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02-24-2014, 02:36 PM   #46
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QuoteOriginally posted by Na Horuk Quote
I prefer to look at the lens reviews on this website you might know - Pentax Forums It even has a wonderful sample photo gallery!
I agree. I like to see reviews and examples by people who actually use the lenses over an extended period of time and compare them to the other lenses that they use.

02-24-2014, 03:59 PM   #47
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QuoteOriginally posted by Kenntak Quote
I agree. I like to see reviews and examples by people who actually use the lenses over an extended period of time and compare them to the other lenses that they use.
the trouble is -- the sample images for all these sites are all over the map. Taking the same shot using different lenses with the same vantage point and all apertures at the same time with the same light, at the very least, removes about a dozen variables from the equation.

My experience with DxO data: it more or less matches my experience with camera lenses across a wide range of brands: Canon, Nikon, Pentax, Olympus, Panasonic. I always try to rent my gear before purchasing and when I don't I often find myself returning or selling the item on eBay. I find DxO's data more useful ACROSS BRANDS than subjective evaluation which are often (as you say) more useful WITHIN A SINGLE BRAND. Since I am not married to any brand having owned literally dozens of camera brands over the past 35 years I'm thrilled that there is a resource out there that, when used appropriately, can be of great assistance.

YMMV

Michael
02-27-2014, 09:02 AM   #48
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QuoteOriginally posted by kh1234567890 Quote
There seems to be a bit of front focus on your camera with all the lenses - have you checked it against live view focus at infinity ?
Unfortunately I do not have the tools to adjust the front / back focus. Could you please point out of the examples of front focus in these shots ?
02-27-2014, 10:48 AM   #49
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QuoteOriginally posted by Stagnant Quote
Unfortunately I do not have the tools to adjust the front / back focus. Could you please point out of the examples of front focus in these shots ?
For example your DA35 Ltd at f2.8 seems to be front focusing - the branches of the near tree seem to be more in focus than the frame centre (presumably you were using the centre focus point). Similarly for the other lenses.

You might want to try taking a few shots of a contrasty distant object (such as the treeline here) at a few different settings of the AF fine adjustment tweak with the lens wide open and compare the shots. Something like a global +2 or so should do it but it will probably need to be slightly different for each of the lenses.

Also correcting CA usually helps to make the image look sharper - just use the Silkypix tool on something in the frame corner (your DA35 Ltd shots needed something like +3 and +1 in Silkypix Pro 5)

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02-27-2014, 11:02 AM   #50
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Thanks for the tips. The CA's were left there on purpose, to show the image as is, for the sake of testing.
02-27-2014, 11:30 AM - 1 Like   #51
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QuoteOriginally posted by Stagnant Quote
Thanks for the tips. The CA's were left there on purpose, to show the image as is, for the sake of testing.
OK. I did something similar until I got bored with it
02-27-2014, 11:48 AM   #52
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These series of shots were made, to compare the performance was different lenses in the same conditions. Also it was interesting to compare primes against the zooms. By the way, surprising as it is, in some cases the kit zoom lens performed better that DA* 16-50.
03-03-2014, 09:36 PM   #53
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QuoteOriginally posted by MJSfoto1956 Quote
So I decided to do some manual "data mining" on the DxOmark website and put together this somewhat interesting chart comparing DxO's concept of "sharpness" (which is really about acuity which they call "Mpix") for DA primes on the K-3.

While I am no Pentax lens expert, the data seems to correlate quite well with the lenses I own and have shot with.

YMMV.

Enjoy!
Michael
Thanks for this map. I will stick with DA50 1.8. It sounds that it is the best low-light DA lens at 1.8 (haha)

---------- Post added 03-03-14 at 09:37 PM ----------

QuoteOriginally posted by MJSfoto1956 Quote
Yup! actually it makes sense: full-frame DOF and diffraction @ f/8 compares well to crop sensor DOF and diffraction @ f/5.6

For fun here is the same chart with the addition of the superlative Sigma -- basically a lens that is sharp from f/1.8 to f/8 on the K-3 !

Michael

---------- Post added 02-21-14 at 03:55 PM ----------



In DxOspeak, Green represents high perceived acuity (their concept that essentially replaces mere "resolution") and red would represent lower perceived acuity.

M
Okay. I will save to buy Sigma 35 instead of FA31...

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