Is there any damage that a lens can have that is unrepairable?

Question

Just wondering after I dropped my lens and had it repaired is there any specific kind of damage that would ruin a lens to the point where you'd be better just buying another used one.

I'm specifically curious about mold, as I've heard stories of that destroying lens elements, but couldn't you just replace those elements?

I'm asking this question to help make decisions about cost effectiveness of preventive measures.

For exampe, if mold dmg can be easily repaired then I won't invest in a dehumidifier case for my lens.

Answer

Since lens replacement parts exist and there are people who know how to disassemble and assemble lenses you can say that theoretically there is no damage that can't be fixed -

However in the real world there are kinds of damage that the manufacturers won't fix and even more kinds of damage where the cost of fixing would be more than the cost of replacing the lens.

Everything below this line is second hand information because I've never personally sent a lens to be fixed, I don't guaranty this information is correct and I will gladly edit or remove this answer if someone that has more experience or official information answers.

• I've heard from multiple people who tried to get mold damage fixed and the companies just returned the lens as "can't fix", so I believe it's highly likely companies will not fix mold damage.

• I've also heard of cases where lens companies won't replace broken inner elements, I don't know if this is a general thing or specific to some lens models.

• And finally I've been told that the front element is always replaceable and that it's one of the cheapest things to fix in a lens - I've only heard this from one source (as part of a "why you shouldn't use a protective filter" speech) so I don't consider this information reliable.

Check more discussion of this question.

Why does fungus form in lenses, and how to get rid of it?

Question

Recently I was using an old Pentax 50mm f/2 that had a quite big green spot, and later I was informed that it was a fungus.

A couple of questions raised from this:

1. Why does fungus form inside the lenses? What kind of "food" does it find in a glass element?
2. How does it form? Due to condensation? Due to bad storage?
3. Does it have any impact in the final image? Some scratches in a lens will probably not appear in the image because to they will be very out of focus. Is this also true for fungus?
4. Finally, when a lens is "fungused": How do you get rid of it?

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What to do about mold/fungus in a camera lens?

by Yuttadhammo

I am living in a tropical country where humidity is pretty high. I never thought it would be possible that something could grow inside a lens, so I haven't been so careful with my canon camcorder. Now I see there is a white spore growing on the inside of the camera lens (see photo below). Is there any way, short of finding a camera shop (doubtful there are any in the country that can handle this), to remove this?

The spore is the white dot in the centre (it's opaque), and the dusty patch on the right of the lens is also on the inside, must be the same stuff.

Answer

For all the following: YMMV*, caveat emptor, no responsibility taken for advice given, you decide whether to try this at home. It may even work :-). Be aware that damage may already be fatal and/or that fatal (to the lens) damage may occur along the way. Best attitude is to regard the lens as a writeoff now, with anything you can gain from it by the methods below being a bonus.

Fungus in a lens will always degrade the image but the amount of degradation may be invisible to mere mortals or may make the lens completely unusable by any standards. Often even a very visually significant lens defect - such as a chip or scratch, will not be instantly obvious in final images to a casual observer. Experts will usually be able to detect almost any defect (or say they can - mere mortals will not be able to tell if they are correct :-) ). Also, lens settings will affect how much a given defect affects a given image.

In some cases the advice given in 1a and 1b below will transform results from generally unacceptable to generally acceptable. In other cases they won't. Only trying it will tell you how good a method will be.

The best advice (but too late :-( ) is to never let it happen. Fungus only grows in moist conditions. Keep your lenses in a well ventilated dry location with dessicant sachets. However -

If it's inside the lens there are two options (apart from disposal). Unfortunately, while either may work, neither is certain to work well.

• 1(a) Shining UV (ultraviolet) light into the lens for an extended period will "discourage" the fungus, how well and how long is uncertain. Simply leaving a lens with iris fully open on a sun facing window ledge in a dry location for weeks to months may produce good results. Cap lens at rear, and tilt so that sun shines into lens during sunnier parts of each day. (Be ware that sun shining directly along the axis of the lens or close to it may focus light onto end cap and melt it - unlikely but check point and degree of focus.) I tried this procedure with an extremely old Minolta 50mm f1:1.4? manual lens and achieved tolerable results. I simply left the lens as above for many months and when I next looked found that mold presence had been very substantially reduced.

  1(b) Light from a germicidal (short wavelength) UV lamp may be used in place of sunlight. This sort of light can blind you or damage your eyes permanently if looked at for substantial periods and can cause "arc eye" - painful but usually temporary inflammation of the eye. This does not mean you should not use such lights at all - simply that they need to be used with due respect. These lights are available from many sources for many purposes and can be very low cost.

  Note that "black light" UV light is not suitable for this purpose. It is longer wavelength and not very biologically active.

  Note also that the short wavelength high energy UV (which is why you are using it) from germicidal UV lamps will also degrade other materials such as some plastics and miscellaneous other material - including, possibly, parts of a plastic lens housing. This depends on material, distance, light energy and exposure time. YMMV but caveat emptor - ie know that you are using a tool with sharp unguarded blades (even though you can't see them) and use with due caution.

  All the above may put some people off UV germicidal lamps. If so, that's good. They are a great and useful tool but not suitable for use by careless or unthinking people.

• 2 . Dismantle and clean. If the lens is so degraded that it is unusable and if the method above does not work well enough then the lens must be dismantled. If the lens is otherwise a 'writeoff" and you are competent mechanically you may wish to try this yourself. Reassembly of a lens capsule is considered to be an expert task and realignment on reassembly may require arcane knowledge. This is why qualified lens servicing people are still in business and cost money to use.

  Fungus often attacks lens surface coatings and may etch the glass itself so the lens may be noticeably or fatally degraded regardless. How much the may/may/may applied in your case is tbd. Some lens cleaning works very well indeed. An aficionado and a good MTR test will probably tell you that something has happened but the results may be very tolerable in practice.

  You will find articles on the internet on lens cleaning methods. I read a paper by either Zeiss or Leitz that suggested that cigarette ash makes an excellent fine cleaning compound (!!!).

---

• YMMV - Your mileage may vary.

• Caveat emptor - let the buyer beware = you are on your own.

Check more discussion of this question.

What to do about mold/fungus in a camera lens?

Question

I am living in a tropical country where humidity is pretty high. I never thought it would be possible that something could grow inside a lens, so I haven't been so careful with my canon camcorder. Now I see there is a white spore growing on the inside of the camera lens (see photo below). Is there any way, short of finding a camera shop (doubtful there are any in the country that can handle this), to remove this?

EDIT: new photo. The spore is the white dot in the centre (it's opaque), and the dusty patch on the right of the lens is also on the inside, must be the same stuff.

Answer

The only course of action here is to get the lens professionally serviced. Once mould spores have got into your lens and started to grow like this there is no other way to get rid of them. In order to prevent this in the future always store your camera in a sealed bag with a couple of sachets of silica granules to absorb any moisture that may have got into the camera during use. This is especially important if your in very humid environments or if the camera has got at all wet.

Check more discussion of this question.

Why fungus form in lenses, and how to get rid of it?

Question

Recently I was using an old Pentax 50mm f/2 that had a quite big green spot, and later I was informed that it was a fungus.

A couple of questions raised from this:

1. Why does fungus form inside the lenses? What kind of "food" does it find in a glass element?
2. How does it form? Due to condensation? Due to bad storage?
3. Does it have any impact in the final image? Some scratches in a lens will probably not appear in the image because to they will be very out of focus. Is this also true for fungus?
4. Finally, when a lens is "fungused": How do you get rid of it?

Answer

For all the following: YMMV*, caveat emptor, no responsibility taken for advice given, you decide whether to try this at home. It may even work :-). Be aware that damage may already be fatal and/or that fatal (to the lens) damage may occur along the way. Best attitude is to regard the lens as a writeoff now, with anything you can gain from it by the methods below being a bonus.

Fungus in a lens will always degrade the image but the amount of degradation may be invisible to mere mortals or may make the lens completely unusable by any standards. Often even a very visually significant lens defect - such as a chip or scratch, will not be instantly obvious in final images to a casual observer. Experts will usually be able to detect almost any defect (or say they can - mere mortals will not be able to tell if they are correct :-) ). Also, lens settings will affect how much a given defect affects a given image.

In some cases the advice given in 1a and 1b below will transform results from generally unacceptable to generally acceptable. In other cases they won't. Only trying it will tell you how good a method will be.

The best advice (but too late :-( ) is to never let it happen. Fungus only grows in moist conditions. Keep your lenses in a well ventilated dry location with dessicant sachets. However -

If it's inside the lens there are two options (apart from disposal). Unfortunately, while either may work, neither is certain to work well.

• 1(a) Shining UV (ultraviolet) light into the lens for an extended period will "discourage" the fungus, how well and how long is uncertain. Simply leaving a lens with iris fully open on a sun facing window ledge in a dry location for weeks to months may produce good results. Cap lens at rear, and tilt so that sun shines into lens during sunnier parts of each day. (Be ware that sun shining directly along the axis of the lens or close to it may focus light onto end cap and melt it - unlikely but check point and degree of focus.) I tried this procedure with an extremely old Minolta 50mm f1:1.4? manual lens and achieved tolerable results. I simply left the lens as above for many months and when I next looked found that mold presence had been very substantially reduced.

  1(b) Light from a germicidal (short wavelength) UV lamp may be used in place of sunlight. This sort of light can blind you or damage your eyes permanently if looked at for substantial periods and can cause "arc eye" - painful but usually temporary inflammation of the eye. This does not mean you should not use such lights at all - simply that they need to be used with due respect. These lights are available from many sources for many purposes and can be very low cost.

  Note that "black light" UV light is not suitable for this purpose. It is longer wavelength and not very biologically active.

  Note also that the short wavelength high energy UV (which is why you are using it) from germicidal UV lamps will also degrade other materials such as some plastics and miscellaneous other material - including, possibly, parts of a plastic lens housing. This depends on material, distance, light energy and exposure time. YMMV but caveat emptor - ie know that you are using a tool with sharp unguarded blades (even though you can't see them) and use with due caution.

  All the above may put some people off UV germicidal lamps. If so, that's good. They are a great and useful tool but not suitable for use by careless or unthinking people.

• 2 . Dismantle and clean. If the lens is so degraded that it is unusable and if the method above does not work well enough then the lens must be dismantled. If the lens is otherwise a 'writeoff" and you are competent mechanically you may wish to try this yourself. Reassembly of a lens capsule is considered to be an expert task and realignment on reassembly may require arcane knowledge. This is why qualified lens servicing people are still in business and cost money to use.

  Fungus often attacks lens surface coatings and may etch the glass itself so the lens may be noticeably or fatally degraded regardless. How much the may/may/may applied in your case is tbd. Some lens cleaning works very well indeed. An aficionado and a good MTR test will probably tell you that something has happened but the results may be very tolerable in practice.

  You will find articles on the internet on lens cleaning methods. I read a paper by either Zeiss or Leitz that suggested that cigarette ash makes an excellent fine cleaning compound (!!!).

---

• YMMV - Your mileage may vary.

• Caveat emptor - let the buyer beware = you are on your own.

Check more discussion of this question.

Fungus in lenses: Why does it form and how to get rid of it?

Question

Recently I was using an old Pentax 50mm f/2 that had a quite big green spot, and later I was informed that it was a fungus.

A couple of questions raised from this:

1. Why does fungus form inside the lenses? What kind of "food" does it find in a glass element?
2. How does it form? Due to condensation? Due to bad storage?
3. Does it have any impact in the final image? Some scratches in a lens will probably not appear in the image because to they will be very out of focus. Is this also true for fungus?
4. Finally, when a lens is "fungused": How do you get rid of it?

Answer

For all the following: YMMV*, caveat emptor, no responsibility taken for advice given, you decide whether to try this at home. It may even work :-). Be aware that damage may already be fatal and/or that fatal (to the lens) damage may occur along the way. Best attitude is to regard the lens as a writeoff now, with anything you can gain from it by the methods below being a bonus.

Fungus in a lens will always degrade the image but the amount of degradation may be invisible to mere mortals or may make the lens completely unusable by any standards. Often even a very visually significant lens defect - such as a chip or scratch, will not be instantly obvious in final images to a casual observer. Experts will usually be able to detect almost any defect (or say they can - mere mortals will not be able to tell if they are correct :-) ). Also, lens settings will affect how much a given defect affects a given image.

In some cases the advice given in 1a and 1b below will transform results from generally unacceptable to generally acceptable. In other cases they won't. Only trying it will tell you how good a method will be.

The best advice (but too late :-( ) is to never let it happen. Fungus only grows in moist conditions. Keep your lenses in a well ventilated dry location with dessicant sachets. However -

If it's inside the lens there are two options (apart from disposal). Unfortunately, while either may work, neither is certain to work well.

• 1(a) Shining UV (ultraviolet) light into the lens for an extended period will "discourage" the fungus, how well and how long is uncertain. Simply leaving a lens with iris fully open on a sun facing window ledge in a dry location for weeks to months may produce good results. Cap lens at rear, and tilt so that sun shines into lens during sunnier parts of each day. (Be ware that sun shining directly along the axis of the lens or close to it may focus light onto end cap and melt it - unlikely but check point and degree of focus.) I tried this procedure with an extremely old Minolta 50mm f1:1.4? manual lens and achieved tolerable results. I simply left the lens as above for many months and when I next looked found that mold presence had been very substantially reduced.

  1(b) Light from a germicidal (short wavelength) UV lamp may be used in place of sunlight. This sort of light can blind you or damage your eyes permanently if looked at for substantial periods and can cause "arc eye" - painful but usually temporary inflammation of the eye. This does not mean you should not use such lights at all - simply that they need to be used with due respect. These lights are available from many sources for many purposes and can be very low cost.

  Note that "black light" UV light is not suitable for this purpose. It is longer wavelength and not very biologically active.

  Note also that the short wavelength high energy UV (which is why you are using it) from germicidal UV lamps will also degrade other materials such as some plastics and miscellaneous other material - including, possibly, parts of a plastic lens housing. This depends on material, distance, light energy and exposure time. YMMV but caveat emptor - ie know that you are using a tool with sharp unguarded blades (even though you can't see them) and use with due caution.

  All the above may put some people off UV germicidal lamps. If so, that's good. They are a great and useful tool but not suitable for use by careless or unthinking people.

• 2 . Dismantle and clean. If the lens is so degraded that it is unusable and if the method above does not work well enough then the lens must be dismantled. If the lens is otherwise a 'writeoff" and you are competent mechanically you may wish to try this yourself. Reassembly of a lens capsule is considered to be an expert task and realignment on reassembly may require arcane knowledge. This is why qualified lens servicing people are still in business and cost money to use.

  Fungus often attacks lens surface coatings and may etch the glass itself so the lens may be noticeably or fatally degraded regardless. How much the may/may/may applied in your case is tbd. Some lens cleaning works very well indeed. An aficionado and a good MTR test will probably tell you that something has happened but the results may be very tolerable in practice.

  You will find articles on the internet on lens cleaning methods. I read a paper by either Zeiss or Leitz that suggested that cigarette ash makes an excellent fine cleaning compound (!!!).

---

• YMMV - Your mileage may vary.

• Caveat emptor - let the buyer beware = you are on your own.

Check more discussion of this question.