Help me figure out what's wrong with my light meter?

[gbroadbridge]

I don't have a gray card. As an imperfect substitute, I held my hand (Caucasian skin tone) 2 inches from the light meters (hoping to cover the entire field of view), trying to keep the same angle relative to the ceiling light in my office. In that setting, the Luna Pro F meter in reflected-light mode and the phone light meter gave identical answers, within the margin of error: The phone app flickered between 1s and 2s exposure, while the Luna Pro F gave me a reading of 1.5s ---- all at F/16, ISO 200.

You know that with any modern film, one stop either way isn't going to make any difference when printed. Or in a transparency.
We're (mostly) not using hand made and coated emulsions with limited dynamic range.

A lot of huf'n'puff when we should all be out making photos

 

[dcy]

Let's say that the Luna Pro F is giving unreasonable readings under normal daylight, which is the shooting conditions I care about the most --- 90%+ of my shooting is in bright sunny days.

Let's say that shooting a roll of film to test is a lot of hassle for me, and it'll quickly hit a brick wall due to my inexperience shooting film, developing film, and judging negatives.

I think I'm just going to return it.

This meter is covered by eBay's standard return policy, and this is precisely the kind of situation the policy was made for. I'll just need to pay $8 shipping and I'll get my money back. I would rather end up $8 poorer than to be the proud owner if a $60 paperweight.

 

[Bill Burk]

When you meter your hand you are intended to increase exposure one stop to ”Place” the reading on Zone VI

You don’t want a gray hsnt you want a slightly lighter shade that a stop more exposure will give.

I honestly don’t trust any cell phone meter. You should just assume the Luna Pro is right and start comparing everything else to it.

In your photos you seem to be orienting the meter same as the phone.

You’re doing that to show the scale right? You took the reading aimed at the tree for example. Right?

 

[mshchem]

My meters are old, but I have 4 or 5 of the same model, they're all in agreement.

I am always grabbing the old Kodak Photoguide books. You can use the examples and usually hit perfect.

 

[dcy]

In your photos you seem to be orienting the meter same as the phone.

You’re doing that to show the scale right? You took the reading aimed at the tree for example. Right?

Yes! That is correct.

Good question. Yes. All the readings were with the light sensor aimed at the target.

 

[MattKing]

Trying to help someone with this over the internet is so much more difficult than in real life, in person!
But I'd be happy to persevere, if you would like, as I'm sure many others would.
FWIW, I think your meter is working correctly.
And I really like working with that model of meter, or a few that are similar.

 

[marhalloweenvt]

I think your meter is working fine. I have read through all comments and think that you haven't found a reliable way to test it.
For me, I will find a nearest grey/white wall and then point those instrument and read the result. If the result in aceptable tolerent (which in some your measurement results), I will call it a day.
P/s: Personally, I don't trust any light meter result output from phone. I would use digital camera with iso 100 and average metering mode to compare with handheld light meter.

 

[dcy]

Trying to help someone with this over the internet is so much more difficult than in real life, in person!
But I'd be happy to persevere, if you would like, as I'm sure many others would.
FWIW, I think your meter is working correctly.
And I really like working with that model of meter, or a few that are similar.

I am happy to persevere!

Brian sounded confident that the meter is wonky, but since you and several other people all agree that the meter is probably working, then I would very much like to keep at it and learn how to use it correctly!

 

[GregY]

My meters are old, but I have 4 or 5 of the same model, they're all in agreement.

I am always grabbing the old Kodak Photoguide books. You can use the examples and usually hit perfect.

Msh.... my meters are old and work too but I know their history......they're not unknowns bought off the internet 40 yrs after production ceased.
Like others, I would verify if it works....but not by comparison with some cell phone app.....
For that matter DCY ..... buy a meter from a photo dealer who's guaranteed it's accurate and in working order.

 

[dcy]

P/s: Personally, I don't trust any light meter result output from phone. I would use digital camera with iso 100 and average metering mode to compare with handheld light meter.

Yeah. I didn't think of grabbing my digital camera.

Here is a screenshot of the metering modes available to me. The default setting sounds sounds like a bit of auto-magic, so I guess maybe I'll choose the center-weighted option.

 

[marhalloweenvt]

Yeah. I didn't think of grabbing my digital camera.

Here is a screenshot of the metering modes available to me. The default setting sounds sounds like a bit of auto-magic, so I guess maybe I'll choose the center-weighted option.
View attachment 408120

Ah, so you have an Olympus digital camera. I also own a OM-D EM10 (1st version) and found that my ISO 100 is not ISO 100. I accidental know this when I was calibrating one of my friend sekonic l-238 lightmeter, so I have to use my reliable sony a7c and pentax digital spotmeter to compare.

 

[mshchem]

Msh.... my meters are old and work too but I know their history......they're not unknowns bought off the internet 40 yrs after production ceased.
Like others, I would verify if it works....but not by comparison with some cell phone app.....
For that matter DCY ..... buy a meter from a photo dealer who's guaranteed it's accurate and in working order.

Minolta:
I have one I bought new, and a couple I bought 20 years ago, and I have a couple Gossen meters I have bought in the last 10 years all work fine.
I doubt there's anything wrong with the OP's meter.

 

[brbo]

I honestly don’t trust any cell phone meter. You should just assume the Luna Pro is right and start comparing everything else to it.

I wouldn't blindly trust a meter that gives reflective reading of gray pavement on Sunny16 day as f16 1/1000s at ISO200. Even if it was called Luna Pro F'n Ansel Adams.

 

[djdister]

Keep in mind that whatever you point a meter at in reflected mode will attempt to render it middle gray. If you point it at a white subject in reflected mode, you will probably underexpose the subject by roughly 3 stops, so you have to mentally adjust the reading (in the case of a white card, open up 3 stops) when metering a subject in reflected mode that is not middle gray (or Zone V).

 

[brbo]

Keep in mind that whatever you point a meter at in reflected mode will attempt to render it middle gray. If you point it at a white subject in reflected mode, you will probably underexpose the subject by roughly 3 stops, so you have to mentally adjust the reading (in the case of a white card, open up 3 stops) when metering a subject in reflected mode that is not middle gray (or Zone V).

Luckily, with a meter that can take reflective and incident reading, it's easy to establish how close the surface is to middle gray.

 

[dcy]

Luckily, with a meter that can take reflective and incident reading, it's easy to establish how close the surface is to middle gray.

How? If the subject is 18% gray then two readings should be the same?

 

[Chan Tran]

How? If the subject is 18% gray then two readings should be the same?

To have the same reading the meter must have the flat diffuser instead of a dome.

 

[brbo]

How? If the subject is 18% gray then two readings should be the same?

Yes.

 

[BrianShaw]

To have the same reading the meter must have the flat diffuser instead of a dome.

Technically true, perhaps, but the difference will be negligible.

 

[Bill Burk]

How? If the subject is 18% gray then two readings should be the same?

Don’t get us started.

18% is a gray standard that you can buy, but it’s not the meter calibration target.

The gray which will match an incident reading is somewhere around 12%.

 

[Chan Tran]

Technically true, perhaps, but the difference will be negligible.

.4 stop

 

[Chan Tran]

Don’t get us started.

18% is a gray standard that you can buy, but it’s not the meter calibration target.

The gray which will match an incident reading is somewhere around 12%.

If the flat diffuser incident is calibrated for C250 and the reflective is calibrated for K14 then 18% gives the same reading. If you use the dome which is calibrated for C330 or C340 (depending on manufacturer) then it's more like 12%.

 

[BrianShaw]

Oh, joy… you bring K and C into the discussion. This should be interesting discussion!

 

[GregY]

Oh, joy… you bring K and C into the discussion. This should be interesting discussion!

 

[wiltw]

I don't have a gray card. As an imperfect substitute, I held my hand (Caucasian skin tone) 2 inches from the light meters (hoping to cover the entire field of view), trying to keep the same angle relative to the ceiling light in my office. In that setting, the Luna Pro F meter in reflected-light mode and the phone light meter gave identical answers, within the margin of error: The phone app flickered between 1s and 2s exposure, while the Luna Pro F gave me a reading of 1.5s ---- all at F/16, ISO 200.

Just for reference...another rule of thumb to keep in mind: The palm is -- generally speaking -- about +1EV compared to an 18% gray card.
My own palm has measured up to +1.3EV compared to an 18% gray card, but today it is +0.8EV brighter...IOW it too is somewhat variable.

And the reading with an incident meter also can be somewhat variable: it can measure somewhat differently at different times and depart from the Sunny 16 approximation 'rule of thumb' even with the meter facing the sun directly (which is not the way to use it). I note you have the hemisphere pointing straight up in your illustration of post #65...not right. It should be held horizontally and facing where the lens of the camera will be -- and that specific (vertical) angle will vary the incident meter reading as you rotate horizontally 360 degrees. This taken from one of my own posts years ago...

posted June 23, 2021​

"1. Just now I metered with my handheld Minolta incident meter (ISO 250, 1/250 shutter), held perpendicular to the ground (as if aimed to the camera lens), and as I rotated the meter 360 degrees I detected readings between f/11 +0.1EV to f/11 +0.7EV at 1:30pm on a birght cloudless sky at 38 degrees latitude. So here right now, Sunny 16 would be underexposed by -0.3EV to -0.9EV! Color transparency would do fine, but color neg would be getting into the possibility of 'muddy color' in the shadows.​

2. One hour later, I metered with my handheld Minolta incident meter (ISO 250, 1/250 shutter), held perpendicular to the ground (as if aimed to the camera lens), and as I rotated the meter 360 degrees I detected readings between f/8 +0.6EV to f/11 +0.9EV at 2:30pm on a birght cloudless sky at 38 degrees latitude. Deviation from Sunny 16 got even greater, by -1.4EV at one side, but better at -0.1EV at the other extreme.​

Many things about photography are not absolute.