Explanation of Hasselblad PM/PME viewfinders

[brad_rhodes]

I am new to hasselblad equipment and have recently purchased a used PME

45 degree prism...but found out that it is not metered for use with the

newer acu-matte screens (it is metered though).

 

Could someone list the different 45 degree prisms out in existence made

by hasselblad and whether they are metered with any technical issues to

be concerned with when using them?

 

many thanks.

/bradRhodes

[Rob F.]

Why not shoot a bracketed test roll and see whether a little exposure compensation will do the trick?

[nicholas_wybolt]

Brad,

 

Which screen(s) do you have? Page 4 of the PME45 manual lists the D-Series screens that the PME45 works with. Also, referring to Rob's response, if you shoot a roll of transparency film, noting the exposure settings, the P5 program mode of the PME45 can be set with permanent exposure correction for your screen(s).

 

-Nick

[Rob F.]

Brad: Having recently read & responded to your post, yesterday I found myself in the position of running across & buying a PME myself. With your question in mind, This AM I loaded up a roll of Plus-X and headed for the picturesque section of town. With the 100mm 3.5 Planar on the camera, and an acute-matte screen, I took a reading off the south side of a sunlit medium-toned brick church. There was some light trim around the windows. Some deep blue north sky was in the frame. In other words, a reasonable approximation of an average scene with 18% average reflectivity. The PME read 1/500 @ 16. I knew that was wrong. The sunny 16 rule would peg this exposure at 1/125 @ 16 (or in my case, my preference was 1/500 at 8). The Minolta digital autometer in incident mode agreed perfectly with sunny 16, not with the PME. Leaving the Max. Aperture control at 3.5 to agree with the lens, I moved the ISO control until the PME agreed with reality. I wound up set to 25. I took the shot. Next, I chose a darker building, still a southern exposure, but shadier. This time I trusted the PME & took the shot. Then I moved on to another church. Still staying with a southern facade, after another shot or two I felt that 32 was a better setting than 25. Another couple of shots, and I started using a Hoya orange filter, a Hasselblad light yellow on the 100mm; and a K2 (wratten #8) filter on the 60mm Distagon. I finished the roll on various subjects & lighting, never consulting the Minolta again.

 

Back home, I processed in D-76 1:1 for 7 minutes @ 68 degrees. Perfect negatives. Exposures were bang on. I decided to get out the standard focus screen to try a reading with it. Reading off the front of my house, which is medium dark red brick, southern exposure, and again with some light trim and north sky, I got 1/125 @ 8--same as the Minolta incident meter.

 

So far, so good. But when I was getting the standard screen out of the box, the instructions for the acute-matte fell out. The instructions first told all about how the PME readings would vary depending on focal length & aperture, but then wound up with the simplistic statement that we should just set the film speed dial to half of the rated film speed. Half? I just scientifically proved it should be a fourth! Back outside, with the Acute-matte reinstalled. This time, each time I took a reading with the PME, the EV shown in the finder went up a half to a full stop, until it reached EV 17. EV 17? Not in my front yard! Conducting a visual inspection, I saw that the little battery door had slid open. Correcting this, it now behaved itself, but gave the right reading, this time, with the ISO dial set to half the film speed, just like it said in the directions. Something caused a difference of one stop The power of suggestion, once I read the directions? I don't think so. Or the battery door (which apparently is also the positive contact point). So we have a mystery. The exposures were perfect with a two-stop correction. But later a one-stop adjustment agreed with the Minolta and the sunny-16 rule. The Minolta's never wrong, anyhow.

 

I doubt I'll get a chance to do anymore until next weekend. But I'll solve it. And I'll let you know.

 

Best Wishes,

[Rob F.]

As a followup note, experience has shown that a one-and-one-half stop correction yields exposures reliable enough to give consistently good reults with EPP100, Provia F 100, and Velvia. I arrived at this using mostly my 100mm Planar and 150mm Sonnar; and to a lesser extent the 60mm Distagon.

 

I found the best way to achieve the correction was to leave the prism set to the speed I want the film exposed at, and just subtract 1 1/2 EV when transferring the reading to the lens.