Sorry... Did not know where to post so here it goes:

Is canned air bad to use to blow the dust off of lenses and filters?

Seems like it would be fine. Could it harm the coatings?

I am talking about not getting the propelent all of the lens, just the air.

Thanks Guys/Girls,

Sam

Its what was used to clean the film mags and lenses when I worked in TV in the 80's so it should be OK.

Canned air in and of itself is not a bad thing. I've been using it for many years. But... each time you use it you run the risk that some propellant may discharge. If the propellant gets on the lens coatings it typically leaves permanent marks. I find the larger cans of air like those available at Costco are less prone to propellant discharge. I use canned air a lot with still cameras and once had one of the smaller cans discharge some propellant onto the front element of a telephoto lens. It left a permanent "patch" of something that no amount of cleaning or solvent was ever able to remove. Fortunately it did not impact image quality.

What John says is correct...don't get propellant on your lens.

NOT WORTH THE RISK! I wouldn't allow any propellant powered canned air near my lenses. Soft lens cloth only.

It seems like high pressure air could blow dust and dirt into the inner parts of the lens where you would not be able to clean them. I prefer using microclean cloths or specifically made lens paper.

I don't know why anyone would want to use canned air on their lense when it is so easy to carry a lense cloth around. I would only contemplate using canned air for those seemingly impossible places to get at. But if you do need to use it on your lense you should have a uv filter fitted so if anything drastic should happen at least it 's only the filter that will get damaged which is reasonably cheap to replace.

Alan

Blasts of compressed air are for removing particles that can scratch the lens or UV filter even when using a soft cloth.

If you have a very dusty lens or filter, compressed air is an accepted and recommended method of removing the dust particles. When used properly there is no danger with compressed air. You simply make sure to release some air from the canister first before blowing on the lens or filter, and you do it at a distance, not up close.

After an all day shoot in dusty conditions I would never use a cloth initially. That is an almost guaranteed way to scratch your filter or lens.

Thanks for that jeff I have always just blown on the lense.

Alan

Blowing on the lenses with your breath may work in the short term. However many folks recommend never blowing on a camera lens. You risk getting saliva on the lens, and saliva can lead to mold. It is unlikely, but possible. When researching this issue recently I read accounts of mold ruining cameras, so it didn't seem like a good idea to me.

You can buy a blower and brush kit for under $5 at any camera store. It is what I use. A blower is not as strong as compressed air, but does the job pretty well, and a camera lens brush used gently will take care of the rest of the debris. Then you can clean with your cloth safely.

It is also true that there are plenty of people who won't use compressed air, as has been mentioned, but if used properly, it will work safely.

[QUOTE=Jeff Harper;1123011]

You can buy a blower and brush kit for under $5 at any camera store. It is what I use. A blower is not as strong as compressed air, but does the job pretty well, and a camera lens brush used gently will take care of the rest of the debris. Then you can clean with your cloth safely.QUOTE]


That's what I use too Jeff.

Have a lipstick brush but no blower on it I shall invest in one as soon as I visit town thanks Jeff and Tim.

Alan

Lens pens are great too, although not a replacement for lens cloths, etc. Here's a typical one at B&H:

Sima | Lens Pen | PLE | B&H Photo Video (http://www.bhphotovideo.com/c/product/169316-REG/Sima_PLE_Lens_Pen.html)

I always stick one in my back pocket when shooting and keep one in each of my gear cases. The retractable brush is cool since it doesn't gather lint and the soft tip is really good for getting rid of fingerprints & other smallish smudges without smearing. For grittier stuff, I usually go canned air/blower brush-->soft brush-->soft cloth (w/fluid if necessary).

Yrs,

Hoi

What I can't figure out is why the compressed air needs a propellent. The pressure of the compressed air itself does the job!?!

What I can't figure out is why the compressed air needs a propellent. The pressure of the compressed air itself does the job!?!

the propellent has the effect of sustaining the overall pressure within the can....

without it the air coming out of the can is slowed down very rapidly... the air still comes
out but at a much lower pressure.... or the pressure is not sustained as long

what I'd be concerned with is... if we are worried about the propellent coming out in
a burst, and that propellent damaging the equipment, why do we not realize that the
propellent is actually coming out of the can when its working correctly and the fact
that the propellent is just coming out of the can in minute sizes... but it could be
coating the equipment but in very small amounts... or the propellent is so small now
that it just gets dilluted even more so... ????

the propellent has the effect of sustaining the overall pressure within the can....



Sorry, I don't quite follow that - the pressure withing a closed system (gas or liquid) is equal throughout the system.

Compressed air is a propellant in it's own right - it doesn't need another propellant as well.

I have one of those cans of air that I can re-fill with my air compressor... what i don't
have is the propellant.

If you take the same volumn of air, same pressure but add a propellant to one of the cans and not the other, I'm pretty sure one of the cans of air will propel the air out of the can
at a sustained flow rate.... while the one without the propellant will not be able to sustain
the flow rate.

I have one of those cans of air that I can re-fill with my air compressor... what i don't
have is the propellant.

If you take the same volumn of air, same pressure but add a propellant to one of the cans and not the other, I'm pretty sure one of the cans of air will propel the air out of the can
at a sustained flow rate.... while the one without the propellant will not be able to sustain
the flow rate.

So how do (for example) car spray painters (obviously need a pretty steady flow rate for that) manage just using compressed air? What flow rate do you need when you're only using it as a duster?!?

(Not having a go at you - merely putting forward the argument for the non-need of propellants for a duster for [deity of choice]'s sake...) :-)

Paint spray guns run at lower pressures on regulated lines. I don't remember specific numbers but probably 15 - 25 psi. When the pressure in the tank of the air compressor that is supplying the regulated pressure, drops to 100 psi, the compressor turns on and pumps back up to maybe 150 psi and shuts off. The air supplied to the spray gun is constant.

Paint spray guns run at lower pressures on regulated lines. I don't remember specific numbers but probably 15 - 25 psi. When the pressure in the tank of the air compressor that is supplying the regulated pressure, drops to 100 psi, the compressor turns on and pumps back up to maybe 150 psi and shuts off. The air supplied to the spray gun is constant.

Greg, I understand how it works - it was a rhetorical question. ;-)

The question was about the propellant being air. The aerosol containers used for "air" sprays are quite small volume and when there is a rapid decrease in pressure (as in when you depress the button), the temperature drops rapidly, which also acts to reduce the pressure further (temporarily) [1 bar/degree K/C]. That's why, if you keep the spray going long enough, it's possible for the can to get so cold that your skin sticks to it.

This can be seen from time to time with scuba cylinders that have accidentally (or otherwise) been left with the valve open - it doesn't take long for the valve to freeze. Not a good idea, as when it gets to that low a temperature, moisture can form inside the cylinder around the neck - which will need to be dried out so as not to rust the steel and ruin the cylinder.

When used in short bursts (which is the best way to use them) it doesn't become such an issue. There is no doubt that other propellants can be added to the air to act as a lubricant for improving constant flow in certain applications but, I would say totally unnecessary for this application - as we don't need a constant flow for a "blow duster".

Let's save the environment huh!?!

I don't know but I would hazard a guess that the air in the can maybe compressed enough to turn it into a liquid form as with most gasses ie: liquid oxygen, propane, butane and thereby not needing a seperate propelant but then again I could be talking a load of B/S any other theories.

Alan

Alan, you're correct. I've used compressed air where a bit of liquid wound up on the surface. For that reason, these things scare me.

I don't know but I would hazard a guess that the air in the can maybe compressed enough to turn it into a liquid form as with most gasses ie: liquid oxygen, propane, butane and thereby not needing a seperate propelant but then again I could be talking a load of B/S any other theories.

Alan

Alan, if there's any moisture in the air, it can turn to liquid when the air is compressed but otherwise, no, the air doesn't turn to liquid (not at any pressure we could get it to anyway. Diving air is the cleanest, driest air you'll ever breathe - it doesn't turn to liquid even at 300 bar (4350 psi for the yanks on here) ;-) which is way, way higher than anything you could stick in an aerosol. (a 300bar cylinder is made from 1/4 inch steel!)

OK steve that seems to be my theory out the window I did think that the aerosl can might be a bit flmsy so if any one out there knows come on share your secret.

Alan

Yep, Scuba air is very very dry... thats why when you breath down two scuba tanks
the beer tastes much better than you could ever believe.. :-)

But the bottom line is I would not suggest using a canned air source with propellant in the
mix for any optical glass cleaning.

and yes, I do have an adaptor for using my dry, clean scuba tank air on lots of my equipment... including camera optics...

Yep, Scuba air is very very dry... thats why when you breath down two scuba tanks
the beer tastes much better than you could ever believe.. :-)

But the bottom line is I would not suggest using a canned air source with propellant in the
mix for any optical glass cleaning.

and yes, I do have an adaptor for using my dry, clean scuba tank air on lots of my equipment... including camera optics...

Heh, heh, heh.... I'm with you all the way my man! :-))

I use the Co2 cartridges and I haven't had anything come out of them but air.

I use the Co2 cartridges and I haven't had anything come out of them but air.

hmmmm.. he, he.... ;-)

I think you might find carbon dioxide comes out of a CO2 cylinder... ;-)

Senior moment?