Few questions to Luna Pro / Lunasix 3 users

[BrianShaw]

That makes sense, @Chan Tran . Can you estimate about how much change you are observing. Preferably in some sort of estimated measurement or percentage over a specific timespan. Im curious if this is a lab measurable phenomenon yet one of no consequence to photography applications.

 

[Chan Tran]

That makes sense, @Chan Tran . Can you estimate about how much change you are observing. Preferably in some sort of estimated measurement or percentage over a specific timespan. Im curious if this is a lab measurable phenomenon yet one of no consequence to photography applications.

I always like to do some experiment. I do not need a meter as I have more meters than I need for photography and even then at times it's more fun for me to do photgraphy meterless. So actually reading these threads I wanted to study more about the CdS cells as well as Solar Cell. I bought some CdS cells and the data sheet said you should expose the cell to the light for 2 hours so I did. I observed at first when I put the sensor under the light the resistance is 130 Ohms and about an hour or so later it's 153 Ohms. and stopped rising. Turning the light off then back on again the resistance went down to 130 Ohms again then started to rise. For me making experiment and making measurements taught me a lot. That's why I am a sucker for measurement instruments of all kinds.

 

[RalphLambrecht]

Leakage currents, self discharge and environmental conditions will have a profound influence, quite likely much more so than actual use. Put simply, the batteries in a meter like this die due to sitting around more so than due to actual use.

exactly. I'm convinced that selfdischarge of my NMH batteries are is responsible for most of the discharge in my case. My batteries last about 3 months.

 

[F4U]

I always like to do some experiment. I do not need a meter as I have more meters than I need for photography and even then at times it's more fun for me to do photgraphy meterless. So actually reading these threads I wanted to study more about the CdS cells as well as Solar Cell. I bought some CdS cells and the data sheet said you should expose the cell to the light for 2 hours so I did. I observed at first when I put the sensor under the light the resistance is 130 Ohms and about an hour or so later it's 153 Ohms. and stopped rising. Turning the light off then back on again the resistance went down to 130 Ohms again then started to rise. For me making experiment and making measurements taught me a lot. That's why I am a sucker for measurement instruments of all kinds.

Thank you. I get old so fast I can't remember which year. Maybe 2011 or 2013 when I became a Luna Pro home-study repair expert, making countless tests and throwing away my years when I SHOULD have been busy improving my financial and living conditions. I hate digressing , so on to the point. which is color temperature. What I discovered is that exposure meters have a very non-linear and unequal response to things which reflect the same amount of light, but are of different colors. It was in that year of study I concluded that the famous Ansel Adams Zone System, and today's methods of distant spot metering and zone placement are not really much, if any more accurate than using incident metering and bracketing a few shots and cherry-picking negatives. Which is what any self-respecting photographer is doing to do anyway. At 68 years of age I don't think I've ever seen the 'perfect" negative. At least not one where I planned and executed be that way. The takeaway is that meter cell linearity response, and shutter accuracy. are everything. Still, a mediocre negative still is the best most of us will ever achieve I'm afraid. Or maybe speaking for myself.

 

[Chan Tran]

Thank you. I get old so fast I can't remember which year. Maybe 2011 or 2013 when I became a Luna Pro home-study repair expert, making countless tests and throwing away my years when I SHOULD have been busy improving my financial and living conditions. I hate digressing , so on to the point. which is color temperature. What I discovered is that exposure meters have a very non-linear and unequal response to things which reflect the same amount of light, but are of different colors. It was in that year of study I concluded that the famous Ansel Adams Zone System, and today's methods of distant spot metering and zone placement are not really much, if any more accurate than using incident metering and bracketing a few shots and cherry-picking negatives. Which is what any self-respecting photographer is doing to do anyway. At 68 years of age I don't think I've ever seen the 'perfect" negative. At least not one where I planned and executed be that way. The takeaway is that meter cell linearity response, and shutter accuracy. are everything. Still, a mediocre negative still is the best most of us will ever achieve I'm afraid. Or maybe speaking for myself.

The exposure meters are very inaccurate as instruments relatively. I don't know if any kind of measurement where a 25% off is considered acceptable and the best meter can hopefully be about 7% accuracy. However, metering accuracy and good negative has nothing to do with each other. As I said I can do quite well without the meter but I like to know about the meter for the meter sake not neccesary for the application of photography.

 

[BrianShaw]

The exposure meters are very inaccurate as instruments relatively. I don't know if any kind of measurement where a 25% off is considered acceptable and the best meter can hopefully be about 7% accuracy. However, metering accuracy and good negative has nothing to do with each other. As I said I can do quite well without the meter but I like to know about the meter for the meter sake not neccesary for the application of photography.

Actually, I think you do know of one... many, if not most, general photography applications.

Even Sunny-11/16 may not have better accuracy as the sun may be constant but the "rule" is simply a convenient rule-of-thumb estimation that works under the right conditions, and can be adapted relatively easily to other conditions. It's not like Sunny-11/16 is a scientifically validated theorum.