Posted by Graeme Lee on September 3, 2006 at 3:36 PM
Hi all,
Sorry if this is a bit basic, but I'm trying to get to grips with exposure and wondered how a 1.4 and 2x converter fits into all this.
Say I was using the sunny 16 rule and was using ISO 400, for overhead sun and shadows, I would have 1/400th, ISO 400 and F16. So, if I were to use a 2 x, I lose 2 stops and I would need to shoot at 1/400th, ISO 400 and F8 (with an f4 lens).
Is this correct?
Regards, Graeme
Posted by Basil Greber on September 3, 2006 at 5:01 PM
Well, depends. You need a true stop of f/16. A good TC will report the true stop (sometimes referred to as t-stop as compared to f-stop) to the camera, so you can simply put it to f/16. Some converters will not report (or people tape pins to prevent reporting to preserve AF with slow lenses), and there you would have to compensate for the two stops lost, meaning set f/8.
Basil
Posted by Graeme Lee on September 3, 2006 at 6:12 PM
Thanks Basil, so my Canon 500 f4 IS, and my EF2xII on a 1d m2 should tell me a "true" stop?
When the above is used, the camera says it's F8 wide open, so I can set it to F16 and not lose light?
Your camera's built-in meter takes into account the light loss caused by the converters so there's no need to manually compensate for it. I'm not sure how you came to the conclusion that setting it to f/16 will not lose light (compared to f/8). With the converter on, you effectively have a 1000mm lens with a maximum aperture of f/8. Stopping it down will allow less light in.
"Sunny 16" is useful for either determining exposure when a meter is not available or to validate a given meter reading. In all honesty if you have a working meter and a digital camera with a histogram, other metering/guesstimating methods are in my opinion quite moot (though still useful to know).
Guy
Posted by Kent Staubus on September 3, 2006 at 9:37 PM
I agree with Guy. I mostly use "sunny 16" to see if my meter is accurate. I'll add a caution here since it's getting later in the year. Sunny 16 only works from 10 AM to 4 PM, as I recall. More than that, it doesn't work in winter when everything is covered in brilliant snow. The extra reflection seems to make it the "Sunny 22" rule in my experience.
Kent in SD
Posted by Don Miller on September 4, 2006 at 12:46 PM
If the rule was ever really useful it was with the latitude of negative film. It's not precise enough for slide film, and useless with digital.
In full sun toward the middle of the day, exposure for a typical subject is about f/16 at a shutter speed of 1/ISO. I don't think it is useless. I know about what my meter should read under certain circumstances. A little sanity check never hurts. Even if it is not a sunny-16 kind of shot, you can make a reasonable guess of how far off it might be. I don't even shoot that much, but I've had four meter failures over the years.
To answer the question: If you have a completely manual system, you would shoot at 1/400 and a click-stop setting of f/8 (because the actual aperture of the lens if f/16 regardless of what the engraving on the lens says). If you have an electronically integrated system, it probably accounts for all this, but it still nice to have an idea of what is going on.
Discussion
6 repliesSorry if this is a bit basic, but I'm trying to get to grips with exposure and wondered how a 1.4 and 2x converter fits into all this.
Say I was using the sunny 16 rule and was using ISO 400, for overhead sun and shadows, I would have 1/400th, ISO 400 and F16. So, if I were to use a 2 x, I lose 2 stops and I would need to shoot at 1/400th, ISO 400 and F8 (with an f4 lens).
Is this correct?
Regards, Graeme
Basil
When the above is used, the camera says it's F8 wide open, so I can set it to F16 and not lose light?
Cheers, Graeme
Your camera's built-in meter takes into account the light loss caused by the converters so there's no need to manually compensate for it. I'm not sure how you came to the conclusion that setting it to f/16 will not lose light (compared to f/8). With the converter on, you effectively have a 1000mm lens with a maximum aperture of f/8. Stopping it down will allow less light in.
"Sunny 16" is useful for either determining exposure when a meter is not available or to validate a given meter reading. In all honesty if you have a working meter and a digital camera with a histogram, other metering/guesstimating methods are in my opinion quite moot (though still useful to know).
Guy
Kent in SD
To answer the question: If you have a completely manual system, you would shoot at 1/400 and a click-stop setting of f/8 (because the actual aperture of the lens if f/16 regardless of what the engraving on the lens says). If you have an electronically integrated system, it probably accounts for all this, but it still nice to have an idea of what is going on.
Pete D.