Should I keep ISO as low as possible?

[andytakeone]

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?

 

[EIngerson]

You should keep it as low as you can while still allowing proper exposure.

Did your instructor use a light meter?

 

[andytakeone]

You should keep it as low as you can while still allowing proper exposure.

Did your instructor use a light meter?

Yes, he did.
So should all studio set ups that have ample lighting be done in ISO 100 then?

 

[EIngerson]

There is no rule. If he set to ISO 200 and used a light meter I'm assuming he just told you to use the settings he read. You'd be hard pressed to notice a difference between 100 or 200 in a studio setting.

It could also be that he was wanting to use F11 specifically and needed to get the shutter speed up. 1/25 is slow enough that you'll still rely on your lights to stop motion.

 

[andytakeone]

There is no rule. If he set to ISO 200 and used a light meter I'm assuming he just told you to use the settings he read. You'd be hard pressed to notice a difference between 100 or 200 in a studio setting.

It could also be that he was wanting to use F11 specifically and needed to get the shutter speed up. 1/25 is slow enough that you'll rely on your lights to stop motion.

I see. Thanks.
So you're saying whether he used ISO 200 or 100 didn't really matter, so he just chose 200 for no particular reason?
He did want to use f/11 specifically, but what do you mean when you say he needed to get the shutter speed up? He kept the shutter speed at 1/25 at all times, he never wanted anything faster.

 

[sashbar]

It depends on your camera, with modern FF or APS-C cameras you can use higher ISO much more freely than 6 or 7 years ago.
You may try for yourself, shoot the same scene with ISO 100, 200, 400, 800 etc and compare the IQ. You will be able to decide for yourself how high you would want to allow it without IQ degradation.
Keeping ISO to basic 100 is one of the most widespread beginners' mistakes these days. You pay for it with slower shutter speed, and end up with blurry images that is much, much worse than hight ISO grain.
I am shooting with an APS-C FUJI camera and often do not mind shooting with ISO 3200 or even 6400.

 

[andytakeone]

It depends on your camera, with modern FF or APS-C cameras you can use higher ISO much more freely than 6 or 7 years ago.
You may try for yourself, shoot the same scene with ISO 100, 200, 400, 800 etc and compare the IQ. You will be able to decide for yourself how high you would want to allow it without IQ degradation.
Keeping ISO to basic 100 is one of the most widespread beginners' mistakes these days. You pay for it with slower shutter speed, and end up with blurry images that is much, much worse than hight ISO grain.
I am shooting with an APS-C FUJI camera and often do not mind shooting with ISO 3200 or even 6400.

I see, but given you don't have to make any concessions with shutter speed or f/stop, you want it as low as possible right?
Not necessarily at 100 per se, but at the lowest mark where you don't have to make shutter speed or f/stop concessions, whether that be at ISO 100 or ISO 3200.

 

[jaomul]

If the lights are not very strong an increase in iso may be needed for proper exposure.

 

[Dao]

There is a possibility that the instructor want to make sure everybody can use the same settings. The base ISO value of some digital SLR cameras is 200 instead of 100 (without boost). i.e. Nikon D300

Or the instructor tried to lower the flash recycle time.

 

[Scatterbrained]

It depends on your camera, with modern FF or APS-C cameras you can use higher ISO much more freely than 6 or 7 years ago.
You may try for yourself, shoot the same scene with ISO 100, 200, 400, 800 etc and compare the IQ. You will be able to decide for yourself how high you would want to allow it without IQ degradation.
Keeping ISO to basic 100 is one of the most widespread beginners' mistakes these days. You pay for it with slower shutter speed, and end up with blurry images that is much, much worse than hight ISO grain.
I am shooting with an APS-C FUJI camera and often do not mind shooting with ISO 3200 or even 6400.

I see, but given you don't have to make any concessions with shutter speed or f/stop, you want it as low as possible right?
Not necessarily at 100 per se, but at the lowest mark where you don't have to make shutter speed or f/stop concessions, whether that be at ISO 100 or ISO 3200.

Generally, the lower iso setting you use the more dynamic range your sensor will display and the less noise will be evident. It's always a compromise, but in general you'll want to keep the iso as low as you can, without going overboard. If you need f/8 and 1/125th then do it, even if that means shooting at iso 3200.
Shooting with strobes it's unlikely you'd need to shoot over 100-400, depending on the situation. I wonder however why use 1/25th. That doesn't make sense unless you're trying to pull in ambient, at which point it would make more sense to lower the lights output and open up the aperture a wee bit.

 

[beagle100]

It depends on your camera, with modern FF or APS-C cameras you can use higher ISO much more freely than 6 or 7 years ago.
You may try for yourself, shoot the same scene with ISO 100, 200, 400, 800 etc and compare the IQ. You will be able to decide for yourself how high you would want to allow it without IQ degradation.
Keeping ISO to basic 100 is one of the most widespread beginners' mistakes these days. You pay for it with slower shutter speed, and end up with blurry images that is much, much worse than hight ISO grain.
I am shooting with an APS-C FUJI camera and often do not mind shooting with ISO 3200 or even 6400.

I agree, shooting at "basic ISO 100" is a mistake --- don't worry about shooting ISO 3200 or ISO 6400 !

 

[Dave442]

Even with my older cameras it is hard to see a difference in the ISO 100 to 400 range. With flash I often go to ISO 160 or 200 just to start at. That also lets you drop the ISO back down if you want to. I find it often helps to not be at the limit of any of the settings so you have some room to move.

 

[astroNikon]

My lightmeter only goes down to ISO 200 - Minolta IV
So when I do studio stuff my ISO is set at 200.

Nowadays one may not notice much noise at levels of ISO 6400
so ISO being at 100 is not so critical nowadays with modern digital cameras. Now we're much more flexible and use it as appropriate for the exposure.

 

[Ysarex]

There is no IQ advantage when ISO is raised. On a digital camera a higher ISO doesn't cause any kind of positive difference in the image but only has negative IQ effects. Those negative effects are very minor at first and not worth trading off against the negative effects of failing to get the shutter speed or aperture that will deliver the best photo.

NOTE: You mentioned that noise increases with ISO increase. Others here have also mentioned noise. Nearly every time you hear or read about the negative effects of raising ISO you hear noise and only noise. Go back and read what Scatterbrained said and please note it's the first thing he mentions. Raising ISO on a digital camera decreases dynamic range. In others words you record less data. Noise can be filtered. Data you don't record just isn't there.

Joe

 

[dennybeall]

Consider that you set speed and f-stop for very specific reasons. ISO is usually set last or automatically to support that choice. You want to keep ISO as low as possible to keep noise down but with modern cameras, as has been stated, you can use an ISO much higher.
The instructor was setting up a specific shot so the ISO setting was just part of the exposure setting.
I often set ISO to 800 or 1200 to get the exposure I want with a f4.0 lens when movement calls for a faster shutter speed.