Mamiya 7 - 150mm Distance Scale

Jesse Taylor · Jun 27, 2011

Someone with a 150mm, could you focus out your window onto a building atleast 50m away and tell me what your distance scale on the lens says? mine is saying between 10m-20m.

do you also notice there isn't much lens movement to get things in focus from across the road to 1km away?

if the rangefinder is out of whack, is it more noticeable with close objects or farther objects?

Klainmeister · Jun 27, 2011

Give me a few hours and i'll help you out bud.

jbbooks · Jun 28, 2011

Jesse Taylor said:
Someone with a 150mm, could you focus out your window onto a building atleast 50m away and tell me what your distance scale on the lens says? mine is saying between 10m-20m.

do you also notice there isn't much lens movement to get things in focus from across the road to 1km away?

if the rangefinder is out of whack, is it more noticeable with close objects or farther objects?

On a vertical 67 meters away, it shows midway between the 20 meter and infinity marks.

Goes to stop at infinity, focusing on a light pole, approximately 1000 meters away.

I tried this with two different bodies and got the same result with both.

When one of mine was out of whack, I checked the rangefinder calibration using a closer distance, like a measured 3 or 4 meters, and verified that it had to be at the infinity stop when focused on something on the horizon.

Jesse Taylor · Jun 28, 2011

i taped a string vertically on my wall, and set the camera on a tripod infront of it (with the 80mm). i set the lens to 1m, and moved the tripod until the patch lined up with the string. i then measured from the wall to the film plane, and it's exactly 1m. does this mean the rangefinder is perfectly aligned or can you only tell from farther distances?

mickster · Jun 28, 2011

On my Mam7 I've always checked for correct focus at infinity focus rather than close-up. I focus on the moon in the night sky; the rangefinder patches should coincide at exactly the point that the lens hits its infinity stop. They shouldn't stop before, and shouldn't go beyond each other when turning to infinity.

The rangefinder is very sensitive; I've found that even distant objects (eg 1 mile or so) focus very slightly before infinity is reached on the lens, whereas the moon focusses at infinity.

Jesse Taylor · Jun 28, 2011

if the rangefinder is out of alignment, how mis-aligned will the moon look at infinity? it's an overcast day today, so i'm curious until the moon is visible.

John Koehrer · Jun 28, 2011

If I recall, infinity for photographic purposes is 500 X focal length. It's really not that far.

SFC · Jun 29, 2011

Judging a len's focus calibration by using a tape measure and the distance scale is a dubious activity. There's still too much room for error with this lens. You just have to take photos at various distances and see.

A lens can be in focus close and not at infinity. I discovered this on a Leica, where I accidentally (and luckily) moved the infinity focus control INTO adjustment.

If you are concerned, have the lens/body professionally adjusted or you'll drive yourself crazy. If you send to the MAC Group, they will get it back quickly for a small extra charge.

Hikari · Jun 29, 2011

Can you focus the moon at infinity? If not, the lens cam could be off.

Mamiya 7 - 150mm Distance Scale

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