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Is the mirror damper really necessary?
Old 07-18-2016   #1
sanmich
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Is the mirror damper really necessary?

After having cleaned all the gooey foam left on my "new" FE2, I am reluctant to install that time bomb again so close to the camera screen.

I know that the foam in the door traps may well not be necessary, and that of the door hinge is a must, but that's not a biggie to clean and install. (and I have used 1mm felt instead of foam)

So..is the foam damping the mirror a necessity and why?
Could a SLR work reliably without one?
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Old 07-18-2016   #2
JP Owens
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Yes, it will work, but it won't be as quiet.
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Old 07-18-2016   #3
sanmich
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Quote:
Originally Posted by photomoof View Post
It depends on the SLR. The Nikon F, for instance, has mechanical damping, and will actually work without foam
The FE2 "actually works" without foams. Do you refer to long term wear?

Quote:
Originally Posted by photomoof View Post
but there will be light leaks.
How?

Thanks!
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Old 07-18-2016   #4
Highway 61
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As written above it will work but the camera will be noisier.

Custom cut a strip of foam off a computer mousepad backside and glue it with regular neoprene glue.

That foam itself is made with closed cells neoprene. It won't deteriorate over time.

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Originally Posted by sanmich View Post
How?
Light coming from the viewfinder eyepiece and finding its bouncing way to the film gate through the gap between the mirror and the focusing screen frame if the foam strip is missing. Ditto on the FE2. A bit sensitive with slow shutter speeds.
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Old 07-18-2016   #5
Ronald M
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I used black wool yarn in place of foam that deteriorates. That is what is used in Hollywood movie cameras.

Glue is same a what camera repair people use. Plyobond adhesive.

Again felt where the mirror stops.
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Old 07-18-2016   #6
Sarcophilus Harrisii
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Whether the model involved is especially susceptible or not is open to discussion, of course, but quite apart from the potential for additional noise and/or vibration, some SLRs can break their mirrors or have them fall off their mounting frames. Absence of the damping foam in any particular case may or may not be critical, however it cannot make it less likely to be an issue. If the manufacturer felt it appropriate to include some foam in their design, personally, I would replace it, (either with original materials or a reasonable substitute) in the interests of long term reliability.
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Old 07-18-2016   #7
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Quote:
Originally Posted by photomoof View Post
Light can always come in through the viewfinder, that is why high end SLRs have a light blind for long exposures where your eye is away from the eyepiece, but it can happen with missing foam also.
Not quite correct.

High end and/or well designed SLRs have a mirror frame that effectively seals against the focus screen's frame preventing light entering from the VF. Sometimes this seal requires intact foam and sometimes the foam is merely a mechanical damper to reduce noise and possibly wear on the edges of the mirror. It's true that some poorly engineered models would leak light around the mirror during long exposures, but I've never known any such models that made the effort to include an eyepiece blind.

The eyepiece blinds that appear on many premium models are to prevent light entering the eyepiece, when your eye isn't present, from influencing the light meter. Generally such cameras will either have a secondary external readout for the meter for use when eyepiece is closed or they have an automatic mode (e.g. Nikon F3).
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Old 07-18-2016   #8
Steve M.
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In my experience w/ lots of SLr cameras, including the model that you have, no, you don't need it. Just scrape it off and leave it as it is. I agree, it is just something else to dirty up your screen. On mine, I never noticed any difference in the mirror "clack", nor did I ever see any signs on the mirror from it hitting up top w/o the foam. You would think there would be, but even after years of use I never saw anything. Go figure.
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Old 07-18-2016   #9
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Replacing the mirror damper foam strip with a piece of custom cut closed cells neoprene foam which will not deteriorate over time is an extremely easy DIY job which takes a few minutes so why not performing it ?

Of course every bit of the old goo'ed foam has to be removed with a Q-tip and a bit of acetone before installing the new foam strip.

On the Nikon F and F2 the mirror clack is noticeably louder if the foam strip isn't there, especially on the F.
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Old 07-18-2016   #10
JoeV
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Perhaps someone can answer this question: does the position of the mirror in its rest position effect the focus calibration between lens-to-viewfinder and lens-to-film plane? And if so, does the thickness of the foam insulation on the mirror matter for focus calibration?

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Old 07-18-2016   #11
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Quote:
Originally Posted by JoeV View Post
Perhaps someone can answer this question: does the position of the mirror in its rest position effect the focus calibration between lens-to-viewfinder and lens-to-film plane? And if so, does the thickness of the foam insulation on the mirror matter for focus calibration?

~Joe
If by rest position you mean when it is retracted just prior to and during exposure, not usually, the mirror position must be accurate for focus with it lowered for reflex viewing, and viewfinder focus calibration is often set by adjusting the lowered height of the mirror Eg by its stop. It would be unusual for the condition or indeed total absence of any damping foam, in itself, to impact focus accuracy except in the event absence did any long term damage to the mirror mechanism, of course. Having said that many variations from the norm have been tried over the last 100 odd years of reflex viewing so someone may be able to cite an example that contradicts the above.
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Old 07-18-2016   #12
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To respond back to the original question, I would think that mirror foam does serve a purpose. The fact that many camera manufacturers use foam to dampen the mirror’s action probably means the engineers felt it was necessary. The only classic 35mm SLR that I know of that doesn’t use mirror foam is the Leicaflex, which uses gearing to govern the up-and-down motion of the mirror.

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Old 07-18-2016   #13
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I once read the following suggestion, but have not tried it myself; therefore, if you do try it, you are on your own. It said you could use the fuzzy felt from the opening in a 35mm film casette as a mirrior damper. It certainly would never turn into a gummy mess.
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Old 07-18-2016   #14
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Quote:
Originally Posted by Spavinaw View Post
I once read the following suggestion, but have not tried it myself; therefore, if you do try it, you are on your own. It said you could use the fuzzy felt from the opening in a 35mm film casette as a mirrior damper. It certainly would never turn into a gummy mess.
I've done this on an Exakta VX500, and found it's not quite thick enough to form a light tight seal.
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Old 07-18-2016   #15
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Quote:
Originally Posted by Mackinaw View Post
To respond back to the original question, I would think that mirror foam does serve a purpose. The fact that many camera manufacturers use foam to dampen the mirrorís action probably means the engineers felt it was necessary. The only classic 35mm SLR that I know of that doesnít use mirror foam is the Leicaflex, which uses gearing to govern the up-and-down motion of the mirror.

Jim B.
Canonflex, Canonflex RP, Canonflex RM, Canon FX and FT as well as the Canon A-series, they all use also a mechanical governor for mirror action, and they all use tje foam.
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