Sunny f/16 rule does not quite work on the M10-R?

[Life By Stills]

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Hi guys,

Hope everyone is well. Happy Friday! I was just wondering if anyone has noticed this - I was doing some test shots with the M10-R with the Voigtlander 35mm f/2 Ultron I (not sure if it matters, but thought I'd add what lens I was using for reference) and I noticed how the camera does not react properly to the old tried and tested sunny f/16 rule. At ISO 400, shooting a sunny scene, it underexposes at f/16 when I use 1/500 as the shutter speed, exposing correctly when I give it one extra stop of light at 1/250 shutter speed.

Wondering if anyone else has noticed this with the M10-R and / or certain lens combos etc?

[Ornello]

31 minutes ago, Life By Stills said:

Hi guys,

Hope everyone is well. Happy Friday! I was just wondering if anyone has noticed this - I was doing some test shots with the M10-R with the Voigtlander 35mm f/2 Ultron I (not sure if it matters, but thought I'd add what lens I was using for reference) and I noticed how the camera does not react properly to the old tried and tested sunny f/16 rule. At ISO 400, shooting a sunny scene, it underexposes at f/16 when I use 1/500 as the shutter speed, exposing correctly when I give it one extra stop of light at 1/250 shutter speed.

Wondering if anyone else has noticed this with the M10-R and / or certain lens combos etc?

See this:

 

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[a.noctilux]

-1EV is nothing to care of.

Just curious, how do you judge the "underexpose" frame ?

How is the light in London ?

How is the histogram in each ?

[TomB_tx]

The brightness of sunlight varies around the world, and often "sunny 16" needs to be modified. Also, that rule came from film days, and film is generally more forgiving of exposure than digital. Sounds like in your example the correct exposure was within one stop of "sunny 16" (which suggests 1/400 shutter) - which I think is all that can be expected.

A lot of users intentionally under-expose with Leica digitals to be sure they don't blow out highlights, as shadows can be recovered better in post processing than highlights.  I believe Leica may have fudged M10-series exposure a bit in that direction. On the other hand, blown highlights generally don't bother me, and I don't care to do much computer work on images. Just to say there's a range of ideas on "correct exposure" - just like digital camera manufacturers fudge quite a bit on "ISO" ratings.

I see others have replied while I was musing on this...

[Adam Bonn]

7 minutes ago, TomB_tx said:

I believe Leica may have fudged M10-series exposure a bit in that direction

+1

When, as a test I set my M9 to base ISO (160), my M10 to ISO200 (which I consider to all intents and purposes base ISO) and use the same lens on each and shoot the same thing, then 9 times out of 10 they select the same shutter speed, despite the higher ISO of the M10 should require a shorter shutter time

11 minutes ago, TomB_tx said:

just like digital camera manufacturers fudge quite a bit on "ISO" ratings.

To be fair digital ISO is a rather arbitrary concept, manufactures have more than one 'standard' (aren't standards wonderful, there's so many to chose from 🙂) to select, and much like how miles per hour and kilometres per hour all denote speed they use different numbers.

The internet has at various stages said 'this OEM cheats at ISO' but it's not really that simple..

(FWIW the DxO measurement for the M10 says that when the camera is set to 200, DxO measure 105, for the M9 they say 160 = 144, in my IRL observations they meter the same at base ISO)

[charlesphoto99]

Also keep in mind f16 on your expensive Leica lenses is the worst aperture to shoot at due to diffraction. They are typically optimized for best performance wide open to f5.6. 

[Mikep996]

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Keep in mind that the Sunny 16 is based in NEGATIVE film.  It does not work as well with slide film and the way slide film reacts is pretty much how digital reacts.  To get the best results from slide film, you "underexpose:"  Same is true with digital.

IOW, if you went from predominately slide film to digital, nothing really changed as far as how you treated the exposure.

Edited March 26, 2022 by Mikep996

[adan]

A lot of good thoughts here so far. Here are a few others.

1) if you want to shoot 1/500th at f/16, then the ISO (film or sensor) should 500, not 400. Right? Otherwise you are starting off already 1/3rd-stop underexposed. Since the M10-R has in-between shutter speeds, 1/350th is a better choice with f/16 and ISO 400.

2) The "Sunny 16" rule is indeed "old" - it was developed sometime in the 1930s, when there were not even many hand-held meters, let alone in-camera meters. One interesting fact about the 1930s is that very few lenses then were coated. So they tended to flare somewhat as general veiling flare, which stole light intended for the highlights and spilled a bit extra everywhere. And multi-coating as on today's lenses did not appear until the 1970s (Zeiss T*, Pentax "Super-Multi-Coating," Canon S.S.C. (Super Spectra Coating) etc.).

3) Additionally in the 1930s, most cameras had leaf shutters (as Ornello alludes to), which iris out from the center - a small aperture like f/11-f/16 is "fully open" for longer than f/3.5 or other wide apertures. That doesn't happen with focal-plane shutters - although Leica's clockwork film shutters are known for running a bit slow if they haven't been tuned up recently (1/500th is often really 1/350-400th, and 1/1000th is often 1/750th).

4) Additionally (again), about 1960 the ASA (American Standards Association) revised how they tested and rated film speed, removed a safety factor, and essentially doubled all the "ASA" film speeds. Tri-X went from being an ASA 200 film to being an ASA 400 film overnight - without a single change in its actual formula or sensitivity.

Once the ASA and the German equivalent (DIN - Deutsches Institut für Normung) film speeds were rationalized into the ISO (International Standards Organization) speeds, that change remained. Also, as mentioned by Adam Bonn, the ISO process for determining digital ISOs is different than that used for film - with film the shadow density of a negative is measured - and digital doesn't produce "negatives". There are actually five recommended methods of determining the ISO of a sensor, and those are only for .jpeg images - since raw data is only data until it becomes a picture in one's post-processing computer.

https://www.iso.org/obp/ui/#iso:std:iso:12232:ed-3:v1:en

So let's just say "Sunny 16" was created to work with different cameras, lenses, shutters and film or sensor ratings than we use today. Although it is usually not more than 1 stop off, even now.

Couple of cases in point:

Around 1981, when Leitz lenses were definitely coated, and Leitz was starting to phase in multi-coating, I recall an employee who had just gotten an M and lens. He said "Man, these Leica lenses are contrasty - I have to shoot my Tri-X at ISO 200, not 400, to get any shadow detail!"

In working with medium-format film recently, I was having real trouble getting shadow detail in sunlit scenes with 1990s multi-coated Mamiya lenses and the "rated" ISO and "Sunny 16" exposures. Then I added a 1960-ish Rolleicord Vb with a Tessar-type Schneider Xenar (single-coated - and a design known to occasionally flare anyway), and its negatives are far more "open" and fully exposed than the Mamiya Sekors at the same settings. It works fine using "Sunny 16" - detail everywhere.

You might try your test with an old-school 50mm Summar or Xenon.

5) As TomB_tx mentions, the light reaching the Earth is variable, especially at high latitudes ("polar night" and "midnight sun" and all that). High latitudes get the short end of the stick compared to the tropics.

If the sun is lower than about 45° from the zenith, its light is losing significant intensity two ways. First, it is passing slantwise through the atmosphere (more miles of air and water vapor) and thus more light is lost to atmospheric absorption and scattering. And second, it is falling on the Earth's surface at an angle, with each unit of light spreading across more surface area. (Ever notice how l-o-o-n-g shadows get when the sun is low?). It becomes essentially "side lighting" even at noon - and for side-lighting the Sunny 16 rule recommends opening up a stop in any case.

The same also applies for any time of day where the sun is low in the sky, even at the height of local summer. The "golden hours" 2 hours after dawn or before sunset need more exposure - unless of course one is looking for the strongly-saturated colors and inky shadows of those hours.

[Ornello]

8 hours ago, adan said:

A lot of good thoughts here so far. Here are a few others.

1) if you want to shoot 1/500th at f/16, then the ISO (film or sensor) should 500, not 400. Right? Otherwise you are starting off already 1/3rd-stop underexposed. Since the M10-R has in-between shutter speeds, 1/350th is a better choice with f/16 and ISO 400.

2) The "Sunny 16" rule is indeed "old" - it was developed sometime in the 1930s, when there were not even many hand-held meters, let alone in-camera meters. One interesting fact about the 1930s is that very few lenses then were coated. So they tended to flare somewhat as general veiling flare, which stole light intended for the highlights and spilled a bit extra everywhere. And multi-coating as on today's lenses did not appear until the 1970s (Zeiss T*, Pentax "Super-Multi-Coating," Canon S.S.C. (Super Spectra Coating) etc.).

3) Additionally in the 1930s, most cameras had leaf shutters (as Ornello alludes to), which iris out from the center - a small aperture like f/11-f/16 is "fully open" for longer than f/3.5 or other wide apertures. That doesn't happen with focal-plane shutters - although Leica's clockwork film shutters are known for running a bit slow if they haven't been tuned up recently (1/500th is often really 1/350-400th, and 1/1000th is often 1/750th).

4) Additionally (again), about 1960 the ASA (American Standards Association) revised how they tested and rated film speed, removed a safety factor, and essentially doubled all the "ASA" film speeds. Tri-X went from being an ASA 200 film to being an ASA 400 film overnight - without a single change in its actual formula or sensitivity.

Once the ASA and the German equivalent (DIN - Deutsches Institut für Normung) film speeds were rationalized into the ISO (International Standards Organization) speeds, that change remained. Also, as mentioned by Adam Bonn, the ISO process for determining digital ISOs is different than that used for film - with film the shadow density of a negative is measured - and digital doesn't produce "negatives". There are actually five recommended methods of determining the ISO of a sensor, and those are only for .jpeg images - since raw data is only data until it becomes a picture in one's post-processing computer.

https://www.iso.org/obp/ui/#iso:std:iso:12232:ed-3:v1:en

So let's just say "Sunny 16" was created to work with different cameras, lenses, shutters and film or sensor ratings than we use today. Although it is usually not more than 1 stop off, even now.

Couple of cases in point:

Around 1981, when Leitz lenses were definitely coated, and Leitz was starting to phase in multi-coating, I recall an employee who had just gotten an M and lens. He said "Man, these Leica lenses are contrasty - I have to shoot my Tri-X at ISO 200, not 400, to get any shadow detail!"

In working with medium-format film recently, I was having real trouble getting shadow detail in sunlit scenes with 1990s multi-coated Mamiya lenses and the "rated" ISO and "Sunny 16" exposures. Then I added a 1960-ish Rolleicord Vb with a Tessar-type Schneider Xenar (single-coated - and a design known to occasionally flare anyway), and its negatives are far more "open" and fully exposed than the Mamiya Sekors at the same settings. It works fine using "Sunny 16" - detail everywhere.

You might try your test with an old-school 50mm Summar or Xenon.

5) As TomB_tx mentions, the light reaching the Earth is variable, especially at high latitudes ("polar night" and "midnight sun" and all that). High latitudes get the short end of the stick compared to the tropics.

If the sun is lower than about 45° from the zenith, its light is losing significant intensity two ways. First, it is passing slantwise through the atmosphere (more miles of air and water vapor) and thus more light is lost to atmospheric absorption and scattering. And second, it is falling on the Earth's surface at an angle, with each unit of light spreading across more surface area. (Ever notice how l-o-o-n-g shadows get when the sun is low?). It becomes essentially "side lighting" even at noon - and for side-lighting the Sunny 16 rule recommends opening up a stop in any case.

The same also applies for any time of day where the sun is low in the sky, even at the height of local summer. The "golden hours" 2 hours after dawn or before sunset need more exposure - unless of course one is looking for the strongly-saturated colors and inky shadows of those hours.

Yeah, I said all this before. Lens coatings, shutters, etc.

[adan]

Well, you know the old journalistic adage: "If your mother tells you she loves you - get it confirmed by a second source."

[Alberti]

I guess that the colour temperature is also a point to consider.

Because it works like a filter; hence some exposure is remapped in a new space, compressing certain parts.

[Alberti]

Double

Edited April 4, 2022 by Alberti

[Life By Stills]

Oh wow! Thank you so much to everyone explaining about the difference between using the sunny f/16 rule on film versus various sensors too! I'm thinking of picking up a film camera again just for fun so will see if I can use the same lens and see what exposures I am using when compared to a digital.

But it's actually all really insightful stuff - I absolutely love the detailed knowledge which many of you have!!! 😍

[RayD28]

In February on a bright sunny day (latitude 38.71) my incident meter read f11 in an open field.  Later in town the incident meter read f16 in sunny scenes.  This made me study the scene and surroundings and I noted there was a large amount of reflected light falling on the scene from a nearby white building with many windows.  Point being there can be other reasons Sunny 16 is less than reliable.    

[davidmknoble]

 Ok, so I have used the sunny 16 rule quite successfully with film (Ilford FP4+ and Kodak Tri-X) and the Leica M3, using both older lenses (summicron rigid 50) and newer lenses (ASPH summicron M’s).  Film has a different response curve to light than a digital sensor.  If you took Kodak Tri-X and exposed it at ISO 100 all the way up to ISO 12,500, you would get pretty poor results without a very specialized developer.  Yet, a digital sensor is just that. The M10 has a base ISO of about 160 (so I use 200).  Exposing at ISO 400 is the same sensor, just under exposing by 2 stops.

I am not saying that sunny 16, with modification, wouldn’t work, but I think the modifications might be different at every ISO. As a further example, shooting higher ISO films is harder with Sunny 16 because the exposure latitude is much less.  Ilford Delta 3200 is very picky about getting a good exposure because it is so sensitive to light.  I do not use Sunny 16 outside of the two films I use quite a bit, because I understand the latitude of the film.

Just some additional thoughts.