[joodiespost]

Its on ebay for 229 buy it now price. Is this a great buy? If so, will this fit on my K-x out of the box?

Thank You

[joodiespost]

And also, this seems to be a major problem for me as I am new to photography whatsoever. How would I know, in other words what would I look for in a different manufacturers lens to know that it fits the K-x? Obviously, Nikon and Canon APS-C sizes doesn't fit the K-x even though the K-x is an APS-C.

Any help would be appreciated ^^

[Eds]

Joodie- I have that lens in K mount on a istDS Pentax. Good basic lens giving quite acceptable IQ. Good lens for achieving maximum focal length range at an affordable price. I would say $229 is a fair price as long as it is in good condition. Eds

[joodiespost]

Thank you Eds for the reply. This might sound dumb but I am a noob. Other than this lens, how would I know if a particular manufacturers lens [other than pentax] with be compatible with my K-x?

[msatlas]

Each brand of camera has its own lens mount. The third-party lens companies (i.e. Tamron, Sigma, Tokina, etc.) make versions of their lenses in each different lens mount. So to get one that works on your K-x you need one that's made in Pentax mount.

The Promaster you've mentioned is actually a Tamron lens re-badged as a Promaster.

Also just a suggestion if you're looking for something to be an all-around lens with a high zoom factor then you may want to consider something that starts at 18mm. This will be a true wide angle on a K-x. Examples:

Tamron 18-200mm f/3.5-6.3 XR Di-II LD Aspherical IF Macro / Promaster 18-200mm f/3.5-6.3 Digital XR EDO Aspherical (these lenses are identical)
Tamron 18-250mm f/3.5-6.3 Di-II LD Aspherical IF Macro / Pentax SMC DA 18-250mm f/3.5-6.3 ED AL [IF] (these lenses are *mostly* identical)
Sigma 18-200mm f/3.5-6.3 DC
Sigma 18-250mm f/3.5-6.3 DC OS HSM

I think the cheapest one is the Tamron/Promaster 18-200. As for whether any of these is a "good buy," well, I'll leave that for someone else.

[Marc Sabatella]

If it says its for Pentax, it fits your camera. It if is a very old manual focus lens and says "M42" or "screwmount" on it, you need an adapter. But otherwise, it works as is. If it's a manual focus focus (will say so in the description), it won't autofocus, of course.

[joodiespost]

Thank you both for the informative answers. Lens compatibility has always been an irking little stumbling block for me.

Gomawayo ^^ [ty in korean]

[Stratman]

you might want to check the marketplace here for a similar lens, I scored a Sigma 28-200 in pristine condition for $50 or $60 , and for the money, it is not bad at all...

[joodiespost]

ty, ill keep that in mind

[Laurentiu Cristofor]

Lens compatibility has always been an irking little stumbling block for me.

Well, I think with Pentax, you have the easiest job. You can make some use of any lens that ever worked on a Pentax camera. It's much easier than for Canikon.

Some things to keep in mind are:

- M42 lenses need an adapter - look for either those with preset aperture or with an Auto/Manual switch - ask here for details once you need them
- Old lenses will be manual focus, so keep that in mind if AF is important for you
- Lenses without an A aperture setting are a bit trickier to use - you'll need to use them in M mode and determine the exposure using the green button

When getting lenses of ebay, make sure to check the following:

- no fungus
- no scratches
- aperture and focusing rings move smoothly
- iris blades close fast and don't stick
- auto/manual switch is not stuck

I managed to see fungus, sticky aperture (iris) blades, and a stuck A/M switch, so these issues do come up, especially with older lenses, so it's better to ask the seller in advance.

Hope this helps

[joodiespost]

thank you for the info, it's so refreshing to know what to look for now with all you guys' help ^^

edit: another question popped up ^^, If i see two lenses that are both 100mm. Priced around the same with more or less similar specs, wouldn't it make more sense to purchase the one with macro functionality over the one without? Or will there be some kind of IQ difference because of the "macro" ability of the other lens? If there is no IQ difference, what would be some of the technical differences be due to one having macro and the other not?

another side question is, would it be okay to purchase a 2x TC for my kit 18-55 lens on the K-x?

Thank you

[Laurentiu Cristofor]

Two 100mm with same maximum aperture at the same price, and one is macro? I don't think you'll see that. Macro lenses are usually considerably more expensive than a non-macro counterpart.

For the TC - no, it's not worth getting it for your 18-55. There's little point in transforming your kit lens in a 36-110 zoom that is twice as slow - you'll probably lose AF capability too. Get a faster longer zoom instead, especially since a good TC is not really cheap. Look into TCs for extending longer lenses, where the resulting lens would be way more expensive than the price of the additional teleconverter.

[joodiespost]

Two 100mm with same maximum aperture at the same price, and one is macro? I don't think you'll see that. Macro lenses are usually considerably more expensive than a non-macro counterpart.

For the TC - no, it's not worth getting it for your 18-55. There's little point in transforming your kit lens in a 36-110 zoom that is twice as slow - you'll probably lose AF capability too. Get a faster longer zoom instead, especially since a good TC is not really cheap. Look into TCs for extending longer lenses, where the resulting lens would be way more expensive than the price of the additional teleconverter.

thank you, so what are some of the differences we will see between a macro and non macro lens with the same focal length? Would one model sacrifice the aperture to become a macro? Any explanation would be appreciated ^^

Thank you

[wallyb]

thank you, so what are some of the differences we will see between a macro and non macro lens with the same focal length? Would one model sacrifice the aperture to become a macro? Any explanation would be appreciated ^^

Thank you

The main difference between a macro and non-macro lens of the same aperture and focal length is that the macro lens will focus much closer. Because of this, the glass inside the lens has to be of much higher quality in order to preserve a level of high quality throughout the focusing range (lens defects tend to increase the closer you focus, so you need to start with something of very high quality in the first place). So generally the only "sacrifice" is a cheap price, i.e a dedicated macro lens will be more expensive. In all other ways it usually performs better. But none of this is to say that a non-macro lens will be any kind of disappointment. They're different classes of lenses all together, used for different subjects and purposes.

[joodiespost]

great, i'm beginning to get a hang of this. I always thought lenses labeled "macro" were for close up shots only. I see that they are even better for other shots, wide or tele than a comparable non-macro lens with similar specs.