Removing lens coatings - Anyone tried it?

[Inazuma]

I really dislike the clinical rendering of modern lenses. I love the flares you get from old lenses, such as this taken with a Minolta 28mm f3.5 (not my photo). 

Modern lenses are convenient though for their autofocus and EXIF data. Has anyone here ever tried to remove the coating from their lens or has any tips on how to do so? What chemicals or tools would you use? Would removing the coating from the front element be sufficient to create the shape of the aperture blades as in the above picture, or would I have to go for the rear element and the internal elements too?

[kye]

Haven't tried it, but if you can find the lens optical diagram for a specific lens then that might show which lens elements have coatings on them.

My guess would be that there would be coatings on the inside as the flare above would be caused by light bouncing back and forth between lens elements inside the lens.  That's why you often introduce reflections when you put on a filter - the light goes through the filter then reflects off the front element of the lens then reflects off the back of the filter then goes through the lens to the sensor.

Can you buy flaring filters for these kinds of flares?  Does anyone know?

You'd have to get two curved elements with a gap between them, perhaps?

[Andrew Reid]

Multiple elements are coated not just the front. So you'd have to do a complete disassembly. Not practical as a DIY jobby!

[tweak]

These characteristics you like are not from un-coated elements. Removing the coatings is far more likely to ruin the image (and lens), rather than achieve something nice.

[matthere]

I came across this video from Richard Gale some time ago, who removed the coatings and tinkered with the Voigtlander 40mm, I am interested in experimenting with coating removal too,

 

[matthere]

If you search lens repair spanner these are often used to get inside..

 

[IronFilm]

Duclos sells lenses with the lens coatings intentionally removed:

https://thecinelens.com/2013/02/26/duclos-lenses-introduces-rokinon•raw-primes/

[HockeyFan12]

Cooke do this with their front element, Sigma Classic is the same idea but I think every element and there's probably some coating, probably not entirely removed:

This doesn't work that well for me because the design is so complex it looks modern and the flares look weird. 

I think it would work but it might not give exactly the result you want.

[fuzzynormal]

On 7/16/2020 at 4:53 AM, Inazuma said:

Modern lenses are convenient though for their autofocus and EXIF data.

I guess that's a big reason why I enjoy vintage lenses.  They certainly offer a more filmic look, and I've never really ever cared about autofocus or EXIF.  1970's FD's are pretty good to take the edge of the "video" aesthetic. Plus, they're radioactive.  Fun with decaying isotopes.

[leslie]

6 hours ago, fuzzynormal said:

I guess that's a big reason why I enjoy vintage lenses.  They certainly offer a more filmic look, and I've never really ever cared about autofocus or EXIF.  1970's FD's are pretty good to take the edge of the "video" aesthetic. Plus, they're radioactive.  Fun with decaying isotopes.

please dont tell me you use it as a pillow 🤕

Maybe buy an old standard lens with fungus or something and have at it, with the same stuff they use to polish telescope mirrors. if you wanted to be technical about it you should probably make a lap so that you dont change the lens shape. do one lens element at a time, record and report findings.

[fuzzynormal]

15 hours ago, leslie said:

please dont tell me you use it as a pillow

No, but I usually eat my breakfast off of it.  Oatmeal.  Gives the outer glass a nice buff when I clean it off before the shoots and the thorium adds a nice metallic aftertaste.

[leslie]

not really a fan of aftertastes. but hey if it works for you....😉

I have however made a (lowish) bid on a pentax m42 35mm with haze and fungus issues, if i win, i'll buy some cerium oxide and give one or more of the lens elements a polish  Since i already have a nice pentax m42 35mm i should be able to compare them quite easily.

[leslie]

mission is a go,  bought the lens, bought a 100 grams of cerium oxide. Should probably get some resin to make a lap or mould with, don't really want to change the lens shape. Probably will "borrow" some half used grinding pads from the old factory next time i go past.  Spent 13 years in the stone industry running bridge saws and cnc's although i think i have done about half a days work in the wet bay polishing a couple of jobs. Ebay thinks the lens should be here by september, Maybe we'll see some results before xmas 😉

[Donald]

@leslie Any luck on that polishing? I'm trying to clean the inside (flat) of a rear element from a Mamiya-6 with the Olympus Zuiko 75mm f/3.5 lens from 1959. I've tried cerium oxide, hydrogen peroxide and ammonia, but no luck yet... in fact, the blemishes from the fungus seem more apparent. Got any tips?

 

[leslie]

Cleaning it probably makes it more obvious, bit like caustics in a pool.

Sad to say its still on the to do list. You may need something a little rougher or abrasive at the start. Cerium is more like the final polishing step i believe. In the stone industry we used different grades of diamond impregnated pads for a polish 50, 100, 200, 400, 800  1500 and a 3000. never worked with glass only stone. Use water lots of water, glass and silica and lens coatings are things you dont want in your lungs. Maybe a mask as well.

Different granites or marbles required some or all of the steps with glass you'd want to do each step and clean, inspect then move on to the next grade of  pad until you got to cerium. You'd have to be meticulous in your cleaning one grain from the previous pad on an optical surface would undo all your hard work.

The other thing i would do is watch a few telescope mirror making utubes. I wouldn't try polishing a lens  with out making a lap for that lens first. Else you'll change the shape of the lens too easily. Which might take the edge of the digital look but would also introduce all sorts of other interesting optical effects. 

Going down this path and you'll learn a bunch of new skills. It will be time consuming polishing stone or glass isnt a quick fix, more a labour of love. Especially since your dealing with curves, Its all doable but it will require some dedicated effort.  

Which is why i bought a really cheap prime lens to start with, but thats as far i have got so far.

[leslie]

On 3/17/2022 at 12:41 PM, Donald said:

@leslie Any luck on that polishing? I'm trying to clean the inside (flat) of a rear element from a Mamiya-6 with the Olympus Zuiko 75mm f/3.5 lens from 1959. I've tried cerium oxide, hydrogen peroxide and ammonia, but no luck yet... in fact, the blemishes from the fungus seem more apparent. Got any tips?

 

i reread your post. since you have said its a flat side. It should be an easier job. Although you'd still need to learn how to polish an optically flat surface from some telescope making forum. There's flat and then there's optically flat.

There's also the fact that the coating cant be too thick. however you'd still need some rougher abrasives to remove the coatings and then proceed on to polishing. 

[Avenger 2.0]

Maybe stupid question, but what if you use a cheap (uncoated) UV filter on the lens instead? Will this not give flares without ruining your lens?

[PannySVHS]

I found the Sigma video not appealng in regards to the "vintage character" of the lenses. To me it was going over the lines. I would suggest buying some affordable M42 lenses, just like Andrew and the EOSHD cats have been suggesting as a valid choice since the existence of this beautiful site and forum.

[majoraxis]

Here's a website with lots of examples of Cooke's that are coated, uncoated front lens element and uncoated front and rear lens elements in side by side comparison shots.

http://www.cookeminirentals.com/uncoated-elements

I prefer the examples with coated lens elements, but I find nothing wrong with the look of a coated Cooke lens in the first place.

I think they way to go is to find a lens that flares by the nature of its design (which could incorporate less than ideal lens coatings and lead to lens flares as well), thus a vintage zoom lens may be just what the doctor ordered.

[webrunner5]

You probably can just take off all the electronic corrections on modern lenses and get all kinds of crazy stuff. New lenses are probably worse than the old stuff.