Luminous Landscape Forum

Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: etrump on September 19, 2007, 09:42:00 am

Title: Stop down exposure problems
Post by: etrump on September 19, 2007, 09:42:00 am

I have been doing some dynamic range and lens testing on my new MF gear getting ready for my first trip using it.

Basically I am photographing a resolution chart and a self made zone system exposure bar.

I am having an unexpected problem when doing stop down exposure testing.

Normally I focus at the largest aperture possible then use the cameras metering to get the exposure.  Then I stop down the lens and either double the shutter speed for each stop or use the cameras metering once stopped down.

The problem I am having is that it always over exposes so my logic is obviously flawed.

Any ideas?

Title: Stop down exposure problems
Post by: Jack Varney on September 19, 2007, 06:29:31 pm

"Then I stop down the lens and either double the shutter speed for each stop or use the cameras metering once stopped down. "

I think you mean that you half the shtter speed, i.e. increase the open shutter duration time.

Have you exposed before stopping down to test the exposure accuracy? Could be a meterring problem or shutter problem.

Title: Stop down exposure problems
Post by: etrump on September 20, 2007, 11:24:34 am

Quote

"Then I stop down the lens and either double the shutter speed for each stop or use the cameras metering once stopped down. "

I think you mean that you half the shtter speed, i.e. increase the open shutter duration time.

Have you exposed before stopping down to test the exposure accuracy? Could be a meterring problem or shutter problem.
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Exposure before stopping down is perfect and metering is similar to other cameras (at least the Canons I have).  It is just the stopped down exposure with the P30+ that seems to overexpose.

Title: Stop down exposure problems
Post by: etrump on September 24, 2007, 12:50:48 am

Quote

Exposure before stopping down is perfect and metering is similar to other cameras (at least the Canons I have).  It is just the stopped down exposure with the P30+ that seems to overexpose.
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I guess it was some strange miscommunication between the camera and back.  Reset everything and she works great now.

Go figure.