Should I keep ISO as low as possible?

spiralout462 · Oct 30, 2015

Portraits= low ISO.

Birds, birds in flight= high ISO.

In general of course.

snowbear · Oct 30, 2015

I bought all them ISOs and by-golly I'm gonna use them all!

Try a couple of test shots with low, medium and high ISO and see what you get. Mix it up - dark & gloomy, bright and shiny, some in the middle. Try to find out what your camera's limitations are.

runnah · Oct 30, 2015

Best practice for extracting the most out of you sensor is to figure out what the native ISO is for your sensor. The native ISO is the one that your sensor will perform the best at. Often it's not the lowest setting.

EIngerson · Oct 30, 2015

The take away answer is yes, you want to use as low of an ISO that your exposure allows. There's a ton of great information in the responses. Good luck and have fun. Post photos often.

andytakeone · Oct 31, 2015

Thanks for the replies everyone, I think I've pieced it together now.
This really helped.

Bebulamar · Oct 31, 2015

Assuming you can have as much or as little light as you want so that you can expose your shot at the aperture and shutter speed you want at any ISO then the best ISO is the native ISO of the sensor. No manufacturer stated this in the spec but all sensor has a base ISO rating. Using ISO below base ISO reduces quality.

Braineack · Oct 31, 2015

andytakeone said:
I was at a workshop the other week where we were using a flash lighting set up, with a couple soft boxes and a beauty dish and the instructor told us to set our settings to something like f/11, 1/25, ISO 200.

judging by the settings im assuming the flashes were incredibly weak, or he also wanted ambient light in the shot.

Bebulamar · Oct 31, 2015

andytakeone said:
I know ISO is a sort of artificial amplification of the sensor which adds more grain as it increases,
but does that mean the ISO should always be kept at 100 unless you absolutely have to increase it?

I was at a workshop the other week where we were using a flash lighting set up, with a couple soft boxes and a beauty dish and the instructor told us to set our settings to something like f/11, 1/25, ISO 200.

Why he insisted on the ISO being 200 instead of 100 is what confuses me. If we have a full flash lighting set up, shouldn't exposure not be a problem?

What if the flash putting out just that much light and the ambient light level is just that much and also I don't know if what you were to photograph has any motion.

Do you think if you use ISO100 and f/8 it would be better?
If the flash can be brighter then you will have to slower the shutter speed to 1/12 in order to have the same exposure for ambient light. But is there any motion related problem? He specified 1/25 shutter speed I think there is ambient light involved otherwise he would choose higher shutter speed.

Braineack · Oct 31, 2015

im wondering if someone simply misheard 1/25 for 1/125sec.

Dao · Oct 31, 2015

OP, can you describe how the environment looks like in terms of brightness? f/11 ISO200 with 1/25 should result a quite dark scene with regular home lights. I just did a quick test with a small bedroom which has two 800 lumens bulbs, the result is kind of dark on the while wall, not black.

vintagesnaps · Oct 31, 2015

I was wondering the same thing, if it was supposed to be 1/125.

I think Dao might be right (several posts back) that the instructor picked an ISO setting for the class that would work with everyone's cameras. That might just be intended as a starting point or what should be used for this assignment/lesson.

You might want to ask the instructor why that setting is being used. I'd suggest too that you may want to ask about ISO in general; your description seems like you don't have a good understanding of it yet (ask what ISO stands for, what it is, how it's used in photography, etc.). It would probably help you learn how to adjust it if you develop a better understanding of it.

Braineack · Oct 31, 2015

I often use ISO 200 in the studio because my 150watt/sec lights arent the brightest.

doubles the output...

Derrel · Oct 31, 2015

Braineack said:
I often use ISO 200 in the studio because my 150watt/sec lights arent the brightest.

doubles the output...

I have powerful studio flash units, but I often will move to ISO 160 or ISO 200 with them because it allows me to use less flash power, so my subjects do not have to be exposed to more Pop! from the strobes than necessary, and the higher ISO level also cuts flash recycling time significantly. That is what I like the most--faster flash recycle times.

When shooting bounce flash stuff with a single speedlight, I usually recommend moving upward, away from the lowest ISO settings, and beginning at ISO 320,400, or 500. SHooting a flash say six feet to a ceiling and then 12 feet to a subject is more than just being at 18 feet....the flash is coming from 18 feet, but it is also diluted/dispersed quite a bit, so using ISO 100 often ends up being a full discharge of the capacitor, which means that there is literally NO possibility to dial in Plus exposure compensation, since the flash is discharging all available energy due to the need for a lot of light at ISO 100. Moving the ISO level upward of 100 when shooting bounce flash also reduces battery drain and also speeds up flash recycle times, and gives some margin for flash exposure adjustments on shots made at 15 feet and a ways beyond that.

15 years ago, the Base ISO level was really where the real image quality was in digital capture, am dISO levels of 400 were only marginally acceptable. It is not that same era now.

SCraig · Oct 31, 2015

You should use ISO just as you would any other setting. Adjust them as necessary to get the shot you want based on the conditions while knowing that there are pros and cons to each one of them. ISO is no more nor no less important than shutter speed and aperture, it's one of the three legs of the so-called "Exposure Triangle" and should be treated as such.