[retired2007]

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are their adapters for off brand lenses to fit Pentax ?
Nixon / cannon ? just wondering, and if so where to find?
thanks

[Rimfiredude]

Macro Lens Adapter Nikon AI to Pentax PK Without Glass K 3 K 50 K 5 K M K X | eBay

Canon FD Lens to Pentax PK Mount Adapter with Optical Glass Cap | eBay

Here are a couple on eBay. Don't know how good they are.

[UncleVanya]

Try searching Amazon or eBay for "brand" to k mount adapter,

However, due to the registration distance, the length between the sensor and the lens mount, there aren't many that work without adding optical glass similar to a teleconverter. This degrades optical quality. There are larger lenses like the Pentax 645 series that can easily be adapted given their longer registration distances.

There are some other options, Nikon will almost work as is albeit with a finicky and insecure mounting. There are minor mods that can be made to make Nikon lenses fit better, and there is a replacement mount for k-mount cameras that allows several brands with registration distances similar to Pentax to work. The mount is third party and voids the warranty but seems like a neat idea.

---------- Post added 01-10-15 at 09:05 AM ----------

The macro one above is another option. Adapters without glass that move the lens forward beyond their intended registration distance act like extension tubes making infinity focus impossible but allowing macro use.

[VisualDarkness]

DKL and M42 mount lenses work with an adaptor! Though most other mounts need either adapters with glass (works as a teleconverter and worsens image quality) or won't be able to focus to infinity or only at really close distances. This is due the flange distance between the sensor and the lens mount being quite big with Pentax K.

Flange focal distance - Wikipedia, the free encyclopedia
There you have a list. For an adapter being possible to focus to infinity without extra glass the distance needs to be bigger than Pentax K, with the exception of M42.

[Lowell Goudge]

See this thread

https://www.pentaxforums.com/forums/22-pentax-camera-field-accessories/96884-...sions-lba.html

Personally I own a Nikon and canon to PK infinity focus adaptor. They are , in reality really cheap teleconverters, the Nikon one is 1.25x and the canon one 1.45x.

They need the magnification to correct for the difference in regestry distance and thickness of adaptor

[boriscleto]

https://www.pentaxforums.com/forums/6-pentax-dslr-discussion/247977-manual-fo...light=adaptist

[dakight]

You can use almost any lens for macro by mounting them in reverse with a filter thread adapter.

[retired2007]

thanks