ISO 400

A lot of glamor and wedding photography I've been checking out seems to be shot at ISO 400 with flash. Why? Wouldn't ISO 100 be better?

In Manual mode if ISO is left on auto then it will be fixed at ISO 400. My guess is that a large portion of photographers leave their camera on auto ISO.

A high ISO will provide you with a more ambient looking background. A lower ISO will show the background on the darker side. I use my ISO to create a desired looking ambient light setting.

I have experimented with a standard setting of lets say 1/80 and 5.6 (in manual with a flash) ... and vary the ISO from 125 to 800. I then internalize the effect that the ISO has on the ambient lighting.

I generally use 400 to 800 ISO>

The quality of ISO400 now is very similar to ISO100 digital...so why not?!

Back when we used film in the 70's and 80's that was not true, you could easily see ISO400 film in use due to the grain. In the mid- to late-90's, ISO 400film granularity improved to the point that one could shoot ISO 400 film instead of relying upon ISO100. That was a blessing, because it made it easier to capture the ambient illumination of the church or reception hall, and photos quit having the look of the dark cave. I quit shooting anything slower than ISO400 for weddings/events, and reserved the use of ISO160 film for certain emulsions' lower contrast and great skin rendition for single portraiture, especially bridal portraiture.

ISO400 also helps to increase the number of shots that can be taken with flash before depleting the batteries, since the flash has to output less light.

And, when the ambient light is sufficient to eliminate flash, ISO400 also helps us to use a fast enough shutter speed to freeze motion for many things (except for the fastest moving little kids!)

thanks for the input!

pophoto wrote in post #11698837
A high ISO will provide you with a more ambient looking background. A lower ISO will show the background on the darker side. I use my ISO to create a desired looking ambient light setting.

I have experimented with a standard setting of lets say 1/80 and 5.6 (in manual with a flash) ... and vary the ISO from 125 to 800. I then internalize the effect that the ISO has on the ambient lighting.

I generally use 400 to 800 ISO>

Although I'm not a wedding photog, I'll agree with this statement -- I don't approach shooting people indoors as if it is a studio with all controlled even lighting, but more for a ambient look where the flash contributes enough light to fully illuminate and freeze motion but having a reasonably slow shutter speed with a higher ISO lets the ambient light give some "atmosphere".

ISO 400 requires less flash power, and image quality is much the same as ISO100.

As another has pointed out, is about the ambient light. I know you may not understand it but when the ISO is high enough, 400 or higher, you can allow more ambient light to fill in the frame. Why it is important? You want a good balance between the flash and ambient lights to give an even light look. The will result in either you can or can't see the background because of the ambient light there or not there.

Sdiver2489 wrote in post #11698694
In Manual mode if ISO is left on auto then it will be fixed at ISO 400.

That is true on my T1i. My 7D, on the other hand, varies the ISO up to 3200 depending on the shooting condition.

Beachcomber Joe wrote in post #11700881
That is true on my T1i. My 7D, on the other hand, varies the ISO up to 3200 depending on the shooting condition.

Even when shooting flash?

The reason is ... even though you have a slightly less noisy image at 100, at 400, you get more ambient light for the same setting. At ISO 100 the room is gonna be dark. At ISO 400, you'll get lights in the background NOT covered by the flash. Gives a more evenly lit look.