# Thread: Need explanation on metering/ sunny 16

1. ## Need explanation on metering/ sunny 16

Hi,
I have difficulty grasping the concept of metering, which i think is a very important thing for me to learn.

Over at John Shaw's book on nature photography field guide, the explanation is really too tough for me to grasp.

Can someone explain it in laymen's term to me? Like when do i know where to meter using spot metering?

And can someone enlighten me on the sunny 16 rule?

Thanks!

Regards

2. Sunny 16? Tot that applies only if you don't have a working meter with you? Basically, when its sunny and you are using ISO100 film, just set aperture to f16 and you will have a good chance of getting reasonably correct exposures when using negatives. Basically, these approximations can be found on the inside of every film package.

Tried it once when I was caught without batteries on an old manual cam, snapped a few shots(Slides) without metering and was surprised to find that they turned out ok.

As for the rest of your query..think u need to paste the extract here, some of us may not have acces to john shaw's book.

3. Oh i see...

As for the metering, lets do away with the john shaw book? Hehe..

What i hope is that some guru can give me some simple explaination on its usage and technique?

And they say...2stops of light or 1/3 stops of light, what do they really mean?

For eg, 'I lost 2 stops of light'

Regards

4. Losing 2 stops of light means that the light loss was equivalent to what shutter speed you would get had you lower the aperture by 2 stops. i.e f1.4 to f2.8.

f1.4 to f2 is one stop, f2 to f2.8 is another stop.

5. Sunny 16 rule just states that under bright, direct mid day sun light, for correct exposure of mid tone subjects, the shutter speed is approximately the film's iso if you set your aperture to f/16. For example, if you are using iso 100 and f/16, under sunny 16 the shutter speed speed would be 1/125s for the correct exposure. In other words under sunny16 rule, for iso100, you can use the following exposure settings:

f/16 1/125s, f/8 1/250s, f/5.6 1/500s, and so on...

A "stop" on the aperture or shutter speed allows double or half of the amount of light reaching the film. First let's look at the aperture values:

f/1, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32... etc

Each of the above is one stop from the next, and allows in double or half of the light. So for example, if you increase the aperture from f/4 to f/2.8, you are allowing double amount of light in. Similary, from f/4 to f/5.6 and you are cutting it by half.

Same for the shutter speed, each of the following are 1 stop from the next:

1s, 1/2s, 1/4s, 1/8s, 1/15s, 1/30s, 1/60s, 1/125s, 1/250s, 1/500s... etc

Now assume an exposure metered by the camera is f/8 1/125s. If you want to keep the exposure constant but want to open up the aperture to f/5.6 for shallower DOF for example, since you are letting 1 stop more light in, you will need to cut 1 stop on the shutter speed, so:

f/8 1/125s ==> f/5.6 1/250s will give you the same exposure. (Aperture open up 1 stop, shutter speed close down by 1 stop)

Similarly, you can also do this:

f/8 1/125s ==> f/4 1/500s (aperture open up 2 stops, shutter speed close down by 2 stops).

Hope that helps.

6. so means say if i use a CPL,
i lose 2 stops of light, means i have use a slower shutter speed to compensate?

7. Oh i see! Thanks ziploc and Zerstorer!

anyone can help me out regarding the metering?

Regards!

8. Originally posted by Wryer
so means say if i use a CPL,
i lose 2 stops of light, means i have use a slower shutter speed to compensate?
Either you open up your aperture by 2 stops, slow down shutter speed by 2 stops, or use 2 stops higher iso. So for example:

f/8 => f/4, 1/250s => 1/60s, or iso 100 => iso 400.

Anyway, if you are using program, aperture priority or shutter priority mode, you shouldn't worry too much about it. The camera's meter will take care of it for you.

9. ## Re: Need explanation on metering/ sunny 16

If you are referring to the Meter Calibration in J.Shaw's book, then this article would elaborate:

am i right to conclude that,

as long as i spot meter on a tone, it will be mid-tone?

For eg, if i spot meter on a brown colour, if i move 1 stop down, it will become a darker brown?

Thanks!

11. Originally posted by Wryer

am i right to conclude that,

as long as i spot meter on a tone, it will be mid-tone?

For eg, if i spot meter on a brown colour, if i move 1 stop down, it will become a darker brown?

Thanks!

12. Erm... "spot meter on a tone" does not make sense, because tone can be any tone, like highlight, mid tone, shadow, or anything in between. Turn to page 25 of your "Nature Photography Field Guide". There is a tonality chart there.

The best way of metering on mid tone is to get a grey card. Otherwise, you can also learn to recognise what in our surroundings are mid tone (note it can be any color). And you got the spot meter part right: the technique will only work on spot and center weighted metering and won't work on matrix/evaluative.

Hope that helps.

13. Ahh...yes!

thanks ziploc!
Think i missed the word mid-tone.

But if i meter on the mid-tone, and move the stops in accordance to my preferance, what happens to the other tones in my frame?

For eg, i spot meter on a beige colour, and i want it to be darker, so i move 1 stop down, what happens to the other colours (or tone, for that matter) in the frame? Will they become 1 stop down as well?

Regards!

14. Yes, everything will be 1 stop darker.

15. Oh i see...

Thank you!

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•