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Old Oct 13, 2008, 2:11 PM   #11
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kezs wrote:
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current d50 + tamron 70-300 with no internal motor means currently it's almost like I need to schedule aa focus and come back later (:-))
FWIW, the Sigma 17-70 is *much* faster than my Tamron 70-300 at acquiring focus. The Tamron 70-300 isn't that slow though...however, it's a lot slower focusing in low light.

From what I've seen of the Pentax 17-70, there's no reason for me to upgrade...the Sigma seems sharper at all focal lengths. However, you'll have to play Sigma roulette to find a good one. Sigma has decentering issues (left side out of focus). I'm on my 3rd copy so hopefully it'll be ok this time. The Tamron 28-75 was even worse...obvious unsharpness and BF issues for the 3 copies I tried and returned.

The K20D w/ 17-70 will be a big step up from your current setup. If you don't have a lot of Nikon gear, it shouldn't be a problem switching. However, if you do sports (long fast lenses) or wedding (lots of flash metering), the Nikon system might do better for you).

In the Nikon world, I'd love to have the latest 24-70 and 14-24 lenses because they're so sharp (and also their 85/1.4 which you can still buy new) but they're bloody expensive. Their 70-200VR is also great but needs to be upgraded for FF support. All of these lenses are sharper than anything you'd find in the Pentax world, but you have to have the deep pockets to buy them...

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Old Oct 13, 2008, 9:32 PM   #12
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[size=2]again, thanks everyone for the extremely useful input.

now, 'play the sigma roulette'? that's what I've been reading about the sigma 17-70, and I really don't feel like playing any roulette in that area

what would you guys suggest as a good all-around lens to go with the k20d? the 16-50 would seem like the best bet. any thoughts?

(edit: typo)
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Old Oct 14, 2008, 9:51 AM   #13
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Morning Kezs,

Well if your going to possibly consider the DA 16-50, I am going to assume that you will probably expand it to the DA 50-135 too, so as to cover the entire focal length range you were originally looking for (17-70).

This pair of lenses, since people apparently wind up (in time) with both of them, were introduced (announced) about a year ago, so they are somewhat new. They are the "*" or star line, Pentax's quality line, and were co-developed with Tokina (also owned by Hoya who purchased Pentax almost 2 years ago now - if I remember correctly). Pentax and Tokina have co-developed other lenses (the DA 10-17 and DA 12-24), where Tokina offers them with the Nikon & Canon mounts (not the Pentax mount). Pentax uses their exterior, a different auto/manual clutch, their coating (which according to some is better - and I would subscribe to this - does a very good job on flair). From what I understand, Pentax also adds quite a bit of expertise into the basic lens design, so it is just not a cosmetic repackaging on Pentax's part. Pentax also adds a price premium over the Tokina lenses (just so that your checkbook is not surprised).

When the lenses came out, (and this is from memory, since I do not have either of the lenses), the 50-135 was an instant success. The 16-50 however had some vocal critics (on other web sites). It was difficult to gage if there were a lot of individual lens problems, or just a few that found their way to very vocal critics. Apparently there was some initial build problems (that Pentax swapped out), that from the sound of postings have been fixed.

http://forums.steves-digicams.com/fo...mp;forum_id=94
http://forums.steves-digicams.com/fo...mp;forum_id=94

If your interested in this route, I would also search the web for postings on the Tokina 16-50 used on the other mounts. I believe that Canon and Nikon users are happy with the set. This would be a bit of apples to apples comparison on the overall design. Again, on image quality - Pentax has had a very good run with their SMC coating in flair control, and that does tend to differentiate the two brands.

Now on the other lens of the set - the DA 50-135, there were a lot of happy users right off the bat. There were no build problems, and it took great pictures, with a lot of happy postings.

Now to just round things out. Tokina - this time last year announced and started delivering a 11-16/f2.8, which makes the lens pair a set of 3 (covering 11 through 135) at a constant f2.8. This lens, again only in the Canon and Nikon mounts, is said to rival and exceed the Nikon offering in sharpness and IQ. However, I was waiting for it to show up from Pentax with the K mount and it has not made it as of yet (so I finally pulled the trigger and picked up the DA 12-24). I bring this up, since you touched on a wide angle also.

Here in the US, Pentax dropped the K20 price to $999 with a street price of $899. I figure that this was done for several reasons - 1) Christmas, 2) Inventory reduction and 3) getting ready for the introduction of the K30/K300 in the 1st Q of 2009 (same time as they introduced the K20/K200 here in 2008). That might provide another option for you to consider. With the K20/200 announcement - the K10 was rebadged and packaged into the K200 (the 10MP sensor). So I am wondering if the K20, will be rebadged and repackaged into the K300, with maybe a more dense sensor for the K30 and with other new and improved functionality - just my speculation on the future.

So there you go - its just my 2 cents thrown in....
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Old Oct 14, 2008, 11:33 AM   #14
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You may want to read through at this recent thread for some discussion on the Sigma 17-70mm (the lens the OP ended up buying for a walk around lens choice). You'll find a link to some tests comparing it to a Canon lens, too.

Walk-around lens choice for Canon 20D

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Old Oct 14, 2008, 12:28 PM   #15
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interested_observer wrote:
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the 50-135 was an instant success. The 16-50 however had some vocal critics
From the sample pics I've seen posted, the 50-135 was sharp enough to be worthy of the DA* label.
The 16-50 looked just ok...I wasn't impressed by its sharpness. I've been more impressed w/ my 17-70's pictures. However, the 16-50 is weathersealed and there's no other lens in that range that is...

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Old Oct 16, 2008, 12:12 AM   #16
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(here's the short version of my reply which got lost after my connection dropped - sorry if I sound too straightforward this time around )

thanks everyone for the input. specially you, i_o; that's more than 2 cents for me

good as the pentax 16-50 seems, right now I think my choice of a general use lens would be between a tamron 17-50 (2.8 constant) and a sigma 17-70 (macro and longer range). the tamron has a pretty good rating at slrgear, and it costs just over half what the pentax does. the "sigma roulette" expression still scares me though. would that apply to tamron as well? I won't be in the US for long, so I won't have time to try around and spend my time exchanging lens right when I'd wanna be using them.

for a longer lens, I'd probably pick up a 55-300... since I'm not a big tele shooter, but I do like to try my hand at it once in a while. the 50-135 seems like a great lens, but my use for it would be kinda limited.

for the wide angle, I guess the tokina is a good choice... though the 2.8 might be somewhat wasted, since architecture shooting does allow using a tripod whenever quality is an issue, and f/8 or thereabout would probably be what I'd be using...

on a slightly different subject, I own a rikenon (ricoh) 55mm 1.4, which is allegedly a pentax screw-type mount. there's also a fisheye for pentax which is screw-type, but its mount is not the same diameter as the rikenon. are there 2 screw-type mount that pentax used as standards? I'm guessing at least one of them is the famous m42. in any case, using an adapter, will any of those beauties meter on a k20d?

once again, thanks.
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Old Oct 16, 2008, 12:48 AM   #17
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Hi Kezs,

I might not have been sufficiently clear in my description on the wide angle offerings. The Tokina 11-16/f2.8 is only currently available in a Canon or Nikon mount. I would hope that Pentax would offer it, they have not yet - however there is no guarantee. Currently only the co-developed 12-24 is available from Pentax in the Pentax K mount, however this lens is a constant f/4, that is rectilinear. I have been very happy with my recently arrived 12-24/f4.

Pentax and Tokina of late usually offers some what the same lenses, however not always. Tokina has an 80-400 lens for the last several years that Pentax has not offered. Actually Tokina stopped offering it several years ago with the Pentax mount. So some of these vendor decisions at times makes absolutely no sense to the users.

I just did not want you to go looking for something that was not available.

So I take it that your leaning towards the K20 body, or one of the others?

I think that you will like the 55-300, others have shown/posted great images with it - and from what I have seen, it complements the K20 very well.

Hope that helps!

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Old Oct 16, 2008, 11:15 PM   #18
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i_o,

sorry, the short version of my reply was perhaps too short at that point...

what I meant was the 11-16 is certainly a good lens, but probably not worth waiting for in my case, since aperture at WA for me isn't important...

about the body... still deciding. I'm discarding the d90 for the lack of in-body stablization, which makes similar-quality lenses more expensive than with pentax or olympus... the 16-85 vr isn't all that great or bright, and costs almost what the excellent zuiko 12-60 does. but between the advantages of the four-thirds system and those of an advanced body like the k20d, I'm still not sure. I feel like the choice of a walk-around lens is crucial... the 12-60 seems like a lens I'll never outgrow (wide enough, tele enough, bright and excellent IQ), whereas the e520 does have a few limitations (1EV max bracketing and highlight clipping, mostly). and I do admire the 4/3s technical aspects, which translate into excellent IQ even with cheaper lenses. the k20d seems like the perfect body and resolution, and is selling for a very good price... though there's no "perfect" all-around lens for it out there - there are very good ones, but usually either not as versatile, not as bright or not as good as the 12-60. it's like I should choose wether I want to upgrade a body or a lens in a few years' time. anyway, it's always a trade-off, right? like a teacher once said when asked about a similar situation... "I went through a similar decision process myself, but I ended up marrying only one woman". it's a fun process, though. looking around and trying to figure out what option I'll end up using the most... you end up learning a lot. and once again I thank you (and everyone) for helping out.
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Old Oct 17, 2008, 7:26 AM   #19
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It sounds like your tossing around the pros and cons of several different systems right now (Nikon D90 versus Pentax K20D versus Olympus E-520). lol

The 16-105mm VR that Nikon's shipping as a kit lens with the D90 would be another option. It's an f/3.5-5.6 lens and seems to do quite well in reviews and tests I've seen. There are pros and cons to any of them (more usable range versus lens brightness, distortion, corner softness, CA, etc.). That Nikkor would give you a zoom range with roughly the same angle of view you'd have using a 24-158mm lens on a 35mm camera.

Edit. My bad... that Nikkor's an 18-105mm lens. So, it wouldn't start out as wide.


Sony also has some lenses starting out at 16mm. They've got a 16-105mm f/3.5-5.6, and a brighter Sony/Carl Zeiss 16-85mm f/3.5-4.5 (and third party lenses available in Minolta/Sony AF mount like the Sigma 17-70mm and Tamron 17-50mm lenses you're looking at). Like the K20D, any lenses you use would be stabilized on a Sony dSLR.

The new lower price on the K20D would be pretty tempting though, especially given it's weather sealing, if you can find lenses that do what you want. As already noted, there's no one perfect choice. lol

You may also want to start a thread in the What Camera Should I Buy Forum, letting members know what you're looking for in a total kit for some opinions on different body/lens combinations.


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Old Oct 17, 2008, 10:06 AM   #20
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kezs wrote:
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the "sigma roulette" expression still scares me though. would that apply to tamron as well?
Yep, depending on which lens. E.g., I tried getting a good copy of the Tamron 28-75. First copy had a really soft 75mm and BF badly at 28mm. Second copy BF at 28mm but was sharp at 75mm. Third copy was obviously used (not new) but still BF'd at 28mm and was soft at 75mm but was sharp at 50mm.

I haven't heard lots of complaints about the 17-50, but the 28-75 seems to be crapshoot. If you get a good copy of the 28-75, it'll rival the best Nikon/Canon have to offer though. Still not sure if I want to keep playing roulette but since I don't use this range much, I'll probably wait until the Sigma 24-70 redesign in December to see if that's sharper than it is now (it's not as sharp or contrasty as the Tamron 28-75).

Sigma's issues typically involve decentering. Tamron's issues typically involve BF/FF. The Pentax 16-50 when it first arrived had lots of BF/FF/softness issues as well, but that seems to have been mostly fixed.

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