KA2F mount lens options

So, the camera I am eyeing off has a KA2F mount, and compatable with KA and KA2. Although there are probably 1000's of opinions about various makes and models, my main concern is am I going to get decent quality glass in comparison to other systems?? I know Pentax make great lenses with good coatings, but how do they stack up against other manufacturers?? I have used Pentax lenses on this camera, but to be honest, my eye is not keen enough to notice any differences. I'll probably only go for 2 lenses at this stage. maybe a 12-24mm and an 18-250 or there abouts to cover most situations.

Cheers.

 

That 12-24 is a fine lens; it's got great sharpness, but I hear the purple fringing is a bit nasty. But that 18-250 is intended to be a jack-of-all-trades kind of lens. That's the kind of lens that a photography newbie puts on his first DSLR and never takes off. Because of that incredible focal range (18 to 250), the image quality is a bit reduced overall; there's some severe barrel distortion and vignetting at the wide end, blurry images at full telephoto and chromatic aberration problems at all focal lengths.

You say you're eying a Kaf2 mount camera. That could be anything. Is it a K100? A K20? I'm curious because if you're getting the K20, then you likely have some cash to spend and my lens recommendations will change.

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If you want to cover your ranges for cheap then I'd recommend this(Staying away from any obscure lenses or manufacturers):

Sigma 10-20 - significantly cheaper than the 12-24 and it goes a bit wider. Downsides are that the image quality is very slightly lower than the Pentax and it's a 3.5-5.6 instead of a solid f4, but I don't think that will bother you. I know Pentax makes a 10-17 lens, but it's fisheye and I don't care for that type of look. This Sigma has very, very reduced distortions for a lens that goes down to 10mm.

Pentax 55-300 - Considering the low price and the large range it covers, this is a very good lens. Respectably sharp and the distortions are well controlled.

The kit Pentax 18-55 II - Just to cover the gap. Not to mention this lens will come with any K200 or K20. The II version is a real improvement over the original 18-55, and that's saying something because the original was fine. The II has increased sharpness (For use with the K20's 14MP sensor) and also, the Fringing, the vignetting and distortion have all been reduced. All that for only $50 more than the original lens. It's by far the nicest kit lens from any manufacturer.

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If you have some cash to spend, then my recommendations change:

Sigma 10-20 - Ok, so this stays the same. It's a really great lens that just happens to be cheap too.

Pentax 31mm f1.8 Limited - A dream prime lens. Blasphemously sharp and great characteristics all around.

Pentax 50mm 1.4 - It's a bit soft at 1.4, but there isn't a better 50mm solution for Pentax unless you dig into the past(*cough* Like I did).

Pentax 50-135 f2.8 - It's f2.8, it's weather sealed, it has great characteristics and it's reasonably cheap. I list this one as well as the 50 prime because the prime goes to f1.4 and it will look better than the 50-135 at 50mm, simply because that's its specialty.

Pentax 200mm f2.8 Prime OR the 300mm f4.5 - They'll take a better photo than any 70-300 or 55-300 at comparable focal lengths. They're both pretty good.


Note: I've excluded the Pentax 16-50 f2.8 lens because it's got some image quality problems which have left me unimpressed. If they release a version II, I'll reevaluate.

 

Thanks Drew for that more than comprehensive review. Im looking at the Samsung GX20, which is basically the Pentax K20D with a few minor menu and cosmetic differences. Its more than enough camera for my hobby. I have used most of those lenses you have mentioned in the Xenon range and a couple in Pentax. Unfortunately, I didnt have enough time to really sit down and take numerous shots with all the lenses at the same focal length and compare them. I did small comparisons with the wides, but not with the tele's.

The 12-24 is a great lens. I got some great day and night shots with it. It will definitely have a permanent place in my bag. With your concerns about the 18-250, I guess I'll really have to try it out again and take more notice of the things you mentioned.

I think I'll head the way of the 18-55II as you have many good things to say about it and at just over A$300, how can you go wrong. If the situation arrises that i need more reach, I can always borrow something else.

Im hoping to get my hands on this kit again in a few weeks when i have time and I'll do a full test and comparison and document everything I do and post some results. Thanks again Drew for shedding some light on what to look for with certain things.

Cheers.

 

Umm, here where I work, we sell the 18-55 II for $149.99. If you're paying $300 for it then you should consider shopping elsewhere!

 

Im in australia mate, everything costs more. Im checking out US websites at the moment for price comparisons because I'll be there at Xmas time so Im looking for a few bargins now. You just found one for me..is that price stable or do things like lenses fluctuate with the market??

Can you give me a price on the 12-24 and the 10-20?? I found the 12-24 here and its close to $900, way more than I barginned for.

 

Ah, I missed that you were an Aussie. That changes things, I suppose.

I'm not sure about online prices, but in all of the shops I've seen in all of the surrounding cities where I live, I've not seen the price of lenses fluctuate very much at all in the past couple of years. Unlike with camera bodies, lenses have much less to improve on with each iteration, so the prices are much steadier over time.


I don't know if I can give you any prices, man. I bought this Sigma 10-20 for $600, and the 12-24 would be $800 if I had decided to buy it, but I have no idea what these prices would be for you. I'd check eBay and see if you could save money despite the shipping costs.

 

if you don't mind manual focusing, any of the Pentax "A" lenses would work for you too. Any K Mount lens will work, but some are easier to use than others. "M" lenses work, but metering is done differently.

 

So on the other end of the cheaper scale, what's the pentax equivelent to say "L" glass?? Is there one??

 

Any of the Limited series, or * series are fantastic lenses. The FA 31mm Limited is one of the best lenses ever made. But, as with high end glass from any manufacturer, they don't come cheap. But, I don't think they'll set ya back as much as the "L" glass from that other company, hehe

Pentax specializes in prime lenses mainly. Any of their prime lenses are damn good, from the old screw mount Takumars, to the K and M series, A series, their primes are good stuff. But I hear really good things about the DA* 50-135 F2.8 zoom, it is a winner, and IF you get a good copy of the DA* 16-50 it produces some great images too ( they have had quality control issues with this lens )

 

This is great info. So 135mm on a 1.6 crop factor, whats that in terms of magnification?? (roughly) Is there a table that shows all the conversions somewhere??

 

Great info? That's just everything I said! Hehe kidding. Anyway, Pentax k10 has a 1.5 crop factor (making the 50-135 work like a 75-202mm lens. The fact that this lens works out to be close to a 70-200mm full frame equivalent is no coincidence - that's a classic lens range from the old days of film)

The k20 has the 1.6 crop factor though - it's got that newfangled CMos sensor. Just so you know.

 

DD, your continued interest and advice does not go unnoticed mate, I sure appreciate it. Yeah the K20 and GX-20 I believe have the same Cmos sensor produced by Samsung while the lens development is probably in the hands of Pentax (dont quote me). It just makes sense when 2 companies join forces to produce a good product (I say good, not great, because they screwed up with the live view and how it works, on the samsung anyway). Of the Xenon lenses that Samsung have released, Im pretty sure they are all Pentax with the Samsung badges. They are much the same on appearance anyway.

I will continue to read up on the things that you both bring up and its always good to be able to have a question answered, because a review is just that. No question time at the end.

Thanks again.