Magic Lantern Forum

Using Magic Lantern => Hardware and Accessories => Topic started by: redaber on September 12, 2014, 11:03:23 PM

Title: Remove Lens Coatings???
Post by: redaber on September 12, 2014, 11:03:23 PM
Hello guys,

This may sound strange but i love when a lens makes alot of flares and light streaks, this could be done by having a uncoated lens... unfortunatly these lenses are very very expensive. Now my question is, is it possible to remove the coating yourself?

Thanks

Title: Re: Remove Lens Coatings???
Post by: PaulB on September 12, 2014, 11:19:03 PM
You could spray the lens with an atomiser full of water before taking the photo. Or with a weak gelatin solution if you're feeling brave.
Title: Re: Remove Lens Coatings???
Post by: redaber on September 12, 2014, 11:25:34 PM
It is going to be used for video :) this a video that show's where i am looking for. i have bought a bunch of canon FD lenses all of them are very fast lenses (1.8 to 2.8 primes, 28,35,50,85,135 cost me 80 bucks, now i need to get the coating off :) )


http://www.youtube.com/watch?v=EnbBfLE3VBE

Title: Re: Remove Lens Coatings???
Post by: Levas on September 13, 2014, 12:24:17 AM
You need a good solvent solution, so the coating can dissolve in the solution and you can wipe it off.
Like alcohol and that kind of stuff, although I think alcohol (ethanol) isn't strong enough to do the trick.

You could try aceton (nail polish remover) although really aggressive solvent, glass can resist it, but plastic can't. So don't spill on plastic stuff around the lens.
Aceton is really nasty on plastic...
Better try it out first on a cheap (non plastic) lens, or a little part in the corner on the lens...
Title: Re: Remove Lens Coatings???
Post by: redaber on September 13, 2014, 12:47:28 AM
Ahh i see, now i need to know if the anti flare coating is only on the front element, do you happen to know if there are any coatings inside that i need to get rid of?
Title: Re: Remove Lens Coatings???
Post by: Levas on September 13, 2014, 12:54:06 AM
I have absolutely no idea, but my guess would be that there are only coatings on the front element and maybe on the back element (to prevent light from bouncing between back element and sensor ?).
Why add coatings to all elements inside the lens...front element coating should prevent all.
Title: Re: Remove Lens Coatings???
Post by: PaulB on September 13, 2014, 01:14:20 AM
Coatings are probably on all elements as light can reflect off any glass surface in the lens assembly.
Title: Re: Remove Lens Coatings???
Post by: mageye on September 13, 2014, 12:59:46 PM
I am no expert on optics, but from this video, I would deduce that the lenses are coated all over. Perhaps I am wrong?

https://www.youtube.com/watch?v=Am5wJUEiNAI (https://www.youtube.com/watch?v=Am5wJUEiNAI)
Title: Re: Remove Lens Coatings???
Post by: redaber on September 13, 2014, 02:24:45 PM
Nooooooo why :( guess i am going to take all the elements out then lol
Title: Re: Remove Lens Coatings???
Post by: redaber on September 13, 2014, 02:26:33 PM
if this is not going to work, do you guys know any lens that has insane flaring?
Title: Re: Remove Lens Coatings???
Post by: Levas on September 13, 2014, 02:33:08 PM
Some other approaches:

put a cheap non-coated uv-filter in front off the lens  :D .

Don't know if you want fake anamorphic lens flare, but google on the words: lens flare fishing line.
And you get lot's of tutorials where they use fishing line in front or back of the lens to create anamorphic lens flares.
Title: Re: Remove Lens Coatings???
Post by: Datadogie on September 13, 2014, 07:22:31 PM
I'm sure l seen a video of someone with a uv filter that had been slightly rubed with sandpaper.
Title: Re: Remove Lens Coatings???
Post by: Datadogie on September 13, 2014, 07:25:59 PM
http://youtu.be/zLHgaWGrzAU
Title: Re: Remove Lens Coatings???
Post by: KMikhail on September 13, 2014, 10:24:04 PM
Coatings have to be on all surfaces. Otherwise there will be about 4% (x0.96) reflective loss of light on every air-glass border there, which would contribute to loss of contrast, flare and loss of light (T stop, which is always higher than F stop). That's why early multi-element lenses were so much darker, than modern multi-coated (multi=many layers on a single surface).

Modern lenses lose only a few percent for a whole lens assembly.
Title: Re: Remove Lens Coatings???
Post by: dpjpandone on September 25, 2014, 06:46:35 AM
don't take your lenses apart, you will never put them back together properly..... use an anamorphic flare filter instead