Subtronic Flash

I don’t know the data from the database but the data here look like collected from manufactures’ technical specs. That doesn’t really make them comparable. There are quiet different rules of expressing data among manufactures.

The Data on Inon gives it 100h x 100v thats the same angle as a Round tube on the Ikelites new DS200

 

the data on subtronics are as followed.

 

Alpha = 106h x 106v

Alpha pro = 108h x 108v

Mega's = 112h x 112v

Maxi = 116v x 116h

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Inon states the coverage in air only. No underwater coverage value. Subtronic and Ikelite state coverage underwater. Furthermore, Subtronic states coverage angles measured circular, not against a flat wall. Think of triangles. Put a strobe towards a flat wall. The distance to the edges of the coverage angle is greater than in the centre. Subtronic states “circular coverageâ€, meaning the same distance across the entire angle. This results in higher guide numbers compared to firing against a flat wall. But it is still underwater compared to Inon’s specs where the coverage underwater is significantly smaller.

I can hardly think of any strobe delivering over 100° ‘flat’ coverage underwater.

I think a laser pointer delivers a perfect guide number with unbeatable size/price/weight/guide number ratio. But you want coverage and warm even lightning as well for wideangle work underwater. Centre Guide number doesn’t really indicate a strobe’s wideangle performance and its brightness around the centre.

Let's say you have two strobes, strobe A guide number = 11, strobe B guide number = 16. Strobe B fires the double amount of brightness in the centre. Now imagine this performance is maintained across a nice coverage angle. Strobe B needs much more energy, will be much bigger than strobe A and requires some Wattseconds.

all flash exposures as i know work on the STSD = GN/F-stop sum.

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Unfortunately it isn’t so easy for underwater strobes. For macro work, there is very little water between strobe and subject. Quiet similar guide number compared to topside. Refraction on strobe’s front glass (flat character) even increases brightness (concentrated beam, shrinked coverage). 1m Distance absorbs some light already. Strobe guide number specs are typically referred to 2m light travel (1m distance). Make it 2m distance (4m light travel) and the guide number becomes a friction compared to topside. Same with colour temperature. A few hundred Kelvin can easily become a few thousand Kelvin difference over greater distance underwater.

What does STSD stand for? SD = subject distance?

Julian

HI Julian

Yeh STSD = Strobe to subject distance.

Well considering all your posting, they all may as well not bother printing any data.

if they cant make a standard test to work a GN value... I guess then we go on the assumption of

IF its Big then it gives out a lot of light, so it must be good...

simple..

Or we simply let independant people run tests and show us their results.

regards

craig

Hi guys,

I just came across this thread.

First off, I would like to apologize for posting the incorrect data regarding the Subtronic Alpha underwater guide number into the digitaldiver strobe database. The correct number, as published in the Subtronic Alpha manual is 14. I have corrected the database.

Also:

I don’t know the data from the database but the data here look like collected from manufactures’ technical specs. That doesn’t really make them comparable. There are quiet different rules of expressing data among manufactures.

All data posted in the database is directly supplied by the manufacturer except for the underwater weight of the Ikelite DS 125 strobe which I calculated myself. The database relies on the integrity of the manufacturers and their testing procedures for accuracy of specs. Every manufacturer has been invited to review the data prior to posting. This included Subtronic. They were very accommodating in supplying me with manuals from which I harvested data on their strobes. They also had time to review my uploaded data prior to posting.

There is a note at the bottom of each strobe database web page acknowledging that data may not be accurate in comparisons across manufacturers lines due to testing procedures.

I am not sure if anyone who put together the digital diver strobe database has ever used a Subtronic. biggrin.gif

 

The best way to compare strobes is in Watt Seconds. All the manufacturers quote this and it avoids the optimism of GN and UW GN.

I have never seen or used most every strobe listed in the database.

Unfortunately all manufacturers do not list watt seconds. Inon for instance.

the same site says GN of Z-240 12 UW

The database does not list an underwater guide number for a unit unless the manufacturer offers it. Inon does not supply underwater guide numbers.

Finally, to help in understanding how the database was compiled, I have copied a thread of emails from September 2004:

Dear Robert,

 

I have forwarded your Mail to my Boss to answer the last questions,

because I'm not so firm in this technical details.

He will answer you in the next Days.

 

PS: Your Page is very fine.

 

Kindly regards

(name removed by Robert Fishman)

 

subtronic gmbh

service

Tel: 07023 909583 Fax: -84

www.subtronic.de

 

    ----- Original Message -----

    From: Robert Fishman

    To: service subtronic

    Sent: Friday, September 24, 2004 7:06 AM

    Subject: Re: technical info subtronic strobes

 

    Dear (name removed by RF),

   

    I attempted to email you previously, but did not receive any replies.  I assume I used the incorrect email address.

   

    I found the user manual you attached very helpful for the strobes contained in it, the alpha, alpha pro, alpha pro macro and Mega Gamma series.  I am still having difficulty though in understanding the German spec sheets for the mini ttl , mini digital, and mini eos 300d ettl.  I must admit I am not an engineer and this may be one reason for my inability to completely understand the data.  I am reluctant to publish the current information that  I uploaded into the digitaldiver.net strobe database without confirmation by the manufacturer (Subtronic) as to it's accuracy.  I hope to be able to include the complete line of Subtronic Strobes, but can not do so until verification of data.

   

    We hope to make the strobe database available to the public on this free web site as soon as possible.  If you can help me proof read the Subtronic data, I would be grateful.  And in doing so, it will allow us to introduce your line of strobes to many English speaking people around the world who are not yet familiar with your flashguns.

   

    You may view the strobe database here:

    http://www.digitaldiver.net/strobes.php

   

    By checking the boxes next to the Subtronic line of strobes, then clicking on the Compare Selected button, you will be led directly to the specs I have uploaded to date.  Unfortunately, I think you might find mistakes made by me.  I would appreciate it if you could point them out and supply me with the correct information.  I will fix any mistakes immediately, before publication.

   

    Thank you again for your valuable time.

    Robert Fishman

    bobf (username)

    www.digitaldiver.net

    http://www.digitaldiver.net/yabbse/index.php

    -------------------------

 

    Robert Fishman

    bob@rfp.com

    www.rfp.com

 

        ----- Original Message -----

        From: service subtronic

        To: bob@rfp.com

        Sent: Monday, September 13, 2004 9:37 AM

        Subject: technical info subtronic strobes

 

       

        Dear Mr. Fishman,

       

        please find enclosed the usermanual for the alpha, alpha pro, alpha pro macro and Mega Gamma series.

        on page 10 and page 12 you find the tecnical datasheet for this flashes.

       

        If you have further questions please contact us again.

       

        Kindly regards

        (name removed)

       

        subtronic gmbh

        service

        Tel: 07023 909583 Fax: -84

        www.subtronic.de

       

        ----- Original Message -----

        From: Robert Fishman

        To: office@subtronic.de

        Sent: Saturday, September 11, 2004 3:56 AM

        Subject: request for specifications

 

        Hello,

       

        I am compiling a database of strobes that are compatible with digital cameras.  Included in the database are specifications that would aid a consumer in his purchase.  I would like to add your strobes to the database.  I have begun with the Mini TTL and the Mini Digital.  I would also like to include the Alpha, Mega, and Gamma.

       

        Because I do not understand the German Language, I am having difficulty in understanding some of the information and terminology that you supply on your web site specification pages.

       

        Is there someone employed by your company that could help me with understanding your information in order to supply specifications with  terms similar to ones found in my strobe database?

       

        To get a better understanding of what I am attempting to accomplish, you may view the present database here:

 

        http://www.digitaldiver.net/strobes.php

       

        We are still in the proof reading stage.

       

        We are not planning to make the database public until Mid September.  I would appreciate it if you could take the time to check my data.  My goal is to supply to the public information that is accurate, objective, and consistent.

       

        The database will be located on a site that is free for the public to view.  It will be part of a larger web site called Digital Diver.  Please feel free to browse the site.

       

        I would appreciate any help you can offer.

       

        Vielen Dank,

        Robert Fishman

       

        I would also like to inform you that I am a full time potter by profession and do not work for any dive related businesses nor do I sell any dive or photo related equipment.

~~~~~~~~~~~~

Currently there are over 50 strobes listed in the database.

Please inform me if any other uploading inaccuracies exist in the database. I will correct them immediately upon confirmation. As always, it is there free of charge, free of opinion, only data supplied by the manufacturer will be found in the database.

regards,

b

Hi Bob

Great stuff & thanks

I got UW GN of Z-240 simply by 1/2 the land value, as that what most simply do and all the books wrote by good people in the field all use the same methology.

regards

craig

I got UW GN of Z-240 simply by 1/2 the land value, as that what most simply do and all the books wrote by good people in the field all use the same methology.

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Yeah. Interesting: Inon ships those little exposure/guide no./distance charts. For Z220 it says aperture 11 for 0.9m distance (underwater). That is almost exactly the topside value divided by two.

IF its Big then it gives out a lot of light, so it must be good...

 

simple..

 

Or we simply let independant people run tests and show us their results.

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I vote for the second way :-)

Julian