Kase Magnetic Lens Cap for K9 100mm Filter Holder

Use only with the K9 holder in place!

If you own the K9 system you know the process of removing the normal lens cap (and protector filter?) and mounting the adaptor ring. Then the CPL and finally the K9 holder itself can be mounted, and then attach 4x4 and/or 4x6 filters. To reduce the faffing around I intended to keep the K9 adaptor rings and these caps on all of my lenses and be rid of the pinch caps that came with the lenses. Unfortunately, these caps don't stay in place well without the K9 holder in place. The reason is that they don't Nest into the adaptor and can easily slide to the side. This is dangerous because they are metal and once they slide to the side the edge is free to contact and scratch the front element of the lens. Being in the camera bag and out of sight you can't tell if there is a problem until it is to late. When the K9 holder is attached to the adaptor ring this magnetic cap does Nest into the holder which prevents it from sliding out of place. The other option is to use the Kase plastic caps which are intended to snap onto the adaptor rings directly. These plastic caps are much less expensive and they solve the carry issue. They add a little to the diameter of the adaptor ring making the lens the size of a large coffee mug. If you have plenty of room in your bag to fit 4 inch diameter lenses then keeping the plastic caps on all your lenses is a good idea. If not then you will have deal with some additional work to mount the filters and K9 holder.