circle near f 11, what's it mean ?

[removed account4]

i have a little circle near f11 on my mf range finder's lens, can someone suggest what it might be for ? the manual ( THANKS dbseney!) says nothing about the shutter or the circle. it is a seikosha-rapid shutter ...

thanks for your insights!

-john

 

[BrianShaw]

Possibly a mark for "range focusing"... set the focus at that mark and everything from x ft to infinity will be in focus.

 

[colrehogan]

If it's a red circle, it could be a mark to adjust focus for IR film. Which rangefinder do you have?

 

[grahamp]

If it is a hyperfocal focus mark then there may be a matching mark in shape or colour on the focus distance scale and aperture ring. If it was an infra-red adjustment mark it would be on the aperture mark scale only, around the near side f4 tick. I doubt very much that it is for infra-red.

I have a 35mm Voigtlander with a triangle and a circle mark on the focus scale, one for near zone focus and the other for hyperfocal length. The apertures are not marked, but you can see which is intended because it is adjacent to the infinity mark on the hyperfocal setting.

 

[removed account4]

hi again

oh, it is a old mamiya 6 iv ( from 1947 +/- )
the cirlce is the same tone as the rest of the fstop dial (black) but the infinity symbol is in red ... i just thumbed through the instructions again, thinking i overlooked it, but nothing regarding the shutter &C ...

thanks for your suggestions!

john

 

[removed account4]

hi again

i have taken your suggestions that the circle indicates the hyperfocal fstop and focus at infinity -- it seems to work well as a point and shoot this way as long as i remember to set the shutter speed right.

thanks for all your help!

-john