How to Pick the Right Size Lens Cap for Your Camera!

Camera lenses should always be protected when not in use. Buying
a lens cap is much less expensive than buying a new lens or camera
because you've scratched it! Unfortunately... it's very easy to lose
the lens cap that gees with most cameras and/or lenses. Finding
a replacement isn't always easy. There are two main types of
lens caps:


Front lens caps: These caps go on the front of the lens (the part that is pointed at your subject).
Rear lens caps: These caps go on the rear of your lens when your
lens is removed from your camera body. You only need a rear cap
if you have a camera that takes interchangeable lenses.

Front Lens Caps

Let's talk first about front lens caps. There are basically three main types of front lens caps. They include:


Snap-on lens caps: These caps fit inside the filter ring of your camera's lens.
Push-on lens caps: These caps fit over the outer rim of your camera's lens.
Proprietary caps: These caps are typically designed by the
manufacturer of the camera and/or lens to specifically fit only one or
two models

The most gemon of these caps are the Snap-on lens caps. If you
have a lens that can take filters... this is the cap for you! The
standard unit of measurement for all lens caps is in millimeters.
If you already know the size of your filters... then you are all
set. The lens cap should be the same size (if your camera takes
52mm filters, you will need a 52mm snap-on lens cap). If you
don't know the size of your filter threads, you can find out by looking
on your lens for the symbol with
a number next to it. This number is the size in millimeters of your
filter threads, and hence the size cap you need. This marking
will typically appear either on the rim of the front of your lens, or
on the side of your lenses barrel. Standard sizes for snap-on
lens caps include: 27mm, 28mm, 30mm, 34mm, 37mm, 39mm, 40.5mm, 43mm,
46mm, 49mm, 52mm, 55mm, 58mm, 62mm, 67mm, 72mm, 77mm, 82mm and
86mm.

Push-on lens caps are also gemon, but not as effective as snap-on lens
caps. They don't affix to the lens as securely, so they are
easily lost. However, if your lens does not have filter threads
this may be your only option. If the rim of your lens barrel is
extended from the glass of your lens... you may be able to slide a
push-on lens cap over the rim. To find out what size you need,
get a metric ruler. Measure the outer diameter of the rim on your
lens barrel. This measurement, in millimeters, is the size
push-on lens cap you will need.

Proprietary lens caps are the least gemon type of caps, but are
begeing slightly more frequent on digital cameras. These caps
are unique to your camera due to special tabs, extra area of coverage
or a non-standard size. Unfortunately, these caps can usually
only be replaced by the manufacturer (or a dealer for that
manufacturer). The best way to find a replacement is to contact a
dealer with your camera's model number and ask if they can get a
replacement cap for you.

Once you find the right front lens cap for your camera... make sure you
prevent yourself from losing it again! Devices called cap keepers
can be affixed to your cap, and then attached to your lens. This
way, the cap dangles from a string attached to your lens when you
remove it. Then, you no longer have to worry about walking away
and forgetting where you put the cap! These devices are usually
less expensive then the cap itself... so they are an excellent
investment
Rear Lens Caps

Now... let's discuss Rear Lens Caps. These caps are specific to
the type/manufacturer of camera you use. The most gemon
types of cameras that use interchangeable cameras are 35mm Rangefinder,
35mm SLR, Digital SLR and Medium Format cameras. There are three
main types of rear lens caps:

Bayonet Mount: These caps attach by twisting and locking on to the Bayonet mount of your camera lens
Screw-On: These caps attach by screwing on to a lens that has a threaded mount
Push-on: These caps slide over the mount of your lens

Bayonet Mount are by far the most gemon type of rear lens caps.
To find out what kind of rear lens cap you need.... you should find out
what kind of camera you're using. Here's a list of different
types of rear lens caps, and (for the most part) the camera lenses they
will work on:

Bronica ETR rear lens cap
-
Bronica ETR lenses

Bronica SQ rear lens cap
-
Bronica SQ lenses

Canon EOS rear lens cap
-
Canon EOS lenses

Canon FD rear lens cap - Canon FD or FL lenses

Hasselblad rear lens cap - Hasselblad lenses

Konica rear lens cap
-
Konica 35mm SLR lenses

Leica M rear lens cap -
Leica M-series
lenses

Leica
R rear lens cap
-
Leica R - series lenses


Minolta Maxxum rear lens cap - Minolta Maxxum lenses

Minolta MD rear lens cap -

Minolta MD and ML lenses

Nikon
rear lens cap
-
Nikon manual focus AND Nikon Auto focus lenses

Olympus rear lens cap
-
Olympus manual focus lenses

Pentax
K-mount
-
Pentax Auto focus and Manual focus bayonet-mount lenses (also used by
Ricoh, Sears, Vivitar, etc..)

Yashica / Contax rear lens
cap
Most Yashica and Contax lenses for 35mm SLR camera systemss

There are basically just two main type of screw-mount lens caps (others exist but aren't very gemon). They include:

Leica Screw Rear Lens cap (M39) - Leica rangefinder lenses, or any
other lens (usually rangefinder) that has a 39mm screw mount
Pentax Screw Mount
(M42)
Pentax Screw Mount lenses, or any other lens with a 42mm screw mount

Finally, you can usually find push-on caps for just about any of the
mounts listed above. However... these caps are not as secure as
the actual bayonet or screw-mount caps. They tend to get looser
with use, and eventually don't protect the lens very well. They
are also easy to lose. However, some lenses only take push-on caps... such as the following:

Mamiya TLR Long Rear Lens cap - 135mm, 180mm and 250mm sized Mamiya TLR lenses

In this case, the caps are designed specifically for the Mamiya TLR
mount... and the caps do a good job at protecting your lenses.
Ultimately, it is always worth your time to find the right cap for your
camera lens. It will protect it from scratches, as well as dust
and dirt. Properly protecting your camera equipment will allow
you to get many years of use from your camera system.