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High quality multicoated UV filter in front of vantage lens
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PostPosted: Tue Apr 22, 2014 2:10 am    Post subject: High quality multicoated UV filter in front of vantage lens Reply with quote
I have been pondering this question for a while and thought to throw it out there and get everyone's opinion. We all know that old 50/60s lenses often have poor coating which could affect image quality in certain light condition. I was wondering if adding an expensive modern multicoated UV filter in front of the lens would will improve lens with a lot of veiling flare? You think this would work? If not, why not?


PostPosted: Tue Apr 22, 2014 2:15 am    Post subject: Reply with quote
I had this same thought a few months back but never followed up on it. Interested to see people's answers.


PostPosted: Tue Apr 22, 2014 2:30 am    Post subject: Reply with quote
I'm thinking it won't make much difference since most high quality UV filters let 99% of the visible light through, so what is different?


PostPosted: Tue Apr 22, 2014 2:42 am    Post subject: Reply with quote
A filter will give more chance to catch flare. I use UV filters to protect my most expensive lenses.

A good hood is more efficient to prevent flare and this is what it designed for.


PostPosted: Tue Apr 22, 2014 2:56 am    Post subject: Reply with quote
I think he was more referring to, if you could buy a filter that had modern multi coatings would it significantly help older lenses with no coating or only single coated? Could it add more saturated colours and contrast? It will likely impact flare as filters do so I think the focus on saturation and contrast should be foremost.

Last edited by Hood on Tue Apr 22, 2014 3:23 am; edited 1 time in total


PostPosted: Tue Apr 22, 2014 3:19 am    Post subject: experimenting-with-stacks-of-uv-filters Reply with quote
http://petapixel.com/2011/06/16/experimenting-with-stacks-of-uv-filters/


PostPosted: Tue Apr 22, 2014 5:44 am    Post subject: Reply with quote
I read this as a recommendation (bad coated or not coated lenses -> use additional filter to reduce flare) in another forum - but nobody there was interested reading my "opinon" as an optics engineer Smile

Every glass-air surface cause reflections.
For normal incident it is about 4% on an uncoated glass, and less than 1% on a coated glass.
For oblique rays it is more normaly.

An uncoated front lens reflects more light back to the filter. So a filter will reflect more light back into the uncoated lens than on a good coated lens. So a filter cause more harm on an uncoated lens than on a coated one.

A very good filter has less reflections than a cheap coated filter - but both reflect more light than no filter.

If you use a filter as protection, you ned to be aware that you get more stray light or flare - not every time visible, but for example at night photography a filter could decay the work much.


PostPosted: Tue Apr 22, 2014 6:44 am    Post subject: Reply with quote
ZoneV wrote:
I read this as a recommendation (bad coated or not coated lenses -> use additional filter to reduce flare) in another forum - but nobody there was interested reading my "opinon" as an optics engineer Smile

Every glass-air surface cause reflections.
For normal incident it is about 4% on an uncoated glass, and less than 1% on a coated glass.
For oblique rays it is more normaly.

An uncoated front lens reflects more light back to the filter. So a filter will reflect more light back into the uncoated lens than on a good coated lens. So a filter cause more harm on an uncoated lens than on a coated one.

A very good filter has less reflections than a cheap coated filter - but both reflect more light than no filter.

If you use a filter as protection, you ned to be aware that you get more stray light or flare - not every time visible, but for example at night photography a filter could decay the work much.


I find this all to be true from my own experience.
But forgetting flare for a second and how a uv filter can cause anomalies etc
Would a good multi coated filter potentially improve saturation and contrast on a non multi coated or single coated lens?


PostPosted: Tue Apr 22, 2014 8:20 am    Post subject: Reply with quote
edited

Last edited by bernhardas on Tue May 17, 2016 7:17 am; edited 1 time in total


PostPosted: Tue Apr 22, 2014 9:08 am    Post subject: Reply with quote
Ok cool. Was just a thought.

I am not trying to make dog turds into jewelry however. I have good glass, I always just wondered if I put a multi coated filter on say one of my old Leica lenses which is very sharp just lacking contrast and saturation due to old coatings, would it improve contrast and saturation if I put a new multi coated filter on it. But you are all saying no, fair enough...but has anyone actually tried it? Done side by side comparisons between the lens alone and then again with a multi coated filter screwed on?


PostPosted: Tue Apr 22, 2014 9:42 am    Post subject: Reply with quote
Hood wrote:

I find this all to be true from my own experience.
But forgetting flare for a second and how a uv filter can cause anomalies etc
Would a good multi coated filter potentially improve saturation and contrast on a non multi coated or single coated lens?


Most UV filters cut UV where the lens + camera would very damp it too. So no improvement there.

But: There are definitly filter that can improve image quality in terms of sharpness. Take a small bandpass filter, and you get rid of color aberrations Smile


PostPosted: Tue Apr 22, 2014 9:51 am    Post subject: Reply with quote
edited

Last edited by bernhardas on Tue May 17, 2016 7:17 am; edited 1 time in total


PostPosted: Tue Apr 22, 2014 12:07 pm    Post subject: Re: High quality multicoated UV filter in front of vantage l Reply with quote
drjs wrote:
I was wondering if adding an expensive modern multicoated UV filter in front of the lens would will improve lens with a lot of veiling flare? You think this would work? If not, why not?


A filter, multicoated or not, has no ability to remove the reflection of other optical elements of a lens. And if the filter is not of high quality, it will introduce its own reflections, further degrading the performance of the lens.

UV filters are one of the greatest deceptions in the history of photography, as ordinary photographic lenses do not transmit UV. The lens itself filters out the UV radiations. The UV filter is totally useless except for the mechanical function of protecting the front lens against accidental shocks.


PostPosted: Tue Apr 22, 2014 12:20 pm    Post subject: Reply with quote
Got it. In order to remove scattering, every element in the lens needs to be resistant to it! Makes sense.


PostPosted: Tue Apr 22, 2014 12:31 pm    Post subject: Reply with quote
drjs wrote:
Got it. In order to remove scattering, every element in the lens needs to be resistant to it! Makes sense.

The inner barrel and the aperture also cause internal reflections.
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