Focusing in low light

[Rafal]

I was wondering what's a good way to focus in low light where the subject is farther away from you? I've read that you could use a flash light but what if the light isn't strong enough, would laser pointers work?

 

[MattK0138]

I doubt laser pointer would be bright or big enough to get a focus on. If you do it manually you might be able to eyeball it.

 

[2WheelPhoto]

I was wondering what's a good way to focus in low light where the subject is farther away from you? I've read that you could use a flash light but what if the light isn't strong enough, would laser pointers work?

Wow, either that flashlight is VERY weak or you're focusing at infinity anyway?

 

[KmH]

Auto focus works by detecting the contrast at edges. A laser pointer would not light up enough area.

Autofocus - Wikipedia, the free encyclopedia

Understanding Camera Autofocus

 

[Rafal]

I was wondering what's a good way to focus in low light where the subject is farther away from you? I've read that you could use a flash light but what if the light isn't strong enough, would laser pointers work?

Wow, either that flashlight is VERY weak or you're focusing at infinity anyway?

I don't want to carry a spot light with me If something is 50-100 yards away your regular flashlight won't do jack

 

[bennielou]

Just shoot manual, with a fast lens, and all is good.

 

[kwik]

I use a flash light and even have used my cell phone once and a while. Normally works fine for me. What are you trying to shoot? Mars?

 

[Rafal]

I use a flash light and even have used my cell phone once and a while. Normally works fine for me. What are you trying to shoot? Mars?

not yet, mars project is for next year. Lets say you're in a dark forest with minimal lighting, a building that's farther away etc.

 

[kwik]

Manual focus, longer exposure is the direction I'd go. But I'm far from a professional.

 

[Rafal]

Auto focus works by detecting the contrast at edges. A laser pointer would not light up enough area.

Autofocus - Wikipedia, the free encyclopedia

Understanding Camera Autofocus

thanks KmH ! , found my answer " Another way to assist contrast based AF systems in low light is to beam a laser pattern on to the subject"

What are such devices called?

 

[KmH]

AF assist. Many speedlights have it. It's behind the red window on the front of units that have it.

http://www.usa.canon.com/cusa/consumer/products/cameras/speedlite_flash_lineup/speedlite_580ex_ii

They use red light. Why do you think they would use red light?

 

[Rafal]

AF assist. Many speedlights have it. It's behind the red window on the front of units that have it.

Canon U.S.A. : Consumer & Home Office : Speedlite 580EX II

They use red light. Why do you think they would use red light?

I have no idea why they use red light, it's more visible maybe? What is the AF assist's limit? Does it work well with something that you need in focus 50 yards away? I don't own one yet so I don't know..

 

[Patrice]

Our eyes are not very responsive to red light so the red focus assist light on some flash heads does not alter our night vision, also will not cause pupils of your subject to contract.

Another point being that the camera and flash electronics are very sensitive to red and infrared light and thus able to more accurately focus when the focus assist is red. Infrared only would likely work as well, but I'm not sure about that.

 

[KmH]

Yep. The auto focus modeule can 'see' wavelengths of light us humans can't see, like IR.

 

[Foxx]

Yep. The auto focus modeule can 'see' wavelengths of light us humans can't see, like IR.