A Bronica conundrum

[whlogan]

Here's a funny..... I use a Bronica ETRS and an AEII prism. when I use a #22 filter, the meter/camera/prism combination results in correct (or nearly) exposure, but whn I use a #29 filter, I am about 1 to 2 stops under exposed. Anybody know why such a thing happens?

 

[Nick Zentena]

The meter is having problems with pure red light? I guess it's less sensitive to red. But a 22 is mostly red to. I wonder if you use a 25 is it in between the 22 and the 29?

 

[glbeas]

What film are you shooting? Some B&W films, Panatomic X comes to mind, has a decided drop in sensitivity at the red end of the spectrum. If your meter does not match that drop in sensitivity you will have the metering errors you mention. In this case you need to recalibrate your EI for use with this filter.

 

[Jonathan Taylor]

From my Nikon F2 manual and other kind folks on the NikonMF list, I learned a long time ago to always compensate for a #25 filter by reducing the ASA setting by a stop (e.g. 400-->200). The F2 manual says that the meter is less sensitive to red. Since then I've always done that on any camera I use, now including my ETRSi. This practice has always seemed to give good results, though I must admit I now use orange filters more often than red.