thinkofcole Posted October 3, 2007 Share Posted October 3, 2007 I have just picked up a Mamiya M645J SLR [top speed 1/500th] with a Mamiya-Sekor 80mm/f2.8 lens...But I can't figure out if there actually is a diaphragm in the lens and, if so, how to set it... Do you just set the f-stop on the lens and the camera does the rest? Or what? Thanks in advance...regards, bob Link to comment Share on other sites More sharing options...
jon_shiu Posted October 3, 2007 Share Posted October 3, 2007 Yes, but make sure the lever on the side of the lens is set to "A", not to "M". Jon Link to comment Share on other sites More sharing options...
thinkofcole Posted October 3, 2007 Author Share Posted October 3, 2007 thanks, John, for the fast reply...If I understand your response, even if I don't see a diagphragm, I just set the lens to M, the f-stop to, say, f16, the camera to, say, 1/250th, and the camera does the rest, right? thanks, bob Link to comment Share on other sites More sharing options...
jon_shiu Posted October 3, 2007 Share Posted October 3, 2007 No, M is for manual aperture. If you set the lens to manual, the aperture should stop down as you turn the aperture ring and you should be able to observe this. If set to A, the aperture will stay at full aperture for viewing and automatically stop down as the shutter is fired. This is normally how you would want to shoot so you can have the modern convenience of viewing and focusing at full aperture. Jon Jon Link to comment Share on other sites More sharing options...
steve_levine Posted October 4, 2007 Share Posted October 4, 2007 "M" is actually for viewing the taking depth of field. In M mode the lens remains stopped down to it's shooting aperture. In "A" mode (auto) the aperture remains wide open for focusing and viewing (but not for DoF previewing). When the shutter is activated the mirror moves, the shutter opens, and the lens automatically stops down to it's taking aperture. After the shutter is done opening/closing, the lens returns to wide open. Link to comment Share on other sites More sharing options...
thinkofcole Posted October 4, 2007 Author Share Posted October 4, 2007 thanks Jon and Steve...Actually I have two Mamiya-Sekor M645 lenses, the 80.2.8 and a 150/3.5...I can definitely see and move the diaphragm on the 150 when I set it to M but I cannot see the diaphragm on the 80 in any position... Does that mean that the 80 is bad? I'd appreciate a reply because I do not want to represent it as ok if the diaphragm is supposed to work and it apparently doesn't work...thanks in advance...bob Link to comment Share on other sites More sharing options...
jon_shiu Posted October 4, 2007 Share Posted October 4, 2007 Hi, the 80 should operate the same as the 150 (unless it is a LS lens with shutter built in). Jon Link to comment Share on other sites More sharing options...
thinkofcole Posted October 4, 2007 Author Share Posted October 4, 2007 thanks, Jon...I finally managed to see the shutter when I shake the lens...So I guess it's damaged and I'm going to sell it on Ebay as-is... Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now