stability of 'sunny 16'

tjwspm · May 13, 2025

DREW WILEY said:
What I can't figure out is that alleged Smartphone reading on the previous post. With Minolta and Pentax real spot meters, 14-1/2 EV is just a stop and a half above a typical sunny day midtone reading.

That's easy to understand. EV 13 is about 35% as bright as EV 14.5, so if you have 14.5 directly against the sun and EV 13 against the reflections, this means that 35% of the sunlight is reflected. It is said that about 30% is the average reflection in the landscape (averaged from fresh snow 80-90% to grass 25% to fresh asphalt 4%). So it fits.

DREW WILEY · May 13, 2025

I admit I don't know how various cell phone cameras either think or don't think. If this particular case is true, then not only is it not a spot reading, but a very questionable averaging if the sun is in fact in the frame - which would totally overwhelm the rest of the reading. But those gadgets are so absurdly prone to flare and so forth, that it makes little difference to me personally. I'll never take pictures with them unless it's a burglar's vehicle or something like that.

BrianShaw · May 13, 2025

DREW WILEY said:
I admit I don't know how various cell phone cameras either think or don't think. If this particular case is true, then not only is it not a spot reading, but a very questionable averaging if the sun is in fact in the frame - which would totally overwhelm the rest of the reading. But those gadgets are so absurdly prone to flare and so forth, that it makes little difference to me personally. I'll never take pictures with them unless it's a burglar's vehicle or something like that.

Not only is a cell phone metering app not spot, but it isn't incident either.

Chan Tran · May 14, 2025

BrianShaw said:
Not only is a cell phone metering app not spot, but it isn't incident either.

I agree that is not sport nor incident but the readout in Lux is confusing. Only incident measurement should the readout be in Lux. With reflected measurement it should be Cd/m²

BrianShaw · May 14, 2025

BrianShaw said:
Not only is a cell phone metering app not spot, but it isn't incident either.

My profound apologies for stating a fact when, in fact, it is likely incorrect. A Google-search indicated that a few apps indeed can do incident light measurement as well as spot metering. Similarly, there are apps that do the essence of spot metering, Either/both may be simulated in some sort of way and what I read appears to have been validated against stand-alone meters.

khh · May 16, 2025

BrianShaw said:
My profound apologies for stating a fact when, in fact, it is likely incorrect. A Google-search indicated that a few apps indeed can do incident light measurement as well as spot metering. Similarly, there are apps that do the essence of spot metering, Either/both may be simulated in some sort of way and what I read appears to have been validated against stand-alone meters.

The incident meter mode often use the dedicated ambient light sensor most decent phones these day have. These sensors are essentially miniturized incident light meters that give a light reading in lux and quite fit for purpose, but of course they're not intended or calibrated for critical photography purposes.

Chan Tran · May 16, 2025

khh said:
The incident meter mode often use the dedicated ambient light sensor most decent phones these day have. These sensors are essentially miniturized incident light meters that give a light reading in lux and quite fit for purpose, but of course they're not intended or calibrated for critical photography purposes.

For photographic purposes an accuracy of about +/- 25% is OK. Imagine if your ruler or thermometer or you voltmeter is that much off.

stability of 'sunny 16'

tjwspm

DREW WILEY

BrianShaw

Chan Tran

BrianShaw

khh

Chan Tran

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