KA Mount on KAF/KAF2 Bodies
At least that is my understanding of it having read the manual and looked up various things.
When I put a F or FA lens (KAF mount) on my MZ7 with the camera set to Manual and the Aperture set manually, the Aperture information appears in the viewfinder. What I was trying to ascertain was whether it was possible to do this with a Prime KA mount lens. I know that it is not possible with a Zoom that has a variable maximum aperture, but what about with a Prime?
* If you select the aperture manually from the camera with the lens aperture ring in the "A" position - the f-stop will be shown.
* If you manually select the aperture from the lens, then older bodies will display the aperture. Newer bodies (including dSLRs) cannot display the aperture.
On the original KAF mount the select aperture was sent to the body by a mechanical "finger". The body would detect the position of this "finger" and linked it into the exposure system.
Some of the 35mm cameras had this linkage (my old MZ-5 and Z1 both had this) and could display the information.
On the new "crippled mount" bodies, this mechanical linkage is not fitted and consequently the body has absolutely no way of knowing where the aperture ring is. It's physically impossible.
...but then most of those bodies allowed selection of the aperture from the body - at least for A, F and FA lenses.
HTH!
Matt
(For gallery, tips and links)
I know the camera already offers lots of options, I guess I am showing my age and hankering after old fashioned manual with modern viewfinder info
Thanks - Steve
I know the camera already offers lots of options, I guess I am showing my age and hankering after old fashioned manual with modern viewfinder info
The MZ3 is perfect for combining modern readout and viewfinder with traditional shutter speed dial and, if desired, manual operation. The slightly older MZ5/MZ5n cameras are also very similar.
...whether I could mimic the KAF lens behaviour with a KA lens by possibly changing some of the contacts.
Not as far as I know
I seem to remember (it was a looong time ago), I had a Tokina lens that would work manually on my Z1 but not on an MZ5 - bizarre! (I did wonder if there are mechanisms for reading through the contacts digitally, but I can only find evidence for the aperture being read through the "finger".
Not that it helps....
There's quite a bit of K-mount info on: http://www.bdimitrov.de/kmp/
Matt
(For gallery, tips and links)
I always assumed the digital contact on the FA series allowed the camera to read the aperture info electronically, but if this is the case I wonder why they don't make use of this ability on the *ist and K series?
If you can set all A and newer lenses to A on the lens, and set the aperture on the camera body (depending on camera) and see the information you want in the viewfinder or top plate, why would you want/need to set the aperture ring to anything other than A (other than habit) ?
Question:
If you can set all A and newer lenses to A on the lens, and set the aperture on the camera body (depending on camera) and see the information you want in the viewfinder or top plate, why would you want/need to set the aperture ring to anything other than A (other than habit) ?
On the K10D and anything else with twin selector wheels, no real reason, other than habit as you say and some people just prefer to change aperture with the right hand. Everything else about the K10D is geared towards letting you work the way you want to, why not this? I'm playing devils advocate there a bit, since the new lenses have no Aperture ring anyway people should probably get used to not using one!
On the MZ-7, because it's faster. The MZ7 doesn't have a proper selector wheel, just a toggle switch which makes going from stopped down to wide open quickly a right PITA, it's much faster to just grab that aperture ring and give it a good twist.
Also its a great way to switch from any mode to Av at the drop of a hat. I've been known to use the Aperture ring to switch to Av wide open nice and quickly even on my *istDL2.
Add Comment
To leave a comment - Log in to Pentax User or create a new account.
984 posts
17 years
Cornwall,
UK