Can A Cracked Filter (Polarizer) Still Be of Use Without Image Degradation?

[DF]

I clumsily stepped on my polarizer causing a sizable crack nearly the entire diameter with it "branching out" slightly with "little veins".
Looking through the lens with it on, you couldn't tell - the crack(s) don't show, as if it's not at all damaged.
Shooting costly Ektachrome, I'm not about to go experimenting to see what if, so, should I/could I keep it or time to get another?
It's a 55mm Calumet issue "Made In Germany" (Schneider Krauznach?) multi coated.

 

[Steve Goldstein]

There's nothing like asking the filter. Can you test it with a roll of black-and-white film?

 

[Taylor K Nankervis]

I've broken or lost a number of filters over the decades, among them the uber-pricey KSM C-POLs by B+W). I don't take the risk of ruining one frame or many, by thinking "nah, it's just a scratch that will come out in the bleach!" So... replace the filter, without a second third or fourth thought. Ektachrome 100 is pricey enough without committing it to a wait-n-see with a crapped flter likely costing less than a roll of E100!

 

[gbroadbridge]

I clumsily stepped on my polarizer causing a sizable crack nearly the entire diameter with it "branching out" slightly with "little veins".
Looking through the lens with it on, you couldn't tell - the crack(s) don't show, as if it's not at all damaged.
Shooting costly Ektachrome, I'm not about to go experimenting to see what if, so, should I/could I keep it or time to get another?
It's a 55mm Calumet issue "Made In Germany" (Schneider Krauznach?) multi coated.

Seriously? It's toast - toss it.

When you need it and the light hits it at the right angle it'll ruin your perfect shot - guaranteed.

 

[RalphLambrecht]

I clumsily stepped on my polarizer causing a sizable crack nearly the entire diameter with it "branching out" slightly with "little veins".
Looking through the lens with it on, you couldn't tell - the crack(s) don't show, as if it's not at all damaged.
Shooting costly Ektachrome, I'm not about to go experimenting to see what if, so, should I/could I keep it or time to get another?
It's a 55mm Calumet issue "Made In Germany" (Schneider Krauznach?) multi coated.

Sorry but this one is FUBAR. Time to get another.

 

[koraks]

Shooting costly Ektachrome, I'm not about to go experimenting to see what if

There's your answer.

Fortunately, it's only a 55mm filter, so not too expensive to replace.

 

[AERO]

Seeing as they don't cost ALL that much..............................

 

[Ian C]

You can pay a lot for a polarizing filter, a moderate price, or a relatively low price. Used filters are also a possibility (eBay, for example).

I own some of each description. They all get the job done.

https://www.bhphotovideo.com/c/search?q=77 mm polarizer&sts=ma

https://www.amazon.com/Vivitar-CPL77-1-Piece-Multi-Coated-Camera/dp/B002IXGKQ0?th=1

 

[bdial]

Have a look at this issue of the Lens Rentals blog, test and then decide.
That said, using a hood on the filter may help, or else just replace it.

Front Element Scratches

We had a chance to make a pretty fun demonstration today, and here it is. As most of you know, we’re very finicky about our gear. We don’t like even tiny scratches on front elements or dust in a lens (although a bit of that is inevitable). We’re like you. We want the lens to [...]

www.lensrentals.com

 

[gbroadbridge]

Have a look at this issue of the Lens Rentals blog, test and then decide.
That said, using a hood on the filter may help, or else just replace it.

Front Element Scratches

We had a chance to make a pretty fun demonstration today, and here it is. As most of you know, we’re very finicky about our gear. We don’t like even tiny scratches on front elements or dust in a lens (although a bit of that is inevitable). We’re like you. We want the lens to [...]

www.lensrentals.com

A scratch on a lens front element is not the same as a cracked filter in front of the lens.
The cracked filter in front of the lens will introduce other visible artefacts due to reflections between the lens and the filter.

In any case, that article would appear to be an attempt to rationalise renting out a scratched lens - have no fear, it'll be alright!

 

[bdial]

A scratch on a lens front element is not the same as a cracked filter in front of the lens.
The cracked filter in front of the lens will introduce other visible artefacts due to reflections between the lens and the filter.

In any case, that article would appear to be an attempt to rationalise renting out a scratched lens - have no fear, it'll be alright!

The lens discussed in the blog is a long way from just scratched, and not something they would hire out.

 

[gbroadbridge]

The lens discussed in the blog is a long way from just scratched, and not something they would hire out.

I read the article.

 

[Petrochemist]

You can pay a lot for a polarizing filter, a moderate price, or a relatively low price. Used filters are also a possibility (eBay, for example).

I own some of each description. They all get the job done.

https://www.bhphotovideo.com/c/search?q=77 mm polarizer&sts=ma

https://www.amazon.com/Vivitar-CPL77-1-Piece-Multi-Coated-Camera/dp/B002IXGKQ0?th=1

Many of mine in sizes below 60mm were only £1 to £2 & generally work better than I'd expect from one cracked across the centre! There's a charity shop near me that always has them in stock at around that price.

It should be easy enough to get an idea of the image it might give just looking through it, though an SLR viewfinder would be much better.

 

[koraks]

The lens discussed in the blog is a long way from just scratched, and not something they would hire out.

What @gbroadbridge likely refers to is the fact that a broken filter sits in a different spot in relation to the optical node of the lens - further out. As a result, damage an dirt on a filter will become visible at an earlier stage than dirt or even cracks in the front element of the lens. Although this does of course depend on the nature of the damage, the lens used etc. E.g. on a wide angle lens and a small aperture, the problem will be much sooner visible.

Either way, it's kind of a no-brainer as there's just no really convincing reason why one would use a cracked filter in front of the lens unless it's for specific testing of that scenario or whatever creative effect obtained that way.

And yes, I think many of us are aware of the test/blog you linked to. It's quite remarkable!

 

[Alan Edward Klein]

Around $20 new. Here's a list from the cheapest.

https://www.bhphotovideo.com/c/products/Polarizer/ci/115/N/4026728357?sort=PRICE_LOW_TO_HIGH&filters=fct_circular-sizes_27%3A55mm%3AREGULAR

 

[MattKing]

See if it will work as an adjustable soft-focus filter instead.

 

[DF]

I guess as the saying goes: you don't see what the camera sees...

 

[Sirius Glass]

Shoot some test shots including some aimed at to near a illumination source.

 

[tezzasmall]

If me, I'd just buy a new one.

Terry S
UK

 

[Kino]

It will just inject another point of uncertainty into any problems that creep up in the future.

Strange streak on film that only intermittently shows up in random places? Is it the film, processing or the filter reflecting along the crack?

Not worth it; discard it.

 

[MattKing]

Take out the glass.
You now have a really shallow lens hood with filter threads at each end that allow for an easily rotatable attachment.
I'm not sure what use that would be, but surely there is something

 

[wiltw]

Take out the glass.
You now have a really shallow lens hood with filter threads at each end that allow for an easily rotatable attachment.
I'm not sure what use that would be, but surely there is something

...protection of the lens' thread against impact damage!
As a 'lens hood', it would not be of much benefit at all!...maybe if the sun is a bit behind you, over your shoulder

 

[reddesert]

A crack in either a filter or the front element of a lens is very far out of focus, which is why it is quite hard to see the effect on film, or in the example from the lensrentals blog. If I cracked or put a little chip in a filter, needed it, and didn't have a replacement, I'd consider using it for the rest of the day, then I'd retire it and replace.

However, a polarizing filter is an even-more-so case, because a colored filter is usually a single piece of either dyed or coated glass, and a PL filter isn't either. It's usually a laminate of polarizing film material to a piece of glass, or between two pieces of glass. Once you break it, the polarizing material should still polarize, but it could start to delaminate from the glass, or possibly distort and become not-flat, which is likely to introduce more artifacts. So I would retire a broken PL filter even faster than a broken colored filter.

I'm still willing to use a lens with minor front element damage (chip, scratch) as it's harder to retire obviously, and I feel front element damage typically has less effect than spots/damage on the rear element.