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Ideal length arms for camera set up?


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#1 CGreathe

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Posted 02 January 2019 - 09:53 PM

Any recommendations on the ideal length for the arms on a double strobe set up? At the moment I have 6" and 4" arms but I've seen people with much longer ones nd wondering what the benefit is, if any? Thanks!



#2 TimG

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Posted 02 January 2019 - 10:58 PM

Hi!
 

I've been using a ULCS 8" plus 5" combination on each of two strobes for almost 20 years and have always found it fine for both macro (they tuck in nicely) and wide-angle. 

 

The argument, as II understand it, for really long arms is to improve wide-angle coverage. But my own experience with Inon strobes  (Z220 and Z240) is that it's much better to concentrate the light onto a relatively small area of reef (which 8+5 does nicely) rather than try and spread light widely. With the 8+5 combination it's easy to get both strobes on the same side which is what I often do.


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#3 Robin-D

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Posted 03 January 2019 - 07:50 AM

Hello,

 

I use (nauticam) 8 and 12 inch arms myself. Not really do I need the length for wide angle, but it allows me to use several stix floats on each arm. I add 2 jumbo floats on the 8 inch and 4 large floats on the 12 inch, to make my camera neutral. With shorter arms, this probably isnt possible, or the floats are so close to the clamps that you cant tuck in your strobe's.

 

It also adds some extra length for back lighting and it allows me to move my strobe with retra snoot pretty far from my subject, if I want to light a bigger area.

 

If still feels very stable underwater. 

 

The downside I guess, is that when tucked in, the setup is still pretty large, so it might be restricted in cracks etc.


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#4 TimG

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Posted 03 January 2019 - 08:45 AM

Hello,

 

I use (nauticam) 8 and 12 inch arms myself. Not really do I need the length for wide angle, but it allows me to use several stix floats on each arm. I add 2 jumbo floats on the 8 inch and 4 large floats on the 12 inch, to make my camera neutral. With shorter arms, this probably isnt possible, or the floats are so close to the clamps that you cant tuck in your strobe's.

 

It also adds some extra length for back lighting and it allows me to move my strobe with retra snoot pretty far from my subject, if I want to light a bigger area.

 

If still feels very stable underwater. 

 

The downside I guess, is that when tucked in, the setup is still pretty large, so it might be restricted in cracks etc.

 

Good point on the space for extra Stix floats, Robin!

 

My system tends to be a bit more negatively buoyant than I would like ideally and I have a full Stix load already. (I tried the Inon Megafloats but just could not get on with them and they were WAY too buoyant).


Tim
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http://www.timsimages.uk
Latest images: http://www.shutterst...lery_id=1940957


#5 Chris.b

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Posted 04 January 2019 - 07:55 AM

I am a relative beginner, but my understanding is that long stobe arms begin to become more important when shooting through lots of water - i.e. when shooting big scene wide angle shots. This is because it will help to avoid large amounts of backscatter.



#6 TimG

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Posted 04 January 2019 - 08:02 AM

Hey Chris

 

Yeah, sort of: the import thing is to light up as little water (and its suspended goop) as possible in between the lens and the subject.

 

The aim is to get the two light cones to meet each other as close to the subject as possible leaving a triangle(ish) of unlight water between camera and subject. Big arms could help but realistically the furthest you are going to get strobe flashes to light is about 2'-3' from your camera.


Tim
(PADI IDC Staff Instructor and former Dive Manager, KBR Lembeh Straits)
Nikon D500, Nikkors 105mm and 8-15mm, Tokina 10-17mm,  Subal housing

http://www.timsimages.uk
Latest images: http://www.shutterst...lery_id=1940957


#7 Chris.b

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Posted 04 January 2019 - 09:41 AM

Thanks Tim,

 

calculating the distance and the strobe power whilst maintaining position...that ain't easy! I need a lot more practice!



#8 TimG

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Posted 04 January 2019 - 01:04 PM

Thanks Tim,

 

calculating the distance and the strobe power whilst maintaining position...that ain't easy! I need a lot more practice!

 

Heheheh, welcome aboard, Chris!


Tim
(PADI IDC Staff Instructor and former Dive Manager, KBR Lembeh Straits)
Nikon D500, Nikkors 105mm and 8-15mm, Tokina 10-17mm,  Subal housing

http://www.timsimages.uk
Latest images: http://www.shutterst...lery_id=1940957


#9 okuma

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Posted 04 January 2019 - 11:01 PM

I went with 2 18" arms for a while, but changed to 2 8 " on each side now. I believe strobe alignment is more critical than going beyond the 2 8" arm set up.


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#10 Interceptor121

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Posted 05 January 2019 - 07:18 AM

I have 3,5,8 segments and I am going to get some 12

 

Generally the 5+8 is the most versatile and unless you shoot some really large subject this covers majority of the scenarios

 

3+5 are useful for macro and also for close up video - if you don't do any video at close range you can skip this

 

8+12 am getting for great hammerhead in essence the long arm in bad visibility allow you to have edge lighting avoiding backscatter. If it was not for this trip so far I have done fine with 5+8 

 

 

To give an idea considering a 90 degrees strobe for simplicity (100-110 need longer arms)

 

5+8 segment with clamps gives you 19" reach plus 6' tray 25" subject at 63 cm from the tray axis is when the strobe beams start to meet

 

8+12 segment with clamps gives you 26" reach plus 6"tray 32" subject at 81 cm from the tray axis

 

In reality as strobes have more than 90 degrees typically when you add more length you don't gain the same distance but a factor of 0.7 for each unit you add

 

This assuming that you put the strobe at 9 and 3 o clock otherwise the subject gets close and closer or backscatter comes


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