I recently have decided to buy the Pentax 67II. Reading the post on LUSENET has been of great help in taking that decision. But a supprising problem, undiscussed of on LUSENET, has popped up. The camera shop allowed me to test the camera before purchase: I wanted to check out the shutter. So, using a Pentax 67II on a tripod with a 90 mm lens focus on infinity, I shot a roll on a white wall — having previously check that all the surface included in the picture was uniformely lighted — and shoot at 1/1000 at f2.8, 1/500 at f 4.0, 1/250 at f 5.6... and so on. All the frames from 1/125 down where uniform in density but, surprisingly, the frames shot at 1/1000, 1/500 and 1/250 showed bands of differents densities: the frames looked like stripes! The camera was send to Pentax Canada Repair Center and, on return, I tested it again... with the same results! The camera was send back again and, with the last test roll in hand, Pentax Canada technician said that it is normal for Pentax's horizontal shutter to give such results at those speeds. That, if it showed on a photograph of a white wall it won't be visible in a photograph of a real subject (as if a sky would not show the bands)! The camera shop tested another camera with the same results: at high speeds the frames showed very easily visible bands of differents densities! Now, my question is: has anyone tested the shutter? What where the results at high speeds? Can it be trusted? Hopefully, my results where accountable to defectuous shutters and are not «normals», as the technician said. I just can't beleive that such an acclaimed camera as the Pentax 67II could not be use with confidence at speed higher than 1/125! And, for all other considerations, I would like so much to use one.

Jean Grothé

-- Jean Grothé (jean.grothe@videotron.ca), January 19, 2001

Answers

One reason for the banding may be that the shutter travel speed varies as its traveling across the frame. This will likely result in consistent banding in consistent locations in every frame. If however the banding that you see is well defined but the location is inconsistent from frame to frame then the problem could be lighting. This effect is similar to using flash with a shutter speed faster than the max sync speed. The P67's shutter allows for flash sync up to 1/30. Faster shutter speeds means a slit exposure so any varying light sources will create exposure "bands". When you tested did you use fluorescent lighting? Remember fluorescent lighting flickers heavily at 60 Hz (most incandescent lights will also result in varying light levels to a lesser degree). All shutter speeds above 1/30 will show banding to some degree. Since the P67 has low sync speed it becomes prone to this effect quicker than the 35mm cameras with very high sync speed or leaf shutter lenses. Try the same test using daylight, if the problem is still present then its likely a shutter travel problem. I've used the P67II for a long time and never confronted this problem so do not see it as a limitation.

-- M.B. (mbarroca@americasm01.nt.com), January 19, 2001.

Thank you for answering my post, M.Barroca.

As for your questions: a) the banding pattern is consistent from frame to frame for each specific speed and shows slight differences between the three differents speeds (1/1000, 1/500 and 1/250); b) the setup was: camera at three feet from white wall, lens set at infinity, with two blue lights in reflectors on each side, all other lights closed.

If I understand well your closing statement, your diagnoctic would be of two defectifs shutters; you don't consider this banding as a normal phenomena for the Pentax 67II.

If so, I would then start searching for a well functionning item.

Thank

Jean

-- Jean Grothé (jean.grothe@videotron.ca), January 20, 2001.

Further informations...

I went to another store and before buying the 67II requested that the camera was tested as to the high shutter speeds. The manager tested two new cameras and, to his amazement, they both had the same flaw: at 1/1000, 1/500 and 1/250 they showed the banding patterns!

Jean Grothé

-- Jean Grothé (jean.grothe@videotron.ca), March 02, 2001.

Inside lighting with alternating current light bulbs - especially flourescent bulbs - can give pronounced banding at any shutter speed over about 1/60. Repeat test with blue sky.

-- Steve Boothe (boothers@wwdb.org), August 07, 2001.