How to properly focus on faces when the assist beam is too far on a dark environment.

[IntrepidB]

I've been shooting portraits and events for a while, and always used lenses that would go from 16 to 70mm.

I recently upgraded to a 70-200mm lens and sometimes I like to use the longer ends and 2.8 aperture in order to get a very nice background. I usually have one external flash which I add a diffuser and/or bounce on walls/ceilings to get a softer light.

My main trigger is a Yongnuo 622tx which has a nice and strong red assist beam that is really useful for focusing in low light. Up to 70mm, the camera can easily make use of the beam to achieve perfect focus.

However, when shooting the 70-200mm above 100mm, the beam becomes too dim due to the distance and the camera is unable to achieve precise focus, especially when the subject is much darker than the background.

Any ideas on how to get around this situation?

 

[jaomul]

If there posed use a small flashlight, if they are not you'll have to shoot in brighter areas

 

[Didereaux]

If there posed use a small flashlight, if they are not you'll have to shoot in brighter areas

...that is with MANUAL focus, of course.

 

[jaomul]

If there posed use a small flashlight, if they are not you'll have to shoot in brighter areas

...that is with MANUAL focus, of course.

No, just get enough light on subject so the camera can autofocus, if someone is posing it's easy enough. Just turn light off once focus is achieved

 

[dcbear78]

What type of camera?

 

[jaomul]

Any camera. The light is seperate.

 

[Didereaux]

If there posed use a small flashlight, if they are not you'll have to shoot in brighter areas

...that is with MANUAL focus, of course.

No, just get enough light on subject so the camera can autofocus, if someone is posing it's easy enough. Just turn light off once focus is achieved

I'm overly cautious!

 

[jaomul]

Cautious is good, sometimes . Any camera that does autofocus only needs to get some contrast on a subject to focus. A small torch or light can help as if its to dark there's no contrast where you need focus point to focus. I don't mean a massive flashlight in the face, but a little led torch can be great

 

[KmH]

That dastardly Inverse Square Law!

Yep.
Any light source that will provide sufficient illumination so the AF system can do it's thing.
It doesn't have to be the little, not all that powerful AF-Assist light in the camera.

 

[Derrel]

That dastardly Inverse Square Law!
Yep.
Any light source that will provide sufficient illumination the AF system can do it's thing.
It doesn't have to be the little, not all that powerful AF-Assist light in the camera.

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[PaulWog]

Any camera. The light is seperate.

Could matter what camera. D750 focuses to -3 EV which can make the difference, for example.

 

[jaomul]

Any camera. The light is seperate.

Could matter what camera. D750 focuses to -3 EV which can make the difference, for example.

No. Principle is the same. Once it gets to dark for the camera. Cameras ability is irrelevant

 

[PaulWog]

Any camera. The light is seperate.

Could matter what camera. D750 focuses to -3 EV which can make the difference, for example.

No. Principle is the same. Once it gets to dark for the camera. Cameras ability is irrelevant

Uhhh, what?

You're saying that every camera stops focusing at the same light level?

 

[jaomul]

Any camera. The light is seperate.

Could matter what camera. D750 focuses to -3 EV which can make the difference, for example.

No. Principle is the same. Once it gets to dark for the camera. Cameras ability is irrelevant

Uhhh, what?

You're saying that every camera stops focusing at the same light level?

No. I did not say that at all

What I am saying is you use the same principle when it gets to dark for the camera to focus without help. Whatever point that is will be different depending on cam specs, but it's the way to overcome this problem is the topic, when it happens, not a number printed on a camera spec sheet

 

[PaulWog]

No. I did not say that at all

What I am saying is you use the same principle when it gets to dark for the camera to focus without help. Whatever point that is will be different depending on cam specs, but it's the way to overcome this problem is the topic, when it happens, not a number printed on a camera spec sheet

Practicality vs. Technicality. The OP is looking for an answer, rather than quibble about photography principles.

What I'm saying is the OP is asking if there's a way to get around this. I'm saying if his camera is older with poor low light focusing capabilities, an upgrade may be in order.

Speaking practically here. Rather than just beaming a flashlight at people & hoping for a natural response.

With that said, maybe a better assist beam could help? The AF assist beam from my SB-700, for example, is pretty good. I'm not sure what flash OP is using. I could lock focus at 200mm with my D750 in near pitch black situations with my SB-700 adding focus assist (although it's a slight bit lopsided in its projection). I haven't put that to the test in a fast-paced paid event kind of scenario though...