Gossen Luna Pro F....need help!

[AdamD]

Hi all, happy Friday.

After getting help for you in another post, I settled on the Gossen Luna Pro F light meter.

I just got it and did some tests. I'm not seeing what I think I should be seeing, but I'm probably doing something wrong. I would think that my DSLR and the Luna would at least be close, but I'm way off....

First, what should you expect given the following: ASA: 125; incident reading, direct full sunlight.
After centering the needle I looked at f16. What would you expect to see the shutter speed be?

Next question....

I'm thinking that I must have the dial wheels set incorrectly. So if someone has experience with this meter, please give me some guidance before I start thinking its a bad meter 😒

Thanks!!

Adam

[AdamD]

One other thing...

I did this initial check to make sure the meter was zeroed and is was.

Also, indoors and at night just walking around the house, I used my DSLR to meter and checked against the Luna. I found that if I rotated the Exposure Factor wheel to 8 (black value) the readings were pretty close at 400 ISO and 800 ISO.

[eli]

Where did you buy the meter?

What were the full daylight settings, on both the camera and meter, asa/iso film speed, shutter speeds, f-stops and any filter factors?

You spoke of using incidental readings, what were you metering and did you try using the dome.

A small, clean Styrofoam cup can be put over the end of the lens for a reading.

Did you take any reflective measurements from both tools?

Did you have your digital camera set to auto-select the best iso/shutter/f-stop for each shot?

Did you take any pictures with both sets of readings, that you can show us?

More info is needed, but if you can, contact another photographer, and compare readings from a known good meter to yours.

Almost every town has a studio or someone doing school photos of teams, etc, that use meters out of doors, and, there is always a club or group of film shooters in the area too.

Just reach out and you'll likely find help is closer than you think.

You've gotten a great meter, but even the Luna Pro F can need professional calibration.

If you find your tool is too far out of kip, Quality Light Metric is the best place to send it, IMO and that of many, many others.

Go ahead and show us some side-by-sides with both settings, and always make sure to keep the Flash Control Button turned off and a new 9 volt battery or two, in packaging, in your kit.

Good luck

IMO.

[Two23]

On a cloudless sunny day between the hours of 11 am and 2 pm, set the ISO to 125. Point it to the southern sky. Reading should be f16 and 1/125s. As for your tests, remember this is an incident meter, and the one in your DSLR is a reflective meter.


Kent in SD

[AdamD]

Kent, that's exactly what I was expecting to see too.

But, it wasn't full sun, so I'd expect something a little slower than 1/125. I wasn't even close. I'm going to fiddle with it today and post some new observation if it might help know if the meter needs calibration or the user needs education. Hoping for the later of the two!

[Two23]

Make sure it's a fresh battery.


Kent in SD

[HMG]

Are you comparing the Gossen in incident mode with the dslr metering in reflective mode?

[AdamD]

I keep things apples with apples. When I compare the DSLR I of course do not use incident; I use reflective.

The battery is new.
My camera is hard set to 125 iso or whatever setting I'm testing at that time.

[HMG]

It may very well be a defective meter if you correctly tested as outlined in post #4 and you got a significantly different result (say > 1 full stop) as you indicated. I'd do one more test before sending it back.

Meter (in reflective mode) against a solid outside wall from about 15 feet away. Compare that to your dslr reading with a 35mm lens (assuming crop sensor). And perhaps post a photo of the face and what you read the setting to be.

[eli]

The Styrofoam cup over the camera lens, will give you an incidental reading, just throw the lens into the infinity setting before taking a reading.

Pick a building wall, walk out 10-15 feet and mark a open area to represent a tripod, take a reading with the meter and camera without the cup or dome, off the same sunlit place on the wall, as if you were photographing it.

Now go to that spot on the wall and with the dome and cup in position, point them, about chest height at an imaginary person or a friend, and take the two reading.

The Luna Pro F (and SBC) sometimes has a lag if the metering trigger is pressed in rapid order, so if you think you rushed that reading, wait 15 seconds and do it again

You can do the same with a spot meter, giving you two meters in one.

IMO.

[AdamD]

This is weird....
Reading only in reflective mode, if I adjust the EF dial to about 8 (black #) the readings will be very close to my D7200 with 35mm lens. On occasion, I'll get a reading that is not close.

Then, when reading in incident mode, if I adjust the EF dial a little closer to "normal" I will sometimes get readings that I'd expect like sunny 16. But again, not always.

When I compare incident readings at the subject or directed back towards the DSLR location and compare to the DSLR reading from it's location, the readings do not match up very well. At times they do but more often than not they don't

I'm going to test this against a friend's light meter maybe next weekend if I can. I can return this one within 30 days.

[Andrew Tymon]

Have you a manual for it?https://www.butkus.org/chinon/flashes_meters/luna-pro_f/luna-pro_f.htm

[darr]

https://cameraartist.com/wp-content/uploads/2020/01/2020-darlene-almeda-2-e1579392382891.jpg

Here is a quick snap of my old Luna Pro F made under studio modeling lights.
For quick visual reference, a few dial readings for the above ambient light is:

ASA/ISO: 100
EV: 10+1/3

ƒ1.4+1/3 @ 1/500
ƒ5.6+1/3 @ 1/30
ƒ22+1/3 @ 1/2

I only keep this meter around because it carried me through photography school back in the 80s, and it is a keepsake that sits in a drawer.
I do not know what type of photography you will be doing with this meter, but I updated my meters over the years to digital.

If you will be doing landscape photography, I would use a spot meter and not an incident. Yes, an incident meter can be used, but why not use a spot meter and learn a little about the Zone System if shooting B&W film and processing is a goal. If you will be shooting in the studio, this is an okay way to meter, but there are better ones available. I have been using a Sekonic 558 incident and spot meter in my studio for 10+ years and it always works. Also, as we get older (like me), the scales on the Luna Pro F become increasingly harder to see.

Best of luck,
Darr

[ericantonio]

Kent, that's exactly what I was expecting to see too.

But, it wasn't full sun, so I'd expect something a little slower than 1/125. I wasn't even close. I'm going to fiddle with it today and post some new observation if it might help know if the meter needs calibration or the user needs education. Hoping for the later of the two!

"Wasn't even close" How far off was it? And I'm pretty sure you have the slidy thing for reflective reading right? Just something I've dealt with and for sure I was on the right position. If I remember correctly, there is a calibration thing on the underside of those.

9v battery all good? Do you have a multimeter to test it?

Also, if you have an iphone, I downloaded a light meter app just to see how far off my cameras and meters are and so far so good, all of them are pretty much spot on the same reading. But that is reflective reading not incident.

[ericantonio]

This is weird....
Reading only in reflective mode, if I adjust the EF dial to about 8 (black #) the readings will be very close to my D7200 with 35mm lens. On occasion, I'll get a reading that is not close.

Then, when reading in incident mode, if I adjust the EF dial a little closer to "normal" I will sometimes get readings that I'd expect like sunny 16. But again, not always.

When I compare incident readings at the subject or directed back towards the DSLR location and compare to the DSLR reading from it's location, the readings do not match up very well. At times they do but more often than not they don't

I'm going to test this against a friend's light meter maybe next weekend if I can. I can return this one within 30 days.

I'm a little confused. How do you get incident reading from your dslr?