Flash light enters the frame

Hi all, kind of a newbie question here, but I am here struggling with this. In wide angle photos, I have really hard life trying not include the strobe light into my picture. My go to position (and the position of all the shots I attach) is behind the camera (10-20 cm), pointed slightly outside, and approx. 30 cm away from the dome to the side. This configuration worked really well with larger domes, but since I switched to the 4.33 dome from nauticam, it seems more difficult not to include the flash light into the frame, particularly the right one. Any idea on why this happens? Please, also advise on "basic" stuff, since I know the basics, but apparently I am missing the point here.

May be a dome defect? Unlikely

Strobe positioning? I think so, but why does it work for the left one and not the right one? And why it is more difficult with the smaller dome?

I am shooting with a EM1 mark 2 in Nauticam housing, and these photos are taken with the 8mm fisheye from Panasonic.

Thank you  

I think as you say it is positioning. My go to is to have the strobes pretty far behind the handles of the housing and pointing out at like 20 degrees.

Bill

Strobe Position and Power Levels.  You can try to reduce strobe power a bit, maybe bump up your ISO some.  

Simply having your strobes out to the side and angled outward a bit will probably expose well, but leave you with a flat image without texture or shadow. I tend use a really long set of arms and then rake the subject with one strobe pointed inward (on the side or top) between the subject and dome.  The second strobe is usually at a lower power level at a more traditional position as a fill light.  I rarely get much backscatter and the images have a much more lifelike dimensional look to them.

15 hours ago, bvanant said:

I think as you say it is positioning. My go to is to have the strobes pretty far behind the handles of the housing and pointing out at like 20 degrees.

Bill

 

Well I actually had them quite a bit behind my dome, maybe I should try more. 

14 hours ago, davehicks said:

Strobe Position and Power Levels.  You can try to reduce strobe power a bit, maybe bump up your ISO some.  

Simply having your strobes out to the side and angled outward a bit will probably expose well, but leave you with a flat image without texture or shadow. I tend use a really long set of arms and then rake the subject with one strobe pointed inward (on the side or top) between the subject and dome.  The second strobe is usually at a lower power level at a more traditional position as a fill light.  I rarely get much backscatter and the images have a much more lifelike dimensional look to them.

I am shooting with Z240, so not the most powerful strobes, lowering the power would make my ISO bump, plus it would be harder to get a darker background. Finally I would only reduce the problem, not avoiding it.

Do you mean that one strobe is placed inward? Aren't you getting any backscatter? I should try this 

Here is an example I shot last week with a similar setup to yours, using a D850 / 15mm Sigma FE / 170mm port + Inon 330 strobes.

The left strobe arm is 12+16+8 and the strobe is pointed inward from the upper left.  The right strobe is closer in to the right an pointed forward.  ISO 250 / F9 / 1/80s  Left strobe is -1.5ev, right is -3ev.  The water conditions in Puget Sound were relatively good by local standards at 25 foot visibility but this is heavily particulate water.  I did not do any Spot removals of backscatter, but I did bring  down to 0 to the Clarity/Texture (midtones) of the green water using LR.  You can see there is hardly any distracting backscatter in the image.

The point of using a lower strobe power is that you don't illuminate the backscatter nearly as much in poor clarity water.  You can boost exposure in post processing to get the brightness you want for the image, selectively if needed.  I shot at -1.5ev & -3ev which is about 1/3rd and 1/8th power for the two strobes.  If I shot in these dark and chunky waters at Full or Half power the image would be blasted out.

If you want a darker background use a faster shutter speed. 1/125 or 1/200.  The strobes don't impact open water background color.  Shutter speed controls ambient light.

The illuminated backscatter you are seeing in the images is due to the "hot spot" put out by the strobe being "seen" in the image. Typically this so because your strobes are too far forward, or are turned up too high (for the water conditions).

The strobes project a cone of light, and the part of this light that is close to the strobe is very bright. Any particulate caught in this will be illuminated. As you increase the power of the strobe, this "hot spot" moves further away from your strobe, and hence into your image.

The wider your lens (the 8mm is pretty wide!), the further back your strobes typically need to be. I start with mine at least behind the housing handles. With smaller housings, you may need to go further back.

Lastly, this advice only really holds when shooting conventional wide angle scenes like the images you shared. 

If you haven't yet, have a look at @Alex_Mustard's book "Underwater Photography Masterclass." His info on lighting is exceptional...

Adam

Thanks a lot for all your advices. As soon as I can get my feet wet, I'll try something different as you said.

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On 10/16/2020 at 8:51 PM, davehicks said:

Strobe Position and Power Levels.  You can try to reduce strobe power a bit, maybe bump up your ISO some.  

Simply having your strobes out to the side and angled outward a bit will probably expose well, but leave you with a flat image without texture or shadow. I tend use a really long set of arms and then rake the subject with one strobe pointed inward (on the side or top) between the subject and dome.  The second strobe is usually at a lower power level at a more traditional position as a fill light.  I rarely get much backscatter and the images have a much more lifelike dimensional look to them.

Great advise. I think Dave has a camera with larger sensor.

For the smaller MFT (because of noise) it may be better not to increase ISO but instead increase shutter speed for more background illumination and, when strobe power is decreased, to increase aperture. Increased ISO with MFT only as the last measure, when aperture and shutter speed are already at their limits...

Wolfgang

@lbedogni

Some great advice already given, so I'll just add one thing:

Are you shooting with any diffusers on your strobes? A diffuser will spread the z240 light out a bit more, lessening the impact of any hotspots.

 

2 minutes ago, oneyellowtang said:

@lbedogni

Some great advice already given, so I'll just add one thing:

Are you shooting with any diffusers on your strobes? A diffuser will spread the z240 light out a bit more, lessening the impact of any hotspots.

 

Yes, I am always using the 4600K -0.5 diffusers 

Don't be afraid to crop.  Sometimes I'll pull a strobe into the frame on fisheye to get the lighting right.  Then crop out the flash from the image.