Canon FTb Black spot on mirror

nickvickvick · May 31, 2019

Hello To everyone,

Im quite new to the forum and sorry in advance if I didnt post this in the right section.
Recently I've started shooting film and couple of days ago I bought a Canon FTb.
Upon inspection I noticed it has a big black spot on the mirror, as you can see in the photos I posted below.
I was wondering if any of you has any advice on what it is and how to clean it.
I haven't attempted any cleaning at all before asking somebody with more experience (as you can see there is some dust particles and some particles that I will clean with the air blower).

Thanks everyone!

480sparky · May 31, 2019

Are you referring to the big black circle smack dab in the middle? That's not a spot... that's a split screen focus aid.
If you mean all the little dust spots, first determine if they're actually on the mirror or on the focus screen itself. If the mirror, it's fairly easy to clean. Focus screens are very fragile and are a different animal to clean.

Soocom1 · May 31, 2019

The little black smudge off center actually looks like (if not a stain) fungus.
But it maybe not be either.
Just looks like it.

nickvickvick · May 31, 2019

480sparky said:
Are you referring to the big black circle smack dab in the middle? That's not a spot... that's a split screen focus aid.
If you mean all the little dust spots, first determine if they're actually on the mirror or on the focus screen itself. If the mirror, it's fairly easy to clean. Focus screens are very fragile and are a different animal to clean.

Hi Sparky,

I mean the big smudge next to it. It is definetly on the mirror. You can clearly see it on the second picture. Could it be fungus? If that's the case, is there any way to clean it?

nickvickvick · May 31, 2019

For anyone wondering, i marked the spot I was talking about. Thanks!

480sparky · May 31, 2019

Try a puff of air (ie, like a Rocket Blower) first. If that doesn't work, go hands-on with a lens brush. If it persists, you might need to use some lens cleaning fluid on a cotton swab.

If a jackhammer doesn't do it, you'll need to send it to a repair facility. Or, you could just live with it as it won't affect your images.

nickvickvick · May 31, 2019

480sparky said:
Try a puff of air (ie, like a Rocket Blower) first. If that doesn't work, go hands-on with a lens brush. If it persists, you might need to use some lens cleaning fluid on a cotton swab.

If a jackhammer doesn't do it, you'll need to send it to a repair facility. Or, you could just live with it as it won't affect your images.

Ah ok, so it won't affect any image at all? I didn't know that, in that case I will just clean it and dont bother with it if it doesn't affect image (showing a black spot on it). I was worried because i thought it might.

480sparky · May 31, 2019

nickvickvick said:
480sparky said:

Try a puff of air (ie, like a Rocket Blower) first. If that doesn't work, go hands-on with a lens brush. If it persists, you might need to use some lens cleaning fluid on a cotton swab.

If a jackhammer doesn't do it, you'll need to send it to a repair facility. Or, you could just live with it as it won't affect your images.

Click to expand...

Ah ok, so it won't affect any image at all? I didn't know that, in that case I will just clean it and dont bother with it if it doesn't affect image (showing a black spot on it). I was worried because i thought it might.

Anything on the mirror, focus screen, pentaprism or eyepiece won't affect the image one bit. All that is for you to see with. When you take a photo, the mirror swings up to allow the film to be exposed. So all the aforementioned bits are removed from the optical path and the only thing in front of the film is the lens itself.

Soocom1 · May 31, 2019

The good thing is that it doesn't affect the image one bit as stated.
The bad news is that it can interfere with composure and may be a sign of other issues.

I had a Minolta I acquired used had a weird odor to it
Turned out to be WD-40 someone sprayed on the mechanism inside.

Took me months to clean it out.

If it continues or builds, check other aspects of the camera.

Derrel · May 31, 2019

It looks to me like,maybe, the silvering on the substrate of the mirror has deteriorated, and I suspect that this cannot be changed by cleaning. Looks like you will have to learn to live with it. The Ftb is a fairly old camera now, and as such, it's not unheard of for such an issue to happen. 35mm SLR mirrors are VERY easy to scratch when cleaning...believe me I have tried, and the softest of cloths or lens cleaning tissue leaves lots of fine scratches.

The spot is BLACK, indicating to me that the spot is UNDER the surface..it is "in the middle of" the mirror, like the meat in a sandwich.

Accept it.

jcdeboever · May 31, 2019

look to me like it is mirror foam. Those probably need to be replaced and well as the door seals. There are probably a lot of videos on this. It is more annoying than anything, I would try and replace them yourself.

nickvickvick · May 31, 2019

480sparky said:
nickvickvick said:

480sparky said:

Try a puff of air (ie, like a Rocket Blower) first. If that doesn't work, go hands-on with a lens brush. If it persists, you might need to use some lens cleaning fluid on a cotton swab.

If a jackhammer doesn't do it, you'll need to send it to a repair facility. Or, you could just live with it as it won't affect your images.

Click to expand...

Ah ok, so it won't affect any image at all? I didn't know that, in that case I will just clean it and dont bother with it if it doesn't affect image (showing a black spot on it). I was worried because i thought it might.

Click to expand...

Anything on the mirror, focus screen, pentaprism or eyepiece won't affect the image one bit. All that is for you to see with. When you take a photo, the mirror swings up to allow the film to be exposed. So all the aforementioned bits are removed from the optical path and the only thing in front of the film is the lens itself.

Thank you for the explanation Sparky, that was very usefull indeed! Cheers!

nickvickvick · May 31, 2019

Derrel said:
It looks to me like,maybe, the silvering on the substrate of the mirror has deteriorated, and I suspect that this cannot be changed by cleaning. Looks like you will have to learn to live with it. The Ftb is a fairly old camera now, and as such, it's not unheard of for such an issue to happen. 35mm SLR mirrors are VERY easy to scratch when cleaning...believe me I have tried, and the softest of cloths or lens cleaning tissue leave slots of fine scratches.

The spot is BLACk, indicating to me that the spot is UNDER the surface..it is "in the middle of" the mirror, like the meat in a sandwich.

Accept it.

Hi Derrel! Thanks for the reply! I have another Canon but it is an FT (older model), do you think i could switch mirror? I can't find anywhere online if they are compatible, the other mirror, altough older, is in perfect condition.

nickvickvick · May 31, 2019

jcdeboever said:
look to me like it is mirror foam. Those probably need to be replaced and well as the door seals. There are probably a lot of videos on this. It is more annoying than anything, I would try and replace them yourself.

Hi jcdeboever! Thanks for your reply. Yes other parts are particles from the deterioting foam, I already ordered a pre cut replacement kit! Shouldn't be too hard to change.

nickvickvick · May 31, 2019

Soocom1 said:
The good thing is that it doesn't affect the image one bit as stated.
The bad news is that it can interfere with composure and may be a sign of other issues.

I had a Minolta I acquired used had a weird odor to it
Turned out to be WD-40 someone sprayed on the mechanism inside.

Took me months to clean it out.

If it continues or builds, check other aspects of the camera.

I will keep an eye out for that, thanks for the advice!