# nikon fm10 and 28mm f/3.5, aperture ring not working?



## den9 (Mar 19, 2012)

i had shot a roll of film with this camera, on my second roll i was messing around with the aperture and this time noticed that the metering wasnt budging. this made me realize that the whole time my aperture was stuck wide open. i was able to close it down with the depth of field button. i cant tell if its the camera or the lens that is causing the problem. i was able to move the aperture ring but the little tab that opens and closes the aperture wasnt moving with the ring. although i was able to push the tab around with my finger. nothing seems jammed up, im thinking there is something missing that moves the tab. any ideas or anyone experience similar problem?


edit- i just found an old 50mm and it seems to work fine, it seems like the 28mm doesnt have a tab to push the aperture tab? around. it springs back on its own but it needs to tab to keep it closed. looks like i have a broken lens, or an odd lens.

double edit

it seems like where the white marked aperture numbers are, is totally missing on my lens.


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## compur (Mar 19, 2012)

Turning the aperture ring when your 28mm lens is on the FM10 should not cause the aperture to change.  It should remain wide open unless you push the stop-down lever.

Turning the aperture ring when that lens is off the camera will cause the aperture to change.

The older lens without the small white aperture numbers by the lens mount is a "non-AI" lens and shouldn't be used on the FM10. 

The FM10 can use AI, AI-S or AF lenses. The 28mm lens in your photo above is  an AI-S mount lens and is fine on the FM10.

To test the 28mm lens and the camera's aperture operation:

Mount it on the camera and open the film door (no film loaded of course).  Set camera to a slow shutter speed.
Look through the back of the camera and fire the shutter at different aperture settings and see if the aperture closes down appropriately when the shutter opens.


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## den9 (Mar 19, 2012)

why would it not change the aperture? like i said there is no little tab so it doesnt change the aperture, my 50mm had one and it did change the aperture. the only way i know for sure is because the 50mm affected the light meter and the 28mm had no effect. 

im confused


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## den9 (Mar 19, 2012)

i looked through with the curtain open and the aperture was changing. the tab doesnt move and doesnt meter properly. so i guess all those pictures i took at f/8 will be super under exposed.

 this is what my lens looks like


a little research tells me i need a meter coupling prong, where the hell can i find one?


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## dxqcanada (Mar 19, 2012)

Hmm, that looks like a non-AI lens as there is no ridge on the bottom ... but it does look new enough that it should.


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## den9 (Mar 19, 2012)

i guess my only solution would be to use a handheld light meter but thats a pain. i got it on a trade, all i wanted was an E series but this is what they had, maybe i can take it back and trade for something else.


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## compur (Mar 20, 2012)

The first photo (in the OP) is an AI-S lens.  The photo in post #4 is a non-AI lens.

From what the OP says it seems quite possible there is nothing wrong with the camera or lenses -- he/she just needs to learn about the different Nikon lens mounts and how auto apertures and in-camera meters work.


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## den9 (Mar 21, 2012)

i completely understand now, it would of been a good lens if i had a light meter. i ended up trading it in for a 35mm ai


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## Derrel (Mar 21, 2012)

den9 said:


> i looked through with the curtain open and the aperture was changing. the tab doesnt move and doesnt meter properly. so i guess all those pictures i took at f/8 will be super under exposed.
> 
> View attachment 4536 this is what my lens looks like
> 
> ...



This 28mm f/3.5 Nikkor is what is now called a "pre-Ai" style lens. This lens may very well mount onto the FM-10, but because the lens lacks the Ai-coupling ridge (visible on the beat-up lens above, where the small,secondary, ALL-white aperture scale is) the lens and the body cannot communicate the aperture in use to one another. The Ai coupling ridge on the lens engages what is called the AI coupling tab on the camera body. The Ai coupling tab is that spring-loaded little do-dad that you can see located around 1 o'clock around the lens mount opening. On some cameras the tab is plastic, on others it is metal. On the better-grade Nikon bodies, the Ai coupling tab had a tiny button that allowed it to "flip upward", so that pre-AI lenses could safely be mounted, and then used with stop-down light metering using the DOF preview button and match-needle or match-diode metering.

The bottom line is this--you don't want to mount any lens that will damage the Ai coupling tab on the camera body!!!


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