• After 15+ years, we've made a big change: Android Forums is now Early Bird Club. Learn more here.

How do you turn off the pre-flash?

A

AGC 88

Newbie
Is there a way to turn off the "pre-flash" when you have the camera app flash to "ON"? Makes subjects like my dog's eye contract and put a blue light on it's eyes. Doesn't when in "auto flash mode". I think I have "pre-flash" disabled on my DSLR. :)

Or, is there an "anti-redeye mode" I haven't spotted yet?

Thanks.
 
It's not there to prevent redeye, that 'pre-flash' is to aid in focusing. If you have the flash on (or set to auto where the light is low enough) the phone assumes you need assistance to auto-focus. I'm not sure if any photo apps in the play store give you that level of control, but it's worth a look.
 
lunatic59 said:
It's not there to prevent redeye, that 'pre-flash' is to aid in focusing. If you have the flash on (or set to auto where the light is low enough) the phone assumes you need assistance to auto-focus. I'm not sure if any photo apps in the play store give you that level of control, but it's worth a look.
Click to expand...

You're right. Forgot. Will check the Google Store
 
Technically a "pre-flash" could not produce a blue reflection, because it would be "pre" the photo being taken. So the blue reflection must either be a reflection of the flash itself or of some other focussing aid. My Pixel 2 has a laser rangefinder it uses in low light, and while that's outside the human visual range reflections of it are visible in photos.
 
Hadron said:
Technically a "pre-flash" could not produce a blue reflection, because it would be "pre" the photo being taken. So the blue reflection must either be a reflection of the flash itself or of some other focussing aid. My Pixel 2 has a laser rangefinder it uses in low light, and while that's outside the human visual range reflections of it are visible in photos.
Click to expand...

Yes it's probably the reflection of the pre Flash light... That stays on the eye long enough to the shoot is taken. In any case it would be good if we could disable it as we can with a Dslr
 
It depends what controls Samsung put in their camera app (I don't have one, so don't know). But you are looking for focussing options, anything to do with focussing aids, focuss assist or similar.
 
AGC 88 said:
Makes subjects like my dog's eye contract and put a blue light on it's eyes.
Click to expand...

AGC 88 said:
That stays on the eye long enough to the shoot is taken.
Click to expand...

I think you're coming to a couple of erroneous conclusions. First, no matter how long you think the pre-flash is on, there is no residual light left over once the picture is taken. The only light from your phone is the actual "flash" (short burst from the LED) when the image is captured. Red eye is a phenomenon where a direct light like a flash bulb shone into a person's eyes at the time a picture is taken illuminates the retina and appears to glow red. The anti-red eye feature on some snapshot cameras is a trick to make a person's iris close. In a flash situation where there is low ambient light, you'd expect a person's irises to be dilated to let in more light. By producing a short burst of a few bright flashes prior to the picture, the iris reacts by closing to a small pupil and letting much less light back to the retina. This technique doesn't always eliminate red eye, but it does minimize it.

A dog's eyes (or many other animals) work a little differently. Most predatory species have what's called a tapetum lucidum, which is a highly reflective layer behind the retina to enhance night vision. Even with the anti-red eye flashes, any light that gets to a dog's eye is going to glow back at you. The color will depend on the species. I have two dogs who's eyes glow an amber color and one whose eye glow blue.

So even if you eliminate the pre-flashing, pic's of your dog will still have the glowy eyes.
 
You must log in or register to reply here.
Back
Top Bottom