Pentax DA 17-70 f4.0

[les_lammers]

Has anyond bought this lens yet.....or do I have to be the Guinea pig? I have seen some pics on the net and *I* liked

them. Not extremely sharp but they look really nice. There is more to a picture than sharpness.

[alisa_stieg]

Just out of curiosity, have you compared it at all to the Sigma 17-70? I've been eyeing that one myself, but the Pentax has the advantage of being a DA...that Sigma is one sharp lens though (at least on the macro side of things).

[les_lammers]

Hi Alisia,

 

No, I have not compared them. I understand the Sigma focuses in a different direction..but it is a nice lens. However, I liked what I have seen from the Pentax. The Sigma is not really a macro but is does focus close. A lot of people like the Sigma.

[pbarnes]

To Alisa - what is the advantage of DA? I thought it just meant it was designed for digital smaller sensors, not film, as is the Sigma 17-70mm. The DA*, of course, is the sealed, weatherproof series of lenses. I had the Sigma 17-70 before the Pentax version was available, and have just replaced it (stolen), the price was so much better, and the quality is very fine. Photozone (www.photozone.de/) gives it a top 5 stars on price/performance.

 

Les: Yes it does manual focus in the opposite direction - but I had not noticed this until I checked just then, despite having used manual focus a reasonable amount lately on both this and my Pentax lenses, so I guess it's not an issue for me.

[mountainvisions]

The advantage should be that it's a bit smaller, it's designed for digital. Wide lenses benefit from digital design while normal to tele lenses really don't that much.

 

Sigma tends to have more QC issues, although I own 4 Sigma lenses (20mm 1.8, 10-20mm, 70-200, and 70-300) all are excellent lenses.

[michael_kuhne]

I have not heard anything bad about this Sigma, only remarks of satisfaction. Only time will tell if the new Pentax is better- but it will only AF with SDM camera bodies, where the Sigma will work on older or newer bodies.

[personalphotos]

From what I've read on the net and the one review on PF, the Pentax seems to have a decent rating.

http://www.digitalcamerareview.com/default.asp?newsID=3676&review=pentax+17-70mm

The Sigma is variable aperture as well which isn't a positive IMO. I'd rather the constant f4 over 2.-4.5. Add the quick shift, better hood (love those 'doors' on Pentax hoods) and SMC, SDM and I think the Pentax is worth the difference. These new lenses are going to gradually leave the non-SDM bodies behind though and that's too bad. This lens seems to be a continuation of the DA16-45mm and if it's as good optically, then they have a winner. That's my most used lens since I got it. Being KAF2 I'll keep the 16-45mm to use on my non SDM *istD.

 

As for Sigma QC, I think that's more historical than current. It seems with the development of the EX series and similar lenses a few years back, Sigma has that basically behind them. I've not seen very much negative about their product in the last few years.. Like Justin, I have the 20mm, 70-200, 10-20 and 105mm macro. All are great lenses.

[personalphotos]

Opps sorry it should say "I'd rather the constant f4 over f2.8-4.5." Not 2.-4.5.

[kfrog]

To Peter Barnes: The DA 17-70mm is not a DA* lens and is not weather sealed. It does have SDM though which is a huge plus. I would think the quick shift focus is an advantage also.

[andrewg_ny]

The Sigma isn't designed for film either. It is a 'DC' lens, Sigma-speak equivalent for DA. It is also not rated as an 'EX' lens either (Sigma-speak for top optical/build quality), though I haven't heard anything particularly bad about 17-70 build.

 

I tend to agree that I'd rather have constant f/4 to 70mm than f/2.8 at 17mm. I find it somewhat irritating that Sigma lenses focus (and zoom?) in the opposite direction from Pentax lenses and find their hoods & caps more difficult to use. The Sigma also uses a (non-standard for me) 72mm filter rather than the common (for Pentax, at least) 67mm size. Will be interesting to see if Sigma ever makes an HSM version for K-mount.

 

Peter: Interesting review. This was of course only one sample but It seems somewhat likely it may not quite match the Sigma in terms of sharpness wide open which is somewhat disappointing, and distortion seems on the heavier side at the zoom extremes. I think any of us who thought it would trounce the excellent 16-45 were probably deluding ourselves--there are always trade-offs. Good if Pentax actually has been managing to improve CA degradation as they also appear to have done on the DA 55-300. I can't say that it may not end up in my camera bag someday...I am undecided.

[renatoa]

"It does have SDM though which is a huge plus"

 

For my K100D is huge minus :(

[mountainvisions]

I agree with Peter (like usual).

 

The EX series which I own 3 lenses is a great series, I'd plastic barreled but the tolerances are what I'd expect from the standard FA glass I complain about being under built. If my 28-70 FA or my departed 35mm FA was built like the Sigma EX series I'd be the happiest guy in the world, as those are/were two of my favorite lenses optically.

 

The constant aperture is more appealing to me than variable aperture. I believe they make variable aperture lenses to market them with the faster aperture but in the real world there is little advantage since on a wide angle lens the faster aperture is at the wider end, where in most cases it won't be used.

 

And I'm not convinced variable aperture lenses are brighter to look through than their constant aperture siblings.

 

But like Andrew said, it seems Pentax has made some strides in reducing CA on it's DA glass, and more specifically it's newer DA glass. That alone is worth something to consider!

[mountainvisions]

Ahhh, darn it. Why can't I type as fast as I think:

 

Should say,

 

"they are plastic barreled"

 

 

not about to start correcting every post I make, as I already have 3 film canisters but just giving myself a little insulation.

[alisa_stieg]

Les, the Sigma I've been looking at is listed as a Macro lens...perhaps there's more than one?

 

http://www.adorama.com/SG1770PXAF.html

 

It is sometimes frustrating using a variable aperture lens, but when you need something faster at, say 35mm, it is

really nice! I really wish the Pentax was faster.,,4.0 is just too slow for me. I guess I need to investigate zoom

lenses with fixed aperatures at a fast speed (2.8 or so), but I don't think there are many choices for Pentax users out

there (grrrrrrrr), at least not that I've found in my recent investigations (which have not been all that comprehensive, in

all honesty).

 

Peter (Barnes), I was under the impression that all DA lenses were weather-sealed and had the quick-shift focusing

system (which is SUPER convenient!), but Douglas said ;"The DA 17-70mm is not a DA* lens and is not weather

sealed."

 

So, what's the deal? I thought all DA lenses were weather-sealed? Can someone please unravel the mystery behind

the letters DA for me? Seriously! Something along the lines of:

 

SMC=S? Multi-layer Coating, SDM=Sonic Drive Motor, DA=?, Di=?, FA=?

 

yada, yada, yada

 

I can't be the only one who would benefit from an explanation of this sort! Thanks in advance to anyone who takes

up the challenge!

[pj_vesterback]

Alisa - There is a difference between the DA & DA* lenses. For the most part I believe that it is the weathersealing

and in some cases SDM. As for the macro Sigma, even tho the website labels it macro, it is not. The mag ratio is

1:2.3. Close to a macro but not quite. A macro lens is at least 1:1. Most now seem to label close focusing lenses

as macro lenses.

[pbarnes]

Alisa; There does not seem to be any published explanation of what the capital letters mean, apart from

that they refer to the DA series of lenses, or the FA series, etc. So these might not be the official decodings

of the Pentax lens acronyms but they work for me:

 

SMC = Super Multi Coated (all Pentax lens are SMC now I think) - reduces flare, I'm not sure what else it

does.

 

FA = Film (A for autofocus,autoexposure) - the older 35mm film series of autofocus lenses

 

DA = Digital (A for autofocus, etc) - designed for digital cameras with APS-C size sensors, i.e. smaller than

the 35mm "full frame", includes all the Pentax digital SLRs so far.

 

DA* = As for DA above, but higher quality build and weather sealed to complement the sealing on the

K10D, K20D and K200D. I think all DA* lenses also have SDMs (see below)

 

SDM = Sonic Drive Motor, a quiet, fast motor built into the lens for autofocusing. Non SDM lenses are

autofocused by a coupling with a motor in the camera body.

 

To help with comparisons with Sigma lenses, here is my rough translation of their codes:

 

Sigma DC = Pentax DA

 

Sigma EX = Pentax DA* (higher (pro?) quality, but not weather sealed)

 

Sigma HSM (hyper sonic motor) = Pentax SDM

 

Sigma OS = optical stabilisation, built into lenses for those cameras that do not have stabilisation built into

the body. (No Pentax equivalent, yeah!)

 

I found a good guide to the Sigma codes and their lens technology at http://www.sigma-imaging-

uk.com/lenses/lens-tech.htm. Is there a Pentax equivalent anywhere?

[pbarnes]

When Google doesn't work for you, try Photo.net - of course there is an article explaining Pentax terms, at

http://www.photo.net/equipment/pentax/#nomenclature. Still don't know what the F in FA stands for, so I'll stick

with F for film, although I realise that the F lenses were introduced at a time when to refer to a piece of

photographic equipment as a 'film camera' was redundant nonsense.

[xpiotiavos]

Doesn't the * designation on the DA* line also refer to the better optical quality of the lens, not just the build quality?

[pbarnes]

Adam, yes, you are right.

[andrewg_ny]

Peter B., can't answer what it stands for, but the alphabet soup is something like this:

 

<UL>

<LI>K - Original K-mount issues. These were often close cousins of earlier M42 screwmount designs.

<LI>M - released with M-series cameras, generally smaller & lighter than their 'K' predecessors

<LI>A - Automatic aperture (for Super Program/A, Program Plus/A, P-series, etc.) - incorporates the 'A' position on the aperture ring.

<LI>AF - One-off autofocus AF 35-70 f/2.8 for ME-F camera. AF equipment built into the lens, will only autofocus on ME-F.

<LI>F - Autofocus, introduced for SF series. Some of these are re-hashes of M and A designs including some semi-archaic features like 'macro modes' on one end of a zoom for close focusing. Zooms no longer one-touch, two-touch zooms friendlier for autofocus.

<LI>FA - Autofocus Mk II, includes additional lens-to-body data including MTF, power zoom on some lenses. Start to see more modern features like aspherical elements (AL) and internal focus (IF) and ED class. Introduced with Z/PZ-series bodies.

<LI>FA-J - Similar to FA technically except aperture ring was deleted for simplicity and cost savings as increasingly bodies could offer 'M' and 'Av' modes without it.

<LI>D-FA - Fairly recent full-frame, aperture ring-equipped designs for use on digital and film.

<LI>DA - Designed for APS-C sensor-sized digital, no aperture ring, may vignette on film bodies.

 

<LI>A*, F*, FA*, DA* - Select top, pro-spec'ed lenses from their respective series. Generally fast f/2.8 zooms or primes. To date, all DA* incorporate weather sealing and SDM.

<LI>Limited - A series of top quality modern prime lenses with metal bodies with technology/features comparable to their DA or FA brethren.

<LI>DA-L - Budget DA lenses with cost & weight-saving plastic mounts.

</UL>

[andrewg_ny]

Alisa, there are a handful of choices for K-mount autofocus constant f/2.8 zooms, K-mount isn't all that lacking

for choices. (d) are discontinued so may be harder to find. The ones that

come to mind (maybe there are others I've forgotten?):

<UL>

<LI>DA* 16-50 (alt. Tamron 17-50 SP, Sigma 18-50 EX)

<LI>Sigma 20-40 EX(d)

<LI>Sigma 24-60 EX, 24-70 EX

<LI>FA* 28-70(d) (alt Tamron 28-75 SP, various Sigma 28-70 EX, Tokina(d))

<LI>DA* 50-135 (alt. Sigma 50-150 EX, maybe not yet available?)

<LI>FA* 80-200(d) (alt Sigma 70-200 EX, Tamron 70-200, Tokina(d))

</UL>

<P>I would not be surprised to see the Tokina 11-16 eventually appear in a DA* edition but this hasn't been

announced/roadmapped.

[alisa_stieg]

Thanks for the info, gang! I had no idea that post on pentax equipment even existed! Good to know!

[alisa_stieg]

And sorry for hijacking your post, Les. I guess you have to be the guinea pig!