Is a Bayonet 135mm compatible with a canon 7d..

[hks_kansei]

A Canon Bayonet will be
A Pentax not without an adapter


A 135mm long Bayonet off a rifle may fit, but I expect it would likely damage the sensor, and mirror, quite a lot.

[jatrax]

Is a Bayonet 135mm compatible with a canon 7d..

Bayonet is the style of mount as opposed thread or screw mount. Many years ago most cameras had screw mounts and the lenses threaded on just like a piece of pipe. Then the bayonet style mount was invented and fairly quickly all camera companies converted to bayonet style. Each camera company invented their own mount of course (and sometimes have had several different mounts) so just saying "bayonet" does not mean much with out knowing the brand. A Pentax bayonet will not fit a Canon bayonet for example.

There is also a "Takumar (bayonet) 1:2.5 135mm lens. This is the only lens series I am aware of that actually has the word bayonet on it. This is a Pentax k-mount lens and was one of the early lenses produced in the bayonet style. At that time Pentax was known for their thread mount, called M42, and so they were very careful to distinguish the new bayonet style from their traditional mount.

Nowadays bayonet does not mean much since AFAIK all camera lenses are bayonet, just different types of bayonet.

Some lenses can be made to work on other brand's mounts with adapters. Whether it is worth the cost of the adapter depends on the quality of the lens and what the adapter has to do to make it work. Lots of people use Pentax M42 mount lenses on Canon for example.

[Miguel]

Yes, a K-mount (bayonet) lens will fit on a 7D with an adapter. You'll have stop-down metering and manual focus. Best to use Liveview to learn the metering characteristics for a while.

M