Sigma 18-50mmf2.8 or Pentax 16-45mm to buy???

Started Feb 4, 2005 | Discussions
Rick Ashford Senior Member • Posts: 1,008
Wrong picture...

The lens you provided a picture of is a Nikkor 18-70. It is not the Sigma 18-50 f2.8.

Wally OZ wrote:
I know nothing about the 16-45 but I have recently acquired an
18-50 2.8 DC, Ok it's taken using a Nikon D70 body but results
should be equal on *istD/s

Here are a couple of samples at f2.8 in this thread

http://forums.dpreview.com/forums/read.asp?forum=1036&message=12160834

Pics of the actual lens here

http://forums.dpreview.com/forums/read.asp?forum=1030&message=12142318

CSLee wrote:

i m planing to buy one of these lens but don't know which one is
better in term of performance (focusing
speed/accurate,sharpeness,contrast and etc.).can anyone please help
me ,i m lose ?.

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Rick Ashford Senior Member • Posts: 1,008
My mistake...

I am mistaken here. I was trying to recall from memory (here at work), and I got it all wrong. The magazine was NOT Popular Photography -- it was Practical Photography (a British magazine). And the Sigma lens reviewed was the 18-50 f3.5-5.6 DC, one of 12 lenses reviewed along with the Pentax 16-45. The Sigma lens was NOT the 18-50 f2.8 EX DC, as I thought yesterday.

However.... it should be noted that this lesser quality Sigma lens got very high marks -- an 88 (of a possible 100) vs. an 89 for the Pentax 16-45 -- only one point difference. They really liked the quality of the Sigma lens for the price. They were somewhat disappointed in the "softness" of the Pentax 16-45. Interesting.

Joseph Tainter wrote:

"Plus, this Sigma lens received a very favorable rating from tests
done by Popular Photogaphy magazine compared to the Pentax 16-45."

Has Pop Photo tested the Sigma 18-50 f2.8? I don't recall seeing
it. I know they have not yet reviewed the DA 16-45.

While I am writing, I have to wonder why my DA 16-45 does not
underexpose?

Joe

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Brett St Pierre
Brett St Pierre Veteran Member • Posts: 7,024
Re: 16mm vs 18mm for WA photography ?

Godfrey wrote:

Brett, you're going to cost me money. The thought of a DA16-45
addition to my lens kit is beginning to buzz in my head.

Sorry, Godfrey, I understand the danger of considering lens purchases, it is an insidious disease that claws at your logic until you can justify it!

I don't think the DA16-45 should be put on a pedestal as far as lenses go (and I am thinking good pirmes here) but in terms of resolution it doesn't give much away to even the better short primes. Wide open (e.g. f/2 or f/2.8) most primes are not wondeful but are usually great from f/4 as you know. My experience is the DA16-45 has very good resolving power even wide at f/4. Sure there is some distortion at the extreme ends of the lens but no more than any zoom and these things are correctable in software

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Brett

The Journey is the Thing

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Lance B Forum Pro • Posts: 31,084
Re: Thanks Brett for the pics...

thw wrote:

never realize that 2 mm wide makes such a huge difference.

I have both the DA 14mm f2.8 and the DA 16-45 f4 and I can tell you there is a fair amount of difference as you can see from Brett's comparo. The 14mm is 90º c to c which is 7º wider than the 16-45 at 83º at it's widest. The Pentax 18-55 and Sigma 18-50 is 76º c to c at it's widest so it seems that there is about 7º per 2mm at these focal lengths(this is not linear).

I also own a Pentax 16mm f2.8 fisheye which is wider again and is somewhere in the vacinity of 105º-110º c to c.

The DA 16-45 is a superb zoom and it is a great standard lens to have on my camera but I would still rather shoot with a prime at these focal lengths if I have enough time.

Whether anyone wants an 18-50 or a 16-45 comes down to whether they want the extra 2mm at the wide or telephoto end. Personnaly I like it at the wide end.

The other consideration obviously, is the extra speed of the Sigma and if that is important to you then that is a factor in favour of the Sigma. I would still buy the 16-45 as it is only one stop slower.

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Lance B

 Lance B's gear list:Lance B's gear list
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Lance B Forum Pro • Posts: 31,084
Re: Wrong picture...

Rick Ashford wrote:

The lens you provided a picture of is a Nikkor 18-70. It is not
the Sigma 18-50 f2.8.

When the link comes up, left click on the photo or where it says enlarge/contact and the rest of the photo should come into view. It will then show the other lens being the Sigma.

Wally OZ wrote:
I know nothing about the 16-45 but I have recently acquired an
18-50 2.8 DC, Ok it's taken using a Nikon D70 body but results
should be equal on *istD/s

Here are a couple of samples at f2.8 in this thread

http://forums.dpreview.com/forums/read.asp?forum=1036&message=12160834

Pics of the actual lens here

http://forums.dpreview.com/forums/read.asp?forum=1030&message=12142318

CSLee wrote:

i m planing to buy one of these lens but don't know which one is
better in term of performance (focusing
speed/accurate,sharpeness,contrast and etc.).can anyone please help
me ,i m lose ?.

-- hide signature --
-- hide signature --

Lance B

 Lance B's gear list:Lance B's gear list
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thw Veteran Member • Posts: 8,089
Some Sigma 18-50 test results
OP CSLee Regular Member • Posts: 381
Re: Sigma 18-50mmf2.8 or Pentax 16-45mm to buy???

CSLee wrote:

i m planing to buy one of these lens but don't know which one is
better in term of performance (focusing
speed/accurate,sharpeness,contrast and etc.).can anyone please help
me ,i m lose ?.

Hi all,

I brought the Pentax 16-45mm yesterday,i compared it with the sigma 18-50mm EX f2.8 in the shop, i found the 16-45mm more sharper than 18-50mm EX f2.8 and the sigma show me slightly back focus at f2.8,f3.5 and f4, the Pentax 16-45mm show me correct focus and more sharp pic. ,so i brought it back.
Thank you for all of your advised.

 CSLee's gear list:CSLee's gear list
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HF Cheung Contributing Member • Posts: 636
Re: Sigma 18-50mmf2.8 or Pentax 16-45mm to buy???

Sorry, did you mean you returned the Sigma or the Pentax?

CSLee wrote:

I brought the Pentax 16-45mm yesterday,i compared it with the sigma
18-50mm EX f2.8 in the shop, i found the 16-45mm more sharper than
18-50mm EX f2.8 and the sigma show me slightly back focus at
f2.8,f3.5 and f4, the Pentax 16-45mm show me correct focus and more
sharp pic. ,so i brought it back.

OP CSLee Regular Member • Posts: 381
Re: Sigma 18-50mmf2.8 or Pentax 16-45mm to buy???

Hi HF Cheung,

i only borrow the sigma 18-50mm EX f2.8 lens from the shop to have a test shot .

HF Cheung wrote:
Sorry, did you mean you returned the Sigma or the Pentax?

CSLee wrote:

I brought the Pentax 16-45mm yesterday,i compared it with the sigma
18-50mm EX f2.8 in the shop, i found the 16-45mm more sharper than
18-50mm EX f2.8 and the sigma show me slightly back focus at
f2.8,f3.5 and f4, the Pentax 16-45mm show me correct focus and more
sharp pic. ,so i brought it back.

 CSLee's gear list:CSLee's gear list
Panasonic Lumix DMC-FZ1 Canon PowerShot 350 Nikon D800E Nikon AF-S Nikkor 35mm f/1.4G Nikon AF-S Nikkor 50mm f/1.4G +3 more
WeeklyPhotoGuy New Member • Posts: 5
Re: Sigma 18-50mmf2.8 or Pentax 16-45mm to buy???

I went back and forth between buying these two lens for a few weeks before I stopped in a shop and actually looked at them and played with them. I read users reviews here of the Pentax 16-45, and Sigma 18-50, and on the web: http://www.shuttertalk.com/articles/sigma1850ex/index.php and

http://www.photographyreview.com/cat/lenses/35mm-zoom/pentax/PRD_303323_3128crx.aspx

Image quality aside, the construction of the Sigma feels far superior to the Pentax. To me the Pentax felt like a toy lens, kind of cheap and delicate. The Sigma felt more compact and sturdy, the finish is nice slip resistant sort of matte finish. The pentax felt plastic-y The reverse zoom on the Pentax also bugged me and could cause built in flash shadows (or not?) These are just personal observations and I think to say one has far superior image quality over the other is coming from a biased opinion. You may need to decide which is more important, Faster or Wider. Pentax 2mm wider VS. Sigma two stops faster. The sigma is also more expensive, the Pentax retail is cheaper and with the $100 rebate right now it's alot cheaper than the Sigma. I hope to get out this week and shooting some walking around NYC shots. I will follow if I find any issues with the lens and/or i will try to post some of them.
L

Escaping Contributing Member • Posts: 839
Wait for the Pentax/Tokina 16-50/2.8 ...

I would get that Pentax 16-50/2.8 that will come out later this year. It will give you both the wide angle and the speed. This 16-50/2.8 is a product coming out of the collaboration between Pentax and Tokina.

see http://forums.dpreview.com/forums/read.asp?forum=1036&message=17615843

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Escaping (CT, USA) http://www.pbase.com/cvanlang
using the current DSLR's: D100 / D2H / *istDS

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Fujifilm X20 Panasonic Lumix DMC-LX7 Panasonic Lumix DMC-LF1 Panasonic LX100 Fujifilm X30 +40 more
fototim Regular Member • Posts: 281
Re: Sigma 18-50mmf2.8 or Pentax 16-45mm to buy???

I have a Sigma 18-50/2,8. It is my walk around lens. I know for a fact that it is very well built. Mine survied a near two meter fall directly into the concrete. The filter thread isn't what it used to be, but it I was able to fit a filter on it, and it performes as new. The DS survived too

I also know that the hood does interfeer when using the in camera flash. Even when the hood is reversed it is visible sometimes.

Having the same dilemma, knowing what I know now, I would have waited for the DA 16-50/2,8
--
Fototim

Hodgjy Senior Member • Posts: 1,865
Re: Sigma 18-50mmf2.8 or Pentax 16-45mm to buy???

I just bought the 16-45. I'm not in least concerned about the reverse zoom because I think it helps this particular lens in reducing light falloff and barrell distortion at the wide end. I also plan to use an external flash for when I need it because in my experience, the inboard flash of most cameras isn't very powerful and should only be used for fill flash.

The sharpness of this lens can't be beat from what I've seen and read about. It was a no-brainer to pick it.

Eilert Ofstead Contributing Member • Posts: 680
Re: Pentax 16-45mm - why "underexposing"?

Several have commented on this lens apparently giving a 1/2 - 1 stop underexposure. Does anyone have an explanation for this phenomenon? Is the f-rating incorrect? Or does the meter fail to utilize feedback from the lens properly? Has anyone done full manual f-setting and compared this lens with others?

Seems a strange mystery....

Eilert

chris gunn
chris gunn Veteran Member • Posts: 8,560
Re: Pentax 16-45mm - why "underexposing"?

Eilert Ofstead wrote:

Several have commented on this lens apparently giving a 1/2 - 1
stop underexposure. Does anyone have an explanation for this
phenomenon? Is the f-rating incorrect? Or does the meter fail to
utilize feedback from the lens properly? Has anyone done full
manual f-setting and compared this lens with others?

I took over a thousand pics with this lens on my last trip.

For what I wanted, it underexposed for the outdoor landscapes
(so I used some compensation). The shots in forests were fine.

Heres one at 45mm, f8?

Perhaps it's a bright sky throwing things out of kilter?

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