Strange method of lens cleaning...

[tandeejay]

I came across this video on you tube that among other things had a "very strange" method for cleaning lenses.

(link starts at 14:10 where the lens cleaning method starts and the lens cleaning method goes to about 14:35)

https://www.youtube.com/watch?v=_9YM...tu.be&t=14m10s

Has anyone come across this before? I'd be dubious trying this on my $1000 lens

[nardes]

I had a quick look and would NOT use toothpaste on a lens...

Some toothpastes probably contains fine particles "suspended" in the paste; if so, these particles may abrade either the lens coatings and may even affect the lens "shape" or "figure" that Canon polishes into the lens during the manufacturing phase.

When I was a schoolboy I ground a Pyrex blank to make the mirror for a Newtonian reflecting telescope. This involved using Carborundum (grit) of decreasing size (from 80 coarse to 240 fine) before polishing with Jeweller's Rouge (messy stuff) to polish out any roughness on the final parabolic figure of the (bare, un-aluminised) mirror. As the project advanced, it was quite easy to see the effects of applying the grit to the Pyrex surface - the glass was simply progressively gouged out, which in my case, was intentional in order to generate a parabolic cross section.

Based on this, I would not clean an optical surface with any substance that contained fine particles of unknown size and hardness. A series of very fine "scratches" or "abrasions" would scatter light at the lens surface and therefore have a negative affect on image quality.

Then, there is the chemical perspective too - who knows what effects those chemicals may have, despite modern coatings being quite tough and resilient.

Cheers

Dennis

[gcflora]

Yeah using two abrasives (toothpaste and ash) on a lens sounds like a really good idea... not

[ameerat42]

It's a rather "hip", panacea-like presentation that would appeal to nongs.

Toothpaste used like this is a "poor person's" rouge. It'd be OK for non-critical glass,
- but lenses?

[tandeejay]

Thanks for confirming my doubts. It also raises doubts about the rest of the "tips" in the video clip.... If they got one wrong, how many others are wrong as well?

[jim]

When he polishes his phone you can see abrasions on the logo. Not necessarily from the polishing of course, but still a bit worrying.

[Boo53]

Well, hmmm, toothpaste is an abrasive/cutting agent, so it would clean it the first time, but.....

What the burnt cackleberry is supposed to do I have no idea

[gcflora]

Well, hmmm, toothpaste is an abrasive/cutting agent, so it would clean it the first time, but.....

What the burnt cackleberry is supposed to do I have no idea

The burnt egg makes a very fine ash. No idea why it's needed though because the toothpaste is abrasive enough as it is. I once polished a soft drink can using toothpaste to see if I could get it shiny enough to quickly make a fire using the sun (it worked great; yes I do weird things)

[Boo53]

The burnt egg makes a very fine ash. No idea why it's needed though because the toothpaste is abrasive enough as it is. I once polished a soft drink can using toothpaste to see if I could get it shiny enough to quickly make a fire using the sun (it worked great; yes I do weird things)

That's what the author thinks happen I'm sure but at those temps I'd doubt there was any reaction in the egg shell. The black residue would be 100% from the candle and I'd reckon it would be a very oily residue, so counter productive.

I've used toothpaste to remove small scratches in the cars paintwork many times - does a good job and saves having to find where the polish has hidden itself in the shed

[gcflora]

That's what the author thinks happen I'm sure but at those temps I'd doubt there was any reaction in the egg shell. The black residue would be 100% from the candle and I'd reckon it would be a very oily residue, so counter productive.

I've used toothpaste to remove small scratches in the cars paintwork many times - does a good job and saves having to find where the polish has hidden itself in the shed

You're probably right about the residue

Speaking of toothpaste's abrasive qualities, one of my hobbies is being insane and looking at boring stuff. If you're in a supermarket you'll notice that there is special toothpaste for dentures. For some reason I was in the supermarket looking at these fascinating tubes about a year ago and wondered what the difference between the denture paste and normal toothpaste was. Apparently normal toothpaste is too abrasive to use on dentures so that's the reason. I wouldn't even use denture paste on my lenses though.

[ricktas]

Most toothpastes contain pumice. It is the same stuff the dentist uses (prophy paste) when they polish your teeth after giving you a scale and clean. Teeth are right up there as the hardest stuff in the human body. A lot different to the delicate glass of a lens. Though most lenses these days are coated in something to make them quite hard.

Having said this, it is not unusual in the dental industry to see wear facets on peoples' teeth due to scrubbing to hard with a toothbrush and toothpaste. So imagine what scrubbing a lens with toothpaste could do.

It is probably not going to damage the lens much if you only ever do it once or twice, and don't scrub the toothpaste in, but repeated use would certainly see the pumice do its job. It assists with removal of staining, plaque and calculus from teeth using its' abrasive qualities.

[arthurking83]

About 10 years ago I had an old Nikon 18-35/3.5-5.6 lens that was going to get trashed.
So I experimented with it to see how duarble these so called lens coatings are supposed to be.

Use a normal kitchen scourer/sponge using the scourer side only.
Made no marks whatsoever on the lens element after a few minutes of trying(hard).

I'm pretty sure that when lens makers use the softer less durable coatings, that they don't use them on the outer surfaces that will get soiled/touched/etc.

So those ED or super ED or whatever coatings won't be on the front face of the lens element, and it makes absolutely no sense for the camera maker to do so if they want to uphold a reputation of any kind.

I know some lenses use a coating on the outside lens simply for protective purposes, like hydrophobic compounds that repel water, or don't allow dust to stick, and I'd be confident that they'll be quite durable, or 'baked into' the glass element.

Maybe in the bad ol days when manufacturers first started using exotic lens coatings, they may have been susceptible to damage, or wear or whatever, but I'm fairly sure out more modern lenses will be quite safe.

So my thoughts(with previous experience) is that if the lens has been damaged(ie. scratched lightly) there's every reason to try something like toothpaste to see if it helps.
But you wouldn't 'clean' a lens using that method .. firstly it just seems like a major waste, when a std microfibre cloth is all you probably really need .. maybe a small dribble of water to help remove stubborn hazy buildup.

[ameerat42]

I did the like once on the removed back element of a pathetic (and not all are) mirror lens.
It had spent two weeks either under silty water after a flood, or waiting to be "rescued"
after it. The coating were crazed, making the lens "milky".

So I did the old "toothpaste on a tissue" trick for some hours (on and off over some days.
By the end of it I got the lens looking more like "skim milk". The coating (from reflections)
was by then cactus, and I did not proceed.

- - - Updated - - -

PS: The flood was the best thing that ever happened to that lens

[Ross M]

That's what the author thinks happen I'm sure but at those temps I'd doubt there was any reaction in the egg shell. The black residue would be 100% from the candle and I'd reckon it would be a very oily residue, so counter productive.

I've used toothpaste to remove small scratches in the cars paintwork many times - does a good job and saves having to find where the polish has hidden itself in the shed

I have a shed that hides things too. It amazes me how much stuff the shed disappears. It's like the twilight zone.

[nardes]

When grinding and polishing my 8-inch diameter F6 parabolic mirror for my home-made telescope, the goal was to generate a paraboloid with an accuracy of ¼ wavelength of visible light (say around 580 nanometres for yellow/green light). This should produce an acceptable image at the eyepiece of the telescope.

So, the final polishing/figuring sessions using jeweller’s rouge involved getting rid of zonal and local defects which deviated from the desired paraboloid shape by some 0.000145 mm. This would only be an “average” quality mirror, an accuracy of 1/10 lambda would be highly desirable.

I wonder how much toothpaste rubbing it would take to produce a zonal or local defect of some 0.0001 mm at the lens surface?

Cheers

Dennis

[ameerat42]

I dunno, but it might end up being a flossed cause