench tests this afternoon to reproduce what surprised me in the water yesterday as I hadn't noticed it when previously using my LSD snoot with a Inon Z-240 strobe.  It makes sense that the amount of light getting through would fall off as the aperture is stopped down (by using the masks).  Perhaps more of the light emitted from the Inon strobes makes it through the snoot or perhapsmy memory is just wrong.

All of the images below were shot with a Nikon D850 and Nikon 60mm Macro lens on the bench.  I set the exposure to "reasonable" macro exposure settings, f/22, 1/250 sec, ISO 160. Starting without a mask in the Retra I then set the strobe power to expose this shot how I typically would, which put the dial at 50 (+2), just 2 clicks from full power. Without changing exposure or strobe power I then proceeded through all the standard circular masks (2 sliders). 

I guess having to start with such high strobe power on the Retra Pros for the snoot (even without a mask) was the biggest surprise for me.  The 3rd largest mask hole looks to be around -2EV darker (in Lightroom) than no-mask meaning to achieve my preferred exposure I would need push the strobe up to full power and ISO to 320.  Guess I will just have to start shooting higher ISOs that I am used to for macro when using this setup. And probably wont even bring the mask with smaller holes when I dive.  Hopefully this realization I have come to is helpful for others, my apologies if this is obvious.  

No Mask in Retra Snoot:
f22_1-250sec_ISO160_Retra_Pro_50%25_no_m

1st Circular Mask (largest):
1st_circle_mask-X3.jpg

 2nd Circular Mask (2nd largest):
2nd_circle_mask-X3.jpg

3rd Circular Mask (3rd largest):
3rd_circle_mask-X3.jpg

4th Circular Mask (4th largest):
4th_circle_mask-X3.jpg

5th Circular Mask (5th largest):
5th_circle_mask-X3.jpg

6th Circular Mask (6th largest):
6th_circle_mask-X3.jpg

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Thanks for this. Really interesting. I’ve just switched from z240 strobes with the LSD for Retra  Primes but not yet Been able to get in the water with them. 

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Interesting indeed! Are you able to do the same tests with your Inon z240, and let us know which power setting on the Inon gets you similar exposure without a mask?

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Posted (edited)

Ok I just converted my LSD snoot back to the Inon Z240 mount and re-ran this test.  To me it definitely looks like the fall off is less significant as the masks are inserted with the Inon.  I found that with the same exposure (f/22, 1/250 sec, ISO 160) the Inon was set to GN8 (2 clicks below full GN11) for the exposure to look right to me, albeit the Inon Z-240 is supposedly a much lower power strobe.

Inon Z-240 @ GN8, no mask

InonZ240_no_mask-X3.jpg

Inon Z-240 @ GN8, 1st circle mask (largest) https://photos.smugmug.com/Retra-Test-Shots/i-G4LrgLr/0/5370afbe/X3/InonZ240_1st_circle_mask-X3.jpg
Inon Z-240 @ GN8, 2nd circle mask (2nd largest) https://photos.smugmug.com/Retra-Test-Shots/i-9VQ3k94/0/17d49964/X3/InonZ240_2nd_circle_mask-X3.jpg
Inon Z-240 @ GN8, 3rd circle mask (3rd largest) https://photos.smugmug.com/Retra-Test-Shots/i-3KWRfHN/0/5edea501/X3/InonZ240_3rd_circle_mask-X3.jpg
Inon Z-240 @ GN8, 4th circle mask (4th largest) https://photos.smugmug.com/Retra-Test-Shots/i-GCc5fTs/0/7d732bbf/X3/InonZ240_4th_circle_mask-X3.jpg
Inon Z-240 @ GN8, 5th circle mask (5th largest) https://photos.smugmug.com/Retra-Test-Shots/i-gCFz2PT/0/3bfb1ab4/X3/InonZ240_5th_circle_mask-X3.jpg
Inon Z-240 @ GN8, 6th circle mask (smallest) https://photos.smugmug.com/Retra-Test-Shots/i-xwsnt7w/0/192e54f5/X3/InonZ240_6th_circle_mask-X3.jpg

I would say comparing this set of images with the different mask sizes also supports my memory of not having to make as significant of power changes when moving through different mask apertures on a given mask card (1-3 or 4-6).

We know the Retra Pro has a very wide and even field of light which is not the case with the Inon Z-240.  However when using the Retra snoot that seems to be a pretty significant disadvantage as far as how much of that light is collimated and transmitted by the snoot. I primarily bought the Retra Pros for wide angle but it is a disappointing to find out the Retra snoot isnt as powerful on the new "high-power" strobes as my old Inon strobes.  I guess its good I have other options for snooting...

Edited by jonjake

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I think it's just physics and geometry - the LSD is taking a circular slice out of the beam and feeding it into the optics to produce your snooted beam.  it's the same size hole in the back end of the LSD presumably in both cases.  The light that doesn't shine into the hole in back will bounce around and some may make its way into the optics but a lot won't. 

I found a lumens to lux calculator and plugged some numbers in.  Assuming the same distance from light source and lumens a 100° beam from the INOn and 130° beam from the retra  and a 1000 lumen source the lux of the beam at 10cm  is 44555 lux for the INON and 27192 lux for the Retra.  I know the Retra has more power, but this just serves to show the difference in lumens per m2 (=lux) between the two beam sizes.  The Retra needs to put of 1.6x more lumens to be as bright as the INON in lumens /m2 of beam which is the same as saying give s the same exposure.

The Retra flash tube is approx 63mm is diameter (scaled from a photo and known outside dia) and generating a 130° beam but the geometry says that hole in the base of the of the LSD is sampling only a 12° beam as it's nearly the same dia as the tube and only 43mm above it.  It's a bit more complex than that as the LSD tube can see both sides of the inside of the tube but the calculations for that get messy. 

The INON on the other hand has 25mm tubes sitting below the the LSD in a T shape.  Quite a difficult geometry to calculate but if we assume its a 25mm dia light source the beam angle to the LSD inlet is 57°, so the LSD is sampling significantly more of the beam just due to geometry.

To sample more of the beam you need to get closer to the flash tube.

The summary is that because the Retra tube is physically larger and has a wider beam angle significantly less of the light it generates enters the LSD tube.  The INON tubes are smaller and have a smaller beam angle so more of their light enters the LSD tube.

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19 hours ago, Oskar@RetraUWT said:

The LSD Ultimate snoot has a focus distance of about 175mm in water.

I would like to see the where the 175mm are in the picture above...

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As Chris mentioned the design of the flashtube plays a major role in how light is distributed and the power output. How the flashguns perform in wide angle situations can be seen here: https://www.retra-uwt.com/pages/flashgun-light-comparison

In macro situations the differences in light beam spread are same but come out less visible (especially on subjects that are very 3D) because the light beam is compressed onto a small area. If we measure the light beam of the Z-240 coming out of the LSD Ultimate snoot, the uniformity of the beam is considerably less than with the Retra Flash PRO. Although in macro photography this is less of an issue.

When comparing both these flashguns for snooting with the LSD Ultimate or a homemade DIY snoot the biggest difference worth noting is the placement of the pilot light. Having a central pilot light being a much better experience when positioning the light.

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4 hours ago, Oskar@RetraUWT said:

 

When comparing both these flashguns for snooting with the LSD Ultimate or a homemade DIY snoot the biggest difference worth noting is the placement of the pilot light. Having a central pilot light being a much better experience when positioning the light.

This is the big advantage to me of the Retras and what sold me on them: accurate positioning. Or at least I hope it is once I get them in the water. Above water tests were certainly spot on and I couldn’t see any obvious light falloff or underexpose issues. 

 I loved the Z240s and think they’re  brilliant - but snoot positioning drove me crazy. 

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I agree with all the points made above.  The centered modeling light of the Retra Prime/Pro makes usability of the Retra snoot greater, the offset when using the Inon can be challenging.

I am happy to have the wide uniform light for wide angle photography.  In the few times I have shot wide angle with the Retra Pros so far I have been happy with them.  They also certainly will work for shooting macro I will just need some adjustments to how I shoot macro (most likely higher ISOs).

The takeaway worth sharing is that while wide uniform light might be ideal for wide angle shooting it has potential downsides for macro shooting, specifically when using a snoot.  In retrospect it makes sense from a physics standpoint but it was obvious to me it would be an issue until discovering it in the water.

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Hi 
 
We have just released a firmware update (2.5) for the Retra Flash PRO/Prime which includes improvements of Smart SL, HSS, BATT/TEST and U2 modes including an updated user manual. The update is done easily with our App, available for iOS and Android devices. Just download the app and follow the instruction for connecting your flashgun to your device.
 
 
 
If you need help with the install please write to: develop@retra-uwt.com

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7 hours ago, Oskar@RetraUWT said:
We have just released a firmware update (2.5) for the Retra Flash PRO/Prime which includes improvements of Smart SL, HSS, BATT/TEST and U2 modes including an updated user manual.

I want to add some information for users, that UW Technics in cooperation and with the support or Retra team updated the firmware of TTL-Converters for Retra HSS and TTL support of this particular firmware version V2.5.  So, all TTL-Converters manufactured last months are tuned for this new firmware.

Edited by Pavel Kolpakov

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24 minutes ago, Pavel Kolpakov said:

I want to add some information for users, that UW Technics in cooperation and with the support or Retra team updated the firmware of TTL-Converters for Retra HSS and TTL support of this particular firmware version V2.5.  So, all TTL-Converters manufactured last months are tuned for this new firmware.

Really good to know, Pavel. Many thanks

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57 minutes ago, Pavel Kolpakov said:

I want to add some information for users, that UW Technics in cooperation and with the support or Retra team updated the firmware of TTL-Converters for Retra HSS and TTL support of this particular firmware version V2.5.  So, all TTL-Converters manufactured last months are tuned for this new firmware.

 

I have a UWT TTL trigger for my Sony a7r IV. I anticipate buying a pair of Retra PRO strobes in the not-too-distant future.

 

How would I be able to update my UWT trigger to have this new firmware?

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53 minutes ago, stuartv said:

 

I have a UWT TTL trigger for my Sony a7r IV. I anticipate buying a pair of Retra PRO strobes in the not-too-distant future.

 

How would I be able to update my UWT trigger to have this new firmware?

It is available to update this firmware for most of TTL boards. Please contact UWTechnics company for details by e-mail (uwtechnics@gmail.com).

TTL boards manufactured since last summer have also some hardwire changes for better Retra Pro support and also this new firmware.

Edited by Pavel Kolpakov
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3 minutes ago, Pavel Kolpakov said:

It is available to update this firmware for most of TTL boards. Please contact UWTechnics company for details by e-mail (uwtechnics@gmail.com).

TTL boards manufactured since last summer have also some hardwire changes for better Retra Pro support and also this new firmware.

 

I got mine in March, 2020. I guess mine does not have the hardware changes. What will I be missing out on by having older hardware?

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25 minutes ago, stuartv said:

I got mine in March, 2020. I guess mine does not have the hardware changes. What will I be missing out on by having older hardware?

If you mean TTL board for Sony A7-A9, the hardwire was upgraded even in spring this year. Probably you have a last version hardwire. Anyway, let's contact by e-mail to specify some technical details.

Edited by Pavel Kolpakov
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14 hours ago, Pavel Kolpakov said:

I want to add some information for users, that UW Technics in cooperation and with the support or Retra team updated the firmware of TTL-Converters for Retra HSS and TTL support of this particular firmware version V2.5.  So, all TTL-Converters manufactured last months are tuned for this new firmware.

Hi Pavel,

Does it means that if we have the previous firmware on the converter it is better not to update the Retras's firmware?

 

Kind regards,

Jose

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15 minutes ago, Joss said:

Does it means that if we have the previous firmware on the converter it is better not to update the Retras's firmware?

Hi Jose,

Please check the User Manual of your TTL-Converter, If it already supports Retra Pro strobe (rotary switch position "7"), you have to update Retra Pro firmware up to V2.5 now.  

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Pavel,

I have one of the original Nauticam TTL converters that I purchased when the D500 housings came out.  Will I need to replace that converter with a new one to work reliably with the Retra Pro V2.5 strobes?

Edited by Jay-11

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I've just done the upgrade on the Retra Prime strobes to v2.5.

Could not have been easier and took less than 5 minutes for each strobe.

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3 hours ago, Jay-11 said:

Pavel,

I have one of the original Nauticam TTL converters that I purchased when the D500 housings came out.  Will I need to replace that converter with a new one to work reliably with the Retra Pro V2.5 strobes?

You mean #26308 product (black color PCB). It did not have Retra TTL profile, no HSS support.  Yes, for usage with Retra Pro, you have to replace TTL board.

Edited by Pavel Kolpakov

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