How To Clean A CPL?

[AshRinz]

Am wondering about filter cleaning. Clean the outside only or both sides? I tried cleaning the inside of my CPL today as I noticed there's a smudge.
But the more I rub, the worse it gets, So how do I actually remove the smudge in the first place. Thank you all.

[Dream Merchant]

How did you get to the inside? Did you seperate the two sheets of glass?

As for the smudge, first try breath and a micro-fiber cloth. Alternate the position of the MF cloth to get a clean area on each swipe. If that fails, try any optical cleaner, which is essentially diluted dish-washing detergent. Diluted Windex is also good.

[AshRinz]

Hmmm...Nope i did not separate the 2 glass. I think i might have touch the inside(nearest to the lens) when i took it off
to put it on my 17-55. I used microfibr cloth, it seems to get worse. Tried brethig into it and wipe, still the same. In the past i've destroyed a couple of
filters when use the so-called lens solution. Dunno if i should try it again.

[Dream Merchant]

What brand/type of filter is yours?

I've heard a lens pen is pretty good.

I've never 'destroyed' any optics using good old dishwashing detergent and copious amounts of water, but that won't work for any kind of sandwiched filter. I have several bottles of lens cleaning solution made for Sworoski optics and can clean it for you if we meet up.

Out of curiosity ... how did you destroy filters with cleaning solutions? What solutions did you use, what carrier and exactly how did you clean the filters? Oh, and what filters were they? I can imagine some acralic filters being attacked by harsh solvents and such, or coatings getting affected. I recently saw someone's filter that had the most incredible circular scratches - TONS of them, so I figured he mush have used an abrasive/dirty carrier and applied loads of pressure.

I really don't know about the durability of modern filters' coatings or optical 'glass'; in the past, and in a tight spot, breath and whatever tee-shirt I was wearing did the trick without damaging the coatings or glass.

[AshRinz]

I was using a lot of Cokin filters. Used lens cleaning paper on them. Then switch to normal type of filters that attached to lens front. Used a solution called lens solution. When applied, they always fail to go off cleanly ersulting in me putting more pressure to clean them, thus more scratches.

Tis time I just want to clean my Kenko Pro 1 Circular polariser. I was shooting at the reservoir yesterday. When I transferred the pictures to my Mac, I realise theres some faint spots on the picture. Looking at the camera mirror, it was clean. Picture taken using the 17-55 were also clean. So I deduce it must be from the cpl that was on the 10-22. Took it off and saw a small smudge on the inside of the filter. Used a lens paper to clean, but it got worse. Switch to micro fibre cloth also the same.

Does anyone know if the CPL is coated with any kind material that cannot be touched or am I just actually spreading the smudge, which I believe was oil residue from my finger that had accidentally touched it.

[Dream Merchant]

Cokins - I will use ... soap and water. Blot carefully then blow dry with a hairdryer in cool setting.

Not sure if CPLs have any coatings.

[AshRinz]

Got myself a glass cleaning solution today. Managed to get rid of the smudge. But I can see the CPL is a bit scarred with fine scratches on some places. Hope it will not affect IQ. Else have to buy a new one

[Dream Merchant]

No offense but I'm quite surprised at how folks manage to scratch glass so easily.

A friend of mine suspects that the materials used nowadays are far inferior to the optical glass used in the 70s and 80s. Any opinions on this?

[UKay]

i always use a optical spray that is available from spectacle shops.. spray liao... wipe clean with micro fiber cloth... so far so good...

[Dream Merchant]

Zat optical cleaner is actually diluted detergent ... much like diluted dishwashing liquid. 

I have the ones made for Swaroski optics ... guess what - same stuff.

[AshRinz]

No offense but I'm quite surprised at how folks manage to scratch glass so easily.

A friend of mine suspects that the materials used nowadays are far inferior to the optical glass used in the 70s and 80s. Any opinions on this?

No worries bro. But i really think your friend is right.

Couple of years ago, I've seen, before my very eyes, an old man who's been shooting all his life, used a newspaper to clean his Russian lens. Needless to say, the images that came from it was still tack sharp with no signs of IQ deterioration. It was an amazing and awe inspiring sight. He offered to clean my Nikon AF-S 28-70 F2.8 at that time. I rejected politely. Cant afford to 'destroy' a $3k lens like dat

[Dream Merchant]

Sigma had a legendary 24 or 28 to 70mm manual lens. It was so outstanding that Leitz bought the license to get Sigma to produce that same exact lens using Leica barrel materials, Leica QC and the Leica label. The glass was all Sigma IIRC. The Sigma version costed S$185.

I used it till it locked up, and I basically ripped it apart just for the heck of it. I took my sharp-edged house key and proceeded to 'scratch the heck outta the front element' ... just for the fun of it. Guess what. No matter how hard I applied pressure, the key slipped right off, and the glass looked none the worse for wear aka, no visible scratches. I would never try that on a modern lens. Yeah, I'm biased towards old school.

[AshRinz]

Hmmm...some things old school are much much better than the new ones.

[UKay]

i still have a arsenal of minolta lenses.. they have been with me since i started photography... even though i almost hardly use them anymore.. i cannot bear to let them go... the coating on the lenses is so good, that its almost unbelievable... i have shot beside canon, nikon, for film... and when its printed out.. the $250 lens beats the red ring and the gold ring lenses hands down, they really dont ake it like they use to... even the hasseblad lenses.. its damn good... but not as good as the old CZ lenses that they use to have... in the name of progress... we have photoshop