Opening Stops, Lose Depth of Field?

[superjoe]

I'm slowly learning how to use the zone system, and while I understand the point of everything, I always see people telling me to open one or two stops for this or for that...How does one use the zone system method without altering the aperture?

I've just been changing the exposure time accordingly and leaving the aperture where I want it. Are they inter-changeable?

I have a feeling this is a ridiculously silly question, oh well.

[noblebeast]

You basically have it right: when discussing exposure a 'stop' can be an actual f-stop, or the shutter speed. Example: you meter something for 1/30th at f/22 - if you shoot it at 1/15th you have overexposed by 1 stop.

Joe

[superjoe]

Cool. So with depth of field out of mind...will the exposure change if I raise the shutter speed vs. raising the aperture? Are they exactly inter-changeable or is it kind of an estimate?

[david b]

Hey Joe,
the zone system rule of thumb is

"expose for the shadows and develop for the highlights"

So when you point your meter at a shadow, you will need to stop down. The meter measures for zone V. You will probably want your shadows at zone III. To do so, you have to stop down two stops.

The same happens when photographing snow. When you point the meter at snow, it measures it at zone V. In order to make it white, you will have to open up two stops.

You can open up or stop down with either the aperture or the shutter speed. Since I always use a tripod and slow film, I prefer to alter my shutter speed so that I do not affect what is in focus.

Also, have a look at my take on developing film.

Click here.

Good luck. I hope this helps.

Welcome to APUG and Happy Holidays.

[bdial]

Generally speaking, they are interchangeable. Each change in shutter speed, or aperture changes the light reaching the film by 1/2 or *2. You may find it worthwhile to test by making a series of exposures at each shutter speed/ aperture combination. The resulting negatives should show even density with each other. Any that are lighter or darker than the others indicate a fast or slow shutter (most likely).

[Christopher Walrath]

And also, Joe, just as each successive Shutter speed is either a doubling or a halving of the duration the shutter is open, each successive aperture setting is either a doubling or halving of the geometric AREA of the aperture. So any adjustment made either doubles or halves exposure whether it is an adjustment in shutter speed or in aperture.

[MattKing]

Originally Posted by bdial

Generally speaking, they are interchangeable. Each change in shutter speed, or aperture changes the light reaching the film by 1/2 or *2. You may find it worthwhile to test by making a series of exposures at each shutter speed/ aperture combination. The resulting negatives should show even density with each other. Any that are lighter or darker than the others indicate a fast or slow shutter (most likely).

Joe:

This is what people are referring to when they talk about "reciprocity".

It applies over a wide range of values, but not universally. People who use telescopes to take photographs of stars have to worry about this (because the light is so dim) but if the light levels are reasonably normal, this works like a charm.

As you begin to get comfortable with this, the creative possibilities reveal themselves (adjusting aperture for depth of field, or shutter speed for motion blur, or lack of it, for instance).

Matt

[copake_ham]

Being "old school" I am very comfortable with the f/stop v. shutter speed ratio - and the creative opportunities etc.

But I still keep scratching my head over using "EV"....?

[BrianShaw]

EV is simple - it is an index for a particular exposure value (amount of light, basically). The same creative opportunities exist since once an EV is set, any set of shutter speed and aperture can be chosen... and you'll know that whatever you choose within that EV will yield the same exposure.

[copake_ham]

Originally Posted by BrianShaw

EV is simple - it is an index for a particular exposure value (amount of light, basically). The same creative opportunities exist since once an EV is set, any set of shutter speed and aperture can be chosen... and you'll know that whatever you choose within that EV will yield the same exposure.

Huh?

Thanks, but ...

I thought I was on your Ignore list?