Hy6 Focus Tests after I adjusted pressure plate
AFTER CAMERA WAS RETURNED FROM FACTORY AND AFTER THE PRESSURE PLATE READJUSTMENT
INTRODUCTION
New focus tests of the Rolleiflex Hy6 (S/N 596540096) are described below.
Tests before and after the camera was returned to the factory for repair showed that no repairs were made to correct the focusing problems that affected the camera from the time it was originally purchased. The problem is that the film plane position error was too great for the focus offset to compensate for the focusing error during autofocus. Furthermore, the film plane positional error was too great for the camera to accurately focus on distant objects even with the lens manually adjusted to the infinity focus stop. One hypothesis is that the film insert was never properly adjusted after assembly, resulting in the pressure plate being too far rearward for the camera to focus properly. Before adjustment, the pressure plate measured approximately 0.70 mm behind the four corner flats that determine the insert’s position relative to the film path in the 6060 film back. The pressure plate was readjusted from 0.70 mm to 0.30 mm prior to conducting the tests represented by the image files in this folder.
The results of the tests represented by the image files in this folder show that the camera, after the adjustment of the pressure plate, is able to achieve accurate auto focus well within the range of offset values (probably close to +10) and is able to focus on distant objects with the lens manually set to infinity.
NOTE: The pressure plate adjustment directly affects the slots through which the film and backing paper must travel when the film is advanced. Reducing the gap below 0.30 mm could impede the film advance function.
Date of test: 11/22/20.
Film was TMax 100 shot at EI 100 and developed in Xtol 1:1.
File numbers correspond to frame numbers. The first shot was an error (mirror was not raised). Shots 2-8 are autofocus tests. Frames 9 and 10 are manual focus of an angled scale with the 80mm and 50mm lenses.
The last shot is outdoors with 80mm lens manually set to the hard infinity.
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INDOOR AUTO FOCUS AND OFFSET TESTS
* The color picture (Nov_Test_Setup_1.JPG) shows the test arrangement.
* Camera was on a tripod.
* Focus area was set to "small" for these pictures as Eric recommended on 10/17/20. Subsequent tests showed that setting the focus area to "Full" actually exacerbated the autofocus inaccuracy in this particular scenario.
* The grid target was centered on the split image in the view finder.
* All pictures were exposed at 1/15 sec at f2.8.
* I defocused slightly before each shot so the camera would have to focus every time.
* Mirror was raised manually before each shot.
* Camera was set to single focus and was done focusing before I removed my finger from the focus button.
Hy6_Roll_6_11-22-20_post_fix_001.jpg Offset = -30 (Skip -- forgot to lockup the mirror)
Hy6_Roll_6_11-22-20_post_fix_002.jpg Offset = -30
Hy6_Roll_6_11-22-20_post_fix_003.jpg Offset = -20
Hy6_Roll_6_11-22-20_post_fix_004.jpg Offset = -10
Hy6_Roll_6_11-22-20_post_fix_005.jpg Offset = -0
Hy6_Roll_6_11-22-20_post_fix_006.jpg Offset = +10
Hy6_Roll_6_11-22-20_post_fix_007.jpg Offset = +20
Hy6_Roll_6_11-22-20_post_fix_008.jpg Offset = +30
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INDOOR MANUAL FOCUS TESTS
Hy6_Roll_6_11-22-20_post_fix_009.jpg Manual Focus w/80mm @ F2.8 at 60"
Hy6_Roll_6_11-22-20_post_fix_010.jpg Manual Focus w/50mm @ F2.8 at 43"
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MANUAL INFINITY FOCUS TEST
Test date: 11/22/20
Film was same as above.
* Camera was set on tripod.
* Focus on each lens was adjusted to the infinity stop.
* Autofocus was never engaged.
* All shots were taken with aperture at f2.8.
Hy6_Roll_6_11-22-20_post_fix_011.jpg Xenotar 80mm at f2.8 at 1/1000 sec (no filter)
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All scans were done on an Epson V600 at a resolution of 2400 dpi, 16 bit grayscale scaled to approx 1200dpi by WP.
