M7 AE lock question

[alexz]

A question to a fellow M7 users on the list:
When using AE lock, holding it down (second "pressure point" as per Leica manual) and recomposing I noticed the supposedly locked exposure may jump approx. 1.3 to 1.2 stop back and forth between the originally locked and nearby value (shutter speeds of course) when I recompose (and measuring area gets covered by different lighting pattern).
When holding AE locked I have upper dot glowing which confirms AE lock, however wen recomposing and the shutter speed jumps to the nearby value (by 1/3-half stop) - the lower dot also gets glowing momentary, when the exposure jumps back to the original locked value - the lower dot goes off.

Does it make sense for a properly operating M7 ?

Thanks, Alex

 

[Ron (Netherlands)]

No, does not make sense, mine was steady (but in the end sold it to finance other projects)

 

[faris]

No. someone with more experience, please advise.

 

[35mmdelux]

I hold my AE lock and exposure remains the same.

 

[sepiareverb]

Do you have fresh batteries in the camera? If the batteries are not suspect, spin the ISO dial back and forth several times- I press my thumb on the center portion and twist it back and forth. It sounds like there is dust under the dial. I was given this tip by Leica NJ and it works well for a while. I wear a lot of wool in the winter and I suspect this is why my M7's get so dusty.

There has been some mention lately about Solms replacing some part under the dial as a more permanent fix- I've not looked into this for my cameras yet.

 

[tightsqueez]

Mine is en route to NJ for the same exact problem, now on it's third trip for yet again... the same problem. It is the dial which is at fault here. Every time I send it in I tell them that when I bump the dial around when I'm shooting, the lower light (ISO) sometimes turns on and off intermittently. I've had this issue pretty much from day one and I bought this with the Passport Warranty. Send it in, be exact and stern with what the problem is and how it happens. Try manually setting your ISO, as I have found that this kept my film speed at least where I wanted it.

Although mine never changed shutter speeds after I had locked the exposure, I'm suspecting at least the dial is to blame for the other issue mentioned. The M7 is an electronic nightmare but I still love mine to death, it just needs a tune up here and there.

 

[peter_n]

Leica Milton Keynes apparently identified the problem as a duff carbon track. See post # 24 in the thread below:

http://www.rangefinderforum.com/forums/showthread.php?p=1156962

 

[tightsqueez]

Not sure about the OP but thanks for that information.

 

[alexz]

Thank you guys.
Well, in fact, I can't see direct relationship between the commonly reported ISO dial issues and mine (AE lock related), it appears even if there is certain malfunctioning with AE in my case it has very little to do with ISO dial.
Now, playing with AE lock a bit more, the problem I described doesn't happen always, but rather intermittently.

 

[peter_n]

This is really a bump to get the thread back to the top of the pile. Sorry we went off track (not a pun 😀). Intermittent problems are difficult and time-consuming ($$$) to troubleshoot. Are there independent technicians in Israel like there are in the US? Very few here can deal with the electronic side of the recent Leica cameras anyway. I did not have this problem with my M7s so I can't help you with a possible remedy, but you may have to send it to Solms and hope that the problem manifests itself when the camera gets there...

 

[alexz]

Yes, I'm still unsure about my particular issue, can't reproduce it reliably so far, today it worked just fine. However, noticed today another potential weird thing in my M7 - being on DX and having ISO 400 film inside, it begun flashing 400 on/off upon power-up with lower LED glowing. I switched to manual ISO 400 setting and it ceased making it stable. Then later today tried to reproduce that issue with DX setting - that time it worked fine at automatic DX...

go figure...

I will let it another chance, will swap the batteries for a new set and will try to gain some more experience with the camera before drawing any conclusions and taking probably quite expensive measures....

 

[sepiareverb]

I wouldn't rule out the ISO system as a possible cause. I have one M7 that has often acted up in various ways which seems to have just been fixed by adding the extra baseplate washer (which I did myself earlier today). Even with low batteries no troubles- a first.

A few things to consider: which DX reader do you have? The older has pins, the newer has no pins. Do you have the extra baseplate washer? The extra washer is a small one (barely larger than the center spool of a 35mm film) which is on top of the baseplate lock. Both of these seem to effect performance quite a bit in some M7's.

 

[alexz]

I have an older reader (balls), not the optical one and there is no washer at the baseplate lock.

 

[peter_n]

They only put the washer on the baseplate when they update the DX reader to optical. After the update the canister rattles around in the chamber a bit hence the washer. I had one of my M7s updated to the optical reader and they did it under warranty, but I've been reading that they have also been doing it for free on out-of-warranty bodies too.

 

[sepiareverb]

I'm wondering how much the cassette moving in the chamber with the old DX reader is to blame for this stuff. I'm going to try the washer on a non-Optical reader body and see what happens. I just have to get some sun to shine so I can finish the Pan F+ in my other M7's!