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11-22-2014, 03:07 PM   #616
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QuoteOriginally posted by Mistral75 Quote
Sharpness is not the alpha and the omega for a lens. One can also take advantage of less distortion, less lateral chromatic aberration, less astigmatism (for a more pleasant bokeh for instance), less coma in the corners and so on.
Yes, I intimated this in the second portion of my post:

"Yes, its annoying that there are many folks with whom you cannot discuss lenses because the first thing they do is look at the measurements by DXO and Photozone."

Since it appears the DA 16-85 will cost roughly twice as much as the DA 18-135, and the DA 18-135 already does a nice job with image quality attributes unrelated to sharpness, the DA 16-85 needs to be sharper. Alternatively, it could be marginally sharper than the DA 18-135 throughout most of its focal length, and significantly sharper at 85mm. And if the price of the DA 16-85 eventually settles to around $200 more than the DA 18-135, it would provide an interesting alternative: wider, shorter but better IQ at 85mm.

11-22-2014, 03:33 PM   #617
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QuoteOriginally posted by luftfluss Quote
(...)

Since it appears the DA 16-85 will cost roughly twice as much as the DA 18-135 (...)
Where does this statement come from?

All prices below are European MSRPs, VAT included.

DA 18-135 was launched at €699, went up to €769 and recently down to €549.

DA 16-85 will be launched at €649. Twice as much as DA 18-135 indeed...
11-22-2014, 03:36 PM   #618
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QuoteOriginally posted by luftfluss Quote
First thing I thought of.

Also, according to Photozone, the 16-45 & 16-50 both do well.
Photozone is a bit out of date since all those lenses were reviewed a 10mp.
DXO mark shows the the lens are OK for sharpness stopped down, but with a LOT of CA.
I would like pentax to make a WA zoom at the sharpness/CA level of a sigma 17-50/2.8
Is that really too much to ask?
11-22-2014, 03:57 PM   #619
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QuoteOriginally posted by Mistral75 Quote
Where does this statement come from?

All prices below are European MSRPs, VAT included.

DA 18-135 was launched at €699, went up to €769 and recently down to €549.

DA 16-85 will be launched at €649. Twice as much as DA 18-135 indeed...


In the US, the DA 18-135 is consistently available for $400 or less. Currently, I see it for $349 (maybe w/o hood)

The current pre-order price for the DA 16-85 is currently ~ $750 USD.

Naturally, the price of the DA 16-85 will eventually drop.

---------- Post added 11-22-14 at 06:04 PM ----------

QuoteOriginally posted by robjmitchell Quote
Photozone is a bit out of date since all those lenses were reviewed a 10mp.
DXO mark shows the the lens are OK for sharpness stopped down, but with a LOT of CA.
I would like pentax to make a WA zoom at the sharpness/CA level of a sigma 17-50/2.8
Is that really too much to ask?
I know the Photozone tests are old, but the relationship of the edge sharpness to center sharpness won't change based on the sensor's MP count. So, for example, if the lens's borders are 75% as sharp as the lens's center on a 10MP sensor, the same 75% should apply on a 16MP sensor.

If the 16-50 doesn't do it for you, I don't know if there's a current Pentax lens that will do what you'd like it to do.

11-22-2014, 04:13 PM   #620
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QuoteOriginally posted by robjmitchell Quote
I would like pentax to make a WA zoom at the sharpness/CA level of a sigma 17-50/2.8 Is that really too much to ask?
Probably not, but if they make it you will most likely also ask for weather sealing and a low price
11-22-2014, 04:13 PM   #621
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QuoteOriginally posted by luftfluss Quote


In the US, the DA 18-135 is consistently available for $400 or less. Currently, I see it for $349 (maybe w/o hood)

The current pre-order price for the DA 16-85 is currently ~ $750 USD.

Naturally, the price of the DA 16-85 will eventually drop.
Do not, I repeat, do not ever compare MSRPs and street prices.

DA 16-85 and DA 18-135 were launched at similar MSRPs, even identical in the UK: £599,99. In the Euro zone, the launch price of DA 18-135 was a bit (€50) higher than that of DA 16-85.

Pre-order prices are almost always equal to MSRP. As you recognise yourself, the price of the DA 16-85 will drop, as the one of DA 18-135 has done. Your previous statement
QuoteQuote:
Since it appears the DA 16-85 will cost roughly twice as much as the DA 18-135, and the DA 18-135 already does a nice job with image quality attributes unrelated to sharpness, the DA 16-85 needs to be sharper.
is therefore void of any legitimacy other than an extemporaneous and erroneous perception.

---------- Post added 11-23-2014 at 12:35 AM ----------

QuoteOriginally posted by luftfluss Quote
(...) the relationship of the edge sharpness to center sharpness won't change based on the sensor's MP count. So, for example, if the lens's borders are 75% as sharp as the lens's center on a 10MP sensor, the same 75% should apply on a 16MP sensor.
(...)
Do not imagine I am picking on you but I am afraid this isn't valid either.

The more MP in the sensor, the higher the ratio between the centre sharpness, which fully benefits from the increase in MP count, and the edge sharpness, which, weaker, only partly benefits from this increase.

In the extreme, when the lens becomes the limiting factor, a further increase in MP count doesn't increase the resolution in the edges (whilst it still does in the centre): when the resolving power of the lens becomes the limit, you can add MPs and increase the sensor's sampling power, you won't get any more detailed data.

As an illustration of the above, I suggest your having a look at the two tests of the FA 43mm f/1.9 Limited made by Photozone, the first one on K10D (10 MP) Pentax SMC-FA 43mm f/1.9 Limited - Review / Test Report


and the second one on K-5 (16 MP) http://www.photozone.de/pentax/736-pentax43f19k5


As you can see from the tables above, the relationship of the edge sharpness to centre sharpness at f/1.9 is equal to 0.63 with the 10 MP sensor and 0.50 with the 16 MP sensor. The centre resolution takes full advantage of the increase in MP count (from 1,774.5 to 2,351 i.e. +32.5%) whilst the edge resolution is only marginally improved (from 1,119 to 1,179 i.e. +5.4%).

Last edited by Mistral75; 11-22-2014 at 04:42 PM.
11-22-2014, 04:21 PM   #622
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my most favorite site for lens reviews is lenstip.com. They haven't tested many Pentax lenses yet, but they're reviewing the lenses quite detailed; I like their charts for the sharpness, which allow you to compare the sharpness over a certain FOV and aperture quickly. Furthermore their reviews are covering many fields. i.e.: Pentax smc DA 17-70 mm f/4.0 AL [IF] SDM – Lenstip Lens review
11-22-2014, 04:23 PM   #623
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QuoteOriginally posted by Jantus Quote
my most favorite site for lens reviews is lenstip.com. They haven't tested many Pentax lenses yet, but they're reviewing the lenses quite detailed; I like their charts for the sharpness, which allow you to compare the sharpness over a certain FOV and aperture quickly. Furthermore their reviews are covering many fields. i.e.: Pentax smc DA 17-70 mm f/4.0 AL [IF] SDM – Lenstip Lens review
focal length instead of FOV

11-22-2014, 05:05 PM   #624
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QuoteOriginally posted by Jantus Quote
my most favorite site for lens reviews is lenstip.com. They haven't tested many Pentax lenses yet, but they're reviewing the lenses quite detailed; I like their charts for the sharpness, which allow you to compare the sharpness over a certain focal length and aperture quickly. Furthermore their reviews are covering many fields. i.e.: Pentax smc DA 17-70 mm f/4.0 AL [IF] SDM – Lenstip Lens review
I like LensTip's reviews too, they are more detailed than Photozone's and addressing more parameters (astigmatism, coma,...).

Unfortunately they have only reviewed 15 Pentax lenses so far, of which 12 prime lenses and 3 zoom lenses:

http://www.lenstip.com/index.html?test=obiektywu&producent=13&przetest=1&szukaj=Search
11-22-2014, 05:32 PM   #625
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QuoteOriginally posted by Mistral75 Quote
Do not, I repeat, do not ever compare MSRPs and street prices.
The MSRP of the DA 16-85 is the current street price.

QuoteQuote:
DA 16-85 and DA 18-135 were launched at similar MSRPs, even identical in the UK: £599,99. In the Euro zone, the launch price of DA 18-135 was a bit (€50) higher than that of DA 16-85.

Pre-order prices are almost always equal to MSRP. As you recognise yourself, the price of the DA 16-85 will drop, as the one of DA 18-135 has done.
I compare the prices at which I can obtain the lens, as do many people. If that's not how you do it, fine.

QuoteQuote:
Your previous statement is therefore void of any legitimacy other than an extemporaneous and erroneous perception.
No. You are not the arbiter of legitimacy.

---------- Post added 11-22-14 at 07:36 PM ----------

QuoteOriginally posted by Mistral75 Quote
....but I am afraid this isn't valid either.
You might be correct and I may be incorrect, however you are comparing 2 different samples - it is not the same FA43 used in each test, according to the attribution at Photozone.

However, you've shown me enough that I will do more research.
11-22-2014, 07:07 PM   #626
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I don't pay much attention to DXO, but I like Photozone because of the lenses I have bought and have experience of, I agree with his assessment. I particular, the Photozone review led me to choose the FA35 as my first prime, which I have no regrets about.
11-23-2014, 03:21 AM   #627
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QuoteOriginally posted by Mistral75 Quote
Sharpness is not the alpha and the omega for a lens. One can also take advantage of less distortion, less lateral chromatic aberration, less astigmatism (for a more pleasant bokeh for instance), less coma in the corners and so on.

If only 'pure' sharpness mattered, the FA Limiteds would be considered as second-tier lenses, which they definitely aren't.
FA ltd are also extremely sharp.

FA31 is simply sharp corner to corner wide open (more than many are at f/8 in corners) and become even better when stopping down.
FA77 is ok wide open, really nice already at f/2.5 and perfect f/4+.
FA43 seems to need to be closed down a little but is perfectly sharp then.

Even by sharpness alone, FA ltd are good to excelent depending of the model.

Our DA21 & DA15, while really strong lenses are a little disapointing on corner performance. Not really as lack of sharpness in absolute term, because they can provide sharp corners, but more due to field curvature that make the corners quite soft on the occasion. To me that's the limit of small wide angle lens on the K-mount. We already see the FA31 size... there a reason it is already quite bigger than the other FA, still 31mmm isn't that wide.

As for a 16-85 consumer zoom or 18-135, one should not expect too much.
11-23-2014, 06:52 AM   #628
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Sounds a perfectly decent lens of useful focal lengths to me. Chances are it will test fine for the kind of lens it is, too, maybe even better than that. At present it is overpriced by 40-45 per cent compared to others of its kind so sales will come when the price starts dropping away from presale/introduction. And if the price doesn't fall then the item won't sell very well. That's about it so far as I can see. If the lens offers above-average overall rendering for landscapes, cityscapes and the like at around say f8 then it would easily appeal to me (above-average = compared to a basic kit lens). If it doesn't then something like a Sigma 17-70mm at a much reduced cost would be a no-brainer alternative, giving up WR but saving $$$ on a tweaked and proven design. We are spoiled for choice.

Last edited by mecrox; 11-23-2014 at 06:57 AM.
11-23-2014, 08:04 AM   #629
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QuoteOriginally posted by Nicolas06 Quote
FA ltd are also extremely sharp.

FA31 is simply sharp corner to corner wide open (more than many are at f/8 in corners) and become even better when stopping down.
Lenstip begs to differ:

"It is clearly seen that in the centre the area near the maximum relative aperture doesn’t provide you with images of the satisfactory quality and to get it you have to close down the aperture to the value of about f/2.2.

On the edge of the frame, even after stopping down to f/2.8, you still don’t get full usefulness of image. Here, in order to get a sharp photo, you must stop down by an additional value of 0.5 EV."

Their assessment matches the wide-open images from this lens that I have seen posted here and in other places.
They look weak, even in web resolutions at around 1000 px.
11-23-2014, 08:16 AM   #630
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QuoteOriginally posted by Nicolas06 Quote
FA ltd are also extremely sharp.

FA31 is simply sharp corner to corner wide open (more than many are at f/8 in corners) and become even better when stopping down.
I don't think so. I use it on K200D and at K-5IIs.
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