How to clean IR cut filter

[Timmyjoe]

Advertisement (gone after registration)

I've got Leica UV/IR cut filters for the Leica lenses I use on my M8. I noticed that two of them look kind of cloudy, even though they are both fairly new. I tried to clean one of them and boy did it make it a mess. Is there some specific procedure for cleaning these?

 

I first used an Giottos rocket blower to blow it off, then tried to use the old "breathe on the filter followed by lens tissue" method. Man, did that ever make it a smeary mess. When you slide the lens tissue across the lens surface, it feels rough. I finallly used some special lens cleaning fluid I use for cinema lenses, and that made it somewhat better, but I am wondering if there's some kind of sprayed on coating that maybe I removed by trying to clean it with lens tissue.

 

Does anyone know the proper way to clean these filters?

 

Thanks for any and all input.

[Advertisement]

The Leica Q3 is available for pre-order at B&H Photo Video and Adorama

[hoppyman]

Tim I always just cleaned mine as with any other coated glass surface. Remove any particles first as you said. Any reputable fluid designed for camera lenses should be OK. Use a CLEAN micro fibre cloth with a few drops on it rather than putting too much fluid directly on the surface.

Personally I often just use the pre-moistened disposable cloths that Zeiss markets (individual sachets).

[Michael Geschlecht]

Hello Tim,

 

Do you by any chance have a gelatin filter?

 

If you do you may well have the results you are describing.

 

Best Regards,

 

Michael

[Timmyjoe]

Thanks Geoff.

 

No Michael, it's not a gelatin filter, they're the filters Leica sells for the M8. Screw on E39 and E46 UV/IR Cut Filters.

 

I'm going to see if I can do a better job using the lens cleaning fluid. I'm using ROR with Kodak/Tiffen lens tissues. Just really surprised how dirty/foggy the filters are, and they're only a couple weeks old. And that slightly gritty feeling the first one had when I first brought a piece of lens tissue into contact with it (after blowing it off of course).

[jamesk8752]

(snip)

Just really surprised how dirty/foggy the filters are, and they're only a couple weeks old. And that slightly gritty feeling the first one had when I first brought a piece of lens tissue into contact with it (after blowing it off of course).

 

Sometimes brand new filters have a thin greasy film on them new out of the box - don't know why, but it has happened to me on several occasions. A thorough wet cleaning has always resolved the problem for me.

 

Regards, Jim

[ho_co]

And your ROR with the Kodak/Tiffen lens tissues is a good bet as well, Tim.

 

BTW, Leica puts the active surface on the inside of the filter when it's on the lens. That is, the part of the filter facing the lens is the part with the multi-layer extinction filter. So cleaning the outside of the glass won't influence the UV/IR-Cut layer. Leica is the only company that guarantees that the filters face that way. It makes no difference optically, but when you're cleaning, it's nice to know that the side that faces the world isn't the side doing the job.

[Double Negative]

Advertisement (gone after registration)

Clean them like any other filter... But use a solution. Your breath won't cut through the funk. I've been using for a couple of decades now, and highly recommend "Formula MC." It has never failed me and works on even "hard to clean" filters.

[gravastar]

And your ROR with the Kodak/Tiffen lens tissues is a good bet as well, Tim.

 

BTW, Leica puts the active surface on the inside of the filter when it's on the lens. That is, the part of the filter facing the lens is the part with the multi-layer extinction filter. So cleaning the outside of the glass won't influence the UV/IR-Cut layer. Leica is the only company that guarantees that the filters face that way. It makes no difference optically, but when you're cleaning, it's nice to know that the side that faces the world isn't the side doing the job.

 

I hope he didn't use ROR. I've found it leaves a very visible oily/detergent like film on coated lenses and filters.

 

I also thought that Leica put the more delicate multilayer IR blocking interference filter on the side that faces the lens. Two out of the eight Leica filters I have had the interference filter facing outwards and I had to take the glass out and reverse it in the mount. Here's how you identify the UV-IR blocking side.

 

Place the corner of a white sheet of paper against the filter surface. Now look obliquely at the reflection of the paper corner. If the paper corner "touches" it's reddish reflection then the corner is against the UV-IR blocking film. If there is a small gap between the corner and it's reflection (which is the thickness of the filter glass) then you are touching the normal anti-reflection coating.

 

The IR blocking layers do seem to scatter light more than the standard coated side and can appear milky. Their surface also seems to exhibit more friction and "squeak" when you try to clean. I've always used isopropyl alcohol and a pec pad for cleaning.

 

Bob.

[Timmyjoe]

I used ROR, Kodak Lens Cleaner, and Isopropyl alcohol, and they all worked about the same. Took alot of work to remove ALL of the smearies.

 

Noticed with the E46 filter, even when I got it spotlessly clean, when you shine a bright light through it from an angle, the whole filter is hazy, like it's covered in a light haze. It's completely uniform, just weird. When you look straight through it, or shine the bright light straight through it, you don't notice it, but when the bright light is coming in directly from an angle, then you can really see it.

 

Anyway, thanks for all the advice. All three filters are now clean. Hope I don't have to clean them again anytime soon.

[ho_co]

I hope he didn't use ROR. I've found it leaves a very visible oily/detergent like film on coated lenses and filters.

Bob, thanks! I'm embarrassed. I always thought that was caused by improper technique on my part.

 

I also thought that Leica put the more delicate multilayer IR blocking interference filter on the side that faces the lens. Two out of the eight Leica filters I have had the interference filter facing outwards and I had to take the glass out and reverse it in the mount.

Ah, now we're getting somewhere! I thought they said the same thing, so I haven't checked.

 

And since I can't figure out how to get the B+W and Schneider (sic) filters out of their mounts, I haven't bothered to check them either.

 

Need to do so, I see! Even on the Expensive Brand.

 

Thanks for the heads-up, I guess.

[ho_co]

Now I've got a question:

 

Everyone has told me to use a microfiber cloth without liquid. That seemed strange to me, and now Geoff says to use it with a little fluid.

 

Anybody got an inside line on this?

 

 

BTW, Geoff, thanks for the word on the Zeiss lens cleaning packs. I hadn't heard of them, and that seems to me a more reasonable idea than reusing a dry microfiber cloth again and again. Do you have a product name for me to look for? They're not the same as I find at the optometrist's, or are they?