Light Meter app for iPhone blows

[Huss]

Many people say this app is great. I have noticed way too many inconsistent/completely incorrect exposure readouts.
Proof below - the correct exposure is 1/60 sec at f4 at ISO 50
Lightmeter app says it should be 1/1500!!! Also, this is a very evenly lit scene, with no harsh contrasts, bright or dark areas to throw it off. Pretty much the easiest scene to meter.

It doesn't do this all the time, most of the time it gives ok readings. Most of the time my guesswork does too...

What is interesting is that the app uses the phone's built in camera's meter as its meter. But the iphone camera gives fine exposures. So that means the app is lame.

I dropped using it a long time ago, using either Sunny F16 or a real meter. I was messing with it today to see if they had improved it. Guess not.

 

[JoeV]

Is there a setting for it to use the front facing camera instead of the rear? If so, perhaps it was metering the sky when you were trying to meter the sidewalk.

~Joe

 

[maddoc]

Is there a setting for it to use the front facing camera instead of the rear? If so, perhaps it was metering the sky when you were trying to meter the sidewalk.

~Joe

The icon right above "aperture" in the screen shot (the camera symbol with two curved arrows) indicates that you can switch between front and rear camera. The iPhone light-meter programs I use all have this feature to switch between reflected (rear camera) and incident (front camera metering).

 

[BillBingham2]

Your subject is not even close to 18% gray.

B2 (;->

 

[dave lackey]

Many people say this app is great. I have noticed way too many inconsistent/completely incorrect exposure readouts.
Proof below - the correct exposure is 1/60 sec at f4 at ISO 50
Lightmeter app says it should be 1/1500!!! Also, this is a very evenly lit scene, with no harsh contrasts, bright or dark areas to throw it off. Pretty much the easiest scene to meter.

It doesn't do this all the time, most of the time it gives ok readings. Most of the time my guesswork does too...

What is interesting is that the app uses the phone's built in camera's meter as its meter. But the iphone camera gives fine exposures. So that means the app is lame.

I dropped using it a long time ago, using either Sunny F16 or a real meter. I was messing with it today to see if they had improved it. Guess not.

Huss, I tried for a year to use this app and in the end my experience was like yours. It sucked. So I got rid of it. The ergonomics drove me crazy and got the MR meter for the M3... Much better but still it was not fun to use.

 

[Huss]

The icon right above "aperture" in the screen shot (the camera symbol with two curved arrows) indicates that you can switch between front and rear camera. The iPhone light-meter programs I use all have this feature to switch between reflected (rear camera) and incident (front camera metering).

You meter what you see on the screen. So if the app was metering the sky, you would see an image of the sky.

 

[Huss]

Your subject is not even close to 18% gray.

B2 (;->

It's a 5 stop difference from the correct exposure. 18% gray or not, that would not account for a garbage app.

Plus, the phone's camera takes a correctly exposed shot of the scene. So 18% or not, the phone gets it right, but the app using the phone's camera (and meter obviously) gets it so wrong. Well, the app is crapp.

 

[thawkins]

The latest technology I use with my range finder cameras is the Leica MR meter or a Gossen Luna pro meter. Involving an iPhone light meter with an M3 defeats the whole purpose of using an M3.

 

[JHutchins]

It's a 5 stop difference from the correct exposure. 18% gray or not, that would not account for a garbage app.

If I were metering off a sidewalk I would open up at least two stops from a reflective meter reading. And based on what I can see of the scene (bright highlights on the shoes, hard but not dark shadows) it looks like a bright hazy/thinly overcast day for which I would open up two stops from sunny sixteen giving about what the meter shows there so I'm a little puzzled at the vehemence of your condensation of the app. Even apart from my general distaste for any claim that there is such a thing as a correct exposure.

 

[Huss]

The latest technology I use with my range finder cameras is the Leica MR meter or a Gossen Luna pro meter. Involving an iPhone light meter with an M3 defeats the whole purpose of using an M3.

Splendid but not relevant to a discussion of whether an app works.
🙂

 

[JHutchins]

The latest technology I use with my range finder cameras is the Leica MR meter or a Gossen Luna pro meter. Involving an iPhone light meter with an M3 defeats the whole purpose of using an M3.

Defeats your purpose perhaps, but not all conceivable purposes for using an M3. An M3 is an inexpensive way to gain access to a wonderful line of lenses, an M3 has the best viewfinder/rangefinder of any M as long as you can live with its high magnification and so limited usefulness for wides, an M3 is just a flat out beautiful camera that is a joy to hold and use. All of these are reasons for using an M3 that are in no way impaired by use of an iphone app to help judge light values.

 

[Huss]

If I were metering off a sidewalk I would open up at least two stops from a reflective meter reading. And based on what I can see of the scene (bright highlights on the shoes, hard but not dark shadows) it looks like a bright hazy/thinly overcast day for which I would open up two stops from sunny sixteen giving about what the meter shows there so I'm a little puzzled at the vehemence of your condensation of the app. Even apart from my general distaste for any claim that there is such a thing as a correct exposure.

Soo... you state you would open up two more stops.

Open up = give more light.
2 stops from 1/1500 = 1/350.

Correct exposure is 1/60.

Unless you mean you would give it 4 more stops than the indicated reading of an evenly lit medium tone scene in the shade.

Which really shows how poor the app is.

And repeating myself yet again, the camera on the phone takes a correctly exposed pic. The app uses the phone's meter....
The picture that I attached is the one shown by the app taken by the phone. It is correctly exposed! But the app gives a completely bogus meter reading for that captured, correctly exposed image.

 

[splitimageview]

Note: iPhone meter apps do not simply grab the suggested exposure from the camera app.

It's up to the developer to create their own algorithm.

There are lots of these. Have you tried others?

Have you compared to multiple types of scenes or just this one?

How do you know 1/60 is 'correct?' What's your reference?

 

[Huss]

Note: iPhone meter apps do not simply grab the suggested exposure from the camera app.

It's up to the developer to create their own algorithm.

Exactly. But it uses the camera on the phone, then throws in it's algorithm to show exposure.

Why don't you tell me, looking at this image, what you think the correct exposure should be?
Remember, open shade, ISO 50. Aperture f4.
Entertain me...

 

[splitimageview]

The developer doesn't use Apple's Camera app algorithms for exposure, is what I'm saying.

So the accuracy of a meter app is pretty much dependent on the abilities of the developer to write an algorithm that takes sensor data and derives light levels from it.

As far as guessing what the correct exposure is from a screen shot from an iphone posted on the web...you're kidding right?? 😉

Seriously, what is your reference meter for the 1/60s exposure?

 

[JHutchins]

Soo... you state you would open up two more stops.

Open up = give more light.
2 stops from 1/1500 = 1/350.

Correct exposure is 1/60.

Unless you mean you would give it 4 more stops than the indicated reading of an evenly lit medium tone scene in the shade.

Which really shows how poor the app is.

And repeating myself yet again, the camera on the phone takes a correctly exposed pic. The app uses the phone's meter....
The picture that I attached is the one shown by the app taken by the phone. It is correctly exposed! But the app gives a completely bogus meter reading for that captured, correctly exposed image.

You're claiming that the "correct exposure" is at least four stops brighter than 1/ISO @f16. I wasn't there, obviously, but based on what I see in that picture that is a recommendation inconsistent with what any handheld reflective meter would give. I see distinct shadows near the feet, bright highlights at the tips of the shoes and a decided yellow cast on the right side of the right shoe suggesting that the sensor was a bit overloaded there. I would not expect a meter to tell me to open four stops from sunny sixteen until there were no visible shadows or pronounced highlights.

 

[giganova]

1/1500, f/4 @ ISO 50 = "Sunny 16", and what you have in your image is a sun-lit scene with shadows. So what's the problem?

 

[ColSebastianMoran]

So... This is totally weird. I get pretty reasonable readings from this app. Very strange.

Only thing I can think of is this app has a "Hold" feature, if I remember. Possible it was "Holding" an exposure from a different lighting condition.

Correct Sunny 16 ISO 50 exposure would be 1/50th at f/16. You sure it's a good exposure at 1/50 at f/4?

 

[drewbarb]

I understand that it would be great to have a single gadget that did everything you might need it to do, and that the iPhone and similar devices try to be just that- but it's no light meter. I carry a little Sekonic 308, which is about the same size as an iPhone. It has one job, and it does it very well. I've noticed the designers didn't try to cram a phone into it.

 

[Huss]

I compared it with a Sekonic L 308.
ISO 50, open shade, correct exposure, which matches my guestimate, indicated at 1/60 at f4

This is the Pocket Light Meter app.

To sum up. I estimated 1/60 at f4 ISO 50 from experience
Sekonic matches at 1/60 f4 ISO 50, reflected reading.

App says 1/1500 at f4 ISO 50

This has been brought as a public service announcement. You are free to use these wonderful apps to determine exposure if you will.

🙂