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multiweb
08-09-2008, 11:30 AM
I've got a Pentax *istD. Recently I bought an adapter to fit my Lens on a QHY8. I'm now enquiring about Pentax Lenses in general. Are they all standardised using the same bayonet attachement, even the newer models or is it something that changed over the years. I have no idea if lenses are interchangeable from camera to camera within the same brand. Thanks for any help.

erick
08-09-2008, 12:20 PM
While we are waiting for the experts, my understanding is the the Pentax-K mount has stayed standard mechanically since the K1000 in the 70s. So the lenses I bought then for my KX should fit on a modern Pentax and perform satisfactorily, as far as aperture operation goes. However, all the mod cons like autofocus etc. won't be available, of course. Plus, of course, the effective focal length changes as per the ratio of CCD size relative to 35mm film. While I've been pondering whether to buy a K100D body, I notice the K200D is out. While I ponder that one and save my pennies, it will probably be superceded as well! :D

Dennis
08-09-2008, 12:27 PM
Hi Marc

Just to add to Eric’s burst above, I have 3 generations of Pentax K mount lenses:

A Pentax, 50mm F1.8 (c1976): This requires manual focusing and manual setting of the aperture.
A Vivitar Series, 1 80-200 (c1985): This requires manual focusing but I can set the Aperture ring on the lens to “A” for automatic.
A couple of Sigma kit lenses that came with my *istDS: Full auto focus, etc.

However, IIRC, you need to make a change in the Menu settings somewhere to allow manual focus, non-auto aperture lenses to work.

Cheers

Dennis

dugnsuz
08-09-2008, 12:59 PM
Early models have a screw (M42) mount, later models have the K (bayonet) mount. An adapter is needed to attach the screw mounts onto your DSLR.
Here's a good link for all things Pentax...
http://www.bdimitrov.de/kmp/lenses/
Doug

erick
08-09-2008, 01:13 PM
I'd forgotten it was named the M42 mount - how about that! Anyway, I've only ever had K mount.

TrevorW
08-09-2008, 04:43 PM
Pentax DSLR cameras are supposed to accept all the K mount lenses, the manual does have a list of compatible lens.

Although in hindsight I would have purchased a Canon camera as Pentax do not support remote assistant for a number of thier camera's.

Podger
08-09-2008, 05:27 PM
I am also looking at a DSLR and while most everyone seems to look only at the Canon I have a Pentax SF7 with K mount lenses so was interested in getting a Pentax DSLR so the lenses didn't go to waste. My local photographic dealer is also into Astronomy and he recommends the Pentax K20D which is a lovely camera and has live view and remote control. However I don't know if it gives the same level of control as the Canon from a laptop. The Canon 40D is reviewed in BBC Sky at Night June 2008. The reviewer concludes "For the purpose of astroimaging, the 40DH is a dream DSLR." The "H" is the Hutec modification to replace the ir filter. I expect details on what the Pentax K20D software can do is on the website www.pentax.com.au (http://www.pentax.com.au). I haven't taken the time to look it up yet.
I noticed in a seperate thread a discussion on lenses - kit one's with the camera vs Sigma, Tokina etc. I have a Pentax and a Tokina lens and the Tokina is better for sharpness. Haven't tried them for astro so don't know how the CA compares.

multiweb
10-09-2008, 12:06 PM
Many thanks for the extra info and links guys. Much appreciated. :thumbsup:

space oddity
10-09-2008, 10:48 PM
In my day , I was a real camera maniac. 8 Pentax bodies and a good 20 lenses ranging from several fisheyes through to the bazooka 500 f/5. All these lenses are compatible in manual mode on DSLRs , had to tweak the settings on my intro DSLR K10 D to get it to work with my old glass. To throw a spanner in the works, it is possible to get an adaptor to use Pentax lenses, both screw mount and K bayonet (may need to remove a pin from the rear of lens) to use these lenses on Canon DSLR bodies . Do note that the sensors prefer their photons to be close to parallel , whereas film does not matter. Edge performance will be better with DSLR designed lenses as opposed to 35mm format lenses. With time, curved sensors will eliminate this problem, so hold on to the old class glass. Canon DSLRs cannot use the old FD lenses:( , but Canon are market leaders and independent lens manufacturers, especially Sigma and Tokina make lenses for Canon and Nikon , but not always for Pentax:(:(:(. If I had my time again on the digital, I would likely make the painful decision to dump the trusty old Pentax.