Need ISO help: There was a discussion earlier today about boosting the ISO on a sunny day to get a higher shutter speed. Can someone explain to me in simple terms how this works? I...

nat Loc: Martha's Vineyard, MA

There was a discussion earlier today about boosting the ISO on a sunny day to get a higher shutter speed. Can someone explain to me in simple terms how this works? I don't fully understand ISO except that on sunny days I keep it at 100-200 and gradually increase it as the natural light decreases. Thanks in advance. Nat

hlmichel Loc: New Hope, Minnesota

nat wrote:

There was a discussion earlier today about boosting the ISO on a sunny day to get a higher shutter speed. Can someone explain to me in simple terms how this works? I don't fully understand ISO except that on sunny days I keep it at 100-200 and gradually increase it as the natural light decreases. Thanks in advance. Nat

I don't understand why you would need to boost ISO on a sunny day.

Personally, I keep my ISO at 100 on bright days and adjust the shutter speed as the light changes--to a certain point. If it is a really bright day, I've gone as high as 1/4000(the max of my camera) to avoid blowing out the scene.

Others will likely have a better explaination but ISO is the sensitivity to light. The brighter the ambient light, the lower your ISO. Since shutter speed also affects the amount of light you are capturing--slower shutter speeds mean more light--raising you boosting your ISO can be an alternative to slow shutter speeds.

traveler90712 Loc: Lake Worth, Fl.

This might help some.
http://ywguiding.com/photo_training_instructional_videos.html

rpavich Loc: West Virginia

nat wrote:

There was a discussion earlier today about boosting the ISO on a sunny day to get a higher shutter speed. Can someone explain to me in simple terms how this works? I don't fully understand ISO except that on sunny days I keep it at 100-200 and gradually increase it as the natural light decreases. Thanks in advance. Nat

It's no different than any other exposure situation...right?

On a sunny day, you should get a correct exposure from the following settings

f/16

ISO 100

SS 1/125

With that being said...if you want the shutter speed to go up...something else (or combination of two things) has to go down....right?

So with your aperture fixed at f/16 and you want a shutter speed that's 2 stops higher...you HAVE to up your ISO 2 stops.

f/16
ISO 400
SS 1/500

OR

f/8
ISO 400
SS 1/1000

It's all a balancing act...when one setting changes or has to change...the other two have to compensate.

rpavich Loc: West Virginia

A good way to get used to this stuff is to have your camera in your hand while watching TV...during commericals set it to the "sunny 16" settings that I mentioned above.

Then say to yourself..."now I want to shoot at f/8...what do I do....?"

Then set the shutter speed 2 stops faster (1/500) and you get the same exposure.

Then change back to the sunny 16 settings and start over...

"I want to shoot at f/4....."

So your f/stop goes down how many places?

f/11, f/8, f/5.6, f/4 (that's 4 stops difference)

So you have to do what to the SS and or ISO?

ONE of them or a combination changes a total of 4 stops....

SO now (since your ISO is maxed out at 100) you click the shutter speed 4 stops...1/250, 1/500, 1/1000, 1/2000.

Bingo! Same exposure but hugely different shutter speed and aperture.

If you do this OUT LOUD during the commercials...you'll get at LEAST a half hour of practice a day...and in 2 or 3 days you'll have this down cold.

nat Loc: Martha's Vineyard, MA

rpavich wrote:

A good way to get used to this stuff is to have yo... (show quote)

Thanks rpavich. I'm going to print this out and put it on my refrigerator. About the commercials...I won't be able to practice when the Geico or E-trade commercials are on, but I can make up the time by not watching Real Housewives!

rpavich Loc: West Virginia

nat wrote:

quote=rpavich A good way to get used to this stuf... (show quote)

No problem....that's how I learned guitar scales, basic music theory, how to read music, and my exposure stuff!

Dheaton Loc: Boulder, Utah

rpavich wrote:

A good way to get used to this stuff is to have yo... (show quote)

That is a very good explaination of a difficult thing to explain. It is not hard to do just hard to explain.

rpavich Loc: West Virginia

Dheaton wrote:

That is a very good explaination of a difficult thing to explain. It is not hard to do just hard to explain.

Thank you!

It IS harder to explain than to do!

Just sitting with someone and a camera for a half hour would make all of this make sense. :)

hlmichel Loc: New Hope, Minnesota

rpavich wrote:

Dheaton wrote:

That is a very good explaination of a difficult thing to explain. It is not hard to do just hard to explain.

Thank you!

It IS harder to explain than to do!

Just sitting with someone and a camera for a half hour would make all of this make sense. :)

Lol. I did say that someone more qualified would give a better explaination.

My problem is that I learned the basics, but not all of the basics. I should have read understanding exposure or something on that order--perhaps then I would know the sunny 16 rule. On very bright days, I tend to shoot from 1/1600 to 1/4000 at 2.8. Of course, I can't use fill flash at that point.

Sigh....so much to learn.

rpavich Loc: West Virginia

hlmichel wrote:

My problem is that I learned the basics, but not all of the basics. I should have read understanding exposure or something on that order--perhaps then I would know the sunny 16 rule. On very bright days, I tend to shoot from 1/1600 to 1/4000 at 2.8. Of course, I can't use fill flash at that point.

Sigh....so much to learn.

But you DID use the sunny 16 rule!

f/16, f/11, f/8, f/5.6, f/4, f/2.8 is 5 stops down from 16.

at 100 ISO that means that you have to speed up the shutter 5 stops to compensate for that amount of light.

1/125, 1/250, 1/500, 1/100, 1/2000, 1/4000 is the same amount of stops!

f/2.8
ss 1/4000 is the SAME as f/16 at ss 1/125!

You did use the rule without knowing it! :)

Dheaton Loc: Boulder, Utah

hlmichel wrote:

quote=rpavich quote=Dheaton br br That is a ve... (show quote)

Oh but you are wrong my friend. You can use High Speed Sync and you can use your flash up to 8000th of a second.

nat Loc: Martha's Vineyard, MA

hlmichel wrote:

quote=nat There was a discussion earlier today ab... (show quote)

hlmichel - thanks for your succinct reply. I didn't realize that ISO could be increased as an alternative to slowing the shutter speed. I'll try that out when the sun comes out the next time. Please read this carefully to make sure I got it right. Thanks

Johnny U Loc: Fredericksburg Va.

ISO or ASA is the speed of the film. Generally 100 is what you would want for a sunny day but action shots will blur. The higher the ISO 400 ,800, 1600 etc. will stop bluring and give you good results but they will be grainier when enlarged. The higher the ISO the grainier the picture becomes. Higher ISO's are better for low light situations.

CAM1017 Loc: Chiloquin, Oregon

nat wrote:

There was a discussion earlier today about boosting the ISO on a sunny day to get a higher shutter speed. Can someone explain to me in simple terms how this works? I don't fully understand ISO except that on sunny days I keep it at 100-200 and gradually increase it as the natural light decreases. Thanks in advance. Nat

the exposure for an image comprises three components. The shutter speed. The aperture (f stop) of the lens and the ISO setting for the sensor. When using film, the ISO was also called the ASA or the sensitivity of the film to light.
Where it was suggested to increase the ISO on sunny days, the intent was to be able to close down the aperture to a smaller f stop inorder to have it in an area where it would have greater sharpness. A lens does not have it best sharpness at a wide open setting like f 2.8. When you change the ISO you have to adjust the shutter speed and the aperture to maintain a correct exposure. When you increase the ISO on sunny days you are able to go to a smaller f stop and still keep a good shutter speed. You do have to watch how much you change the ISO so that you don't start to develop problems with noise in your image.
Hope this helps. :-D