Pentax owners, please help me understand Kaf2 mount limitations and lenses I can use

m8o

Hello hardware-o-phites... To those who have K10Ds (edit: or K100 etc), or anyone who may know. I'm having trouble understanding exactly which lenses I can not use with the K10D, K100, etc...

Given this Pentax Lens Family Tree:
http://www.bdimitrov.de/kmp/technology/summary/index.html
....I know I can use all Kaf2, Kaf, and Ka lenses from the manual. I understand older lenses can be used too though? Or not really...? edit: I know about the need for lenses with the 'A' lock, but I understand other lenses 'can' be used. I'm having trouble understanding the caveats to all that.

I was thinking of buying a nice old fast SMC K mount lens. The seller said they think the K10D needs the Ka and just a K mount would not work.

But is it just that this 'mod' is needed to 'mask' the '*' contact?
http://www.bdimitrov.de/kmp/technology/K-mount/crippled.html

So 'can' I consider old 'K' lenses? I assume it'll be totally 'manual' though, correct? I think though if I win a 1.7x AF TC on eBay, this lens will get some rudimentary AF functionality, via the 'green' AF button... yes?

I hear praise about old Pentax fast lens (great 'zoo' lens w/1.5x crop of d-slr and/or TC). If I get a f/1.4 or f1.8, even if used with a 1.4x, 1.7x TC I have it'll be a fast prime lens with nice reach; with 2.x TC it'll still be faster then the Sigma 100-300mm f/4 I'm getting (though yes, not by much).

Thoughts & recommendations? Thanx for reading and any assistance that may be offered.

stuffjunkie

K10D and all those old lenses...

m8o wrote:

Hello hardware-o-phites... To those who have K10Ds (edit: or K100 etc), or anyone who may know. I'm having trouble understanding exactly which lenses I can not use with the K10D, K100, etc...

Short answer: None
All Pentax lenses will work (some with reduced fuctions) on your K10D. Note, Ricoh mount lenses can bind on the camera even though it is generally thought to be compatable with PK mount.

You will want to set the Use Apreture Ring setting to Yes. Check your manual or shuffle thru the menu settings to find it. It has no effect on DA (DA*) lenses and those other lenses with the apreture set to "A". This setting will make older lenses useable.

Screw mount (m42), 645 and 6x7 lenses mount using a special adapter for each type/size. Manual focus, manual apreture only( stopped down metering) and only work in Manual M mode.

K & M mount lenses (and those above) need that Use Arpeture Ring setting ON. Manual focus of course. They only work in M mode. To get a meter reading you press the green button. Set your apreture & shutter speed (focus, compose etc...)and you're good to shoot.

A lenses are manual focus (of course) and have more functionality when set to "A". Off the "A" setting they will work like M lenses above.

When you mount a lens w/o electrical contacts the K10D will ask for a focal length to use with SR. SR with every Pentax lens ever made!

Given this Pentax Lens Family Tree:
http://www.bdimitrov.de/kmp/technology/summary/index.html
....I know I can use all Kaf2, Kaf, and Ka lenses from the manual. I understand older lenses can be used too though? Or not really...? edit: I know about the need for lenses with the 'A' lock, but I understand other lenses 'can' be used. I'm having trouble understanding the caveats to all that.

I was thinking of buying a nice old fast SMC K mount lens. The seller said they think the K10D needs the Ka and just a K mount would not work.

But is it just that this 'mod' is needed to 'mask' the '*' contact?
http://www.bdimitrov.de/kmp/technology/K-mount/crippled.html

So 'can' I consider old 'K' lenses? I assume it'll be totally 'manual' though, correct? I think though if I win a 1.7x AF TC on eBay, this lens will get some rudimentary AF functionality, via the 'green' AF button... yes?

Sure! You need to have the focus~in the neighborhood and the AF1.7x will do the rest. Nice fast lenses are the best here...past f/5.6 it will have problems (YMMV)

I've used a AF1.7x with a 300mm (so that's 510mm, crop= 765mm!!) A nice zoo lens.

I hear praise about old Pentax fast lens (great 'zoo' lens w/1.5x crop of d-slr and/or TC). If I get a f/1.4 or f1.8, even if used with a 1.4x, 1.7x TC I have it'll be a fast prime lens with nice reach; with 2.x TC it'll still be faster then the Sigma 100-300mm f/4 I'm getting (though yes, not by much).

Thoughts & recommendations? Thanx for reading and any assistance that may be offered.

Hope that helps a bit

m8o

Thank you very very much. Yes, very comprehensive and I appreciate it.

One final follow-up perhaps? Are there any instances where the internal exposure meter doesn't function and I'd need an external light meter? I thought I read about instances with particular lenses but I can't find those given all the searching and reading I did over the months.

Thanx again!

Miguel Delinquento

m8o wrote:

One final follow-up perhaps? Are there any instances where the internal exposure meter doesn't function and I'd need an external light meter? I thought I read about instances with particular lenses but I can't find those given all the searching and reading I did over the months.

The only situation where you will have problems are with certain M42 lenses that do not have an Auto/Manual switch. These will only work wide open because they lack the capacity to be stopped down by the Pentax body. The meter works at the maximum aperture, but that is not very functional to me. Fortunately these lenses are not that many. Be sure to ask sellers about the switch as a way of quickly establishing your risk.

Fully functional use of classic old lenses is one of the pleasures of being a Pentax DSLR owner. I prefer the "A" automatic lenses, but have plenty of "M" and M42s. The latter work well in AV mode, you just have to purchase the Pentax brand of adapter--not a knockoff. The color rendition is certainly a bit different form modern computer-designed lenses and the sharpness can be very similar.

Use of "M" manual lenses require a bit more work in that you have to press a button to revise the meter reading every time you change the aperture. My favorite "M" lenses are the sharp 135 f3.5 (very cheap still) and the Russian Zenitar 16mm fisheye which becomes more of an ultra wide. Very well built, and surprisingly sharp, and lots of fun. Super cheap on the big auction site. You really only have to set it on f8 and get your shutter speed right.

One final thing, if you use the flashing red in-focus indicator lights with your DSLR, realize that that function will work fine with old lenses.

m8o

That's really helpful. Thank You! I really appreciate the advise on the adapter needed too. I see a lot of "screw mount" and other (6x7) lenses selling, and am at a loss to whether they can be used, what I need, and how they act. I appreciate the primer. I need to research and will soon. Again, really appreciated, thanx.
-steve
edit: p.s. I'm quite sure the next lens (in addition to something real long and kinda fast) I'm getting is a 1.4 FA , for low light auto-focus that I know I won't be able to to 'by eye' with a manual.

Miguel Delinquento

Another focusing aid
You are welcome.
I just got a hold of a FA 50 f1.4 used for a song. Excellent. I must admit to not being a big fan of autofocus. I don't like surrendering that bit of control, though it is nice for snapshots. I almost always shoot AV or M.
I still use a classic, M42 SuperTakumar 50mm f1.4 which is also quite sharp. I don't have many problems focusing in lower light. The FA50 will replace this due to its superior lens coatings, but the color rendition of both lenses are very pleasing.
Earlier this year I purchased a split-screen from a Chinese website. Works quite well, especially for <$30.
Being an old SLR guy, I like old technology like that and a big bright viewfinder for aging eyes.

m8o

My problem I discover is I wear glasses. I can't get my eye close enough to the viewfinder with them on; or I bend the nose piece or create other damage keeping them on. When I take the glasses off, I can get the eye right into the viewfinder, but unless using a tele lens, I can't see sharply enough to be able to manually focus. :cry