[Thagomizer]

When I was shooting old folding cameras without meters, I found this website's information very helpful: The Ultimate Exposure Computer.
I printed up small versions of the relvent tables, laminated them, and kept them with me. I should see if I can find them again and try using them with my DSLRs...

[stevebrot]

A cloudless stretch of blue sky with the sun above 45degrees and not near the area measured, should match/be very close to the sunny 16 rule. Indeed this is the usual way to calibrate a (reflected light) light meter. The reason it works is because the blue sky is a midtone.

I am not meaning to directly contradict what you said here, but it is important to understand that "Sunny 16" is a method of estimating exposure and is not directly related to conventions for metering, though the two definitely draw from the same well.

For the sake of most readers, the differences may be summed with a set of bullet points:

• Film/sensor sensitivity (ISO or EI) numbers are determined by the response of the medium to light at various intensities
• Meters measure light and translate the measurement to suggest EV settings for a particular film or sensor sensitivity
• Meter calibration is related to the response curves used to assign ISO speeds
• Sunny 16 assumes light at a particular intensity to derive useful EV settings in the absence of a meter
• Meter readings under of certain known light values (18% gray, green grass, northern sky) under Sunny 16 conditions will return an EV similar to that produced by Sunny 16

The Wikipedia article on Film Speed has an extensive discussion summarized in the section that deals with both metering and Sunny 16 and continues to a discussion of Exposure Index, the practical alternative to ISO sensitivity.

Film speed - Wikipedia

Below is additional discussion from my understanding of this stuff.

I find it useful to think of "Sunny 16" as simply assuming that a scene will be well-served by an EV series of shutter speeds for f/16 where the shutter speed is 1/(ISO film speed). The convention is based a particular light regime and the expected response (characteristic curve) for commonly available films for pictorial photography. That it works is a happy coincidence. Note that it starts with two assumptions and makes a third regarding results on the negative. It depends heavily on the second (film response) and even heavier on the fourth that I have not yet mentioned. The subject is assumed to not include large areas at the extremes of the film's dynamic range. For things like snow scenes and white beaches for example, Sunny 22 might be more appropriate. As noted earlier in this thread, there are tables for those special cases.

Metering, OTOH is simply measuring either reflected light from the subject or incident light striking the subject and calculating an EV based on the film speed. The only assumptions are that the film will cooperate by capturing the full range of light values present on the subject for that EV and that the meter was reading an appropriate sampling of light.

So why does a reflected meter reading of a green lawn or the northern sky at midday give an EV similar to Sunny 16? Probably because an incident reading of midday sun on a clear day satisfies the first of the basic assumptions of Sunny 16 only this time we actually measured it. The tonal light values of the green lawn or northern sky are about the same, perceptually, and the film response is designed to build similar densities on the negative for each. Whether that value is near black or near white for a given EV depends on the film speed. The expected values for grass and the northern sky are similar to the value for an 18% gray card, hence the tie-in for EV calculated from incident readings.

Yes, I said films because it was with film that "Sunny 16" was worked out and it is the response to light from those films that allows it to work. Aren't digital sensors the same? The answer is complex, but the short and happy version is that yes, they are basically the same for digital cameras whose sensor response sensitivity is 18% gray traceable (CIPA Standard Output Sensitivity or SOS). Those cameras include those bearing the Pentax brand label. For cameras using other methods, YMMV.

I don't know about the rest of you, but my brain is overfilled.


Steve

[Lhorn]

Interesting discussion. I recently got a Spotmatic with a broken meter and wanted to give it a try. On a cloudless day one week ago in my backyard (Northern California) at 1:30 pm I was especting this to be an f16 day. However checking my exposure with my K1000 and ME Super showed that I was underexposed 2 plus stops. I guess my location and the time of year I ought to be thinking f11 or even 8 as a starting point.

[Wasp]

Here is one I made earlier, using said sunny f/16 rule. Not living near a beach or in a snowy climate, I stick to f/11. The exposure was 1/400 second at ISO 400. I made some minot adjustments in Darktable but the exposure was spot-on.

Auto exposure is not much use in mixed lighting like this, especially when you are striving for a certain look and feel, like I am.

Equipment used included an SMC Pentax M 28mm f/2.8 and a Samsung NX1.

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Last edited by Wasp; 04-20-2019 at 02:17 AM.

[35mmfilmfan]

Probably a silly question, but does the focal length have any effect on the basic principle of this guideline ?

[clackers]

Probably a silly question, but does the focal length have any effect on the basic principle of this guideline ?

Focal length or sensor size do not affect the guideline, as it is about exposure.

[Wasp]

Probably a silly question, but does the focal length have any effect on the basic principle of this guideline ?

Not in the actual exposure but you have to take the focal length into account when choosing the shutter speed if you are hand holding. An exposure of f/11 at 1/100 second on ISO 100 is perfectly good with a 50mm lens, but not so much with a 500mm. Then again, SR might save the day.

[jack002]

This thread made me research it. I knew of the sunny 16 rule, but now I know for sure what really works. As of last week in the midwest US near about noon with a clear sky the rule is sunny 11. (as was said in here, it depends on your location and season to really be 16)
Having a light meter that you trust all the time makes you ignorant of things like this. Good to know. I have studied some on EV and this is related.

[PjayPages]

Wow, thank you all for the very helpful information. I greatly appreciate it! Is there any generalized guidelines like the 'Sunny 16' for indoor shooting? Or is it all up to how you want to expose the shot?

[pschlute]

Wow, thank you all for the very helpful information. I greatly appreciate it! Is there any generalized guidelines like the 'Sunny 16' for indoor shooting? Or is it all up to how you want to expose the shot?

Have a look at this link which was posted earlier Ultimate Exposure Computer

Shooting indoors is going to be about 9 or 10 stops less light.

[Wasp]

Shooting indoors under available, artificial light is a real challenge. Getting the color balance right can be tricky enough with a digital camera. When working with color film, you are really pushing the envelope. To do so without a light meter is to venture into uncharted territory. I salute you, sir!

[PjayPages]

Have a look at this link which was posted earlier Ultimate Exposure Computer

Shooting indoors is going to be about 9 or 10 stops less light.

Yes, I was going through this link. Although it was just a quick browse. I'll read more in depth. Thank you for the suggestion.

[arnold]

Yes, I was going through this link. Although it was just a quick browse. I'll read more in depth. Thank you for the suggestion.

Bear in mind that one cannot assume the shutter speeds are accurate. High speeds in particular, on older cameras can be off a stop. I doubt my Yashica Lynx still can shoot 1/1000, so I allow a half stop compensation. Generally, using the sunny 16 rule, I use a scale of five stops open for normal indoors, closing gradually to f16 in full bright sunlight.
I recently shot a roll of 24 with only Sunny16, (Pentax SV) and all were acceptable. I stepped into a bookstore from a bright outside, and opened up five stops for this result.
[IMG][/IMG]

[PjayPages]

Bear in mind that one cannot assume the shutter speeds are accurate. High speeds in particular, on older cameras can be off a stop. I doubt my Yashica Lynx still can shoot 1/1000, so I allow a half stop compensation. Generally, using the sunny 16 rule, I use a scale of five stops open for normal indoors, closing gradually to f16 in full bright sunlight.
I recently shot a roll of 24 with only Sunny16, (Pentax SV) and all were acceptable. I stepped into a bookstore from a bright outside, and opened up five stops for this result.
[/url][/IMG]

Opening up by 5 stops, you mean by moving from a f16 to like a f2.8?

[arnold]

Opening up by 5 stops, you mean by moving from a f16 to like a f2.8?

That is correct. However, if the indoors is not bright, then and extra stop of two (f2.0 or 1.4) if available will work. So, generally you will be safe if you use f11 in sunny conditions, and f4 in the shade with little need of a light meter. You have to use your discretion in cases where there is both shade and sun, but that applies even with a meter. There is something to be said for the freedom of shooting "from the hip with a manual camera" and not be enslaved to menus and automation.