Autofocus with Ambient Light Eliminated?

[surfoxy]

Hey folks, I've been poking around a bit for an answer to this, and maybe I'm not asking the question in the right way, 'cause I can't figure it out.

I'm new to flash photography, or at least haven't done it in years, and never did it enough to really learn anything. Now I have a new setup.

I'm trying to take some headshots and get rid of all the ambient light. So I'm setting my camera such that the exposure would be dark without the flash.

My problem is that it's so dark my camera isn't grabbing focus in AF, presumably 'cause...there's basically no light.

Is there a way around this? I can't find anyone discussing it on the bazillion YouTube videos about simple flash setups.

I'm sure it's something easy I'm missing. I know I can shoot manual, but would like to see if there's a way to do it with AF.

Thanks!

Camera: Sony A9II
Lenses: Sigma 85 1.4 DG DN / Sony 24-70 GMII / Sony 70-200 GMII
Lighting Setup: Godox X-ProC trigger / Godox TT600s Speedlight off-camera / Shoot-through umbrella / Reflector

--

Chris

 

[surfoxy]

I turned off Live View Display.

--
Chris

 

[NAwlins Contrarian]

My problem is that it's so dark my camera isn't grabbing focus in AF, presumably 'cause...there's basically no light.

Is there a way around this?

OK figured it out...

I turned off Live View Display.

There are two separate problems, and these two posts appear to confuse one with the other.

If there isn't enough ambient light for your camera to reliably focus, then you just have to either (1) add more of ambient light (and possibly use more flash power to render the ambient light inconsequential), or (2) if your subject is close enough, rely on a camera with a dedicated autofocus illuminator and use it. My A9 has one, so I assume your A9 II does too. Here's an excerpt of the page from the A9 manual about turning on the AF illuminator:



If the A9 II has the same limitations, depending on how you want to work, the focus illuminator may not work for you.

The viewfinder setting is a rather separate issue: when you're working with a flash, especially where it's providing more than a little fill, you don't want the viewfinder simulating the exposure because it cannot account for the flash and therefore its image is too dark to be functional. You appear to have found that setting.

 

[Teila Day]

(...)

I'm trying to take some headshots and get rid of all the ambient light. So I'm setting my camera such that the exposure would be dark without the flash.

I'm curious to know your shutter speed and aperture setting.

My problem is that it's so dark my camera isn't grabbing focus in AF, presumably 'cause...there's basically no light.

Most cameras will focus with the lens wide open irrespective of your aperture setting.. so say you're using a f/1.2 lens.. the camera will focus with the lens gaping open, and will only stop down to whatever aperture you've selected (let's say f/8) right before the photograph is taken. Such is one of the advantages of fast lenses, even if you never shoot with the lens wide open. Another advantage is having a brighter viewfinder while you set up your shot or especially if you're trying to manually focus a lens.

 

[surfoxy]

The second one is my issue, despite my wording. Thanks.

 

[DirkPeh]

Despite the camera, the flash he is using (TT600) has an AF assist beam/light.

 

[NAwlins Contrarian]

Lighting Setup: Godox X-ProC trigger / Godox TT600s Speedlight off-camera / Shoot-through umbrella / Reflector

So two questions:

(1) can a TT600 be set to provide almost like a short-duration modeling light for focus assist and/or other use when off camera and shooting through an umbrella? If so, what setting do you use?

(2) Does the X-ProC trigger (which is the Canon version of the first XPro trigger) provide control over any functionality other than maybe 'fire' when mounted on a Sony? I have the XPro II S (i.e. Sony version of the second XPro) trigger, but I would have thought the Canon version would have been limited when used on a Sony--or maybe only in TTL mode, because maybe on other-than-TTL all it gets from the camera is the 'fire' signal? Or maybe HSS is limited too? Is there some chart of what works and what doesn't?

Thanks!

 

[tugwilson]

Lighting Setup: Godox X-ProC trigger / Godox TT600s Speedlight off-camera / Shoot-through umbrella / Reflector

So two questions:

(1) can a TT600 be set to provide almost like a short-duration modeling light for focus assist and/or other use when off camera and shooting through an umbrella? If so, what setting do you use?

The TT600 pulses a red light (which you can;t disable) which I think is intended to be AF assistance but almost certainly doesn't work for mirrorless cameras.

(2) Does the X-ProC trigger (which is the Canon version of the first XPro trigger) provide control over any functionality other than maybe 'fire' when mounted on a Sony? I have the XPro II S (i.e. Sony version of the second XPro) trigger, but I would have thought the Canon version would have been limited when used on a Sony--or maybe only in TTL mode, because maybe on other-than-TTL all it gets from the camera is the 'fire' signal? Or maybe HSS is limited too? Is there some chart of what works and what doesn't?

The Canon version will not support HSS or TTL on a Sony camera.

 

[DirkPeh]

Despite the camera, the flash he is using (TT600) has an AF assist beam/light.

I agree that sometimes a flash will provide an autofocus assist, and I actually have a pair of TT600s, but I haven't tried them in such a situation, so I'm curious about their function(s) and your experience.

I have the TT685 II on my Fuji. The assist beam works.

Lighting Setup: Godox X-ProC trigger / Godox TT600s Speedlight off-camera / Shoot-through umbrella / Reflector

So two questions:

(1) can a TT600 be set to provide almost like a short-duration modeling light for focus assist and/or other use when off camera and shooting through an umbrella? If so, what setting do you use?

(2) Does the X-ProC trigger (which is the Canon version of the first XPro trigger) provide control over any functionality other than maybe 'fire' when mounted on a Sony? I have the XPro II S (i.e. Sony version of the second XPro) trigger, but I would have thought the Canon version would have been limited when used on a Sony--or maybe only in TTL mode, because maybe on other-than-TTL all it gets from the camera is the 'fire' signal? Or maybe HSS is limited too? Is there some chart of what works and what doesn't?

Thanks!

 

[NAwlins Contrarian]

Despite the camera, the flash he is using (TT600) has an AF assist beam/light.

I agree that sometimes a flash will provide an autofocus assist, and I actually have a pair of TT600s, but I haven't tried them in such a situation, so I'm curious about their function(s) and your experience.

I have the TT685 II on my Fuji. The assist beam works.
But that's when it's mounted in the camera's hot shoe, right? The OP's stated lighting setup (quoted below) seems to be a different situation.

The OP, post: 68070417, member: 2009600"]

Lighting Setup: Godox X-ProC trigger / Godox TT600s Speedlight off-camera / Shoot-through umbrella / Reflector

So two questions:

(1) can a TT600 be set to provide almost like a short-duration modeling light for focus assist and/or other use when off camera and shooting through an umbrella? If so, what setting do you use?

(2) Does the X-ProC trigger (which is the Canon version of the first XPro trigger) provide control over any functionality other than maybe 'fire' when mounted on a Sony? I have the XPro II S (i.e. Sony version of the second XPro) trigger, but I would have thought the Canon version would have been limited when used on a Sony--or maybe only in TTL mode, because maybe on other-than-TTL all it gets from the camera is the 'fire' signal? Or maybe HSS is limited too? Is there some chart of what works and what doesn't?

Thanks!

[/QUOTE]

 

[surfoxy]

Yeah it’s off camera. Its the Sony version, don’t know why I put C on there. Anyway, the live view off solved it.

Thanks all!

--

Chris

 

[Digitalis32]

I'm trying to take some headshots and get rid of all the ambient light. So I'm setting my camera such that the exposure would be dark without the flash.

The trick here is to have the camera and flash at a fixed power setting where the ambient light doesn't have any contribution to exposure, indoors even on a well lit day outside would require ISO 100 f/0.95 1/250th but at ISO 100 f/11 1/1250th ambient light doesn't have any chance of impacting exposure. Mosh flashes these days have high speed sync capability, where it is possible to work with very high shutter speeds that mitigates the impact of ambient light. Though with each flash brand has their operational quirks to getting the best results is likely to require some experimentation.

--
A camera is just a camera. Who is behind it, matters far more.

 

[surfoxy]

Does anyone use an ND filter instead of HSS? I only ask because I have them but have never looked into HSS. Just curious, not really an issue I’m facing right now, but could come up for some outdoor senior portraits in a couple months if I want to use a wide aperture.

 

[Off The Mark]

Does anyone use an ND filter instead of HSS? I only ask because I have them but have never looked into HSS. Just curious, not really an issue I’m facing right now, but could come up for some outdoor senior portraits in a couple months if I want to use a wide aperture.

Yes. In many cases, an ND (or stopping down) will give you a higher ratio of flash power to ambient power than using HSS.

Neil van Niekirk used to have an article on his site where he compared using an ND filter versus HSS and he found that you would get about 1.5 stops higher flash to ambient ratio using ND versus HSS. I don't think he has that article on his site anymore, but you can search for yourself:

Photographer NJ & NYC - NJ / NYC photographer / New Jersey

Photographer NJ NYC, Headshot photographer NJ NYC, Editorial photographer NJ, Corporate Event photography NJ NYC, Time-Lapse Photography NYC,

neilvn.com

The other issue is that HSS is more likely to overheat your flash guns quicker than shooting them at full power but NOT in hss mode.

One main drawback is that using ND or stopping down results in a lower shutter speed, which may be too slow if you are trying to capture fast action (like a person running / dancing / jumping or such.

 

[rumple]

Does anyone use an ND filter instead of HSS?

Always, if I have time to setup a shot. Usually, if I don't.

HSS works, but is much less efficient than ND filters because some or most of the flash is wasted on the shutter curtains, not getting to the sensor - so the flash needs to be a lot closer, sometimes too close, to the subject. With ND's, one simply sets the camera to x-sync, sets the flash to "beat the sun" if that is what is desired, then shoots.

A misconception is that the ND makes it harder to beat the sun because it reduces flash. It reduces flash and ambient at the same time, so as long as one can get the flash overpowering the sun at, say, f/11, sticking on an ND just means opening up the aperture to compensate for both flash and ambient. Flash power stays the same.

A link that goes through the HSS inefficiency: http://betterfamilyphotos.blogspot.ca/2010/05/improving-flash-efficiency-with-nd.html , and another: http://neilvn.com/tangents/high-speed-flash-sync/

I can "beat the sun" with a single bare SB-900, but would more typically use two so they aren't working as hard, have longer range, and recycle more quickly.

My DSLR gear - fast lenses and bright viewfinders - was perfectly usable with five stops of filters. Consumer gear, with slow lenses (but then, one can't use more than 2 or so stops with a 5.6 lens) and dimmer viewfinders, might not be. Five stops is as much as I ever use. With MILC cameras, composing is unaffected by ND filters - MILC cameras just brighten up the EVF.

I suppose that, when shooting at f/1.4 in bright sun with flash as the key and ambient under-exposed, HSS or HyperSync would be helpful. Let's do the sunny 16 math: under-exposing ambient means about f/22; using ISO50 (works on my gear) gets us back to f/16; using x-sync of 1/200 gets us back to f/11. Five stops down is f/2. So yes, I'd need hypersync or hss or a shaded shooting area for f/1.4 (or could go with six stops). Otherwise, NDs would be fine and much more efficient for flash - although it's worth acknowledging than many people prefer HSS because it frees them from filters and brightens up their viewfinder, which is absolutely fine by me. Some prefer HSS because they think high shutter speeds freeze motion - which is a whole 'nuther discussion.

Using HSS does remove the need to purchase ND filters, but you may have them anyway and HSS flashes can cost more than non-HSS flashes.

 

[surfoxy]

Thanks! Appreciate the info.

 

[surfoxy]

Super. Thanks for all that!