Problem with F3 or lens or ???

[richard_driscoll]

<p>As I recall the F3 has a main mirror like all SLRs but also has a sub mirror attached to it that reflects light onto the meter photocell after going through a partially silvered patch on the main mirror. When you look into the camera with lens removed and open the shutter on B, can you see that the sub mirror gets out of the way? It think it should fold up against the main mirror. Rather a long shot I'm afraid.</p>

 

[steve_levine]

<p>The likely culprit here is what's called the shutter "braking mechanism". This causes the shutter to bounce erratically into the frame. This was common in F3's with lots frames through them.</p>

<p> </p>

[steve_levine]

<p> The F3 has an " Electro magnetically controlled, <strong>horizontal-travel,</strong> titanium foil focal-plane shutter".</p>

<p>The braking mechanism failure caused that exact type of phantom black marks too. A few years ago I was quoted $250 to fix one. Which would have been money wasted, due to the current low selling prices of F3's.</p>

[sven_felsby]

<blockquote>

<p>With great difficulty I mounted the lens on a D200</p>

</blockquote>

<p>You risk breaking off the AI meter coupling tab on the D200 by mounting a pre-AI lens.</p>

[david_mcniven]

<p>Vertical banding was the usual result of shutter damper problem with the F3, this is underexposure biased toward the upper part of the gate and variably distributed, indicating that the vertical slit at highest speeds is nonexistent at the top or narrower than at the bottom - the higher the shutter speed the narrower the slit and the greater the difference in exposure between the top and bottom of the frame. At slower shutter speeds the exposure differences are less pronounced.<br>

A quick check of the shutter goes like this:<br>

First you have to tell the camera that the back is closed while it's open so you can set the shutter speed to 1/2000. As the back closes it presses a tiny button in the top seal groove, 10mm. from the hinge. There is a special tool but you need to improvise here, the button needs to remain pressed throughout.<br>

After firing the shutter 3 times the set speed is made available by the frame counter mechanism switch. The reason for this design is so that when you close the back after loading film, winding to frame 1 won't be delayed by long shutter speeds in aperture-priority with a lens cap on.<br>

Hold the camera at arm's length facing an evenly-illuminated white wall, fire the shutter at 1/2000 and watch the film gate. If the shutter is OK the gate will appear evenly lit but darker than the wall. At 1/1000 it will look 1 stop brighter and so on up to about 1/30. You can check slit width using flash but this check is better for your present purpose.<br>

If the shutter is the cause of your problem you will see a dark area at the top of the gate.<br>

Takes a lot less time to do than to explain.</p>

<p> </p>

[david_mcniven]

<p>Forgot to mention, do it without a lens. Doh.</p>

[dave_wilson1]

<p>Yep, the last shot, "Up High" sure looks like shutter trouble, but the way it presents itself is certainly odd. The center neg of the contact also has a similar shape. Interesting thread...</p>

[cameralumina]

<p>Thanks David. I will try that out. I hope I will be able to discern the difference. Anyways, I am going to pick up a roll of color negatives. If they also come out badly, I guess I will sacrifice this camera to a repair shop for parts...</p>

[nic_olas]

On 1/25/2010 at 2:11 AM, cameralumina said:

<p>Thanks David. I will try that out. I hope I will be able to discern the difference. Anyways, I am going to pick up a roll of color negatives. If they also come out badly, I guess I will sacrifice this camera to a repair shop for parts...</p>

This is a loooong time since a reply, but did you sort this out? Thanks! I have an F3 demonstrating the same artefacts on films

Edited July 15, 2023 by nic_olas
added pictures