M6 light meter correct exposure range

[caffeineorme]

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Hi,

so since I"m new to the forum and film Leicas this is going to be my first post. Recently acquired a M6 Classic (170x serial number) and I'm going through my first roll. When using the light meter I noticed that the range of when it says the image is correctly exposed is quite large. Or at least it appears to me as  such. Lets say having the camera set to ISO 400 and 1/250 both triangles are being fully lid between  f1.4 to f4.5. So after I determined that range and I go for the middle at around f2.8 I'm pretty much at the same reading from my M10R or some exposure metering app (since i don't have a dedicated exposure meter).

So long story short.. I wonder if that behaviour of the light meter and the LEDs is correct or whether it should be more 'strict'?

Any feedback is highly appreciated.

Best,

Gert

[Graham (G4FUJ)]

Doesn't sound right to me.

[jaapv]

Both arrows will remain lit within this rang but one or the other will change intensity to indicate over ot underexposure. 

[caffeineorme]

thanks for the feedback so far. but in the range mentioned above they are fully lid. the intensity ramp up happened already before. also i ordered other batteries (some recommended in the manual) and see if that makes a difference. for now i only have  LR44 from two different brands with the same behaviour tough.

[Matlock]

4 minutes ago, caffeineorme said:

thanks for the feedback so far. but in the range mentioned above they are fully lid. the intensity ramp up happened already before. also i ordered other batteries (some recommended in the manual) and see if that makes a difference. for now i only have  LR44 from two different brands with the same behaviour tough.

It is best to steer clear of LR44 batteries as they are Alkaline, SR44 are the best choice.

[jaapv]

I use CR ⅓N batteries 🪫 single3V lithium 

[Anbaric]

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46 minutes ago, caffeineorme said:

So long story short.. I wonder if that behaviour of the light meter and the LEDs is correct or whether it should be more 'strict'?

I also use lithium (alkalines are the most likely of all to leak, which could have very expensive consequences for an M6).

You should see a difference in brightness between the triangles when the reading is only half a stop out; there should be a very clear difference a full stop away from the correct reading. If the correct reading is f/2.8 but everything looks the same between f/1.4 and f/4.5 in steady light with a fresh battery, then I'm afraid something is wrong, probably with the meter. Just to rule out some other issue, are the aperture blades opening and closing as they should at every stop? If you have a second lens, does the same thing happen? If you leave the aperture constant, but adjust the shutter speed instead, do you see similar behaviour? How about if you leave aperture and shutter speed constant and change the ISO? You might also try gently wiping the battery contacts and door contacts with a soft cloth.

Edited April 26, 2022 by Anbaric

[Matlock]

19 minutes ago, jaapv said:

I use CR ⅓N batteries 🪫 single3V lithium 

So do I but sometimes they are not easy to come by so 2 SR44s are the best bet in that case.

[davidmknoble]

@caffeineorme, @Anbarichas a good set of tests to rule out various things that might cause this.  I do agree the behavior is odd, even for the old M6.  

I checked the manual to be sure, because I do not remember such a wide range of exposure with both triangles lit, and I do not have my old M6 anymore.  Both triangles lit should effectively cover +/- 1/2 stop over and under exposure along with the correct exposure.  Otherwise, +/- 1 stop or more is only one triangle.

It is also possible the ISO dial has some worn contacts.

I would try varying ISO’s, and a wide open f/stop in medium light (to avoid the need for a faster shutter speed than 1/1000). And see if you can get the proper behavior.  Regardless of the batteries, if the meter is bright, I would think it would be closer to -1/2, 0 +1/2.  Also the fact that you said the middle exposure was pretty close to other metering tells me the meter is picking up light pretty well…

Let us know what happens.

[caffeineorme]

Thank you everyone for the feedback. So on all of my lenses it behaves the same. tested with four Voigtlander lenses. A very good suggestion was leaving aperture and shutter speed constant (f2, 125) and just changing the ISO. Doing so the light meter indicates optimal exposure (both triangles fully lid) between about ISO 400 and 1600 or around 800 and 100. And that's quite some range. So I'll reach out to some camera service and otherwise try to return the camera since the original seller told me he purchased it from a store and it actually has another year of warranty from that store. 

[Anbaric]

In case this is useful if you end up re-testing the camera after a service, I just had a play with my M6 and found that at around 1 stop out, one of the triangles is not always completely extinguished, but is (at least) very much fainter than the other, and even half a stop difference is detectable (as above). At around 1.5 stops out (at most), you should only see one triangle. But because the metering angle of view is quite narrow, you have to be careful the reading isn't changing as you fiddle with the controls. Ideally, put the camera on a tripod and choose a combination of shutter speed, aperture and camera position where the triangle intensities are exactly balanced when the aperture is in a click stop somewhere in the middle of its range. Then you can experiment at +/- 0.5, 1, 1.5 etc. Incidentally, it can be helpful to think of the M6 Classic shutter speed dial as a 'thumbwheel', where you need to move the back of the dial in the direction of the metering arrows.

[caffeineorme]

@Anbaricthank you a lot. So the thing that really confuses me is that the metering seems to be ok in the middle of the range. Just the range being way too large. The guy from the service was super helpful on the phone and told me he's going to take some measurements later when i get there but chances are I would need to send it to Leica to get it repaired there. Not the hardest thing since I'm located in Berlin, Germany. But since the seller (who on top of everything is in Italy) described it with everything being excellent I'd rather return it in case there's really something to fix cause then it's obviously not aligned with to common understanding of excellent. Well.. so far everyone involved (including the seller) is super helpful. Thanks so much.

[grahamc]

27 minutes ago, caffeineorme said:

...the thing that really confuses me is that the metering seems to be ok in the middle of the range. Just the range being way too large. 

This is correct - I have an M6 and as others have mentioned, the 'range' on mine is as follows:

Correct Exposure is indicated by: Both arrows bright 
Half stop under or over is indicated by: One arrow faint (but visible.. let's say half-strength) and the other arrow remains Bright (right arrow bright indicates half stop over exposed, left arrow bright indicates half stop under exposed)
One full stop under or over = As above but the fainter arrow disappears completely and only one arrow remains . (right arrow bright indicates full stop over exposed, left arrow bright indicates full stop under exposed)

So, the 'range' of this indication is "plus or minus one stop". 

(After you travel further in the same direction of over or under exposure the remaining single arrow possibly becomes fainter, but I don't notice that in use .... I use in the way mentioned) 

Best of luck with the return or fix, and sorry to hear it !

 

Edited April 26, 2022 by grahamc

[Anbaric]

3 hours ago, Anbaric said:

In case this is useful if you end up re-testing the camera after a service, I just had a play with my M6 and found that at around 1 stop out, one of the triangles is not always completely extinguished, but is (at least) very much fainter than the other, and even half a stop difference is detectable (as above). At around 1.5 stops out (at most), you should only see one triangle. But because the metering angle of view is quite narrow, you have to be careful the reading isn't changing as you fiddle with the controls. Ideally, put the camera on a tripod and choose a combination of shutter speed, aperture and camera position where the triangle intensities are exactly balanced when the aperture is in a click stop somewhere in the middle of its range. Then you can experiment at +/- 0.5, 1, 1.5 etc. Incidentally, it can be helpful to think of the M6 Classic shutter speed dial as a 'thumbwheel', where you need to move the back of the dial in the direction of the metering arrows.

Sorry, there's an error in my post. Graham and David have it right, and the meter is more precise than I suggest above. The threshold for seeing only one triangle is indeed 1.0 stops out (not 1.5 stops). At 0.5 stops out you should see one bright and one dim. Even at an intermediate position (about 0.25 stops out on a lens with 0.5 stop clicks) you can detect a difference. Apologies for the confusion!

[jaapv]

I would return the camera, as the electronics are irrepairable due to parts being unavailable.

[Matlock]

1 hour ago, jaapv said:

I would return the camera, as the electronics are irrepairable due to parts being unavailable.

That is a slight oversimplification as it depends on what is the fault. Spares are no longer available but not all repairs require parts.

[jaapv]

The electronics do normally require replacement - It <might> be some bad contact but I would not risk it.

[caffeineorme]

thanks for all the feedback. took it to some repair shop that has quite a lot experience with m cameras and they’ll run some checks. so expecting to get results by friday. i’ll keep you updated. 

[grahamc]

19 hours ago, Anbaric said:

Sorry, there's an error in my post. Graham and David have it right, and the meter is more precise than I suggest above. The threshold for seeing only one triangle is indeed 1.0 stops out (not 1.5 stops). At 0.5 stops out you should see one bright and one dim. Even at an intermediate position (about 0.25 stops out on a lens with 0.5 stop clicks) you can detect a difference. Apologies for the confusion!

Thanks @Anbaric

I realised I forgot to mention that of course the further you travel away from correct exposure , one arrow will still remain lit (indicating whether you are over or under exposed as a starting point).  So you could be 3 stops over as a starting point but there would be one arrow (same as one stop over), and on my M6 I can't see any difference in intensity of that arrow at 1 stop versus 3 stops. 

So I tend to get a 'correct' exposure first and then work my way outwards - when the meter goes from 2 arrows to one then I know I'm a stop over or under and I count up or down from there if necessary . 

Just in case that wasn't clear for the OP

 

Edited April 27, 2022 by grahamc

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[caffeineorme]

@Anbaric@grahamcthanks a lot and no worries. guess i got it right nonetheless. and after all i'm used to my m10r. also keeping in mind that one can go half stops with the shutter speed dial on that one plus the center dot which the m6 does not have. again... as long as the metering in general is working i might be fine with the larger range cause that's something one gets used to. since i'm mostly doing street photography my feeling for the lighting there mostly is very accurate and one could still get a dedicated exposure meter. well lets see what the feedback will be from the service person.

so.. maybe someone knows what components / settings play into the light meter circuit? shutter dial, iso dial, battery compartment in a way more than providing power?, the actual diode for measuring light, the shutter curtain  with that white / grey-ish dot... anything else? trying to understand how those things play together. also i noticed that the lens might have a little room to play with the chance to overturn it a little. but not always. really gotta pay attention to how you attach the lens. but is there something in the lens-mount that might have impact on the whole process.

btw.. pic of the camera attached. i'd say the shutter curtain and the whole camera look pretty good given the age. except for those small zinc related blisters. but i don't mind those. really little on the top case. 

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