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Today, I tried to take a picture with my wife's camera, and when I was done I went to put the lens cap on, but the outward part was facing the lens, and now the lens is scratched. Very, very expensive mistake for such a seemingly trivial accident, I feel.

I'm normally quite careful with the camera, but I'm not familiar enough with the lens cap to know which way is which on first glance.

Is there any type of lens cap that will stop itself short of destroying the lens if you accidentally put it on backwards because you're not paying attention?

Or should I just never touch the camera?

Thanks in advance.

mattdm
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James M. Lay
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    I have never seen a lens cap of any lens or any camera that could be put on backwards, or that would touch the glass if held backwards against the lens. – Chenmunka Dec 29 '19 at 15:17
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    What camera, lens, and lens cap was this? – mattdm Dec 29 '19 at 16:29
  • Use a lens hood. Use the cap as a coaster. – OnBreak. Dec 30 '19 at 03:37
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    Scratches are generally undesireable, but you did not "destroy the lens". – osullic Dec 30 '19 at 15:11
  • I mean, the shots are blurry. – James M. Lay Dec 30 '19 at 22:45
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    Pictures are worth a thousand words. Please take a picture of the scratched lens and add it to your post. You would have had to intentionally try to destroy the lens with the lens cap in order for the pictures to be blurry. – scottbb Jan 01 '20 at 17:15
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    @james-m-lay A single scratch is unlikely to noticeably affect image quality. Blurry images could be caused by oil (fingerprints) on the front element or even just simply missing focus. – xiota Jan 01 '20 at 19:54
  • @Hueco I have a bag full of lens caps. They're too unstable to be used as coasters. – xiota Jan 01 '20 at 19:56
  • @xiota try some 80 grit until the surface is flat. Progress up gradually to 400grit. I like running things up to about 1000, personally, to really polish it back to what it was...but smooth and level now. – OnBreak. Jan 01 '20 at 20:08

5 Answers5

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Is there any type of lens cap that will stop itself short of destroying the lens if you accidentally put it on backwards... ?

Although some old caps are made of metal and may damage the glass or filter threads if not used carefully, most modern lens caps are made of plastic and will not harm the lens if accidentally put on backwards, unless they have been dropped on the beach. (Sand will scratch glass.)

Is it possible you just made a light mark on the coating that can be wiped away?

You can try gluing half a ping pong ball to the front of the lens cap. You can also purchase caps that have already had a similar procedure performed. Presumably, these caps have other functions that you might find useful.

white balance lens cap

Some other options:

  • Pay attention to what you're doing.

  • Use transparent lens caps that are semi-permanently affixed to your lenses. These are often referred to as "UV filters", but what they really filter out are oil, dust, and scratches. (High-quality "multi-coated" filters should have minimal effect on image quality.)

  • Use lens hoods instead of caps. These function similarly to car bumpers.

  • Use pre-distressed lenses and cameras. An extra scratch or two just adds "character". (See Fuji X Weekly: Distressing a Camera.)

    distressed camera

Or should I just never touch the camera?

What does your wife say?

xiota
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Most lens caps are plastic, front lenses usually are glass. It seems a bit strange that this combination should be able to cause scratches, or at most to the coatings. What information are we missing here?

user88681
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    I should post a picture of the lens cap when I get home. Maybe that will clear things up. – James M. Lay Dec 29 '19 at 18:10
  • The front lens element probably has an antireflective coating on it, which is not as hard as the glass underneath it. – RoG Jan 01 '20 at 16:01
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This doesn't directly answer the question you're asking, but at a more fundamental level, scratches on the front element usually aren't a big deal. Minor scratches probably don't have a visible effect in most of the images you take. See also, What is the effect of a scratched lens?

But directly to your question, I can suggest three things:

  1. Don't put on the lens cap by feel. Be deliberate and slow, watching what you are doing, when putting it on.

  2. Get a different lens cap that doesn't have any protrusions on the front, so that if it is put on backwards, it won't impinge on the glass.

  3. Modify the lens cap, perhaps gluing on a disc of plastic, so the front is physically larger than the front of the lens. "Manhole cover" comes to mind.

  4. This might seem completely bonkers, but many pros just completely forego lenscaps. For mechanical/incidental protection, they rely on lens hoods to keep stray objects away from the front of the lens. Personally, I tend to follow this when I'm shooting, and only put on lens caps when I'm done with the session, or putting everything away back home.

scottbb
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  • To suggest a 4th, get a UV filter or protection filter if the lens has a front screw mount. – floodpants Dec 30 '19 at 10:30
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    @drinxy Some people do that, but I never recommend it for general always-on protection. I only use them and recommend them in specific scenarios, such as when shooting on beaches / near the ocean (wind-blown sand and salt spray will degrade lens coatings in short order). See also: Are there any downsides to using a good-quality UV filter? – scottbb Dec 30 '19 at 18:08
  • Agreed, but in the context of OPs question I feel that they are a valid choice as a last line of defence. I probably should have been more specific in my comment though. – floodpants Dec 30 '19 at 21:17
  • @drinxy totally understood. I see where you're coming from, and to be honest, if a person were in the "protection above all else" mindset, I might even recommend them. =) – scottbb Dec 30 '19 at 21:20
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AFAIK there are only two types of caps:

The "outer pinch" one:

enter image description here

which is often the one that comes with the lens, and the "inner pinch" one:

enter image description here

that has the nice property of being usable even with a lens hood.

Neither has hard and sharp protruding parts on either side. The way you hold an "inner pinch" one makes it very difficult to put it on backwards by mistake, when you know how to use them.

xenoid
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    There are also metal lens caps, and the kind that is pulled over the outer edge of the filter thread... but that is mostly vintage stuff. Though that would explain it... vintage lens with first gen blue magnesium flouride coating, metal lens cap, ouch :) ... and then there are the special caps for ultrawides... – rackandboneman Dec 29 '19 at 22:02
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A solution I use on some of my lenses is to screw on an "empty" filter ring to the lens. I take an old/inexpensive/scratched UV filter or similar and simply remove the glass (by either disassembling or carefully breaking the glass). This means that the lens attaches to the filter ring instead of the lens directly, and therefore sits 3-4mm further away from the lens than usual.

Of course, this is only relevant if you don't want to use a filter with your lens. Otherwise, a good quality UV filter does the same job and provides much better protection.

RoG
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