Can filters IMPROVE lenses?

Without going into the physics of why...the simple answer is NO.

Think of it this way, adding a filter adds two more surfaces of glass....which increase flare. The multicoated filter would only increase flare by a smaller amount but it would still be an increase.

You may want to try using a good lens hood with those older lenses.

 

I doubt it. A filter has never improved a lens for me. Filters have improved images when used to change contrast ratios, or correct color temperature. But a crappy lens or worn out coating really don't seem to be correctable. I have also experienced "improvement of images" by using a lens hood on lenses, especially older uncoated lenses... that that I consider int eh same category of improvments as mentioned above when discussing contrast or CC filters. Even a lens hood doesn't necessarily imoprove a lens but it can improve the image taken with a lens. So semantics aside of wheter filters/hoods improve the lens or the resulting images... use a lens hood on your old Leica lenses and you'll likely like the results.

 

for what it's worth, the mtf of a system is the product oall mtfs. so, if one element is perfect(mtf=1),the product will not improve, but only be stabilized at best. consequently, the answer must be 'no'.

 

Most definitely not. The best thing you can do with an uncoated or beat up lens is to be diligent flagging stray light off the front element. If the only light hitting it is image-making light then you are getting the best that lens can do.

 

A lens hood will help reduce flare.

 

A single colour filter (e.g. a yellow Y2) can certainly improve the black and white performance of a lens that otherwise suffers from chromatic aberration.

 

Ka-chink

Awesome. I believe (from what I know) you really nailed that one.

 

I confess to keeping a UV filter as protection on a Sonnar, which is a beautiful lens but which also has very soft glass.

For those older single-coated lenses, a lens shade/hood works really great at reducing flare.

 

Regarding the flame war, both sides are correct but the correctest one depends on the situation. If you are in a clean studio environment work without. If you are on a beach on a sandy day definitely wear one, the filter will get salt and sand on it, but the lens will remain safe. Just use a bit of brian

 

Some lenses of course demanded that a filter was fitted for it to work properly at all, Principally 'cat' lenses AKA Mirror lenses, where there was a slot in the back to take the appropriate lens for what you were taking, but were required to finish off the optical path of the lens, but other lenses- no I don't think so.

 

A UVa filter left on an expensive, in demand, older lens throughout it's lifetime can "improve" the resale value of that lens.

 

i think so too, because it protects the front element from cleaningmarks

 

No.

 

I like that endorsement!

 

Which bit though?

 

you see, the trouble with common sense is that it isn't all that common, but the op question is a good one and not so easy to answer. i tend to believe that a good filter cannot hurt and may help to improve the optical performance of an otherwise mediocre system. it is worth a test, and we'll see.

 

Possibly. A monochrome filter will help out a lens with chromatic aberrations.

But - putting a multicoated filter on a single coated (or uncoated) lens will not make it perform like a multicoated lens. It can't, if you think it through. There are all of the un- or single coated surfaces there in and on the lens, reflecting precisely as they always do. A far more effective approach would be to use a proper lens shade, which will make a huge difference in how an uncoated lens performs.

 

Any and all filters will degrade lens optical performance very, very slightly. It does pay to buy the most expensive filter you can afford. Too many people make the sad mistake of slapping a $5.00 bottle top on a $3,000 apo lens and wonder how they could manage to "waste so much money on that lens!". Modern filter spectral coatings have reduced light transmission lost to around 1%, sometimes as low as 0.3%. None of this of course is visible in the end result.

If a lens has worn coating, scratches, fungi or whatnot, it's not a given that any particular filter will improve the optical performance; it can't: a filter is just there to alter the characteristic of the light entering the lens. A damaged lens may well produce much more flare with a filter than without because a filter is an additional layer of glass and thus an extra reflective surface.

 

At risk of introducing another variable into the conversation.
A good polarizing screen - granted difficult to use on your Leicas - will boost the color and BW contrast of any lens.
Most people will pick out the higher contrast photo as being the better photo.
Given that lower contrast is the primary effect of flare, a polarizing screen used with a lens hood should give you the best you can get out of any particular lens.

 

I am glad that I am not the only one to realize this.

 

also, if there are no stupid questions, then, the world must be full with inquisitive idiots.

 

I have had photos with weird reflections from the filter. I didn't realize how often it happened to me until I went back and looked at hundreds of old pictures. It was over 20%.

I mostly take outdoor photos in sunny/daylight conditions. But I also had a lot of flash photos where it happened.

I also learned that I don't like polarizers either because they kill sparkly highlights like what you get on water.

I seldom use a filter now but I try to always use a lens hood.