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02-02-2009, 02:39 PM   #16
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QuoteOriginally posted by Ash Quote
Well then, perhaps you can enlighten the ignorant such as myself as to what the two lenses are designed for (if they are for different purposes) apart from the obvious one extra stop, SDM and weather sealing?
the 45 is a compact, cheap (cost) lens that is a stellar performer, when the sun goes down chances are a flash is needed for compensation.

the DA* is, as you already seem to know, but comically seem to not understand, is weather sealed, which already opens up a world of opertunities, has SDM, a feature that should not be overlooked, and can only be appreciated when used and not just read about, and the fact that its faster, allowing low-light photography, and most importantly, shallow(er) depth of field control for more creative photography

all this at a higher cost


apples and oranges

02-02-2009, 03:30 PM   #17
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QuoteOriginally posted by Gooshin Quote


apples and oranges
I find it more tangelos and bananas, but I respect your personal fruit opinion (PFO).
02-02-2009, 03:45 PM   #18
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And what makes you think that I don't understand or have not used those features Gooshin?

Comparing IQ between lenses ain't apples and oranges. Perhaps the features and applications of the lenses are, but the thread was just about IQ.
02-02-2009, 07:42 PM   #19
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QuoteOriginally posted by Ash Quote
And what makes you think that I don't understand or have not used those features Gooshin?

Comparing IQ between lenses ain't apples and oranges. Perhaps the features and applications of the lenses are, but the thread was just about IQ.
couple of things

first, IQ stands for image quality, you want to talk about IQ, you have to talk about alot of things, not just raw MTF data

second, distortion figured, the % are rather useless, because if you look at your off-centered garage pictures, you cant tell the difference

third, you're using a K10D, so really, which is the weaker link, since its been mentioned that some lenses perform better on the K20.. and what about the K100D guys, ehh?


you're reading MTF charts from photozone and you want to make some sort of definitive claim?

what do you photograph... bar codes? is your photography focus bar codes?

look at the numbers again that you so carefully examined, compare them to each other in absolute terms, the difference is laughly negligable.

i regress, these lenses are funemetnally different and aimed at different usages and requirements, they also have noticebly different pricetags.

the difference in IQ, which you are so eager to define, is negligeble

ergo, this whole thread is useless, because you ansewred your own question during the conclusion of your first post

gaaah

*facepalm

02-02-2009, 08:18 PM   #20
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I'm happy for you Gooshin.

Thanks for your productive contribution, not at all presumptuous or condescending, and wasting your precious time on such a useless thread.

Last edited by Ash; 02-02-2009 at 08:50 PM.
02-02-2009, 08:25 PM   #21
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pomegranates and kiwi fruit?
02-02-2009, 08:57 PM   #22
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QuoteOriginally posted by Gooshin Quote
distortion figured, the % are rather useless, because if you look at your off-centered garage pictures, you cant tell the difference
I can certainly see the difference, and distortion is something I care a lot about.
02-02-2009, 09:17 PM   #23
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QuoteOriginally posted by audiobomber Quote
I can certainly see the difference
yes, and the '50 is distinctly 'wavy' rather than just bent! Fix that in your photoshops! Not very nice at all!

02-02-2009, 09:42 PM   #24
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QuoteOriginally posted by audiobomber Quote
I can certainly see the difference, and distortion is something I care a lot about.
both are noticebly distorted

distorted differently, but distorted

if i showed you these two photographs on the street and asked you how much more % was one over the other, what, you're going to tell me that one is half a point moer than the other? come now.


QuoteOriginally posted by Ash Quote
I'm happy for you Gooshin.

Thanks for your productive contribution, not at all presumptuous or condescending, and wasting your precious time on such a useless thread.
good! thank you for your understanding.
02-02-2009, 10:01 PM   #25
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I think the first garage door looks better, although in truth I do not now, maybe it is in reality all wavy and bent like the DA 16-50 seems to show. I will never have both lenses to compare them, so I find this thread useful for my daydreaming about the next lens I might buy. Thanks Ash!

I cannot understand for the life of me why someone would comment on a thread to call it useless, exposing to everyone who reads this that they have too much time on their hands, and choose to use that time being unkind.
02-03-2009, 06:21 AM   #26
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QuoteOriginally posted by Gooshin Quote
both are noticebly distorted

distorted differently, but distorted

if i showed you these two photographs on the street and asked you how much more % was one over the other, what, you're going to tell me that one is half a point moer than the other? come now.
The percent change between 2.52 and 3.63 is 44%. For landscapes it will rarely matter. For architectural photos, it matters a lot. Percentages aside, the difference in the garage door photos on my personal distortion meter is the difference between acceptable and unacceptable. I would not own a 16-50 unless I also owned a lens with acceptable distortion at 16mm (or wider).

PS, I don't consider F2.8 fast enough for indoor/low light photography, so although an extra stop is better it's not that big a deal to me. I still need a fast prime.
02-03-2009, 07:31 AM   #27
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QuoteOriginally posted by audiobomber Quote
The percent change between 2.52 and 3.63 is 44%. For landscapes it will rarely matter. For architectural photos, it matters a lot. Percentages aside, the difference in the garage door photos on my personal distortion meter is the difference between acceptable and unacceptable. I would not own a 16-50 unless I also owned a lens with acceptable distortion at 16mm (or wider).

PS, I don't consider F2.8 fast enough for indoor/low light photography, so although an extra stop is better it's not that big a deal to me. I still need a fast prime.
if you want to swindle your math that way, go ahead, i like to think of it as distortion from a base point, not distorted over the other


image A is distorted 2.52 % over base, ie, a straight line

image B is distorted 3.63% over base, which means image B is only 1% more distorted than image A

but we can play this numbers game all you want, your choice.


also, 2.8 is better than 4 regardless. (for light), and if you dont shoot in low light at F2.8, well, you're missing out on alot of photos then, because its doable.

Last edited by Gooshin; 02-03-2009 at 08:07 AM.
02-03-2009, 08:07 AM   #28
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QuoteOriginally posted by Gooshin Quote
if you want to swindle your math that way, go ahead, i like to think of it as distortion from a base point, not distorted over the other
If the worst lenses had distortion of 100%, then I would agree with you. The 18-250 has the highest distortion figures in Pentax mount, at 4.32%. Obviously its distortion level is extreme, just look at this photo.



You say the 18-250 is only 0.69% more distorted at 18mm than the 16-50 is at 16mm. I say the 18-250 is 19% more distorted. What would someone say who didn't know the respective numbers, 0.69 or 19%? Clearly distortion has to be judged on a relative basis, since 100% distortion is functionally meaningless.
02-03-2009, 08:13 AM   #29
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QuoteOriginally posted by Gooshin Quote
if you dont shoot in low light at F2.8, well, you're missing out on alot of photos then, because its doable.
Its doable, but not good enough to avoid buying a faster prime. I just bought an FA 35 2.0 because the 28mm 2.8 wasn't fast enough. I'm hoping the DA*30mm will be F1.4. The main point is that even if I had the 16-50 instead of the 16-45, I'd still bring neither to a museum, I'd bring the 35mm 2.0.
02-03-2009, 08:33 AM   #30
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its still visually distorted

once something is visually distorted, distorting it by half a point is not going to make you go bannans, which is what you seem to be trying to prove

now if you slap on a fisheye lens, thats a different story.

plus you're shooting a rectangular object with a lens that distorts, to what, prove that the lens distorts... ohhkey

i'm not understanding what you are trying to prove here,

you are telling me, that if i was to show the two ORIGINAL images that the OP posted, to a random person, you're telling me that they would say that image B is FORTY FOUR PERCENT MORE distorted than image A?

because thats what you are telling me, and you're wrong, no one will give you an answer like that.
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