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02-06-2017, 06:26 AM   #1
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Sigma 17-70 Contemporary Vs Sigma 17-50 sharpness.. in which review to believe?

Hello, I have a doubt on what lens to buy as every-day use zoom.. the thing i care the most is overall sharpness, and i'm reading around discordant opinions about the sharpess of the Sigma conremporary 17-70 f2.8/4 and Sima 17-50 f2.8..

According to those websites:

Sigma 17-70mm f/2.8-4 DC Macro OS HSM C Lens Review
VS
Sigma 17-50mm f/2.8 EX DC OS HSM Interchangeable Lens Review

and

Sigma 17-70mm f/2.8-4 DC Macro OS HSM \"C\" sample images
VS
Sigma 17-50mm f/2.8 EX DC OS HSM sample images

if you look at the charts and the still life/VFA target comparison the 17-70 is way sharper at 17mm and full aperture, and stepping down it goes improving..

but here: Sigma 17-70mm f/2.8-4 DC Macro OS Contemporary Lens Image Quality

the 17-50 in superior at every focal length, even the old 17-70 is a lot better than the contemporary...

Have i to assume they tested different copies (some good/some bad)? What is your experience?

Ps. All i'm talking here is about sharpness, i don't need the costant f2,8

02-06-2017, 06:34 AM   #2
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Unless you are printing quite large, or doing massive crops, there's probably not a significant practical difference. Ultimately I chose the 17-70 because of the close focusing, and 70mm is nice to have. If absolute sharpness is your goal, neither lens is the perfect choice.
02-06-2017, 06:48 AM   #3
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QuoteOriginally posted by Kozlok Quote
Unless you are printing quite large, or doing massive crops, there's probably not a significant practical difference. Ultimately I chose the 17-70 because of the close focusing, and 70mm is nice to have. If absolute sharpness is your goal, neither lens is the perfect choice.
I'm a graphic designer and it happens to me to shoot for print and posters, but not in large formats.. let's say that i'm not looking for the sharpest lens in the world, i just wanted want to understand which one of those two is better
02-06-2017, 07:09 AM   #4
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I chose the 17-50 and have been satisfied with the sharpness - yours is a very specific application, however. Here's the closest thing I have that might help - a flat wall at 17mm f8.



02-06-2017, 08:07 AM   #5
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QuoteOriginally posted by Exhale Quote
Ps. All i'm talking here is about sharpness, i don't need the costant f2,8
Since you don't need f2.8, I would rather look at the good old Pentax 17-70 or the newer 16-85.
02-06-2017, 08:29 AM - 1 Like   #6
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I have been pretty impressed with my Sigma 17-70/2.8-4 (C), but would seriously consider the 17-50/2.8 if I were in the market and the prices were comparable. You can read my full review of the lens here at PF or just run through the terse bullet points below in regards to comparing the two lenses:
  • I have found the 17-70 (C) to be consistently sharp with no particular optical faults at all focal lengths
  • Sigma Dock for firmware upgrade and AF tuning
  • Some early reviews reported softness at 17mm on the 17-70(C) due to AF problems, this was addressed with firmware update
  • See detailed reviews here at PF for comparisons of the various Sigma 17-70 versions
  • Focus breathing at the long end with the 17-70 (C)...does 17-50 do the same?
  • HSM generation
  • Size, weight, and filter size
  • Option for multi-point, in-lens AF adjust (see Sigma Dock above)
  • Manual focus throw
  • No, the 17-70 (C) does not have quick shift despite reviews that say otherwise
  • Zoom creep
  • Owned 17-70 (C) for almost three years...no regrets...

Sigma 17-70mm F2.8-4 DC Macro HSM (Contemporary) Lens Reviews - Sigma Lenses - Pentax Lens Review Database (Note: I rate my lenses conservatively on review)

My photos on Flickr taken with the 17-70 (C):

Fotostevia on Flickr: Sigma 17-70/2.8-4 (C)


Steve
10-11-2017, 07:32 AM   #7
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Hello. Do you have any preference on Sigma 17-70 or Sigma 17-50 ?
03-22-2018, 05:21 PM   #8
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QuoteOriginally posted by luismpg Quote
Hello. Do you have any preference on Sigma 17-70 or Sigma 17-50 ?

I'd like to know users thoughts on this too please.

Do either of these have lens stabilisation that I could use in video mode, or were these dropped on all Sigmas with Pentax mount?

Thanks.

03-22-2018, 05:27 PM   #9
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QuoteOriginally posted by richandfleur Quote
I'd like to know users thoughts on this too please.

Do either of these have lens stabilisation that I could use in video mode, or were these dropped on all Sigmas with Pentax mount?

Thanks.
I have both, and like both, Rich!

Neither have IS, although curiously, my 150-500 does.
03-22-2018, 07:00 PM   #10
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I take the reviews with some grain of salt, though they are helpful. Things can change when focused at various distances, which most tests do not do. I have a number of lenses in the focal lengths of these two. The Pentax mount of the 17-50mm f/2.8 omits the shake reduction incorporated for the Canikon mounts. Maybe this allows more concentration and time on QC for optical purposes in the Pentax copies? I recently acquired one and I am delighted with its performance, its build quality, and its quiet AF. I wanted the f/2.8 aperture for times when I need that, and the price was right. I've been surprised by how good it is.

I believe in looking at real image tests most of all, although DXO, lines of res, etc. can be helpful for evaluation. I looked at these tests before my purchase. I find very little difference in the better, older version 17-70mm compared with the 17-50mm at 17mm and f/2.8 wide open when pixel-peeping in these tests. I pay less attention to corners than I do edges and centers. In the still life, I look at the brush area at the right side and numerical wheel, the printing on the lower label on the Samuel Smith bottle towards the image bottom, the figure on the Hellas label, the edge of the basket on the left and the center. The 17-50mm seems to lose just a little at mid FL (28mm) wide open, but too bad both were not tested at the same mid FL- the 17-70mm was at 35mm. However, the 17-50mm lost a little more wide open (f/2.8) at its extreme long end of 50mm (no surprise at its longest FL), while the 17-70mm held up well wide open at its long end of 70mm. BUT then it has lost the f/2.8 advantage over most of its range. With my copy of the 17-50mm in shooting at various distances and FLs, I have found good to very good and even excellent results even wide open depending on center to edge and FL, but stopping down very little even to f/3.2 improves sharpness noticeably when f/2.8 is coming in just at the "good" level, even at edges!

Mine is doing better than the tests have indicated! It is not of internal-focusing design, so it should not have "focus breathing". The focus collar does rotate during AF, so keep your fingers back! The front element does not, so it is fine with rotational filters.

Last edited by mikesbike; 03-22-2018 at 07:20 PM.
03-22-2018, 08:06 PM   #11
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QuoteOriginally posted by mikesbike Quote
I find very little difference in the better, older version 17-70mm
Again, it depends on the review whether either previous version of the 17-70 are "better" than the current "C" version. The PF staff seemed to feel the "C" to be a step up. I am surprised to read that your lens uses block focus (extends to focus near). Rare is the modern zoom that is not internal focus.


Steve
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