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 1

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.

Answer 2

As jrista said, almost any lens can be fixed, but you have to compare the cost of repair against the value of the lens.

Nikon will often charge over $200 for repairs, but you can probably get a lens cleaned in most parts of the world for $50-100. You have to weigh that cost vs the cost of the lens. Repair or cleaning might cost most of the value of a kit lens, but be worthwhile for a $2000 professional lens.

Mold can be prevented by regular use of your equipment. UV light will kill the mold, so having your lens outdoors periodically should prevent it (but won't remove it once it's there). A small amount of mold won't generally ruin the IQ of a lens. Unless it's really bad it usually only causes loss of contrast or some flare, but most times it's not noticeable. A dry box needs to be weighed against the value of the equipment it's protecting, and it depends on the humidity of your location whether it's even necessary.

The other main preventative measure is having a filter of some sort on the lens. This can help protect the front element of the lens from scratches, or possibly protect the front element or outer rim/filter threads if the lens is dropped. Whether this actually helps depends on how you drop it I guess, but it's debatable whether it's worthwhile. The problem is a cheap filter can degrade the image quality (do you want to put a cheap $20 filter on a $1500 lens?, but an expensive filter may not be worth it (do you want to put an $80 filter on a $150 kit lens in hopes it might protect it?). Some debate about this topic can be seen here.

Other things that can go wrong: the most common would be autofocus mechanisms that stop working, aperture blades that get stuck, zooms that don't zoom smoothly. These can result from droppage, moisture, or old age.

Answer 3

They are precision assemblies, even though the components might be simple or cheap, replacing them requires a great deal of work comparable to making it in the first place. Anything affecting the lens elements (misalignment or damage) would require a factory rebuild and potentially huge expense. Anything less you might choose to live with.