This may be a total noob question...

My dad had a decent Pentax 35mm SLR (I forget the model but it had AF etc. and was moderately fancy for the time) with a couple of good lenses. I believe I can buy a digital body & re-use the lenses which should get me a decent setup for low outlay.

eBay lists categories of Pentax bodies: K Body, Q Body and "Lithium ion" body, can anyone tell me the differences between these?

Also, which would be a decent pick 2nd hand as a solid basic digital body? I don't need bells & whistles or "more megapixels".

Edit: Just to follow up, I've dug the gear out and the list is as follows:

  • SFXn 35mm body
  • 1.7x AF Adapter
  • Manual 50mm lens
  • 28-80 1:3.5-4.5 AF lens
  • 70-210 1:4-5.6 AF lens
  • Tamron Tele-Macro 100-300 1:5-6.3 AF Lens

I've asked a new question about what I've got and how useful it is.

  • 1
    \$\begingroup\$ Do note that although almost all K-mount lenses will work on a modern Pentax DSLR, the older varieties will not be as fully functional as the newer ones. The most obvious is manual focus versus autofocus. Not so obvious is accurate metering with the lens wide open (as pretty much all modern DSLRs do with modern lenses). The Pentax K-mount entry at Wikipedia gives a pretty good rundown of the various sub-variants of the K-mount as increased functionality was added over time. \$\endgroup\$
    – Michael C
    Jul 5, 2017 at 3:02

3 Answers 3


Pentax introduced autofocus with their K-mount, so the camera in question is most likely to use that mount. Before that, they used a screw-mount, so you should easily be able to tell which you have.

Pentax has the reputation of one of the best compatibility with legacy lenses. Pretty much any Pentax (or third-party) K-mount lens built since 1970 can be used on a Pentax DSLR. All of them have model numbers starting with K: K-1, K-5 IIs, K-70, K-200, K-P, etc. Generally speaking, fewer digits are used with higher-end offerings, which means more direct controls.

The obvious choice for legacy Pentax lenses is a K-1 which is the flagship DSLR and the only full-frame one in the line-up. It is expensive but will use legacy lenses with the same field-of-view as on a film body.

All other Pentax DSLRs are APS-C which means that the field-of-view of lenses gets reduced by 1.5X, so everything will appear more zoomed-in. The K-5 IIs is spectacular in this category but a K-5 II and K-5 is almost as good. The K-7 is one generation older but still very good.

There are Q-mount cameras which use a completely different mount. This is not popular and there is often a rumor circulating that it has been silently discontinued. It has a huge crop factor, 4.6X to 5.6X, depending on the model, so adapted lenses significantly longer. Image quality is also rather low as it is akin to an ultra-compact.

Lithium-Ion is a type of battery, nothing to do with the body. Nearly all digital cameras on the market (if not all current ones) use this type of battery but older models, until the K200D also supported standard AA batteries which could be Lithium, Alcalin or, more commonly for rechargeables, NiMh. The last two models that supported AAs also supported Lithium-Ion batteries which have less capacity but are at least rechargeable when compared to plain Lithium AAs.

  • 1
    \$\begingroup\$ Excellent answer thanks. The lenses aren't screw mount so must be K-mount. I do realise LiIon is a battery, just wondered if it was eBay being weird or if there was a separate line of bodies due to some odd battery design. I can't justify an expensive body at this point, I'm ditching a Canon POS, sorry, P&S as I have a smartphone that whips it for everyday use so the DSLR would be for occasional fancy use only. \$\endgroup\$
    – John U
    Jul 4, 2017 at 12:07

K Body, Q Body and "Lithium ion" body, can anyone tell me the differences between these?

Q mount is a not very popular small sensor ILC mount that Pentax developed and, I think , still sell. It's not compatible with SLR or DSLR lenses. Forget it entirely - most people have.

K mount is the generic name for the Pentax SLR/DSLR mount.

It has evolved over the years but with possibly a handful or rare exceptions you can physically mount and use any K mount lens on any Pentax DSLR.

The PentaxForums.com website has extensive information on the K mount and most things Pentax.

I've used both Pentax film and DSLR bodies and I've used ancient (but lovely) 50mm f1.7 'M' lenses (the original bare-bones K-mount fully manual) on my K100D and K10D without problems.

Note that Ricoh (long ago) used a version of the K-mount which you'll sometimes see lenses with. These lenses should be avoided ! They can "lock" into the body and be very hard to remove.

Most Pentax bodies have a way of metering (or forcing metering) with even the most basic M lenses (of course you still have to set the aperture !).

"Lithium-ion" refers to the fact that many Pentax DSLRs can/did use rechargeable AA batteries instead of proprietary lithium-ion batteries. At least one model (maybe more) can use either.

Typically lithium-ion batteries have a larger charge and some people don't like AA's. However you can't just run down to the supermarket and buy a spare Pentax lithium-ion battery for your DSLR in an emergency, whereas you can buy precharged AA NiMh long-lifes (like enloops) all over the place. As flashes often (always ?) take AA's I prefer them myself as I can pack a bunch of them in my kit bag and I'm good to replace whatever I need quickly (and a small recharger lets me replenish them from a wall socket).

Also, which would be a decent pick 2nd hand as a solid basic digital body? I don't need bells & whistles or "more megapixels".

Avoid the K110D because it has no sensor based stabilization. I'd avoid the older pre-K models as well for the same reason (although they're all good solid stills cameras otherwise).

Avoid the K-x DSLR if you expect to mount manual focus lenses or want to use manual focus. The reason for this is simply because Pentax removed the visual focus confirmation in the viewfinder from that model. It's otherwise a very nice DSLR with (I think) the same sensor as the Nikon D5000 but the much nicer (IMO :-)) Pentax handling.

Before I'm assassinated by Nikon fanboys, I did own a D5000 and I liked it, it's just that for me the handling on Nikon's never felt as natural as Pentax models.

If you don't need megapixels I'd consider any other Pentax DSLR. For a modern level of good ISO and dynamic range I'd suggest something from the K-R onward, but if you're OK with pre-D5000 levels of ISO and dynamic range (and I shot a wedding a few years back with a K10D) I'd go for a K10D, K200D or K100D. The K200D is basically a cut down K10D, but is water resistant (!) and uses the same sensor as the K10D. The K100D is only 6Mp but as it was the first DSLR I felt entirely natural handling, I have a soft spot for it. Took some of my favorite personal shots with it as well, including some with my beloved Pentax 50mm f1.7 M.

An alternative approach is to grab a MILC, ideally one with focus peaking and a decent EVF, and use a simple adapter to mount you Pentax glass.

The MILC approach has an additional advantage : you can use focal reducers to restore the full frame use of your lenses (as most Pentax DSLRs are crop frame). I've done this myself with a Sony NEX F3 and both dumb-simple adapters and focal reducers (cheap eBay ones). A very satisfying way to shoot if you're good with manual focus (which is OK with focus peaking). Handling is quite different from a DSLR, but it was a painless adaptation for me.

The MILC approach is quite good for fun. I'd probably avoid it for anything serious (indeed I did avoid it when I shot that wedding with a K10D, as I had been using my NEX for quite some time).

I'm not really a video person so I have no real idea what video capabilities the Pentax bodies have. If you need video I'd grab a Sony NEX MILC or possibly a Panasonic GH model if you're OK with the smaller sensor.


To a first approximation, old Kmount lenses are compatible with current Pentax SLR's (there are a few edge cases). Pretty much any "K" series digital SLR will be OK. Choosing which one is a matter of budget and goals and preferences around new versus used and warranty versus no warranty.


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