[bentleyroyce5]

Hi ALL

I'm new here need help / assistance with lens adaptors on KS2 2x adaptors for what will work on my lenses & where to get good onesbut as a reasonable price?

[kypfer]

You'll need to specify exactly which adaptors you're interested in and for what purpose.
"Lens adaptors" would usually imply, (to me), devices for attaching non-K mount lenses, whereas "2x" would imply a telephoto adaptor.
In the "Pentax world", the former is usually M42-PK, the manufacturers' own product often being recommended as the most reliable.
For telephoto adaptors, the initial question would be "Which lens do you want to use it with?" … a final maximum aperture of at least f/5.6 being quoted as necessary for reliable a/f operation.
Obviously "reasonable price" will be a very subjective matter … quality (if such an attribute can ever be ascribed to a telephoto adaptor) never comes cheap

[marcusBMG]

Hiya Bruce (fancy, being called Bruce from OZ?..) welcome.
Pretty much I would advise not bothering with 2x teleconverters. On digital you are better off just cropping the image. For longer telephoto focal length there are cheap manual focus options that will do better than a basic lens + tc. If you are still keen on trying tc's out then one to get might be the vivitar etc 2x macro tc - its one of the better 7 element ones and has a macro focusing helicoid incorporated, which is interesting to use with eg a good fast 50mm.
K mount and M42 mount lenses are easily usable on all pentax dslr's, the latter with either the compact adapter that keeps infinity focus, or a flanged adapter. OM, CY can be made to fit with a bit of modding of the lens mount, or with a 3rd party "adaptist" mount on the camera. Otherwise forget it.

[mlag]

If you want a tele convertor (TC)
& maintain autofocus capability
& maintain light/aperture control
on any modern pentax lenses (with electrical contacts in lens mount)
then the best option is the latest pentax 1,4x hd da convertor.
It offers decent 1,4x magnification, good optical quality, and the convenience of full transparency of lens information for focus, aperture etc control.

Other older or offbrand convertors are not offering full electrical contacts and not the correct (extended) focus length calculation towards camera..., hence are more for manual lens control and older manual lenses without contacts...

There are some pitfalls with teleconvertors:
- they change the maximum aperture of the lens => a f4 lens behaves like f5.6 with 1,4x TC and f8 with a 2x tc. If you start with a lens like the 55-300 with f6.3 at 300mm, you get f8 or f11 with a TC. This f8-f11 is the point where the autofocus system of the camera doesn't get enough light to allow reliable focus (so will hunt), except maybe on a sunny day with the latest camera’s...
- a TC magnifies not only the image ( and multiplies the focal length as you expect), but also all lens ’faults or imperfections’. A cheap tele lens with a TC will behave like a much cheaper lens... a lens that is decent sharp wil become soso sharp or slightly unsharp, slight purple fringing will become obvious purple fringing etc...

So to be successful with TC’s in general, it is better:
- to start with a f2,8 or f4 lens
...and a good image quality lens (a zoom is perhaps less good than a prime lens here)
- use a modest 1,4x rather than 2x or 3x magnification
- check if a matching TC exists for your lens. Or respect the target focal length : some TC’s are intended for shorter lenses, other for longer teles.
- don’t expect miracles. A native 400mm or 500mm lens will outperform a TC+lens combo of similar focus length.

Pentax DA Teleconverters - Lens Reviews and Specifications - SLR and Interchangeable Lenses - Pentax Lens Reviews & Lens Database

Pentax K-mount Teleconverters and Adapters - Lens Reviews and Specifications - SLR and Interchangeable Lenses - Pentax Lens Reviews & Lens Database

Note also that tele's (native or with a TC) of 400mm or more need a steady hand or tripod, and high shutter speeds to reduce motion/shake blur (like 1/500 or faster) because they are much more sensitive to lens vibrations (shutter pressing, mirror shake, ...). With a TC that results in f8 or so aperture, it is difficult to obtain these 1/500 or faster shutter speeds.

A worthy alternative are second hand (up to 400-500mm-ish) zoom tele’s...like the sigma’s or older pentax models...which can be found if patient on secondhand lens shops.

[bentleyroyce5]

Hiya Bruce (fancy, being called Bruce from OZ?..) welcome.
Pretty much I would advise not bothering with 2x teleconverters. On digital you are better off just cropping the image. For longer telephoto focal length there are cheap manual focus options that will do better than a basic lens + tc. If you are still keen on trying tc's out then one to get might be the vivitar etc 2x macro tc - its one of the better 7 element ones and has a macro focusing helicoid incorporated, which is interesting to use with eg a good fast 50mm.
K mount and M42 mount lenses are easily usable on all pentax dslr's, the latter with either the compact adapter that keeps infinity focus, or a flanged adapter. OM, CY can be made to fit with a bit of modding of the lens mount, or with a 3rd party "adaptist" mount on the camera. Otherwise forget it.

I've got a 2x adaptor simalar to this but the auto focus side does not operate on the KS2,
Thanks for your advice & keep shooting great photo's

[UncleVanya]

Hi ALL

I'm new here need help / assistance with lens adaptors on KS2 2x adaptors for what will work on my lenses & where to get good onesbut as a reasonable price?

There are 1.4x and 1.5x af ones that aren’t too expensive and work well. Which lenses are you interested in using a teleconverter with specifically?