Question How to narrow strobe lighting area for macro?

[Searcaigh]

Thank you to all the divers who replied.
I’ve just updated my original post with more details about my shooting setup and the issue I’m facing, so everyone can better understand the situation.
Hopefully, I can find a solution soon.

You should have posted as a separate post to clarify the responses received.

Use a low ISO as also suggested. When I shot film I used Fuji Velvia, which was 50 ASA, and rated at 30 for better colour saturation.

Strobe angle is also important, you shouldn't be pointing them directly at the subject, it takes experience to sort out strobe angles and learning what is best for the camera / lens setup, so you need to spend a couple of days diving and learning what your set up can do.

 

[Tassie_Rohan]

I see that the YS-03 is Slave TTL-only: it has no manual control or power adjustment.

While you mention you are shooting in manual exposure mode, what camera flash mode are you using: auto, fill, manual, etc? Also - what metering mode are you using (spot, center, matrix, etc)?

Shooting the camera in manual mode, while the flash is in TTL mode, can lead to under or over exposure depending on the above settings.

I don't use this strobe, Sony cameras or TTL , but for starters I would test the TTL set up. In a dark room with a test subject set camera to A, S or P mode, set camera flash mode to 'Fill' and play with exposure and flash compensation settings as required. Try with or without the focus flight. See if you can get decent shots that way first.

With Manual exposure and TTL flash you set a manual exposure to get the background lighting. The strobe then completely ignores this and fires until the camera determines that the metering area averages mid grey. Being a strobe this will be your foreground being lit up. This is ok if the subject fills the metering area. Its less ok if the metering area is a small critter with a water or distant background: the strobe will overexposure the critter and foreground until the entire metering area averages a mid-grey exposure. In such cases test spot metering in a dark room with a small subject and an empty background, and be prepared to use the flash compensation setting to dial flash exposure down a stop or two.

On focus lights and it being too dark to focus - I use a small 1000 lumen focus light with strobe auto off, usually at half power (500 lumens) without any issues. What helps here is setting my screen to always be bright regardless of exposure settings (ie turn off exposure preview). I can see the shot, and if its in focus, even when manual shooting night dives. I'm sure Sony has this feature somewhere in its set up [EDIT: Turn off 'Live View Display' in one of the camera settings sub menus]

Cheers
Rohan.

 

[Searcaigh]

Some additional information from Kate Jonker

Black Backgrounds - without a snoot...​

To nail those gorgeous black backgrounds that make your subjects POP, use a fast shutter speed (1/250), a low ISO (ISO100), and a small aperture (F11 for compacts, F18 for TGs and F20-F25 mirrorless / DSLRs).

Use a narrow beam torch of no less than 1000 lumen, or a small strobe without a diffuser and point it back towards your housing so that the outer edge of your light lights your subject but not the reef behind it (see picture below).

Those settings cut out all ambient light, and your torch / strobe is the only source of light. BIG TIP: It is much easier if the water is behind your subject as there will be nothing for your strobe / torch to light.

This will make your critter pop while the background falls into darkness.

 

[Ukmc]

Some additional information from Kate Jonker

Black Backgrounds - without a snoot...​

To nail those gorgeous black backgrounds that make your subjects POP, use a fast shutter speed (1/250), a low ISO (ISO100), and a small aperture (F11 for compacts, F18 for TGs and F20-F25 mirrorless / DSLRs).

Use a narrow beam torch of no less than 1000 lumen, or a small strobe without a diffuser and point it back towards your housing so that the outer edge of your light lights your subject but not the reef behind it (see picture below).

Those settings cut out all ambient light, and your torch / strobe is the only source of light. BIG TIP: It is much easier if the water is behind your subject as there will be nothing for your strobe / torch to light.

This will make your critter pop while the background falls into darkness.

I read your post with an interest but I didn’t get “pointing light towards the housing” part. Can you please explain it a little bit better?

 

[Tassie_Rohan]

I read your post with an interest but I didn’t get “pointing light towards the housing” part. Can you please explain it a little bit better?

To preempt @Searcaigh I have hired only the very best graphic artists for the following diagram:

See your strobes as cones of light. You want to catch your subject on the edge of the light cone.

I rarely point my strobe at the subject - as it lights up backscatter and the background. My strobes are often pointed at my hands.

Cheers
Rohan.

 

[Searcaigh]

Can you please explain it a little bit better?

 

[Ukmc]

To preempt @Searcaigh I have hired only the very best graphic artists for the following diagram:


View attachment 913440


See your strobes as cones of light. You want to catch your subject on the edge of the light cone.

I rarely point my strobe at the subject - as it lights up backscatter and the background. My strobes are often pointed at my hands.

Cheers
Rohan.

Thank you. I love your artwork!
I can not wait to try it and see how it works in my hands.

 

[Tassie_Rohan]

In this shot, with a nice black background, have a close look at the shadow from the hydroid's stalk:

The shadow is towards the camera.

To get this shot I put the strobe above and slightly behind the hydroid, pointing back towards the camera.

See your strobe as a cone emitting light, and your lens as a cone receiving light. Where those two cones intersect is where your image will be.

The shot was taken during the day, but by increasing aperture (F16+), using a fast shutter speed (1/250) and low iso (100-200) I was able to keep ambient light to a minimum. I purposely lined up a shot with a lot of water behind, rather than background objects that would reflect the light.

 

[theoceanlens]

To preempt @Searcaigh I have hired only the very best graphic artists for the following diagram:


View attachment 913440


See your strobes as cones of light. You want to catch your subject on the edge of the light cone.

I rarely point my strobe at the subject - as it lights up backscatter and the background. My strobes are often pointed at my hands.

Cheers
Rohan.

Thanks, that’s super helpful — and I have to say, I really love your art!