Nikon AI / AIS Curiousity

tb_a · Expire: 2019-08-28

Gardener,

The thread began about "quirky" communication between Nikon bodies and certain lenses. I am everything else but a Nikon expert. However, there is at least a camera which is able to communicate with all lenses ever produced by themselves.
I do have Pentax cameras and all lenses form their different production lines. The only MF lenses which are working as designed on digital Pentax are their SMC-A lenses. There is no doubt about that.
If any other MF lenses are being used then at least there is no communication at all between the lens and the body. Furthermore the old K-mount lenses will not meter correctly as the lens stays always fully open when mounted on camera. The only way to change this, is to "modify" the lens mechanically. However, as soon as you make this, the lens will not work correctly also on old Pentax film bodies as then only the stop down method (like M on the old M42 lenses with M/A switch) will be possible.
So, there is a Nikon capable of communicating with the old lenses or maybe some other Nikons too. I don't know and I don't actually care.
But there is definitely no Pentax available which is able to communicate with other lenses than the Pentax-A lenses. Though other lenses are also somehow usable, some better and some others not.
From my point of view Nikon has done the better job.
If Pentax will come up with a FF digital SLR, then it will be interesting again for me whether they have done something about or not. Until further I don't bother any longer as I prefer to use my Sony FF DLSR instead, where at least all the M42 lenses are compatible the same way like on Pentax DX-DSLRs.
I have also no problem when you have a different conception or believe.
Have a nice day.

scsambrook · Expire: 2011-11-18

t b_a writes
that I do have Pentax cameras and all lenses form their different production lines. The only MF lenses which are working as designed on digital Pentax are their SMC-A lenses. There is no doubt about that.
If any other MF lenses are being used then at least there is no communication at all between the lens and the body. Furthermore the old K-mount lenses will not meter correctly as the lens stays always fully open when mounted on camera. The only way to change this, is to "modify" the lens mechanically. However, as soon as you make this, the lens will not work correctly also on old Pentax film bodies as then only the stop down method (like M on the old M42 lenses with M/A switch) will be possible.

I'm not sure if this is really correct - On my old K100d I get good exposures using the PK lenses with manual metering - that is, 'stopped-down' using the control ring which surrounds the release button. On my K30, I get good exposures using the 'green button'. I'm happy to say this is less convenient than seems to be the case with the Nikon models mentioned (which I've never used) but there's no need to make any mechanical alterations to the lenses. I know you have to tell the camera the focal length if you want it in the EXIF data, but not doing so has no effect on operation.

Let me say that I hope I've not misunderstood what was written - as usual, I've no wish to get into an argument but I worry that less experienced forum members may be left with a false impression of how older lenses work on newer Pentax DSLRs.

And somebody mentioned Nikon Pronea - Hey! I had one of those and thought it was great, within the limits of the APS system Very Happy

tb_a · Expire: 2019-08-28

Stephen,

Having studied my manual again and taken into consideration what you are stating here I have to admit that I now finally found the method with the ring around the aperture button. The trick is to hold the ring in that position manually for metering in M-mode only.
So you are right. Thanks a lot for that enlightenment!
Maybe Pentax digital cameras are way too complicated for me?
Fortunately I've ruined only 1 lens up to now (Takumar 135mm F2.5 Bayonet) and simply stopped using the other lenses on the K20D. Wink

At least for me this little controversial discussion was quite helpful and I might use my Pentax more often in future.... Smile

Nevertheless, the aperture setting is unfortunately not recorded in the exif. It's just the far better way to use the "stop-down" metering for non-Pentax-A K-mount lenses. Though I still have no advantage of using those lenses on Pentax compared to the usage on Ricoh or Sony. Sad

Oldhand · Posted: Wed May 27, 2015 11:40 am Post subject:

At least both Pentax and Nikon have continued to support their classic lenses to a point that other manufacturers have not.
Being able to use the Nikon F mount and the Pentax K mount right up to the current DSLR versions is a big plus.
Well done Pentax and Nikon
OH