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Old Feb 11, 2007, 7:27 PM   #1
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I'm a complete novice with regards to the slr world (digital and film) and am looking to purchase a k100d here in the near future. One advantage that people say about the k100d is that you can use old lenses on the new bodies. I was trying to research exactly what type of lenses would work. I see that there are k mount and ka mounted lenses. One site says that "k" mounted lenses would work but with some restrictions. It also said that there weren't any restrictions on the ka's. Can anybody help me out as to what would be the most common fit for the k100?
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Old Feb 11, 2007, 8:23 PM   #2
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I'm still a bit confused about this as well, but as I understand it, K-mount lenses are the basic, fully manual bayonet-mounted lenses. KA lenses use the same bayonet mount, but have some contacts on the mount so the camera can automatically control the aperture. KAF lenses are like KA lenses, except there is additional contacts so the camera can also control the focus automatically.
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Old Feb 11, 2007, 9:00 PM   #3
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Its a matter of AE/AF vs AE only, as far as I can see. There might be fully manual plain K cameras but I think most were at least AE.
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Old Feb 11, 2007, 9:03 PM   #4
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Briefly you have the following lenses when you are talking about K-mount lenses:

- K or M lenses are manual lenses. The camera needs to be set to M mode, you set the aperture on the lens, focus manually, and push the AE-L button so the camera can temporarily stop down the lens and meter. There is a nuance to this, but this is the basic way to get them to work. There's a lever on the lens that the camera uses to stop down the lens when you push the shutter (this allows you to focus with the lens wide open).

- A lenses are auto exposure and manual focus. Theyhave electronic contacts that can talk to the camera. You set the lens to the "A" setting on the aperture ring and the camera will set the aperture on the camera.

- F lenses are auto exposure and auto exposure. You will have the same functionality with an F lens on a K100 as you would an FA lens.

- FA zoom lenses have an added power zoom function that sounds neat. The K10 is the first digital camera that supports it (there are several top-of-the-line film cameras that they were designed for). I don't have any of these lenses, so can't address how they work.

You can also use screw-mount lenses but need a screw mount to K-mount adaptor. The camera can't even stop the lens down (like they can with a K or M lens) so you either have to focus with the lens wide open then stop it down to the aperture you want, or try to focus with the lens already stopped down (the viewfinder gets really dark).


P.S. You can use FA lenses on the K100 with auto exposure and auto focus, you just won't have the power zoom function.
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Old Feb 11, 2007, 10:19 PM   #5
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Power zoom is sort of a useless thing IMHO.... unless it is variable speed.

One thing I don't miss about the P&S's... all power zoom.... and rather impercise.

AE and AF the camera can do much faster than I.... but zoom... no I can do that much faster and precisely than any power zoom I have ever delt with. (and the only thing you have to do mormally for most shots with good adaptive AE/AF)
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Old Feb 11, 2007, 10:50 PM   #6
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mtngal wrote:
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*- F lenses are auto exposure and auto exposure.* You will have the same functionality with an F lens on a K100 as you would an FA lens.
I think you mean F lenses are auto exposure and auto focus.
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Old Feb 12, 2007, 7:52 AM   #7
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Yes - what I get for staying up too late last night! F lenses do offer auto focus and auto exposure.
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Old Feb 12, 2007, 10:32 AM   #8
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Maybe this will help, you'll find these tables in the manual and our user reviews of Pentax digital SLRs. Only DA and FA J lenses and D FA/FA/F/A lenses having an "A" position on the aperture ring can be used.

[align=center]Compatible Lenses[/align]




[align=center]Aperture Ring Use[/align]

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