I think im still not understanding how my flash works

[MohaimenK]

So Mo, you're saying that if you have your ISO at 100, your flash off camera, shutter speed at 1/60th, and the flash is at 1/4 power, if you up your ISO you will only increase the brightness of the ambient light?

Yes. So if you change the ISO to 200 and leave the shutter speed the same and the flash the same, it will not effect the brightness of the subject but the ambient light will be brighter behind the subject.

 

[Village Idiot]

Whoever said with ETTL the flash goes lower than 1/128 has no idea what they're talking about. Sorry its just the wrong information.

When you need to squeeze every very bit of power from your Speedlite, switch it to Manual mode and set it to 1/1. In E-TTL, the Speedlite uses a bit of its power for the pre-flash. By switching to Manual, you eliminate the pre-flash and send all the juice straight out in one big burst.


Conversely, if you are shooting in Manual at the lowest power setting and still have too much light, switch over to E-TTL. The pre-flash will suck up a bit of power and thereby reduce the intensity of the flash. The change will be small, but it might be just enough.


and no Kundalini, if the subject is away from background then the shutter speed/iso won't matter UNLESS shutter speed is ridiculously low and ISO is extremely high. When using flash, the flash will be same intensity on the subject at 1/125 shutter speed vs 1/160 shutter speed. The flash doesn't doesn't stay open enough to matter. Same with 400 ISO or 800 ISO. ONLY thing will change is the ambient light being darker vs brighter. (please don't start an argument with me saying I don't know what I'm talking about)

Oh, and one more thing. You don't know what you're talking about. ISO will have an effect on the exposure from the flash. It can be an effective way of getting more juice out of your flash if it's not strong enough.

 

[o hey tyler]

So Mo, you're saying that if you have your ISO at 100, your flash off camera, shutter speed at 1/60th, and the flash is at 1/4 power, if you up your ISO you will only increase the brightness of the ambient light?

From what I learned, it will affect both ambient light as well as the reflected flash light when ISO value is increased.

...But you didn't learn that from Mo's post. Because he said that changing the ISO from 400 to 800 wouldn't effect the light reflected from the flash, just the ambient exposure, no?

 

[Village Idiot]

So Mo, you're saying that if you have your ISO at 100, your flash off camera, shutter speed at 1/60th, and the flash is at 1/4 power, if you up your ISO you will only increase the brightness of the ambient light?

Yes. So if you change the ISO to 200 and leave the shutter speed the same and the flash the same, it will not effect the brightness of the subject but the ambient light will be brighter behind the subject.

Still wrong. Take your flash out of your bag, hook it up and shoot with all setting the same and cranking the ISO up from 100, to 800, to 6400. You'll see the light.

 

[o hey tyler]

So Mo, you're saying that if you have your ISO at 100, your flash off camera, shutter speed at 1/60th, and the flash is at 1/4 power, if you up your ISO you will only increase the brightness of the ambient light?

Yes. So if you change the ISO to 200 and leave the shutter speed the same and the flash the same, it will not effect the brightness of the subject but the ambient light will be brighter behind the subject.

lol wut?

 

[MohaimenK]

I'm reading too many things these days. If you have time, go read it here

http://neilvn.com/tangents/flash-photography-techniques/3-dragging-the-shutter/

 

[MohaimenK]

So Mo, you're saying that if you have your ISO at 100, your flash off camera, shutter speed at 1/60th, and the flash is at 1/4 power, if you up your ISO you will only increase the brightness of the ambient light?

Yes. So if you change the ISO to 200 and leave the shutter speed the same and the flash the same, it will not effect the brightness of the subject but the ambient light will be brighter behind the subject.

Still wrong. Take your flash out of your bag, hook it up and shoot with all setting the same and cranking the ISO up from 100, to 800, to 6400. You'll see the light.

VI, thats where I said "rediculously high/low" I wasn't comparing ISO 100 to ISO 6400. I was comparing ISO 100 to ISO 200 even ISO 400.
Same as shutter speed 1/125 to 1/150 or even 1/200. Do not compare a 1 sec exposure to 1/200 and say that the flash will have no effect.

Anyway I've provided link. You guys are welcome to read it. It's worked for me so far. I can't spend the rest of the day getting into arguments. Thanks :mrgreen:

 

[Dao]

So Mo, you're saying that if you have your ISO at 100, your flash off camera, shutter speed at 1/60th, and the flash is at 1/4 power, if you up your ISO you will only increase the brightness of the ambient light?

From what I learned, it will affect both ambient light as well as the reflected flash light when ISO value is increased.

...But you didn't learn that from Mo's post. Because he said that changing the ISO from 400 to 800 wouldn't effect the light reflected from the flash, just the ambient exposure, no?

Increase the ISO from 400 to 800, it WILL AFFECT both ambient and and flash light. So you are correct.

 

[o hey tyler]

Now, comparing the controls between what affects ambient exposure, and what affects manual flash exposure, we can see that there are two common controls – aperture and ISO. This means that shutter speed becomes the independent control for available light exposure. So when we balance manual flash and ambient light, it makes most sense to start by adjusting the shutter speed, since adjusting the aperture or ISO in an attempt to change the ambient exposure, will also affect the manual flash exposure.

From the site you linked, Mo.

 

[Dao]

Mo. Let's make it simple.

When the flash output one unit of power, you photo will be exposed correctly.
Double the ISO from 100 to 200. Now, the camera still receive the same amount of light (one unit), but the signal is now amplified and appeared that the camera receives 2 units of power. Therefore, the photo will be overexposed.

 

[MohaimenK]

Dao, with the ISO higher just one stop even 2 stop, the ambient light will change but the the light output from flash will not change because it's so fast.

However, if you were to take this shot outdoor during the sun shining bright then yes, with higher ISO the subject will change. Because the ambient light is effecting the subject also. Does that make sense?

Sorry I'm just thinking as a wedding photographer doing mostly indoor shots and going by what I've read and understood. How bout to be fair, I'll go and do some test shots this weekend with different settings and post? If I'm 100% wrong then I'll admit my mistake.

 

[o hey tyler]

It doesn't matter how fast the pulse is as long as you're under the x-sync speed. More light is grabbed at a higher ISO. That's the way it works. Dao explained it in a very easy to understand way. As did the site you linked.

 

[Village Idiot]

Yes. So if you change the ISO to 200 and leave the shutter speed the same and the flash the same, it will not effect the brightness of the subject but the ambient light will be brighter behind the subject.

Still wrong. Take your flash out of your bag, hook it up and shoot with all setting the same and cranking the ISO up from 100, to 800, to 6400. You'll see the light.

VI, thats where I said "rediculously high/low" I wasn't comparing ISO 100 to ISO 6400. I was comparing ISO 100 to ISO 200 even ISO 400.
Same as shutter speed 1/125 to 1/150 or even 1/200. Do not compare a 1 sec exposure to 1/200 and say that the flash will have no effect.

Anyway I've provided link. You guys are welcome to read it. It's worked for me so far. I can't spend the rest of the day getting into arguments. Thanks :mrgreen:

Adjusting the ISO in any amount will affect the overall exposure of the...exposure...

You just may not be able to tell. Using an extreme comparison like 100 to 800 to 6400 lets you see the difference and what's happening.

 

[Dao]

Mo. I believe you maybe confused with shutter speed vs flash power.

Changing the shutter speed from 1/200 to 1/100 has no effect on the flash exposure. But
changing the ISO value from 100 to 200 will affect the flash exposure.

 

[Village Idiot]

Dao, with the ISO higher just one stop even 2 stop, the ambient light will change but the the light output from flash will not change because it's so fast.

However, if you were to take this shot outdoor during the sun shining bright then yes, with higher ISO the subject will change. Because the ambient light is effecting the subject also. Does that make sense?

Sorry I'm just thinking as a wedding photographer doing mostly indoor shots and going by what I've read and understood. How bout to be fair, I'll go and do some test shots this weekend with different settings and post? If I'm 100% wrong then I'll admit my mistake.

Come on guy, this is 100% wrong.

ISO basically changes the sensitivity to the sensor. As long as light from the flash is hitting the sensor, the ISO changes the exposure from the flash. It's just like adjusting the aperture, except now you're changing the noise in the image and not the DOF.