Scratch on filters, how bad will it show on end product?

[Leigh B]

If your lens needed one it would of came with one.

And if a lens needed a camera body, it would have come with one.

What nonsense.

Back when I was repairing Nikons, I can't remember how many folks brought in lenses with the front element scratched, and even broken, wanting us to fix it. Not doable for any reasonable price.

Do you have fire insurance on your house? Do you expect it to catch fire?
Filters are cheap insurance.

- Leigh

 

[Leigh B]

You would be unable to focus on it at all.

That's precisely my point.

You can't focus on a scratch, just like you can't focus on a toy. The scratch will not appear in the image.

There may be an aberation like flare that shows up as a result, generally only if you're pointed at the sun.

- Leigh

 

[AgX]

And if a lens needed a camera body, it would have come with one.

What nonsense.

You are comparing apples to oranges.

SLR bodies and their taking lenses are designed as modules to be interchangable.
A taking lens and its filter, if necessary, would be designed as a unit.

 

[Leigh B]

A taking lens and its filter, if necessary, would be designed as a unit.

How can they be designed as a unit when they're designed and made by different companies ? ? ?

- Leigh

 

[AgX]

The point is that IF filters were necessary they were made as a unit with the lens.

 

[Leigh B]

The point is that IF filters were necessary they were made as a unit with the lens.

That's absolutely ridiculous.

Should Ford start making gasoline, since that's essential to the operation of their cars?

B+W (a good German company) makes the finest filters in the world.
They don't make lenses. Should they stop making filters?

- Leigh

 

[AgX]

Again you are comparing things on different levels.
Leaving these UV/lens protecting filters aside, B+W and others are making filters as accessories for lenses, not as essential parts.

Making filters would be in the capability of lens makers (and some filters may even have been made by them).
But gasoline making is something else than making cars.

 

[Leigh B]

The definition of "essential" depends entirely on the user and the working environment.

In my world, UV or similar filters are essential.

I don't care about your world.

- Leigh

 

[AgX]

You may be totally right in your world, but you expect the whole camera/optics industry to adapt to your world.

The number of scratched lenses I came across, is so low I really have to think hard. What I well come across are fingerprints that in a few cases have left corrosion marks. And general corrosion at the the front surface with unknown cause. Both cases likely could have been avoided by a protective filter indeed.
Another issue would be cleaning marks. Likely more destruvtive to image quality than a single prominent mark. These too could be avoided by a lens protection.

 

[Leigh B]

You may be totally right in your world, but you expect the whole camera/optics industry to adapt to your world.

I only make recommendations. I don't "expect" anyone else to conform.
Just trying to help those with less experience.

The number of scratched lenses I came across, is so low I really have to think hard.

That's because you didn't earn your living repairing cameras .
We saw lots of such and worse.

What I well come across are fingerprints that in a few cases have left corrosion marks. And general corrosion at the the front surface with unknown cause. Both cases likely could have been avoided by a protective filter indeed.
Another issue would be cleaning marks. Likely more destructive to image quality than a single prominent mark. These too could be avoided by a lens protection.

Certainly cleaning marks, fingerprints, and other degradation of the front coating are major problems with image quality.
Those will be on the front surface of the lens system, regardless of whether that surface is a lens element or a filter.
The advantage of having a filter first is it can be replaced cheaply (relatively) if the degradation is severe.

I've never heard the term "corrosion" in the context of a lens, since the materials are glass and aluminum (or brass).
Perhaps this is a translation issue.

- Leigh

 

[Gerald C Koch]

In a way a scratch on the front element of a lens would actually be preferable to a scratch on a filter. This is because a lens cannot image a defect on its surface. You're not going to see a line on any prints. As mentioned flare will increase. However a filter is separated optically from the lens. In other words the filter is not an element of the lens so a scratch may appear in any images. In this case painting it black etc may do more harm than good. This works for lenses but not for things in front of lenses. If you wear glasses then you know that any smudge or crud on the glass is visible to you.

 

[Leigh B]

In other words the filter is not an element of the lens so a scratch may appear in any images.

Kindly identify a lens* that can image a subject one to two millimeters in front of the front element.

- Leigh

* (other than a microscope objective)

 

[mgb74]

In a way a scratch on the front element of a lens would actually be preferable to a scratch on a filter. This is because a lens cannot image a defect on its surface. ...

But I can make a scratch on a filter completely disappear for approximately $20-30. I can't do that with a scratch on a front element.

And let's keep in mind the context of the thread - as defined by the OP - where he had a deep scratch on a filter that very likely would have otherwise been on the front element of his lens.

 

[AgX]

I've never heard the term "corrosion" in the context of a lens, since the materials are glass and aluminum (or brass).
Perhaps this is a translation issue.

Corrosion is a general term applied in materials research. It also is applied in english language scientific literature on glass.

 

[Larry Bullis]

But because the scratch is on the FILTER which is not the surface of the lens but is mounted in front of it, the scratch will appear in the image as an obstruction which will be very blurry, but visible, and probably quite detrimental to the image. It won't be just flare, and it won't only appear if pointed at the sun.

I learned this at great expense when I was shooting with a pinhole on my 8x10 with a gel filter mounted in front of it. The filter had dust specks on it. It produced very annoying diffuse smudges which were really hard to identify since they were pretty big, and I wasn't expecting them to be. It took me some time to figure it out. Now, someone may say that since it's a pinhole, it's different, that everything seen by the film with a pinhole is equally (un)sharp, but that's not true. If the filter is closer to the hole than the hole is to the film, the image of the dust on the filter will be enlarged - and the filter was very close to the hole so there was quite a lot of enlargement.

This is also true if there's an obstruction on a filter in front of a lens. The image of the scratch will be very diffused, obscure, and much enlarged, but it will degrade the quality of the image, and the particular character of the degradation will vary with the size of the aperture.

Since we seem to disagree, perhaps the OP would shoot something with the filter on and let us know what it looks like for our edification.

That's precisely my point.

You can't focus on a scratch, just like you can't focus on a toy. The scratch will not appear in the image.

There may be an aberation like flare that shows up as a result, generally only if you're pointed at the sun.

- Leigh

That's precisely my point.

You can't focus on a scratch, just like you can't focus on a toy. The scratch will not appear in the image.

There may be an aberation like flare that shows up as a result, generally only if you're pointed at the sun.

- Leigh

 

[darkroommike]

Paint the scratch over and any problem (if actually of visible effect in the photograph at all) will vanish.

Used to do this with front glass, too. Got a scratch or divot, just fill it with black paint, the filter is so close to the front of the lens that it will not show at all, the unpainted scratch on the other hand scatters light and causes flare. Good tip.

Until you get your new filter, use a lens hood to minimize non-image light hitting the scratch and after you get your new filter, use your hood to add some physical protection to your filters.

 

[darkroommike]

So, tl;Dr don't trip over this?
View attachment 172171

Wow, that's not a scratch that's a gash. But the paint should still work.

 

[Theo Sulphate]

Back to the OP, Army35mm..

He's using a yellow filter for B&W work, so this isn't a question of using a filter or not.

Army35mm, I'd recommend a hood rather than a case. Also, that scratch looks deep and nasty to me, so personally I'd replace that filter.

That said, when I buy a new lens, I do put a UV or Skylight filter over it. Partly for effect, but mostly because a hood alone can't protect the front element from debris tossed up by the wind, passing cars, or whatever.

 

[MattKing]

I learned this at great expense when I was shooting with a pinhole on my 8x10

This occurred because you were using a pinhole, rather than a lens. The obstruction was visible because of the extended depth of field that one gets with the pinhole in comparison to a lens with an aperture.
Do you recall what the effective f/stop of your pinhole was?
A "pure" pinhole allows just one ray of light from each part of the subject to go through the pinhole and reach the film. An obstruction will entirely block a number of those rays.
A focusing lens allows multiple rays of light from each part of the subject to go through a number of different parts of the lens and reach the film. An obstruction will entirely block some but not all of those rays. The unblocked ones are capable of forming an image on the film.

 

[Larry Bullis]

This occurred because you were using a pinhole, rather than a lens. The obstruction was visible because of the extended depth of field that one gets with the pinhole in comparison to a lens with an aperture.
Do you recall what the effective f/stop of your pinhole was?
A "pure" pinhole allows just one ray of light from each part of the subject to go through the pinhole and reach the film. An obstruction will entirely block a number of those rays.
A focusing lens allows multiple rays of light from each part of the subject to go through a number of different parts of the lens and reach the film. An obstruction will entirely block some but not all of those rays. The unblocked ones are capable of forming an image on the film.

It's true that there will be differences, but an obstruction is an obstruction. With a lens it will affect the image. The effect of the obstruction will be more concise but still very diffuse as you stop down. Just put a blob of peanut butter on your filter and see what it does.

 

[Army35mm]

Woah, I go away for a bit and everything turns into a shit storm, lol. Okay, so a couple facts I'm putting out here. Reason I'm using Yellow filter is for b/w photography. I ALWAYS use a uv file if I'm not using any other filter. I've got about 3-4 I've smashed up already;that could easily have been my lenses... I suppose if purity of the lens is issue, I get it. But I'd rather not bust my lenses up. My nikon takes a beating every time I'm out (hopefully less now since I got a peak design capture mount)
Thanks for the tips, I'm going to d/c my use of this filter.

 

[pbromaghin]

Surprised? Heh heh. You're new here.

 

[Leigh B]

Woah, I go away for a bit and everything turns into a shit storm, lol.

An s s ? ? ? No way. This has been a church social.

Wait until you encounter an argument. You'll learn what an s s is.

- Leigh

 

[Larry Bullis]

Woah, I go away for a bit and everything turns into a shit storm, lol. Okay, so a couple facts I'm putting out here. Reason I'm using Yellow filter is for b/w photography. I ALWAYS use a uv file if I'm not using any other filter. I've got about 3-4 I've smashed up already;that could easily have been my lenses... I suppose if purity of the lens is issue, I get it. But I'd rather not bust my lenses up. My nikon takes a beating every time I'm out (hopefully less now since I got a peak design capture mount)
Thanks for the tips, I'm going to d/c my use of this filter.

Well, I go away and when I get back, I discover that there are consequences for being gone for six years. Nobody remembers me, but it's my own fault. I never revealed who I am, and who would remember anonymous posts? I'll correct that on my profile sometime today if I can squeeze it in, or, if I can't, soon.

In my 54 years of constant engagement in photography I've had a lot of opportunity to make mistakes and I've tried to learn from the many I've made. I had a lot of help from the photography students I taught in several colleges for about 30 years, who provided a further wealth of experience. I used the pinhole example because since my livelihood depended on having things reliably "turn out", I never would have used a corrupted filter. That's a mistake I have never made. I thought I could get away with presenting an analogous example.

I think I owe a certain apology to you all, because my peanut butter comment probably was a bit reactive. Mattking's response was kind of a gob smack; I think you'll understand why.

I was a frequent contributor to Pinhole Journal, even wrote the text for an entire issue. I have about 100 works in the Pinhole Resource Collection in the Palace of the Governors Museum in Santa Fe, including the eye of the needle camera I made for photographing a camel in the most ridiculous project I ever did. One of my Pinhole images was used on the cover of Eric Renner's first edition of _Pinhole Photography_ and I was a part of the Poetics of Light show at the Governor's Museum. I'm sure that there are people who've thought more about the relationship of pinhole to the lens, but I'm also sure there aren't many, especially who aren't physicists.

Wow! What a come-uppence! Whack! So this morning, I did a couple of searches on APUG. I searched for my friend and colleague Don Cardwell, and got a lot of results. I searched for myself and got only one result where I had signed my name to a post in 2008.

Forums can get a bit raw. I remember the old Alt-Photo-Process usenet group, which actually ejected members in protracted flame wars; I heard after I left in disgust that they even ejected Dick Sullivan. This APUG group is very civil, even when things get a bit hot, which I agree, this thread really isn't. Most of us have been through some tense episodes. I appreciate everyone's bringing their experience forward to help the community. This time, I have learned something really important about myself. SHARE! Share not just my knowledge and experience, but share myself as well. Thanks to you all.

Larry Bullis

 

[carusoswi]

Personally, I have taken many a photo using my lenses, all of which get a filter upon purchase that never comes off unless I want to install some specialized filter for a particular photo or group of photos. All of those photos are, to some extent, degraded by the filter. However, except for flare, that degradation is as undetectable to the eye as scratches and dust on an unprotected lens. My glass is not exotic, but I paid for all of it with my money, and am not about to chance that my clumsiness or some unforeseen circumstance will damage my lens. That's just me. If you are a professional, then, perhaps, the added image quality is worth exposing your lenses to such damage. Besides, if you shoot for pay, you can justify the occasional need to replace equipment. I cannot. When I buy a lens, I expect to keep and use it for as long as I shoot photos.
There is no right or wrong here, just different perspectives from which we all engage in the wonderful act of taking photos.
My 2-cents.

Caruso