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04-28-2011, 08:22 AM   #16
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Ahhhh!!!!

QuoteOriginally posted by GregK8 Quote
Here is a comparison at 18mm and f4.0. The first image is the DA* 16-50, the second from the same spot using the 18-55mm kit lens. By my eye the second image needs to have it's EV boosted by +1/3 to equal the first.
QuoteOriginally posted by GregK8 Quote
This second set of shots is at 50mm and f4. The image from the 18-55mm needs at least a full +1 of EV to make them the same on my monitor.
Straighten that picture, or level your desk...EEEK!

And did anyone notice how CURVED the ceiling is in BOTH SHOTS...?

Cheers,
Cameron

04-28-2011, 09:35 AM   #17
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QuoteOriginally posted by Cambo Quote

And did anyone notice how CURVED the ceiling is in BOTH SHOTS...?
There's definitely barrel distortion at the wide end of both lenses. It seems much worse in the kit lens to my eye.
04-28-2011, 09:48 AM   #18
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QuoteQuote:
Different lenses are also optimized for different focal lengths. I'll bet at 50 mm the DA* trumps the kit at any aperture.

According to PhotoZone, the kit lens [old version] almost equals the 16-50 in MTF at 50mm and mid-apertures and has considerably less CA. The 16-50 is better wide open generally and has a speed advantage. Otherwise, they produce comparable images.
04-28-2011, 10:13 AM   #19
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QuoteOriginally posted by Cambo Quote
Straighten that picture, or level your desk...EEEK!

And did anyone notice how CURVED the ceiling is in BOTH SHOTS...?

Cheers,
Cameron
This is the sort of thing I don't worry about so much since it is so fixable in software like Lightroom (presets now available). In addition, with a lot of landscapes, you don't even notice the distortion -- more the colors, contrast and sharpness.

04-28-2011, 12:04 PM   #20
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QuoteOriginally posted by tempelorg Quote
Wow, does else everyone agree on this?
Check out the sticky thread or article or wherever it is that the different kit lenses are explained, but yes, this is an absolutely 100% certain fact, made quite clear in Pentax' own marketing materials and in posts by John Carlson himself. 18-55WR = 18-55II + weather resistance.
04-28-2011, 01:08 PM   #21
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Expensive lenses tend to preform better at wider apertures. Most lenses preform admirably at f8.
04-28-2011, 01:34 PM   #22
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QuoteOriginally posted by paperbag846 Quote
Expensive lenses tend to preform better at wider apertures. Most lenses preform admirably at f8.
Except, maybe, superzooms?
04-28-2011, 01:52 PM   #23
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QuoteOriginally posted by Rondec Quote
Except, maybe, superzooms?
I'd like to see an example before I make a judgment there. I'd imagine even a superzoom would be acceptable at f8.

Likely their biggest flaw would be flare resistance.

04-28-2011, 02:35 PM   #24
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QuoteOriginally posted by tempelorg Quote
Wow, does else everyone agree on this?
QuoteOriginally posted by Marc Sabatella Quote
Check out the sticky thread or article or wherever it is that the different kit lenses are explained, but yes, this is an absolutely 100% certain fact, made quite clear in Pentax' own marketing materials and in posts by John Carlson himself. 18-55WR = 18-55II + weather resistance.
And if Im not mistaken, 18-55WR minus WR, Quick Shift and metal mount = DAL 18-55mm Kit lens (new generation K-x and up).
04-29-2011, 07:59 PM   #25
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QuoteOriginally posted by tempelorg Quote
Wow, does else everyone agree on this? I see significant quality differences between the two of mine. Not that it really matters as I don't have use for the AL II any more, but since I wondered if I should sell it on eBay, I should probably point out the possibility of having a really badly produced individual sample.
I'm starting to conclude that sample variations plays at least as big a part in lens quality than design does. It would be very responsible of you to point out what you may feel is a performance shortcoming, but you might be hard-pressed to sell a lens that you declare to be poor quality. Perhaps a good compromise would be to offer full-res downloads to the purchaser to demonstrate the quality of the lens before completing the purchase. In fact we really don't know what Pentax considers an acceptable range of quality for the lenses, so both your lenses might be considered ok by the manufacturer. Given the low price of the lens, the last thing you want is to deal with a return from an unsatisfied customer.

Paul
04-30-2011, 12:33 AM   #26
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QuoteOriginally posted by tibbitts Quote
Perhaps a good compromise would be to offer full-res downloads to the purchaser to demonstrate the quality of the lens before completing the purchase
Good idea, Paul. Will do that.
04-30-2011, 12:46 AM   #27
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Oh, one more note on the first post: When I did my diffraction/sharpness tests with my various (mostly cheap) zoom lens, I also found that the DA* 16-50, at f/2.8, is sharpest at 18mm, than got worse to the middle (28mm) and slightly better again at 50mm. I only measured the center of the img, though, using a Siemens sheet. OTOH, with the DA 18-55 AL WR, I found that it was sharpest at the middle focal range (28mm), at f/5.6, compared to 18mm and 55mm.
Can others confirm that?
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