Who are we?  Featured Cameras  Articles  Instruction Manuals  Repair Manuals  The Classic Camera Repair Forum  Books  View/Sign Guestbook

Micronta 35 aperture Log in | Log Out | Topics | Search
Moderators | Register | Edit Profile

Classic Camera Repair » Maintenance & Repair » Micronta 35 aperture « Previous Next »

Author Message
Top of pagePrevious messageNext messageBottom of page Link to this message

Krafty5260
Tinkerer
Username: Krafty5260

Post Number: 43
Registered: 02-2008

Rating: N/A
Votes: 0 (Vote!)

Posted on Monday, January 31, 2011 - 02:55 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Greetings all,
I haven't been here for a while, but here I am again. I just received a Nihon Seiki Mocronta 35 viewfinder camera. It's cute. That's what attracted me, plus the description read, very good condition (well, except for the dent in the finder housing, and the loose focus ring, but I digress). It has a Yamato look and feel, but it's not a Yamato variant. It's a sibling of the Ranger 35, and Nescon. My question for the day is, aren't apertures supposed to open symetrically, in a concentric pattern? This one opens eccentrically, and when fully open, still blocks some glass in a crescent pattern. I've seen that before and I'm just trying to determine if that's correct, or not. Is that right, or is this another problem with this camera? I'm not completely discouraged, just trying to assess what needs to be done.
As usual, any input is appreciated.
Thanks again,
Michael
Top of pagePrevious messageNext messageBottom of page Link to this message

Donnie_strickland
Tinkerer
Username: Donnie_strickland

Post Number: 104
Registered: 09-2006

Rating: N/A
Votes: 0 (Vote!)

Posted on Monday, January 31, 2011 - 05:13 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Rick Oleson has one; maybe you could ask him about it:

http://tinyurl.com/4tc6v4z
Top of pagePrevious messageNext messageBottom of page Link to this message

Scott
Tinkerer
Username: Scott

Post Number: 126
Registered: 07-2006

Rating: N/A
Votes: 0 (Vote!)

Posted on Monday, January 31, 2011 - 06:38 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

I've never seen a crescent shape, but I do have several good-quality Japanese rangefinder cameras (Olympus 35RC, Olympus Trip 35, for example) that have 4 aperture blades that make almost-square diamond-shaped apertures, which even at "wide open" still appear 4-sided.

If the shape is not even symetrical, my guess is that the pivots of one or more of the blades is out of place.
Top of pagePrevious messageNext messageBottom of page Link to this message

Krafty5260
Tinkerer
Username: Krafty5260

Post Number: 44
Registered: 02-2008

Rating: N/A
Votes: 0 (Vote!)

Posted on Monday, January 31, 2011 - 08:16 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

That's what I'm thinking. How can one possibly get a decent photo from a lopsided aperture? Square makes some sense, as long as it's concentric with the lens. This just can't be right. Hmmm. Thanks for brainstorming with me, Scott.
Top of pagePrevious messageNext messageBottom of page Link to this message

Rick_oleson
Tinkerer
Username: Rick_oleson

Post Number: 1119
Registered: 07-2006

Rating: N/A
Votes: 0 (Vote!)

Posted on Monday, January 31, 2011 - 09:18 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

The aperture has 6 blades, in a uniform hexagon shape. The shutter, however, has 2 blades, each having a crescent shaped edge so that when fully open it clears a circle. If one blade was missing or stuck open, the remaining blade would form a sort of crescent shaped opening when in the closed position.
Top of pagePrevious messageNext messageBottom of page Link to this message

Krafty5260
Tinkerer
Username: Krafty5260

Post Number: 45
Registered: 02-2008

Rating: N/A
Votes: 0 (Vote!)

Posted on Tuesday, February 01, 2011 - 06:27 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Hey Rick,
Thanks, for the input. What I see with the shutter on B is an aperture opening offset at about 7 or 8 o'clock, and, of course, it is larger or smaller depending on the aperture setting, but never concentric or fully open. And, the focus ring is loose from the helical. If I turn the aperture ring all the way in one direction, or another the helical will move, but not with the ring. This camera needs some help. I'll have to put in on the list.
Thanks again,
Michael

Add Your Message Here
Post:
Bold text Italics Underline Create a hyperlink Insert a clipart image

Username: Posting Information:
This is a private posting area. Only registered users and moderators may post messages here.
Password:
Options: Enable HTML code in message
Automatically activate URLs in message
Action:

Topics | Last Day | Last Week | Tree View | Search | User List | Help/Instructions | Program Credits Administration