Did I ruin my mirror!?

Discussion in 'Camera Building, Repairs & Modification' started by mporter012, Jan 19, 2013.

  1. mporter012

    mporter012 Member

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    Hello -

    I am relatively new to photography and made the stupid mistake a few months ago of cleaning my mirror on a Nikon FE2 and a few lenses with my t-shirt while out taking photos one day. I didn't realize this could have done damage until I read a few threads on here which were stating how fragile the mirror is and that if it needs cleaned you should send it to a professional.

    So do you think I've have ruined the mirror? How about the lenses? With the naked eye, everything appears ok, but I don't know.

    Any feedback would be great.

    Thanks
     
  2. eddie

    eddie Subscriber

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    If everything seems OK, it is.
     
  3. EASmithV

    EASmithV Member

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    I clean mine with soft cloths and pec pads. All is well.
     
  4. summicron1

    summicron1 Subscriber

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    lintless cotton is a good cleaner, although don't rub. Front surface mirrors like in an slr should be handled gently but if yours looks ok, it is ok, even if it were scratched it would still work just fine. The mirror surface doesn't effect image quality and a cupla scratches won't degrade what you see in the finder.

    you should see the mirrors on some of my old exaktas....wow.
     
  5. nick mulder

    nick mulder Subscriber

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    It's not the surface of the mirror you need to be worried about the most, but the position of the mirror with regard to the ground glass - it needs to replicate what is going to film exactly (within a spec that is) - what good is an image that looks ok to the eye if it isn't the same image that is going to film ?
     
  6. paul ron

    paul ron Member

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    A good quality mirror has a coating on it that protects the suface silver. You more than likey did no damage to it at all.. use a delicate hand when cleaning, a hot breath, a cloth not paper to clean lenses n mirrors, you'll be fine..

    get a can of air to blow it out after cleaning instead of trying to blow it out by mouth.. dry air.
     
  7. AgX

    AgX Member

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    Even if one would see a scratch on the mirror, what matters is if one would see it at the focus plane, that is the groundglass. Keep in mind that the mirror in a SLR is acting at the unfocused part of the imaging beam, so next to any distorted rays will be enough plain rays. Furthermore a scratch will likely only affect the reflectivity of the (that tiny part) of the mirror.

    A fibre blown to underside of the groundglass/fresnel-lens assembly would in any case be more visible.
     
  8. Ian Grant

    Ian Grant Subscriber

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    Older mirrors do damage very easily and it's surprising how quickly they deteriorate. I'm in the middle of restoring some pre-WWII SLRs and they will all have new mirrors by the time they are finished (two have already). (These are large SLR's 6x9 and Quarter Plate with big mirrors compared to modern cameras).

    All SLR/TLR mirrors are front surface and originally used silver, this tarnishes and deteriorates badly cleaning accerlerates this. Modern mirrors use aluminium and this is coated, cleaning removes the silicon coating.

    New mirrors are remarkably cheap £16 for my Quarter Plate reflexes and the same company can recoat any SLR mirror but you need a technician to remove it. I will get my Exacta mirrors recoated as they do cut the viewfinder brightness considerably.

    Ian
     
  9. tkamiya

    tkamiya Member

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    One thing to keep in mind is that mirror position affects how you will be able to focus on the subject. Somewhat surprisingly any SLR type cameras have a rather fragile mirror support at both top and bottom. If you apply pressure to the mirror in order to clean it, it can affect where the mirror rests. What that would do is, it will change what your view finder will show that the image is in focus. It will then not match when the image will actually focus on film. That will, in turn, make it so that if you focus on the image on your view finder, the image is no longer focused on your film = blurry out of focus image.

    Try this.... put on a lens with a widest aperture and the longest focal length. Open the lens wide open, say f/1.8. Put your camera on a tripod. Focus on a subject near by very carefully. Snap a photograph. When you develop your film, take a magnifying glass and examine the negative. Is it in focus? If so, you are fine. If not, you need to send it into an adjustment.

    Little scratch here and there on mirror will not affect anything except your pride....
     
  10. Poisson Du Jour

    Poisson Du Jour Member

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    A long, long time ago I gave the mirror of my Olympus OM4 a scrub and was horrified to find millions of tiny scratches on the surface (I used a piece of tissue!!). This crazing (circular swirls and scratches) was sufficient to befuddle the meter of that particular camera and the mirror was subsequently replaced for $460 (1984 price) with $180 labour. The repair job came with the advice "never, ever touch or put anything on the mirror" and said those mirrors are front-silvered, so extremely easy to scratch even with the finest microfibre cloths. I have not touched any mirror since that early lesson in DIY.
     
  11. AgX

    AgX Member

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    I can't see how scratches on a mirror could interfere with the meter, as long there is no substantial change in the overall reflectivity.

    In those cases where the meter is located behind the meter typically only a fraction of the light is sent to the meter, so a smaller change in overall reflectivity would already affect the meter.

    But still I cant see how scratches could be of affect. Maybe aside of the visible scratches a seemingly even abrasion has taken place.
     
  12. Ian Grant

    Ian Grant Subscriber

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    Any scratches on a mirror will cause light scatter, and a front surface mirror will scratch far easier than a lens, it's also the position in the light path between lens and screen which gives it a far greater effect.

    Ian
     
  13. mporter012

    mporter012 Member

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    Thanks for all the advice. I'm not so much worried about the scratches now (it really doesn't appear to be scratched with the naked eye), but I am slightly concerned with the possibility that i moved the mirror.

    What's rather annoying is the cost to even get the things looked at by a professional. Might as well buy a new camera or DIY.
     
  14. AgX

    AgX Member

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    If you moved the mirror (bent the mirror mechanism) the viewfinder image would be off center compared to the image at the film gate.
     
  15. E. von Hoegh

    E. von Hoegh Member

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    A T-shirt? Seriously?:blink:

    Firstly, how did the mirror get dirty? A mirror shouldn't get dirty. Keep a lens or a body cap on the camera at all times and it won't. I use a Nikon F which I bought about 1994. It came to me with a clean mirror, and I've never had to clean it.

    Second, the force you may have applied to the mirror when you stretched the T-shirt over your finger, reached into the mirror box, and 'cleaned' the mirror may have damaged the mechanism that moves or holds the mirror in the proper position. Such a procedure could also damage the focussing screen, which is just above the mirror.

    Third, a T-shirt is for wearing, not cleaning optics (any optics, even cheap binoculars) with. A search of this site will turn up the correct procedure for cleaning lenses, but here's a hint - it's better to keep your lenses clean, than to keep cleaning your lenses. Use the lens cap, it's what it's for. Of course, the lens will eventually get schmutz on it. Then you clean the UV filter you put on the lens to protect it.:smile:
     
  16. GarageBoy

    GarageBoy Member

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    Mirror glass/coatings are really soft
    Don't touch them, just blow dust off with a bulb and leave it alone