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01-25-2015, 12:04 PM   #106
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Yeah, only a few really understand the ltd design outside of Pentax. The idea of small, well crafted lenses that concentrate on prodution great pleasing actual image instead of optical perfection. That's smart of Pentax as apparently this come together. It by designing smaller apperture lenses with fewer elements that you get the best flare resistance, best constrast... and small size.

As for the rendering my understanding is that by undercorrecting some optical imperfection, you can make it look better even through you'll have to live with theses imperfections. Again that may be something that go well with a small design.

The * lenses look like more classic high end lenses to me while the ltd try to be small and may hide their imperfection behing interresting rendering. That very cleaver. Maybe too cleaver as most don't ever notice the result is actually quite good.

01-25-2015, 12:37 PM   #107
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QuoteOriginally posted by Nicolas06 Quote
Maybe too clever as most don't ever notice the result is actually quite good.
That's why they're "Limited"!
01-25-2015, 04:16 PM   #108
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QuoteOriginally posted by Nicolas06 Quote
Don't know if they are always related but the thing about flare is that in many case the only symptom might be reduced contrast on the whole shoot overall. It is only in extreme case you'll see the photo completely washed out or with artifacts.

To me the issue is prevent in many more situations than what we think of and a lense that key high contrast in thoses situation will perform really better, even through it might not show in resolution numbers of reviews.
I know. I think I read somewhere that a guy claimed he got much better sharpness out of the FA 50mm 1.4 when using a hood, even going so far as saying that the FA 50mm 1.7 was not better at all (although many perceive it to be), it just wasn't as susceptible to the effects of flare because it has a smaller aperture (or some other reason, could have to do with the optical formula as well).

QuoteOriginally posted by Nicolas06 Quote
I don't know... maybe reviewers could give resolution and contrast number in studio with lights in different position like center/corner ... ?
Now you say reviewers should try to isolate variables?

Anyway, not sure this is relevant to the original question. I will say this: the 16-50 is probably much more susceptible to flare than any of the limiteds, especially with the new HD coatings. Pentax should really update the DA* line imho. HD coating, replace SDM with something better, improve the optics of the 16-50...

---------- Post added 01-26-2015 at 12:20 AM ----------

QuoteOriginally posted by Nicolas06 Quote
Yeah, only a few really understand the ltd design outside of Pentax. The idea of small, well crafted lenses that concentrate on prodution great pleasing actual image instead of optical perfection.
Still, if I am going to spend 900 euros on a lens, I'd like it to be more versatile, i.e. so that I can shoot with it in low-light too. The 20-40 doesn't fit that bill imho.

Last edited by starbase218; 01-25-2015 at 04:23 PM.
01-26-2015, 03:59 AM - 1 Like   #109
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QuoteOriginally posted by starbase218 Quote
I know. I think I read somewhere that a guy claimed he got much better sharpness out of the FA 50mm 1.4 when using a hood, even going so far as saying that the FA 50mm 1.7 was not better at all (although many perceive it to be), it just wasn't as susceptible to the effects of flare because it has a smaller aperture (or some other reason, could have to do with the optical formula as well).



Now you say reviewers should try to isolate variables?

Anyway, not sure this is relevant to the original question. I will say this: the 16-50 is probably much more susceptible to flare than any of the limiteds, especially with the new HD coatings. Pentax should really update the DA* line imho. HD coating, replace SDM with something better, improve the optics of the 16-50...

---------- Post added 01-26-2015 at 12:20 AM ----------



Still, if I am going to spend 900 euros on a lens, I'd like it to be more versatile, i.e. so that I can shoot with it in low-light too. The 20-40 doesn't fit that bill imho.
The 16-50 is always going to be more prone to flare, even if it gets better coatings, because it has more glass. The more lens elements, the bigger the lens, the more prone to flare your lens will be. This to me, is why the limiteds are a lot better in that department -- they just don't have as much glass inside to cause reflections. The 20-40, even with its HD coatings isn't as good in this respect as the DA 15 or, 21 (original SMC version).

But my experience with the 16-50 is that you can avoid flare if you just partially block the sun. Weaker light sources like lamps at night aren't an issue at all.



01-26-2015, 10:39 AM   #110
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QuoteOriginally posted by starbase218 Quote
I know that flare can cause significant drops in contrast, but the two are not necessarily related, are they?
To some extent, yes. There's a sort of "veiling glare" that affects contrast and color:

QuoteQuote:
Veiling glare is stray light in lenses and optical systems caused by reflections between surfaces of lens elements and the inside barrel of the lens. It is a strong predictor of lens flare image fogging (loss of shadow detail and color) as well as “ghost” images that can degrade image quality in the presence of bright light sources in or near the field of view. It occurs in every optical system, including the human eye.... Lenses with low flare have been traditionally known for their excellent color performance. Color saturation is higher, especially in shadows. Low flare may be as responsible as sharpness for the exalted reputations of many classic Leica and Zeiss lenses. Even though lost color saturation and contrast can be recovered with digital processing, lenses with low flare will always have an edge in quality.
Bright light sources are often the chief culprit, but I've run into veiling glare issues even in the absence of obvious bright light (such as sun, or reflections of sun off water, mirrors, etc.) Last summer I was shooting at Crater Lake with the F 70-210. For a series of shots around noon, I noticed lower contrast for images that included the sky. Not sure how or why that happened. Shots that included the sky a few hours later did not suffer from this issue. But light can be funny that way; which is why the only way to really get to know a lens is to use extensively. Often the only difference between a very good lens and a better lens is merely greater consistency of output. My DA 15 more consistently produces images with better contrast and color (particularly in shadow areas) than does my DA 17-70.

---------- Post added 01-26-15 at 10:01 AM ----------

QuoteOriginally posted by starbase218 Quote
Still, if I am going to spend 900 euros on a lens, I'd like it to be more versatile, i.e. so that I can shoot with it in low-light too. The 20-40 doesn't fit that bill imho.
Photography is all about tradeoffs. Faster lenses tend to be larger, heavier, and require more glass. Precisely because they use more glass, they will be more prone to flare issues. So if you need fast lenses, you'll to sacrifice on the weight and on the flare control/contrast.

I would also point out that, whereas there are several options in terms of fast zooms (DA* 16-50, Tamron 17-50, Tamron 28-75, Sigma 17-50, Sigma 18-35), before the introduction of DA 20-40, there were no high-end slow WR standard zooms for the K-Mount. Those of us who are landscape photographers don't need f2.8 (we're most shooting around f8), so these slower lenses (like the DA 20-40 and the DA 16-85) fit the important (and often ignored) Landscape photography niche.
01-26-2015, 12:07 PM   #111
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for my experience i prefer zooms, i sold my 21mm & 70mm Ltd and i searched for a DA* 16-50 and 50-135mm.
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