Stops

[SabrinaO]

I know what f/stops are... but what are people referring to when they say they are going to underexpose ambient light by a stop? Or when someone says they need a stop of more light?

 

[Patrice]

1 stop more means twice as much light: either reduce shutter speed by half (ex. 1/250 to 1/125) or increase aperture by one f stop (ex from f/4 to f/2.8).

1 stop less is the reverse.

The same can be accomplished by either increasing ISO to twice it's current value or decreasing it to 1/2 it's current value.

 

[tirediron]

A "stop" is simply the de facto unit for exposure. It's nothing more than a doubling or halving of the value. Aperture, shutter-speed and ISO are all commonly expressed in stops. A change from 1/125 to 1/250 is a change in shutter-speed of 1 stop. Needing one stop more light would be the opposite, say a change from 1/1000 to 1/500 of a second, or from f8 to f5.6, or even ISO 400 to ISO 200.

 

[Vtec44]

A "stop" is simply the de facto unit for exposure. It's nothing more than a doubling or halving of the value. Aperture, shutter-speed and ISO are all commonly expressed in stops. A change from 1/125 to 1/250 is a change in shutter-speed of 1 stop. Needing one stop more light would be the opposite, say a change from 1/1000 to 1/500 of a second, or from f8 to f5.6, or even ISO 400 to ISO 200.

Good to know. I've always thought it's the aperture opening and didn't realize it's the exposure rating.

 

[SabrinaO]

A "stop" is simply the de facto unit for exposure. It's nothing more than a doubling or halving of the value. Aperture, shutter-speed and ISO are all commonly expressed in stops. A change from 1/125 to 1/250 is a change in shutter-speed of 1 stop. Needing one stop more light would be the opposite, say a change from 1/1000 to 1/500 of a second, or from f8 to f5.6, or even ISO 400 to ISO 200.

Thank you! So when people say they are going to underexpose by a stop... they could mean they can do it by either aperture, ISO or shutterspeed... ?

 

[ann]

correct.

 

[gsgary]

This should be one of the first things a beginners learns after buying a camera, it's the first thing they teach at college

 

[tirediron]

...when people say they are going to underexpose by a stop... they could mean they can do it by either aperture, ISO or shutterspeed... ?

it can also mean increasing or decreasing light through the use of strobes or other light sources as well.

 

[Derrel]

A "stop" is simply the de facto unit for exposure. It's nothing more than a doubling or halving of the value. Aperture, shutter-speed and ISO are all commonly expressed in stops. A change from 1/125 to 1/250 is a change in shutter-speed of 1 stop. Needing one stop more light would be the opposite, say a change from 1/1000 to 1/500 of a second, or from f8 to f5.6, or even ISO 400 to ISO 200.

Thank you! So when people say they are going to underexpose by a stop... they could mean they can do it by either aperture, ISO or shutterspeed... ?

If a person wanted to, or needed to, a one-stop underexposure could be accomplished by lowering the ISO 1/3 of a stop, by speeding the shutter up 1/3 of a value, and by closing the lens down 1/3 of an f/stop.

 

[Bitter Jeweler]

If a person wanted to, or needed to, a one-stop underexposure could be accomplished by lowering the ISO 1/3 of a stop, by speeding the shutter up 1/3 of a value, and by closing the lens down 1/3 of an f/stop.

That's tooooo complicated!

 

[clanthar]

This should be one of the first things a beginners learns after buying a camera, it's the first thing they teach at college

Yep, first thing I teach.

And now to make this more fun:
How many stops in a photographic print?
How many stops in a landscape? Sunny day? Overcast day? Backlit?
How many stops can your camera capture? RAW? JPEG? FILM?
Can your camera capture all the stops in the scene? What if it can't?
How many stops on your display? LCD? CRT? Laptop?
Is the range of stops on your display the same as the range of stops in a print?
Is the range of stops your camera captures the same as the range of stops in a print?
Is the range of stops in a print more, less or the same as the range of stops in a scene?
What if the scene has more stops than the print can hold?
What if the scene has less stops than the print can hold?
What if all of the above are different?

Joe

 

[Derrel]

Sabrina,
One of the nicer things about digital SLR photography is when using FLASH of all types is that with a d-slr camera, the user can easily and quickly adjust the camera's ISO settings downward or upward to in effect, add or subtract exposure, as a way to fine-tune the image exposure. If for example, you are using a manually adjusted flash system, either speedlights or monolights or box-and-cable, and you have the flash set to let's say its highest power output, and the exposures are too dark, the ISO in use can be raised by 1/3 or 2/3 of a stop. Normally, cameras must be re-set from factory default of 1/3 stop exposure adjustment to the option of 1/2 stop adjustment increments, so if a 1/2 stop adjustment is needed, that usually needs to be done by setting one of the camera's custom function setting to the 1/2 stop option.

In doing outdoor fill-flash work using OFF-camera, NON-dedicated flash units, one way to get fill-in flash that is lower in power than the "daylight" exposure is to set the ISO on the flash units HIGHER than the ISO the camera is set to, beginning around a two-stop difference. So, for example, if the camera is set to an ISO 100 exposure, the off-camera flash (or on-camera but NON-dedicated or "dumb" flash) unit would be set to say, ISO 400, if it is at the same distance from the subject as the camera is. If the flash is a bit farther back, or zoomed to a wide-angle beam spread, the two-stop difference between camera at 100 ISO and flash at 400 ISO will result in an effectively LESSER flash output of from 2 and 3/4 to 3 or 3 and a half stops less flash than the daylight exposure, which will be about right for many types of very subtle outdoor fill-flash that will maximize dynamic range, and not look overly-flashed.

 

[SabrinaO]

THIS is what I wanted to know. I read it some places and its just not clear on what exactly they are stopping down. So its all three components....

 

[SabrinaO]

This should be one of the first things a beginners learns after buying a camera, it's the first thing they teach at college

Yep, first thing I teach.

And now to make this more fun:
How many stops in a photographic print?
How many stops in a landscape? Sunny day? Overcast day? Backlit?
How many stops can your camera capture? RAW? JPEG? FILM?
Can your camera capture all the stops in the scene? What if it can't?
How many stops on your display? LCD? CRT? Laptop?
Is the range of stops on your display the same as the range of stops in a print?
Is the range of stops your camera captures the same as the range of stops in a print?
Is the range of stops in a print more, less or the same as the range of stops in a scene?
What if the scene has more stops than the print can hold?
What if the scene has less stops than the print can hold?
What if all of the above are different?

Joe

I never went to school. But I want to learn.

Are you being sarcastic in all this lol?

ETA: Finished reading it all..lol. Why did i even ask?

 

[Derrel]

THIS is what I wanted to know. I read it some places and its just not clear on what exactly they are stopping down. So its all three components....

Well, yes and no Sabrina. When a person says, "try stopping the lens down," or "you need to stop down more", or "try stopping down more next time", that is referring to the LENS aperture. "Stopping down" the lens means closing the lens diaphragm "down", from a wide aperture like f/2.8, to a narrower, smaller aperture, like f/5.6 or f/8, for example. "Stopping way down" would be closing the lens diaphragm down quite significantly, to say, f/16 or f/22 with a conventional lens; on a view camera lens, stopping "way down" is usually in the f/64 to f/256 range. The opposite is "opening up" the aperture, and shifting from a small, narrow aperture, to a wide, big, light-admitting aperture.

The shutter's adjustments are usually referred to as "slowing down" or "speeding up" the shutter. A full Exposure Value shift, such as from 1/60 to 1/125 second is often called a "one-stop" adjustment, and the term "Full Step adjustment is also pretty common."

ISO adjustment is usually referred to as "lowering the ISO" or "dropping the ISO" when going from say ISO 800 to 100,etc. When adjusting the ISO the other way, we say "raising the ISO" or "boosting the ISO".