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Lens cap for 37mm lenses?

Discussion in 'Olympus Cameras' started by ohaya, Mar 13, 2016.

  1. ohaya

    ohaya Mu-43 Regular

    75
    Mar 1, 2016
    Hi,

    Does anyone know if this lens cap will fit on my Olympus/Panasonic lenses that have 37mm diameter (like the 12-32mm)

    Brand New Schneider / B+W #300 37mm Push-On Lens Cap Lenses Caps

    Also will that fit on a 37mm filter?

    I'm confused because it says "OD" vs. "ID".

    Thanks,
    Jim

    EDIT: Sorry I forgot to mention that I'm specifically looking for a push-on/slip-on lens cap rather than the ones that have the "ears" that you have to squeeze.
     
  2. Holoholo55

    Holoholo55 Mu-43 All-Pro

    Aug 13, 2014
    Honolulu, HI
    Walter
    The cap is sized to fit on the outside (OD) of the lens rim or filter. You'll have to use a calipers to measure that because I don't see that dimension listed in the usual set of specifications. You'll note that the seller suggests that a cap 2-3mm larger than the filter size would probably fit.
     
  3. ohaya

    ohaya Mu-43 Regular

    75
    Mar 1, 2016
    I don't have calipers immediately available, but will measure when I get one, but what you said is why I am confused. Why does the cap have to be 2-3mm larger?

    I mean does that mean if I measure the OD of the filter as 37mm, I should get a 39mm or 40mm lens cap? Why would that be?

    EDIT: BTW, I happen to have an old Leica cap and that "loosely" fits over the 37mm filter, but it's too loose. That cap also has felt lining the inside.
     
  4. wjiang

    wjiang Mu-43 Hall of Famer

    The problem is that those push caps only fit on the outside, but the outer diameter is not a standardised dimension, unlike the inner filter thread which is where most modern caps sit. Unless you have an original push cap it's hard to ensure a good fit. Even then, I find that the cheap push caps that come with things like conversion lenses wear out very quickly.
     
  5. Holoholo55

    Holoholo55 Mu-43 All-Pro

    Aug 13, 2014
    Honolulu, HI
    Walter
    The dimension they're giving for these lens caps is the inside diameter of the cap. That means it has to match up with the outside diameter of the lens or the filter. Since the outside dimension of the front of the lens is usually not given in the regular list of specifications, you'll have to measure it to get a good fit. So, if you measure the outside of the lens and it's 37mm, a 37mm cap should fit. The seller is suggesting getting a cap 2-3mm larger than your filter size because the filter size is the inside diameter. To fit one the edge of the lens, he's suggesting getting a push-on cap 2-3 mm larger. However, you have to understand that this is only an approximation, and the lens cap may be too loose or too tight for your lens.

    Getting a match may be difficult, and although you don't like the "push button" type of lens cap, it will be a lot easier to find one of those for your lens than the push on kind.

    As WJiang noted, the push on caps tend to wear out after a while and fall off. I had experience with those as those were the standard type of cap back in the old 35mm film days. IMHO, I think the inner squeeze type caps are more secure.
     
  6. ohaya

    ohaya Mu-43 Regular

    75
    Mar 1, 2016
    Hi,

    Ok, thanks for the explanation. I'll measure the filter OD and order based on that. BTW, I'm also getting one of those "automatic" caps for my 12-32mm to try.

    Also BTW, although I'm not there now, I'm originally from HI :), so nice to meet you :)!
     
  7. Holoholo55

    Holoholo55 Mu-43 All-Pro

    Aug 13, 2014
    Honolulu, HI
    Walter
    Aloha to you Ohaya!
     
  8. ohaya

    ohaya Mu-43 Regular

    75
    Mar 1, 2016
    Hi,

    Thanks.

    FYI I just measured the OD of the filter, and it's like 40.33 - 40.4mm, do what size lens cap would be appropriate?
     
  9. Holoholo55

    Holoholo55 Mu-43 All-Pro

    Aug 13, 2014
    Honolulu, HI
    Walter
    Well, you'd want to find one that matches that dimension. I took a quick look on eBay and there aren't many affordable choices, unless you want to buy a set from Russia. :)

    I suggest going with a side-pinch or center-pinch 37mm filter-size cap. Didn't the lens come with one?
     
  10. Clint

    Clint Mu-43 All-Pro

    Apr 22, 2013
    San Diego area, CA
    Clint
    Op/Tech USA makes a Hood Hat, a neoprene cover intended for use on lens hoods but works as well on lenses. A better choice than the push on lens caps.
     
  11. ohaya

    ohaya Mu-43 Regular

    75
    Mar 1, 2016
    Yes, the lenses came with the pinch type covers, but I really dislike them. I have hard time getting them on without looking at what I'm doing and oftentimes they are completely seated. That happened last night when we were out. I put the cap on, I thought but when we got out of the car, it was gone. Thank goodness, we found that it had fallen under the seat.

    Like I said, I have one of those automatic ones ordered. I'll try that.