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Ikelite 8" Dome port Flare


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#1 zissou

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Posted 11 September 2008 - 05:04 PM

I was hoping to get some help with a new ikelite dome port issue I'm having. The problem is happening with a D80, tokina 10-17 with an ikelite housing and 8"dome.

I have a single ds-125 stretched out on an 8 and 12 inch arm.

In some of my photos I'm getting a pretty severe flare from the strobe. The attached photo, taken at night (Cocos Island), has a pronounced example.

This must be related to strobe positioning, however I was wondering what thoughts people had in minimizing this.

Thanks for any advice you might have.

Also - I've been using the smudge tool to try and blend this out. What other techniques are there for hiding this in CS2/3?

Attached Images

  • flare.jpg


#2 rtrski

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Posted 11 September 2008 - 05:44 PM

I think you want to pull the strobe BACK, behind the plane of the edge of the dome and dome port. Then the backscatter and sidescatter from the strobe head can't light up the front ring of your lens.

from the backscatter you might also have the strobe aimed too 'straight' at your subject - try tipping it out a bit more, e.g. aim it almost parallel to the axis of the lens, not pointed 'in' as much.

Current rig: Sony SLT-alpha55 in Ikelite housing, Sigma 105mm f2.8 DC Macro w/ Ike 5505.58 flat port or Sigma 8-16mm f/4.5-5.6 DC HSM behind UWCamStuff custom 5" mini-dome. Dual INON z240 Type IVs triggered with DS51 for TTL mimicry, or DS51 alone with home-made ringflash assy for macro.

 

Topside, unhoused: Sony SLT-alpha99, Sigma 150-500mm + 1.4TC (Saving for Sony 70-400 G2), Sigma 15mm diagonal fish, Sony 24-70mm f2.8 CZ, Tamron 180mm f2.8 Macro...all the gear and nary a clue...


#3 zissou

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Posted 11 September 2008 - 06:11 PM

Ok that is clear.

So the flare is caused by light from the strobe directly hitting the front of the lens, which then reflects off the dome and into the image?

By pulling the strobe back the housing/back of the port would block any strobe lighting from directly striking the lens.

Angling the strobe more parallel to the lens will reduce back scatter.

Thanks, strobe placement is a new challenge for me.

Wellington

#4 PriusDrIVER

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Posted 15 September 2008 - 03:31 PM

I have the same thing on several images from diving in bright day light with amazing clarity. The light coming from outside of the dome port was enough that the reflection of the entire ring of the lens is visible, including the text. Of course, its typically rare that I have the vis and abundance of light that I experienced diving Clear Lake, I don't have any of the flawed images online...not something I want to share with everyone :uwphotog:
http://www.hydrofoto...Clear_Lake.html

edit: My issues were without strobes though. I think the other poster was right on the glare/flare issue. As fr back scatter, you want to only light your subject and not the water between the lens and the subject. So paint only the items you want to see with the strobes, if you light up all of the particles floating in the water between the lens and the fish (or whatever) you will see primarily all of the stuff floating in between. Think of it as driving in the fog with high beams on. Strobe placement is a challenge for sure, or maybe its 1/2 the fun.

Edited by PriusDrIVER, 15 September 2008 - 03:34 PM.