c220 and black series 55mm focussing

henk@apug · Jan 8, 2012

I have bought a 55mm f4.5 black series lens to use with
a c220 body. The lens is in great shape. I have noticed that when I focus at infinity
the distance scale does not intersect the curve for 55mm at
infinity mark (I am at the 7ft mark). I know I must test
but it this definitely a problem ? Perhaps some of c220 users
experience the same ?

Thanks !

Jojje · Jan 9, 2012

I have never bothered with Mamiya distance scales which seem a bit clumsy. So I had to check the combination, C220 with a "blue-dot" 55mm. Reading when focused - with my worsening eye-sight - at infinity: about 2 meters! Very close 7 ft.
And I have adjusted the focusing screen self. (BTW checking Mr Butkus' manual is worthwhile.)
Take a picture of a steel ruler at full stop at about 1 meter and you will see if you're near the ballpark.

grahamp · Jan 9, 2012

Your distance scale looks like this? http://grahampatterson.home.comcast.net/~grahampatterson/grahamp/c220/c220lside.jpg (you may have to zoom it a bit).

The 55mm line is the left-most red line. The thickness of the line is almost as much as the difference from 1m to infinity, so it is bordering on useless

But having infinity at 7' or thereabouts seems wrong. Either the scale is misplaced, or the focus is suspect. You need to check the film plane focus. If the finder and the film plane agree, you can always put on your own scale.

Graham

henk@apug · Jan 10, 2012

Thanks for the info !

I will check focus first with Mr ButKus' C220 repair manual.

Jojje · Jan 10, 2012

I must underline the fact that my Mamiya focuses correctly - whatever the readings on the scale might be. Just checked with other lenses, 105, 65 and 180mms. All these seem to show approximately correct distances at their scales - maybe an anomaly only related to 55 mm lens?

grahamp · Jan 10, 2012

If I have some time tonight I will play with my 55mm on my C220 and see what I get. If the focus and taking lenses are focusing correctly, then we are looking at a lens that is spaced out from the lens panel more than usual (assuming the scale is correct). I can see a logical reason for someone doing this - the back focus on the Mamiya lenses varies, and spacing one might match the bellows extension to another focal length. But that is speculation.

Graham

Dr.Pain-MD · Jan 11, 2012

When I shot with a C33 and C220, I never bothered with the scales. They were always off even though my pictures came out in focus. I say don't bother with the scales and just run a test roll for safety's sake.

henk@apug · Jan 11, 2012

I have done a focus test as described in the C220 repair manual and focus seems ok.
Shooting film will confirm this, I hope

paul ron · Jan 11, 2012

The scales are just for reference anyway. I'd never rely on it. As long as the film plane agrees with the VF, that is what counts more.

The scale plate can be adjusted but why bother.

grahamp · Jan 14, 2012

I finally had a chance to test my C220/55mm combination in daylight. The 80mm scale is right, the light blue line next to the 65mm and 80mm lines is about right at 3.5 feet, but infinity comes in around 30'. I was using a tree around a mile away for the focus point.

I'm of the opinion that the scale line is just wrong, at least in these instances.
The 80mm scale has an infinity to 3.5' extension of about 8mm
The 65mm scale has an infinity to 3.5' extension of about 3.5mm
The 55mm scale has an infinity to 3.5' extension of about 3mm

Out of curiosity I checked the lens on my C330 body - same result. Up to now I had not considered that there could be two 55mm variants. Either that of the Mamiya 55mm focus scales are universally wrong, which is hard to credit.

Graham

Jojje · Jan 16, 2012

Thanks for reassurance, Graham!

c220 and black series 55mm focussing

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