Luminous Landscape Forum

Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: MichaelEzra on February 08, 2008, 10:31:52 am

Title: Mamiya 55mm 645 lens
Post by: MichaelEzra on February 08, 2008, 10:31:52 am

I noticed that my Mamiya ZD camera is consistently underexposing with 55mm AF lens. The underexposure is about 1-1.5 stops when automatic metering is used. My other AF lenses 80mm and 150mm do not seem to cause such underexposure. Has anyone noticed this strange behavior?

Title: Mamiya 55mm 645 lens
Post by: TMARK on February 08, 2008, 12:07:36 pm

Sounds like an aperture blade is sticking.  Send it up to MAC in Westchester.  Turn around time is pretty quick.

Title: Mamiya 55mm 645 lens
Post by: MichaelEzra on February 08, 2008, 12:18:31 pm

hmm interesting idea. Though, if it was sticking, would not it overexpose, as metering is done with wide open? I will test shooting in aperture priority, wide open.

Title: Mamiya 55mm 645 lens
Post by: Morgan_Moore on February 10, 2008, 04:44:44 am

Quote

hmm interesting idea. Though, if it was sticking, would not it overexpose, as metering is done with wide open? I will test shooting in aperture priority, wide open.
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If the metering is done wide open then the reading will be correct

Ith the metering is don 'nearly wide open' due to sticky blades then then over exposure will occur

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