The Lens Cap

The Lens Cap: More Than Meets The Eye
"That which costs little is less valued." - Miguel de Cervantes

     Now you may be thinking: "Really? He's chosen lens caps as a topic to discuss?"

     Yes I have. 

     I realize that most people think a lens cap is so simple, that there's really no reason to ever mention them. Not even in a blog about photography... We all know how to use a lens cap, right? It's not rocket science. Well actually, it might be. You already know a lens cap is used to protect the front and back of the lens when the lens is not being used. There are some other things, however, that you may not have thought of, and I'd like to share them with you now. 

     First, you should know there are 3 types of front lens caps, and 2 types of rear lens caps. They are as follows:

     1. Front end snap on (which is available as edge pinch or center pinch)

     2. Front end screw-on

     3. Front end slide on

     4. Rear end screw-on

     5. Rear end slide on

     Let's start at the front with the snap on types. This is the most common type of front lens cap, and if you have a lens that was built within the past 15 years, it most likely has this style of cap. The edge pinch caps have been a Canon standard for some time, and Canon is just recently switching over to the center pinch style. What am I talking about? On the lens cap itself, there are two spring loaded tabs that actually fit inside the threaded part of the lens when placed, and must be pressed simultaneously in order to release the cap. This is a great design, unless you want to leave your lens hood on and still have the ability to place and remove the cap. Because of having to pinch the edges, the lens hood would be in the way and you'd be forced to remove it to get the cap off. With a center pinch style cap, the spring loaded tabs are placed in the center of the cap, and are easily accessed with or without a lens hood in place. Not sure why Canon decided to wait so long to make the change, as Nikon has been doing this for some time now. Anyway, that's the snap on type. 

  Front & Back Of  A  Front Snap-on Type Lens Cap

   Next is the front end screw-on type. This type of cap actually utilizes the threads of the barrel to attach itself to the lens. This is a far more secure style of attachment, as it won't come loose in the camera bag or while walking. However, it also means that you'll be adding several seconds to the process of getting the camera ready to shoot, and if you frequently find yourself needing to shoot at a moments notice, then a screw-on cap is probably not what you want. There is a solution to the slowness of a screw-on lens cap, and it's fairly new also, so it may not be available to you. It's a screw-on type cap, that also has a built in hinge for the actual cover. So when you need to shoot, you just push a small button on the edge of the cap assembly, and the cover quickly folds back. It's still attached to the lens, it just hangs down out of the way. You can check it out here.

     The last of the front end caps is one that is less likely to be seen or manufactured, except for specialty lenses. It is the slide on style and it does just what it sounds like. It slides right onto the front end of the lens. It works, but it also has the potential to slide right off again, even if you don't want it to.

     At the rear, you have your choice of a screw-on type, or a push on type. The screw-on version uses the lens mount to attach itself securely to the rear of the lens. This is the most common type of rear cap for newer lenses. 

Two Rear Screw-on Type Caps; One Canon, One Generic

     The slide on type for the rear is exactly the same as the front end version, and comes with the same benefit of easy application and removal, as well as the same downfall of unwanted removal. Again, this type is not common anymore, and you'll likely only find it on older or specialty lenses.

*On the inside of your lens cap, you should find the size of lens
 it's compatible with, imprinted in mm.

     Of course you have to have an accessory for your accessory, and that's where the lens cap strap comes in. It's a small string that attaches itself on one end to the cap, and on the other end to the camera or lens. It's a nifty little thing, and if your prone to losing your caps all the time, it may just be worth a few dollars to invest in one. There are several variations of products available to help keep you from losing your lens caps; several devices are available that allow you to secure the cap to the camera strap for safe keeping, while others mount directly to the camera or to your belt and securely hold the caps there. I'll leave some links at the bottom of this page to product pages so you can see what I'm talking about and decide which option, if any, is right for you. Personally, I just put my front lens caps in my pocket. 

My 17-40L With Screw-on Style Rear Cap

     What about brand name caps vs generic caps? I've had both, and to be honest, the only difference is that one has a fancy brand name logo on the front, and one doesn't. They both function the same, they both grip the same, and they both protect the same. If you'd like to see "Canon" or "Nikon" or "Sony" or whatever brand you have on your caps, then fine. Otherwise, you can save some mula by just buying the generic version. It could likely be the difference between $5 and $15.

     Did you know you can also buy custom made lens caps? That's right, custom lens caps. It's mostly for people with a very old or unique lens that doesn't have a cap already. One such provider, is a machinist who makes not only custom fit caps, but many other lens accessories as well. You can check them out at www.skgrimes.com. Another way to get some sweet customization on your lens caps is to place something over the front of it. For example, a sticker of your favorite rock band, your name or business name, a big yellow smiley face, or whatever else you like. You can spray paint the cap with some funky colors, maybe glue some glitter, diamonds, or fake fur to it... You get the idea. Here's another website that may be able to help out: www.objektivist.at

     *One great idea is to put a pure white sticker on the inside of the cap. You take a picture of it during your photo shoot, and later use it to get an accurate white balance for all the photos!

     Now about the rocket science part... 

The following is a true story, but it has been re-written by me. I am not a professional historian, 
I wasn't there, and the information I'm repeating was obtained through the internet. 
If I've made a mistake, I apologize, and I'd be happy to correct it. 

Scientists working on Venera 11 

     In 1978, the USSR had a mission to explore the planet Venus. They had already sent out at least 10 rockets on this mission during previous years (some of them not on the official record). On December 23 of that year, they launched Venera 11; their official 11th rocket sent to explore the atmosphere and surface of Venus. The rocket consisted of two main sections: a lander, which would actually land on Venus and take readings from the surface, and a flight platform, which would receive signals from the lander and relay them back to Earth. The flight platform had a nice set of fancy equipment for reading gamma rays and the like, while the lander's equipment was designed more for physical matter like dust or dirt. The lander also had two color cameras which of course required lens caps to protect the lenses on the journey through outer space. Well, it finally came time to remotely remove the lens caps and behold the amazing environment of Venus. Unfortunately, they were unable to do so. Clearly, someone in the engineering department underestimated the potential complexity of a lens cap. So they continued on with the 95 minute visit, and transmitted lots of very interesting data about the scorching hot planet back to Earth. Future visits would prove to be more successful in regards to cameras and lens caps. We should be very grateful to these scientists for teaching us all more about this galaxy of ours!

     So there you have it: lens caps are rocket science. 

     Hope you enjoyed reading this; have you done anything interesting with your lens caps? Share your stories, comments, questions or corrections in a comment below! And, I would LOOOOOVE it if you share my articles using the little icon thingies below!! :)

The Sensei Cap Keeper Plus

The Capbuckle

The Hufa Lens Cap Strap Holder
The Nice Clip