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03-24-2009, 10:54 PM   #16
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QuoteQuote:
ASDF: DA 16-45 f/4 and DA 17-70 f/4 tend to perform better than f/2.8 zooms at f/4, resolution-wise.
Can you substantiate the above statement? What does "tend to perform better" mean? What does "resolution wise" mean? Thanks.

03-24-2009, 10:59 PM   #17
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QuoteQuote:
WerTicus just ordered a 24-70 f2.8 sigma
see how it goes.

There are 129 owner reviews of this lens here:

FM Reviews - 24-70mm f2.8 EX Aspherical DG DF
03-24-2009, 11:15 PM   #18
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A zoom is a useful and convenient tool as a walk around, general purpose lens. For most applications a reasonable one should be ample for most peoples needs.
For larger prints and other reasons such as bokeh, colour rendition etc. a prime will usually be better. Newer lenses such as the Pentax 50-135 for example can be exceptions though and the gap in quality between Primes and Zooms is getting smaller.
03-25-2009, 12:03 AM   #19
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QuoteOriginally posted by Jewelltrail Quote
Can you substantiate the above statement? What does "tend to perform better" mean? What does "resolution wise" mean? Thanks.
"resolution-wise" means "in terms of border MTF results on photozone.de." I provided one example. Here's DA 16-45 (at 45) pitted against DA* 16-50 (at 50, f/4)

DA 16-45 (45mm, f/4)
(center) 2024.5
(border) 1890

DA* 16-50 (50mm, f/4)
(center) 2009.5
(border) 1496.5

BTW, there was a whole thread about this, as far as I remember.

And you're welcome.


Last edited by asdf; 03-25-2009 at 12:16 AM.
03-25-2009, 12:15 AM   #20
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QuoteOriginally posted by soccerjoe5 Quote
I miss zooms at times. I'm torn between the 17-70 and the 16-50. Had a 16-50 but sold it for DA Limiteds. I like the performance of the 17-70 more but the build and sealing of the 16-50 is awesome.
BTW, I actually assumed the simpler (although not MF friendly since the focus ring is rather loose and moves as the camera focuses) mechanism of the DA 17-70 would be more reliable and last longer, simply because it was simpler.

"Thaaat's right, Dude. The beauty of this is its simplicity. If the plan gets too complex something always goes wrong. If there's one thing I learned in Nam--" -- Walter Sobchak. (I feel like changing my sig. and avatar. )

And I definitely didn't expect any zoom to replace a good set of primes. And you're doing an incredible job with your set.

Last edited by asdf; 03-25-2009 at 12:28 AM.
03-25-2009, 12:32 AM   #21
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QuoteQuote:
ASDF:
DA 16-45 (45mm, f/4)
(center) 2024.5
(border) 1890

DA* 16-50 (50mm, f/4)
(center) 2009.5
(border) 1496.5
asdf--thanks for the reply--I appreciate it.

The above comparison only shows the 16-45 vs one zoom, the Pentax 16-50 2.8, and then only @ one aperture. You stated the 16-45 "tends to perform better than 2.8 zooms" My question concerned both your wording ie, "tends to perform better" and your inclusive use of the plural ie., "zooms."

I guess my next question should be this: Are you saying the Pentax 16-45 f4 out performs all similar focal range, f2.8 zooms? Or are you just speaking of the Pentax to Pentax performance?

QuoteQuote:
asdf:BTW, there was a whole thread about this, as far as I remember.
Sorry. I missed this thread--I do my best to keep up here, but can not read every thread. That is why I ask questions when things like this arise.
03-25-2009, 12:39 AM   #22
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QuoteOriginally posted by Jewelltrail Quote
asdf--thanks for the reply--I appreciate it.

The above comparison only shows the 16-45 vs one zoom, the Pentax 16-50 2.8, and then only @ one aperture. You stated the 16-45 "tends to perform better than 2.8 zooms" My question concerned both your wording ie, "tends to perform better" and your inclusive use of the plural ie., "zooms."

I guess my next question should be this: Are you saying the Pentax 16-45 f4 out performs all similar focal range, f2.8 zooms? Or are you just speaking of the Pentax to Pentax performance?

Sorry. I missed this thread--I do my best to keep up here, but can not read every thread. That is why I ask questions when things like this arise.
Good point. Sorry, I must have mistyped there. I was specifically thinking of DA* 16-50 and may have extrapolated too much.
03-25-2009, 12:54 AM   #23
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asdf: Thanks--your numbers inspired me to do some quick searching--I returned with these:


Tamron 17-50mm f 2.8 Resolution Figures



@ 17mm f4

(center) 2219
(border) 1956

@ 24mm f4

(center) 2174,5
(border) 1851,5

@ 35mm f4

(center) 2163
(border) 1865

@50mm f4

(center) 2065,5
(border) 1927,5

03-25-2009, 01:04 AM   #24
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Interesting. Hmm...That's on a 12MP Sony. Perhaps, that's not a fair comparison with 10MP, K10D results above.

On a Canon, we get the following:

35 (f/4)

1937
1872

50 (f/4)

1903
1848

Too bad the Pentax tests aren't on a K20D and the Pentax mount Tamron wasn't tested.

QuoteOriginally posted by Jewelltrail Quote
asdf: Thanks--your numbers inspired me to do some quick searching--I returned with these:


Tamron 17-50mm f 2.8 Resolution Figures



@ 17mm f4

(center) 2219
(border) 1956

@ 24mm f4

(center) 2174,5
(border) 1851,5

@ 35mm f4

(center) 2163
(border) 1865

@50mm f4

(center) 2065,5
(border) 1927,5
03-25-2009, 03:55 AM   #25
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Okay I've been playing with the sigma 24-70 f2.8 today ... seems super heavy, since i have not had the 50mm off the camera for months now. But the quality is pretty good, i can see that it is not as sharp as the 50mm but its not far off really.

Ill give it a few weeks and see if i fall in love or not. She's never going to lose the weight though !
03-25-2009, 09:44 AM   #26
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asdf: Too bad the Pentax tests aren't on a K20D and the Pentax mount Tamron wasn't tested.
I have the Tammy on my K20 and I do a ton of testing with her.
03-25-2009, 10:10 AM   #27
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QuoteQuote:
asdf: On a Canon, we get the following:

35 (f/4)

1937
1872

50 (f/4)

1903
1848

Yes, that is what happens to resolution after the Canon automatic noise reduction kicks in!



; )
03-25-2009, 10:53 AM   #28
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QuoteOriginally posted by Jewelltrail Quote
I have the Tammy on my K20 and I do a ton of testing with her.
I was talking about photozone...
03-25-2009, 11:03 AM   #29
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QuoteOriginally posted by Jewelltrail Quote
Yes, that is what happens to resolution after the Canon automatic noise reduction kicks in!
Zing!

But seriously, that photozone test was done on a Canon 350D (pictured on the first page of the review) which has an 8MP sensor. photozone folks even mention that the tests should only be compared within each system.
03-25-2009, 12:19 PM   #30
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asdf: I was talking about photozone...
I know what you were talking about. I spent some time with that review myself.
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