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08-05-2007, 11:38 PM   #1
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Continue to like DA 50-200

Though the poor review of DA 50-200 in photozone.de

Hin's Tech Corner: Photozone.de Pentax DA 50-200 review

I continue to like it for all situations. I even use it for indoor portraits with my kids and I find it very versatile in zoom in from a farther distance.

Some pictures to follow in next post.

Thanks,
Hin

08-05-2007, 11:39 PM - 1 Like   #2
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Few pictures in hiking last weekend

Few pictures taken while hiking with my older boy last Sunday. All have no post processing except hasty cropping in Picasa

Hin's Tech Corner: Picasa Tutorials

#1


#2


#3


#4


#5


#6


#7


#8


#9


#10
http://farm2.static.flickr.com/1266/1025002679_9f08702038.jpg[/IMG]

I am newbie with untrained eyes and use 'P' mode exclusively. C&C are needed and welcome.

Hin

Last edited by hinman; 08-09-2007 at 01:32 PM.
08-05-2007, 11:41 PM   #3
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Missing #10

#10


Thanks,
Hin
08-06-2007, 06:34 AM   #4
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A blog entry using two pictures

I pick two images and put it into a blog with writing from Lao Tsu on Enlightenment

Hin's Photo Blog: Enlightenment by Lao Tzu

And I prefer my DA 50-200 over my kit's len for the sharpness, range, color, and bokeh. Though I don't have an interesting subject to shoot, I have great liking on the color, bokeh and 3d effect and perspective that I get in the shot





Comments & Critique are welcome. I am newbie with untrained eyes and lack of knowledge in improvement.

Thanks,
Hin

08-09-2007, 11:02 AM   #5
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Themed blog post with Pentax pictures

I am new to my dSLR and I come from p&s world with my Fuji F30 and Casio ex-z750. So far, it has been a blast but I do better with my Fuji F30 for night pictures, results such as that with my Fuji F30, I can't reproduce with my Pentax K100D.

Hin's Photo Blog: Macau Night Pictures with Fuji F30

It has to do with my skills. But I am very blessed to have purchased dSLR and try to learn as much as sharing them in my blog pages

Hin's Tech Corner: Picasa Tutorials

And sharing them with religious contents, poem and songs that are dear to me

You are my hiding place
Hin's Photo Blog: You are My Hiding Place

Enlightenment by Lao Tzu
Hin's Photo Blog: Enlightenment by Lao Tzu

Not easy to be me (superman lyrics)
Hin's Photo Blog: Not easy to be me

Thanks,
Hin
08-09-2007, 06:38 PM   #6
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My wife and I like your photo of the thistle with spider. Very striking.
08-09-2007, 07:27 PM   #7
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Yeah, very nice shot.

I had a bunch of potentials with a shot of a butterfly on a flower taken with my Tamron 70-300, but the buttefly's wings were tattered for some reason.

There was a bee buzzing around but it was impossible to catch it holding still long enough to take a picture.
08-09-2007, 07:29 PM   #8
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Photozone review on the lense wasn't very good, but as your images had shown, in a experience hand it will produce great images! You should check out the Pentax photo gallery site, as I notice a number of images were shot using the very same lense and they are awesome! If I remember correctly, some of the shots from Julie Smith on that site uses that lense. Here is the url for it
PENTAX Photo Gallery

08-10-2007, 10:17 AM   #9
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QuoteOriginally posted by eman Quote
Photozone review on the lense wasn't very good, but as your images had shown, in a experience hand it will produce great images! You should check out the Pentax photo gallery site, as I notice a number of images were shot using the very same lense and they are awesome! If I remember correctly, some of the shots from Julie Smith on that site uses that lense. Here is the url for it
PENTAX Photo Gallery
Actually, it's more of a yield and QA issue.
Many of us are getting "good samples."
Others are getting (including PhotoZone.DE), what Pentax calls, "within specifications."

My DA 50-200mm performs nothing like the PhotoZone.DE pics, which clearly have issues.
On another forum, I've noted someone else with a "within specifications" example, same deal.
The PhotoZone.DE reviewer or users aren't bad, their lens is clearly limiting.

In all honesty, I wish Pentax would cut their yield by 20-25% and just charge 20-25% more.
Because when you get a "good sample," which a lot of people are, the lens is an outstanding value.
When you get a sample "within specifications" -- which seems to be 20-25% of the cases -- it's definitely a lens that only cost $200 or less.
08-10-2007, 11:17 AM   #10
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QuoteOriginally posted by bjsmith Quote
Many of us are getting "good samples."
Others are getting (including PhotoZone.DE), what Pentax calls, "within specifications."
Which leads me to the question, the lens is so inexpensive its internal mechanism cannot be hi-tech stuff, then its lightweight can only mean relatively softer materials in contact with moving parts; so ... how long will the good copies retain the tight tolerance to remain good copies?

Last edited by Kguru; 08-10-2007 at 11:26 AM.
08-10-2007, 11:42 AM   #11
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QuoteOriginally posted by Kguru Quote
Which leads me to the question, the lens is so inexpensive its internal mechanism cannot be hi-tech stuff, then its lightweight can only mean relatively softer materials in contact with moving parts;
Not true.
Materials technology has advanced very far in just the last 5-10 years.

Boeing's 787 Dreamliner is just one example.
The 787s are supposed to go 15 years without overhaul, compared to only 7 with standard aluminum hulls.

Heck, there is a movement in NASA to bring back the VentureStar, and drop the Orion Project.
Why? The VentureStar originally failed and eventually was dropped because of the materials failure of its tanks, which no one thought would be feasible just 5 years ago.
Now the materials technology is not only available to contain the cryogenics, but it's becoming commodity and very long lasting -- in addition to being lighter than what even the specs called for.

(yes, I'm a former defense engineer, so my apologies for the analogies)

QuoteOriginally posted by Kguru Quote
so ... how long will the good copies retain the tight tolerance to remain good copies?
Don't know, but new polycarbon and other light materials can be very long-lasting.
"Softer" materials are not the issue here, not at all.

It's a yield-QA decision process, one where I think Pentax could afford to tighten their process and discard another 20-25% of yields to remove that small subset of lenses.
The fabrication is not exacting, and that's what you get with a commodity process.
The counter is then to put in place a range of tolerances and allowances, discarding anything that doesn't "make the grade."

So, again IMPO, Pentax should tighten those tolerances which would give them an outstanding product, while only removing an additional 20-25% yield.
I don't have any emperical evidence or figures for that number, but it's been about 1 out of 4 or 5 that have complained about the inconsistent IQ of their DA 50-200mm.
I'd like to gather more, but it could also be that Pentax really just looks for glaring defects and ships anything else.

My DA 50-200mm is outstanding, as is my DA 16-45mm (sans the blue-yellow CAs which are expected).
My DA 18-55mm "kit" is tolerable, definitely probably not the best sample, but I only paid $60 or so for it, and it's expected to be soft in the corners (mine just seem more so than othes).

Last edited by bjsmith; 08-10-2007 at 11:47 AM.
08-10-2007, 12:11 PM   #12
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QuoteOriginally posted by bjsmith Quote
Materials technology has advanced very far in just the last 5-10 years.
Boeing's 787 Dreamliner is just one example.
I agree with 80% of your "arguments" (for lack of a better word).
The remaining 20%: you didn't include into your considerations the 50-200's low-cost.

(a) In my experience low-cost light materials mean low durability.
(b) In similar FL & price bracket current Sigmas and Tamrons weigh nearly twice as much as the 50-200. Does that mean Sigma & Tamron are so far behind in lightweight technology, or because Pentax use lower durability (compared to S & T) materials?
(c) If Pentax has created this lightweight yet durable material for the 50-200 why don't they use it for lenses like the 31mm for example, to make them less heavy?

PS: By durability here I don't mean against breakage, I'm talking about micrometre wear that can easily upset a good copy.

Last edited by Kguru; 08-10-2007 at 12:21 PM.
08-10-2007, 01:17 PM   #13
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QuoteOriginally posted by Kguru Quote
(a) In my experience low-cost light materials mean low durability.
A true general rule of thumb, but there are many exceptions, as mentioned above.

QuoteOriginally posted by Kguru Quote
(b) In similar FL & price bracket current Sigmas and Tamrons weigh nearly twice as much as the 50-200. Does that mean Sigma & Tamron are so far behind in lightweight technology, or because Pentax use lower durability (compared to S & T) materials?
Wrong, go check the websites and the weights of Sigma and Tamron 50-200 qequivalents, which happen to be 55-200 in both cases. The Sigma weighs 310g, the Tamron is 300g while the Pentax is 255g. Double, eh? And what about the fact that Sigma and Tamron BOTH have internal motors, HSM in Sigma's case and normal micro-motor in Tamron's, while the Pentax has no motor to speak of. They don't show the weights of the Sigmas and the Tamrons in Pentax mount, but I bet the weights are very close to 255g.

Maybe you were trying to compare the 50-200 to Tamron and Sigma's 75-300 lenses? If so, why? First, they are *full-frame* lenses, making them use more glass than the Pentax, second they have more range.

QuoteOriginally posted by Kguru Quote
(c) If Pentax has created this lightweight yet durable material for the 50-200 why don't they use it for lenses like the 31mm for example, to make them less heavy?
The same material is used in all the non-limited and non-DA* lenses, including the DA16-45 and DA12-24 (they have metal zoom rings, though). As for the 31mm Limited, that line of 3 FA limiteds was created to emulate the classic *metal* primes when it comes to look and feel, why would they put plastic in there?

Hope this helps.

Cheers,
-Asad
08-10-2007, 05:02 PM   #14
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QuoteOriginally posted by Kguru Quote
(a) In my experience low-cost light materials mean low durability.
In my experience as an engineering product manager ...
- Cost isn't just about materials
- The weight of materials doesn't not translate into sturdier materials (especially not in the past 5-10 years)
- Pentax's fab in Vietnam is actually newer, so it sports newer technologies that are now "commodity"

Cost is more than just about input, but many aspects of Quality Assurance (QA).

You can ...
- Use lower costing components of less exacting tolerances and still get most excellent results
- That requires you to discard samples that are poor results of the process.
- How many samples depends on how you define your tolerances and allowances

From what I've seen, Pentax is ...
- Getting good yields of excellent quality, despite using commodity components of low-cost in the process
- Setting their tolerances and allowances too low, which causes them to ship 20-25% of samples that are less favorable

That might be a factor of their QA decisions. I.e.,
- Pentax may only look for major defects and discarding those
- Inconsistency and "harder to notice" IQ issues may not be tested, because additional testing costs money

QA can be the "biggest cost" in any product fabrication -- especially the more testing it involves.

E.g., Even though NASA has switched to commodity hardware and software since the '90s, QA costs are still high.
NASA once tried to slash QA budget 90% like they did hardware and software development, this was the infamous Mars Polar Lander.
The result of killing 90% QA was that one contract software developer in Texas was using metric and another software team at another contract in Colorado used Imperial units -- in two different routines that eventually interfaced.
It turned into the biggest embarrassment in NASA's history.
Post-review showed that basic engineering and QA practices were utterly ignored, because of the sheer cost to implement them.

QuoteOriginally posted by Kguru Quote
(b) In similar FL & price bracket current Sigmas and Tamrons weigh nearly twice as much as the 50-200.
The DA 50-200 is already a very, very small and compact unit to begin with.
I don't care what material they used, the design is very small.
So your "weight" argument is already biased in that regard.

QuoteOriginally posted by Kguru Quote
Does that mean Sigma & Tamron are so far behind in lightweight technology, or because Pentax use lower durability (compared to S & T) materials?
It could be many things.
But yes, Pentax's Vietnam fabrication facility (shared with Tamron I believe?) is actually circa 2003 technology.
The massive strides in polycarbonate and other optical technologies would easily blow away an older fabrication facility in cost v. performance.

New fabrication facilities are expensive to build (and likely a reason why Pentax shared the cost with another company).

Just ask AMD. They just can't keep up with Intel.
Back when Intel had not done a complete architectural redesign of x86 since 1994 (NetBurst was not a completely new design, just a "refit"),
AMD's 5 year newer architecture (1999/Hammer v. 1994/P6) kept them ahead, even though they were 18 months behind Intel in fab.
Now that Intel actually redesigned a full and new architcture (2006/Core), AMD's lack of being anywhere close to Intel's fabs really hurts.

QuoteOriginally posted by Kguru Quote
(c) If Pentax has created this lightweight yet durable material for the 50-200 why don't they use it for lenses like the 31mm for example, to make them less heavy?
Redesign costs. You can't redesign things overnight.
Furthermore, older fabs still have their uses, for old designs that still sell well.
So not only is it that you can't redesign things overnight, but you still have old facilities that can still make those older designs.

Likewise, AMD and Intel also have older fabs, where AMD makes EEPROM and Geode NX (embedded Athlon) and Intel makes EEPROM and XScale (embedded ARM) at 90-130nm processes.

But as Pentax redesigns new, prime lenses, they will ship more, cheaper, commodity polycarbonate designs.
It will be interesting how they balance fab, QA and other costs on their DA* lenses.

QuoteOriginally posted by Kguru Quote
PS: By durability here I don't mean against breakage, I'm talking about micrometre wear that can easily upset a good copy.
I know.
And if that is the case, then Boeing wouldn't stop using Aluminum, let alone Titanium, in favor of new composites.

I mean, we don't still use Titanium all over aircraft, only limitedly.
It's more than just about cost, a lot of it has to do with better materials for the job.
And the techniques to do so are now commodity, with more on the way.

Engineering product management 101 here.
It costs real money and time to build modern fabs, redesign components and the fact remains that you have older fabs and older designs that are still "good enough" to pump out products.
Not everyone always works on the "sexy, new" product, and it's often more difficult to maintain the old one.

As I always point out, NASA's greatest engineering lifecycle achievement wasn't the moon -- the Apollo "product" lifecycle of only 5 years.
NASA's greatest engineering lifecycle achievement was the Space Shuttle -- a product of, now, 30 years.
NASA actually had zero (0) design failures on the Shuttle, a system of 100,000 parts.
What NASA had were two (2) (actually more than 2) "material review" (MR) QA oversights.

One was when the sealant on the O-Rings were changed in 1985 -- a change due to new EPA regulations on the chemicals used.
The MRs failed to catch the fact that the O-Rings were now suseptible to weather and environment, where they were not before.
Unfortunately, no one sold the old sealant, and that's when it came down to an availability/feasibility issue.
The engineers did not properly assess the risk, and the result was proven in the sheer statistics of launches from 1985+ (but not before the change).

The other was when the insulation on the external tank was changed in 1997 -- also a change done by the EPA (back in 1987 which took effect in 1997).
The new, CFC-free insulator has severe tensile strength issues, and can "break apart" instead of holding together.
This is an extreme issue for not merely just the Shuttle, but our ballistic missile arsenal which uses rope to "pull off" insulation as the missile rises.
I've seen this crap first hand in White Sands, and it's scary that we can't use CFC insulation anymore where tensile strength is a requirement.
The EPA has given NASA an exception on CFC insulation since 2003, but just like the sealant prior, you can't find CFC-based insulation these days.

It was easy to find suppliers when a design was only 5 years old.
When you have a product that is made for 30 years, materials become a real issue.
NASA only has so much money to throw QA at a problem, and the Shuttle is getting too old and needs a complete redesign.
Unfortunately, Project Orion isn't it.

Prior, NASA thought it was the Lockheed Martin VentureStar prototype.
But that was canceled because the cryogenic tanks required lightweight materials not invented yet, and NASA eventually gave up (and Lockheed stopped using their own money).
That was not even 10 years ago now and, ironically, not only have they invented the new materials in that time, they work better than aluminum now.
Which is why many in NASA are calling for a refocus on VentureStar, and a cancellation of Orion.

This is just sample insights into the "real world" of an engineering product manager -- from materials to QA to lifecycle and product lifetime.

Last edited by bjsmith; 08-10-2007 at 05:19 PM.
08-13-2007, 07:28 AM   #15
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50x200 and tc

has anyone used this lens with a 2xs tc???
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