How can I preview exposure and autofocus with flash in a low light studio?

Question

Yesterday I had my first portrait shoot in a studio. I already had pre-imagined my lighting setup: a single softbox flash on the right for the general exposure and a big reflector on the left to soften and brighten up the depths.

During the shoot, however, my liveview preview was almost pitch black, which is understandable when I was using 1/60s, f/2.2 and iso 50 in a dimly lit studio. The only light source for the autofocus was a light through the softbox which was turned on when the flash wasn't firing.

Below is an example of what I saw in the liveivew (left) and the actual image I took (right):

Thankfully my Sony A7 III did an amazing job keeping track of the model's eye to focus on. It seemed like it brightened up the liveview every time I took a picture with prefocus on. Most of the time, I could work the composition with the little time I had when the liveview exposure was increased during AF. All planned pictures of poses exceeded my expectations so everything turned out fine.

I think I should improve my workflow in this studio situation and realized I don't know enough of studio flash usage with my camera.

How can I preview the flash exposure and simultaneously use AF in liveview?

Answer 1

Many cameras allow you to set your live display to "preview" or "framing". "preview" adjusts the brightness and depth of focus to match the expected photograph, "framing" is supposed to help with, well, what you were doing.

In a few of my cameras, "preview" effectively reverts to "framing" if you switch on flash mode (but not if you use "slow sync" in which case the flash is supposed to be more of a fill-in). What your camera does in which circumstance and whether there are controls for changing the mode of your display between "framing" and "preview", I don't know.

PostScriptum: from the manual of your camera available from Sony's web page:

1 MENU → (Camera Settings2) → [Live View Display] → desired setting.

Hint When you use a third-party flash, such as a studio flash, Live View Display may be dark for some shutter speed settings. When [Live View Display] is set to [Setting Effect OFF], Live View Display will be displayed brightly, so that you can easily check the composition.

That sounds like it should cover your use case.

Answer 2

You simply cannot preview the exposure of light that does not exist at that moment. You had modeling lights on, which is about the best you can do.

You do not have to use such a dimly lit studio environment. But you do generally want to start with a dark frame exposure (or nearly). To help with AF/live view you could turn up the modeling lights if available (but "proportional" is usually the better choice), or bring up the room lights some and use a higher sync/shutter speed. You could also use a smaller aperture, if that was suitable for the desired image (often is for a studio pic); as long as you had more flash power available. And make sure exposure preview is disabled; otherwise you will see your dark frame exposure.

Answer 3

Comments tell me my initial assumption was incorrect, but I'll leave it here, just in case.

You cannot use the rear screen on many cameras to preview exposure, as they auto-adjust to try to give a 'best view' in all lighting.

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I'm assuming your softbox flash was a regular strobe light?

That's why the pros use studio flashes, which contain modelling lights. These let you see the general shape of the lighting before the shot is taken, and is also hugely useful to just be able to actually see in the room, and as something to help out auto-focus.
The idea is that the flashes almost completely overpower the modelling lights, so they don't really interfere with the end result.

Being in a similar position, I only have regular strobes, I often use video lighting squeezed in tight to the softboxes to mimic modelling light. It doesn't quite work, because you cannot achieve the exact same angles, but it's a reasonable close-approximation, for zero additional budget [as I have them anyway, for video].

I have considered trying to squeeze some small consumer LED spotlights, rear-facing inside the softboxes to better approximate my angles - but this is a project currently awaiting trial.

Answer 4

While technically my answer was answered by Tetsujin, i wasn't satisfied and dug a bit into it.

It seems I've had a misconception about the EVF because it obviously simulates the picture you're getting when pressing the shutter button. When using a flash, it won't know anything of it and can't calculate that in.

There is however a workaround it seems: disabling live view in the EVF. Doing this allows you to see what the sensor sees, without using the dialed-in exposure for my flash. As long as there is some light hitting the sensor, it helps a lot on AF/Composition.

The option is called "Live View Display" and is located under "Display/Auto Review1" on my Sony A7 III.

Assigning a button (I used C3) will then allow me to switch back and forth when necessary (on, when using the camera in natural light, off when in studio).

This does not eliminate the issue of "previewing the flash" but rather in combination with a small light source and some test shots it will be a lot easier to make composition and focus adjustments, without touching the settings.

Thanks for all the answers!

Answer 5

Although the specific case's question has been answered. I would like to answer the more broad question:

How can I preview the flash exposure and simultaneously use AF in LiveView? (in a low light studio)

For me, the mentality of this kind of shooting needs one simple solution. Working with continuous light sources. We live in an era in which Led lights are powerful but cold enough to add any type of modifiers including softboxes, which were impossible in the tungsten lamps era.

But as I understand the question, I would say that a "preview" is also given by experience. You have more or less the knowledge of how a specific light will render a result. But even if you do not have years of experience, that is what test shoots are for. You make some test shoots to "preview" the light, make corrections and then you sort of forget about light and focus on expression and framing.

And as the question also mentioned that is working on a low-light studio, that part can be addressed by not making the studio that dark that you can't see.

Almost any simple flash will overpower a "normal" interior light.

Also, there is probably no need to turn off the modeling lamp of studio flashes, unless some technical detail, some heating, or the case you need the pupils of your subject really open.