Talk:Sunny 16 rule

Much of the content of the aperature/light table was lifted from The Ultimate Exposure Computer, which explictly denies the right to copy the material featured on the page for any purpose. Copied the last version of the table in its place.

--Cintrom 22:27, 22 April 2006 (UTC)

Added a link to Fred Parker's Ultimate Exposure Computer to the page. This is some excellent content that pertains to this article, and I obtained permission from Fred Parker to link to his page. Yes, this is overkill - But after the previous copyright infringement, I felt it was better to stay on the safe side with Fred.

--Achra 16:01, 20 June 2006 (PDT)

Add to the discussion that the rule is adjusted a stop for fall/winter Sun vs spring/summer Sun when you live at a latitude where the Sun's noon time altitude changes significantly. —Preceding unsigned comment added by 50.46.174.62 (talk) 11:45, 1 March 2011 (UTC)

f/16 compared to f/8

In Germany they say: "f/8, wenn die Sonne lacht". If I do so, how do I have to adjust the time? Instead of 1/100 (@ ISO 100) then 1/400 or 1/800? --91.6.92.24 (talk) 16:22, 27 May 2012 (UTC)

I personally feel that f/11 is more accurate than f/16 for average scene. Something has to be pretty bright for f/16. However, if you want to use the f/8 rule, since that opens the aperture by two stops compared to f/16, lower the shutter speed by two stops. (Lenses are generally sharper at f/8 than f/16.) Bubba73 ^{You talkin' to me?} 07:20, 6 April 2015 (UTC)

I am not so sure how accurate the rule is. It was usual to round to the nearest whole stop, though on most manual cameras the aperture is continuous. Most electronic cameras with manual or aperture priority mode allow 1/2 or 1/3 steps for the aperture. But negative films usually have one stop underexposure latitude, and two or three stops over, so one more stop of exposure is probably good. Note that the rule is based on incident light, so works the same with dark or light subjects. You want dark subjects to come out dark, and light subjects to come out light. (But the printer might try to compensate, and undo what you carefully do.) Gah4 (talk) 08:30, 27 October 2016 (UTC)

step versus stop

@Dicklyon: What is a "step"? The sentence is talking about a change of 1 f-stop, since the exposure time is halved. Bubba73 ^{You talkin' to me?} 22:57, 11 June 2019 (UTC)

I asked on the photography group and they also think that "step" is ambiguous. Bubba73 ^{You talkin' to me?} 02:47, 13 June 2019 (UTC)

All that I know call them stops, though I don't know so well the reasoning. Many now have steps, increments that you can set, of 1/2 stop or 1/3 stop. I believe stop is the WP:COMMONNAME, whether or not it should be. Gah4 (talk) 13:34, 15 June 2019 (UTC)

I think they are called "stops" because lenses with aperture rings have stops at f/1.4, f/2.0, f/2.8, etc. Each change of 1 stop changes the light by a factor of two - higher or lower depending on which way you are going. Shutter speeds correspond to that change. Aperture says "In general, these structures are called stops...". "Stop" is used in that article more than 40 times and "step" is never used. Bubba73 ^{You talkin' to me?} 16:08, 15 June 2019 (UTC)

Many of the earlier cameras used a waterhouse stop, a disk with holes in it that could be set with one of the holes in the appropriate position. Exactly why it is called a stop, is hard to know. Most apertures now are continuous, though with detents at appropriate positions, sometimes at half stop increments. Gah4 (talk) 00:03, 16 June 2019 (UTC)

I believe that calling the unit an f-stop is fine, in the case of aperture settings, but as noted, stop is probably best. Gah4 (talk) 00:06, 16 June 2019 (UTC)

halve

In the paragraph in question, it indicated that one can open the aperture, and in compensation halve the shutter speed. There is a complication in shutter speeds, that they are commonly written in units of seconds, or fractions thereof, and so not speeds. In contrast, one says increase the speed, appropriate for the usual meaning of speed, when setting a shorter shutter open duration. Note that, corresponding to ASA and ISO values, a higher value means higher speed, and so halve should indicate a slower shutter speed. It would be best to avoid this ambiguity and not use the word halve. Gah4 (talk) 00:11, 16 June 2019 (UTC)

Maybe instead of "shutter speed" it should say "exposure time". Bubba73 ^{You talkin' to me?} 01:07, 16 June 2019 (UTC)

That should work. Gah4 (talk) 04:05, 16 June 2019 (UTC)

latitude

There are recent edits regarding latitude. Seems to me that the difference between latitudes isn't all that huge, and an important part of this rule is that films have some latitude. (Less for slide films, though.) But closer to the equator, with the sun higher, there will be less light on the front of subjects, which likely partly compensates for any higher sun intensity. Of course clouds change everything. Gah4 (talk) 02:00, 30 May 2020 (UTC)

Are you purposing mixing both uses of latitude into this note and not saying which the heading refers to, just to amuse us? Or is there a question? Dicklyon (talk) 15:56, 30 May 2020 (UTC)

Not intentional. There is a recent edit, already reverted, with the summary: This rule generally holds good in temperate areas, however the intensity of ambient sunlight varies considerably according to latitude. For example on a sunlit day in Sydney Australia the intensity of the sunlight might well be up to four times that of a sunlit day in London, requiring an f-stop of f32 or a shutter speed number equal to four times the ISO number of the film. These adjustments need to be added to all other exposure values based on the system. Actual discussion of sunlight is in Solar_irradiance where you can see that Australia is not four times London, but maybe two. This is for a horizontal surface, not what one normally uses for photographic subjects. Gah4 (talk) 22:46, 30 May 2020 (UTC)