Help: 70-200 VR DoF Preview

Help!

My 70-200 VR is exhibiting some strange behavior. I'm trying to evaluate whether I can fix it or whether I have to send it off for repair. I've had it for a couple of years.

The only problem is that the lens will not stop down when I hit the depth-of-focus preview button on the body. I've tried this on two working bodies (D100, D200). Other lenses will stop down, but my 70-200 won't. The lens works fine during shooting-- it will stop down to the requested aperture when the shot is taken.

There are no "FEE errors", and I have the same problem when I use a teleconverter (no surprise).

Has this happened to anyone? What was the fix? Everything about the lens seems fine except the DoF preview (and I know the bodies are fine). The blades are not stuck because they work during shooting.

Thanks,

• Mike

I've figured things out with some more experimenting.

The DoF preview uses a mechanical stop-down lever on the body (which connects to the lens's lever). The problem: the lens's mechanical lever sticks when its wide open, so the body cannot stop down the aperture. The lens uses electronic actuation during non-previews ("real" shots), so that's why there's only a problem during the DoF preview.

So, the 70-200 VR with the sticky lever is going on a trip to Nikon service...

• Mike

photo99 said:

Help!

My 70-200 VR is exhibiting some strange behavior. I'm trying to
evaluate whether I can fix it or whether I have to send it off for
repair. I've had it for a couple of years.

The only problem is that the lens will not stop down when I hit
the depth-of-focus preview button on the body. I've tried this on
two working bodies (D100, D200). Other lenses will stop down, but
my 70-200 won't. The lens works fine during shooting-- it will
stop down to the requested aperture when the shot is taken.

There are no "FEE errors", and I have the same problem when I use a
teleconverter (no surprise).

Has this happened to anyone? What was the fix? Everything about
the lens seems fine except the DoF preview (and I know the bodies
are fine). The blades are not stuck because they work during
shooting.

Thanks,

• Mike

Click to expand...

Do you get correct exposures with the 70-200 when using smaller than maximum aperture? If not it is most likely a lens problem.

The following a checks you can make though they do not necessarily cause your symptoms.

If you press the camera dof preview (with no lens in place) the lever at quarter to the hour should move anti clockwise. This is how the camera stops down the lens either for dof preview or when taking a picture.

Next make sure the lever on the back of the lens at quarter to the hour moves smoothly anti clockwise and opens up the aperture at the same time - if it is stiff from a knock you might be able to free it. If it moves OK but the lens does not open up it is an internal lens fault.

Finally on the camera front at 5 past the hour outside the chrome flange ring there should be a slightly protruding black lever which moves anti clockwise. If this gets broken off G lenses still work but D lenses do not.

As dof is working with other lenses either you cannot get correct exposure stopped down with the 70-200 or it is something I have never come across.
--
Leonard Shepherd
Most modern cameras are capable of taking better pictures than their owners.

photo99 said:

I've figured things out with some more experimenting.

The DoF preview uses a mechanical stop-down lever on the body
(which connects to the lens's lever). The problem: the lens's
mechanical lever sticks when its wide open, so the body cannot stop
down the aperture. The lens uses electronic actuation during
non-previews ("real" shots), so that's why there's only a problem
during the DoF preview.

So, the 70-200 VR with the sticky lever is going on a trip to Nikon
service...

Click to expand...

Mike, this is interesting, because I always thought the mechanical lever connection between the body and lens was used when the shutter is released. This mechanism has been on Nikon bodies forever. How did you determine that the lever is not used when the shutter is released as opposed to DOF preview? On the other hand, I've always wondered how the camera can adjust the lever so accurately. On lenses with an aperture ring, and with bodies that didn't control the aperture electronically, a mechanical "stop" was in effect via the aperture ring. This means the camera always moved the lever "all the way", but it was stopped at the correct position based on aperture ring position. Without this mechanical stop, the camera would have know exactly how far to move that lever to get accurate exposures.

I have had the same issue with my lens. If you use a separate focus button other than your shutter release button, you have to gently touch the shutter release button to cause a resetting of the cameras operations. I know this sounds crazy but it has worked for me. I ofter use my dof button so I know what an annoyance that can be.

Thanks for all the responses!

The matter, I have determined, is purely mechanical and limited to the DoF lever on the lens. The aperture can be stopped down two ways: electronically and mechanically. On the D100 and D200, the DoF preview uses a mechanical actuation while "taking the actual shot" (shutter release) invokes the electronic actuation.

The small, DoF preview lever on the lens gets jammed in the wide-open position. It somehow "sticks" so that the body's mechanical acutation cannot stop down the aperature via the lever.

I can dismount the lens and manually unstick the lever. When I put it back on the body, the DoF preview will work 4 or 5 times before sticking wide open again. I can recreate the same sticking effect by sliding the lens's DoF-preview aperture lever back and forth.

All exposures (electronic actuation) work fine stopped down. I can see the aperture stopped down (electronically) if I set a long exposure (3", f/11, e.g.).

So, the problem is purely mechanical, limited to the DoF lever sticking in the lens. Luckily, it's stuck wide open and not closed.

I'm reluctant to send the lens back at this time since I hardly use DoF preview on the 70-200, and fixing the problem would certainly requiring pulling apart the entire lens and reassembling it. I may be asking for more problems by fixing this DoF lever issue... Maybe I'll send it back closer to the warranty expiration.

• Mike

Valkender said:

I have had the same issue with my lens. If you use a separate focus
button other than your shutter release button, you have to gently
touch the shutter release button to cause a resetting of the
cameras operations. I know this sounds crazy but it has worked for
me. I ofter use my dof button so I know what an annoyance that can
be.

Click to expand...