DX Read Problem on M7

[aaron_johnston]

For my past feew rolls of film (all Fuji Provia 400f from the same

box), I've had a problem with my M7 reading the proper ISO speed via

DX (stated speeds range from 25 to 400). I have also had the problem

of the shutter simply refusing to fire after the 24th exposure even

though these are 36 exposure rolls. I gave the camera a semi-hard

whack against the baseplate and that seemed to convince it to continue

firing past the 24th frame but the DX woes continued.

 

I put a roll of NPS160 in today and it read the ISO fine on the first try.

 

All evidence seems to point to a fault with the Provia but I thought I

would ask anyway just to be sure. Any feedback would be appreciated.

[bob soltis]

I just sent my M7 to Leica USA for the same problem. DX read 25 to 400 then the camera died.

 

Bob

[kent_tolley2]

On the can of Provia you'll notice a pattern of black and unpainted squares which are read by the contacts inside your cam. The first thing I'd check is that the film can is clean. If not, the gold contacts inside your cam won't read it correctly. I suspect the means of reading is electrical charge flows through the silver squares but not thru the black squares. And the pattern itself changes with ASA. If a silver square has grease or a gold contact inside your cam is greased, where electrical charge should flow it won't and you'll get a mis-read.

[geoff b]

I had a similar problem with my M7 only with Astia 100F. The ISO reading would flash 25

on DX or manually selected to 100 when first turned on, it got to the point where I didn't

trust it at all.

I was about to send it back to Leica but then stopped using Astia in that camera and things

have settled down to normal, very reluctant to ship the camera away as the down time is

quite long.

Every other film works fine no matter the ISO. Must try another roll of Astia this weekend

as problems don't go away by burying your head in the sand, thanks for reminding me!

[kent_tolley2]

Alternately if a black square has not enough paint to prevent the electrical flow then it will look like a silver square to the sensing system and give a mis-read.

[michael j hoffman]

"Any feedback would be appreciated."

 

Get an MP. You'll avoid that sort of problem altogether ;-)

 

Michael J Hoffman

[keirst]

I always manually select film speed on my M7s because they only sometimes seemed to read

the speed correctly on DX, so I gave up using that feature. I've never had a problem with the

manual film speed setting. I guess Leica's DX film speed reader isn't well designed. Since

there is only one row of sensor contacts, I don't think it reads film length info from the

canisters.

[christoph_frick1]

I've had a few wrong DX interpretations with my M7 with Provia 100F:

the display said "25" and the meter behaved accordingly.

 

What helped was to move the ISO dials around a bit -- I thought maybe there is some oxidation in the potentiometers...? -- On the other hand, I can't remember having had this problem with other films.

[aaron_johnston]

I shot a whole roll of NPS160 today and the only problem I had was the shutter release jamming after five exposures. After another love tap to the baseplate, it resumed functioning. I'll probably just send the camera in for repair. Thanks for all the feedback.

[davo s]

Leica have a new method of reading DX coding. The gold plated sensors are replaced with IR LEDs. This was done recently on a customer's camera with a similar problem.