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06-11-2012, 01:04 PM   #16
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Nope, the DA15ltd has less barrel distortion, mentally high central sharpness, and better edge sharpness than the DA14 (according to Photozone.de)
I will sometimes ignore MTF numbers as they are performed on a flat surface and may not tell the whole 3d story. The barrel distortion is twice as much however, and I don't see how anyone could mis-measure barrel distortion. And in the end, often the MTF numbers hold up. In the case of the 21 they don't, the lens obviously has enough other qualities that it's obvious, it's strong without having great MTF numbers. Also check the 14s CA numbers, again, they aren't bad but not like the 15s. I'm glad you love your 14, and if I had one, it's possible we'd just say 'oh it's good enough" but not having either it doesn't have home field advantage. Besides having compared it to 3 other lenses, one that we already own... the 15 has already passed the smell test. Thanks for bringing that up though.

06-11-2012, 01:10 PM   #17
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0.5 vs 0.7 is not twice as much.
one positive thing about the measurements for the DA14 is slightly less chromatic aberration.
06-11-2012, 01:26 PM   #18
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Formally the DA 14mm f/2.8 produces only a moderate degree of barrel distortions (~1.7%)
Lateral chromatic aberrations (color shadows at harsh contrast transitions) are fairly well controlled for a lens in this focal length class. The average CA width at the image borders varies around 1.2px which will be visible at times.
MTF numbers @ F8 2178, 2007, 1607
QuoteQuote:
The DA 15mm f/4 Ltd produces moderate barrel distortions (~1.5%) - this is comparatively low although you may spot the problem in very critical situations.
The average CA pixel width at the image borders stays at and below 0.9px

MTF Numbers @ F8 2246, 2086, 1951
Not to mention the 15's 2352 out of 2350 MTF score in the center at F 5.6. I'd have to read up on their testing methids to see how that's even possible.

For some reason I thought the Barrel distortion on the 15 was .8, not 1.5, however, I still would have been fine if I hadn't re-read the numbers. As I recall none of the other lenses I look at had barrel distortion under 2%
06-11-2012, 01:30 PM   #19
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I was looking at the DXO test, funny how they come to slightly different results.

06-11-2012, 01:46 PM   #20
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I was looking at the DXO test, funny how they come to slightly different results.
Well this way we know what every body thinks.

That Tamron 10-24 looks awesome overall, great numbers for barrel distortion and CA, almost on par with the 14 on photozone. Not quite there with the MTF scores but possibly also worth a look. No one has spoken for it yet.
06-11-2012, 01:59 PM   #21
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Pentax is coming with a new wide angle lens.

btw why isn't the pentax 12-24 in your list?

at 12mm not the best but at 15mm most likely comparable barrel distortion with the DA15 since it's -0,578% at 18mm

http://www.photozone.de/pentax/133-pentax-da-12-24mm-f4-al-ed-if-review--test-report?start=1


it's too bad there isn't a DA*11-16 or we would be done already
http://www.photozone.de/canon-eos/379-tokina_1116_28_canon?start=1
06-11-2012, 02:07 PM   #22
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btw why isn't the pentax 12-24 in your list?
It's CA is way too zoom like.

It's edge numbers are excellent, but it's not as center sharp. But +1 for consistency, which is actually something I might think about.

Back to the DxO thing.



Now I'd have to read up and see what "metrics" refers to, it all gets so complicated. It shows the 15 with half the barrel distorion though.

Last edited by normhead; 06-11-2012 at 02:13 PM.
06-11-2012, 02:12 PM   #23
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QuoteOriginally posted by normhead Quote
That Tamron 10-24 looks awesome overall, great numbers for barrel distortion and CA, almost on par with the 14 on photozone. Not quite there with the MTF scores but possibly also worth a look. No one has spoken for it yet.
Just wait until RioRico reads this thread!

06-11-2012, 02:20 PM   #24
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Lets say the difference is around 0,2 to 0,4 %
06-11-2012, 02:37 PM   #25
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Just wait until RioRico reads this thread!
Ya, is he on vacation or something? I'm not sure I could get a 14 if i wanted it, forget about the stuff RioRico throws out here.

I find it hard to take a site like DxO seriously though. There are no good Pentax lenses according to DxO. The higherst rated Pentax lens is the new 35 2.4, which is a great lens, but better than every otehr Pentax lens? Really? It's rated at 15 out of 50, right down in the poor range. They have tested no 3rd party lens on Pentaxes. Most Pentax lenses are rated under 15, the highest on other systems are rated at 35. The Tamron 90 is very highly rated on the Nikon D4, 10 points higher than any Pentax lens... I just don't know what to do with these ratings. There is no way I know of to compare. The haven't rated even one 3rd party lens on a Pentax, so, you can't even guess what their numbers mean, except that if you want a good lens, you should be buying anything but a Pentax. In other words, there may be uses for them, but I fail to see how they have any kind of testing standards, their numbers are complete fabrications at the worst, or useless for Pentax users at best. Every one on the Pentax forum and the guys at photozone have the FA 100 WR and the Tamron 90 rated as pretty close.

Rating of the Tamron 90 on a D4= 25. Rating of a D FA 100 WR on a K-5 14. You know, I really don't even want to know what DxO's explanation is, I'm sure it would just hurt my head. This despite the fact that the D4's sensor rating is 89 and the K-5s is 82. But to break this off cleanly, their full of it up to here when it comes to Pentax. I can't figure out what their numbers mean, and i doubt anyone else can. And I bet the reason they don't post any third party lens reviews on Pentax K mount lenses is that it would completely discredit everything they've published. I can't believe they don't know they have a problem with these numbers. They're trying to sell product. I think they're covering their own sorry asses by doing things the way they do. Their K-5 sensor rating was a bone thrown to Pentax to keep them from challenging their fudged ratings. They are making money from this some how. I wouldn't be surprised if the corporations are paying for the ratings. It makes as much sense as anything else you see on the site. Pentax paid for a good rating for their body, and probably couldn't afford to have their lenses top rated.

Last edited by normhead; 06-11-2012 at 02:54 PM.
06-11-2012, 02:43 PM   #26
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Really just try them out and see which one you like, hands on experience is what counts if you ask me
06-11-2012, 02:53 PM   #27
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QuoteOriginally posted by normhead Quote
Rating of the Tamron 90 on a D4= 25. Rating of a D FA 100 WR on a K-5 14. You know, I really don't even want to know what DxO's explanation is, I'm sure it would just hurt my head.
You need to compare the Tamron score on a D7000, not D4.
06-11-2012, 02:58 PM   #28
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Just get the 15 ltd, only thing it is missing is WR.
06-11-2012, 03:05 PM   #29
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QuoteOriginally posted by normhead Quote
If your competitor having expanded to meet the demands of a hot market doesn't go under. I shopped at Sam the Record and and Toronto Camera for years. Both expanded, put stores all over the place and grew and kept expanding for years, until they collapsed. It could go either way. Which is a couple quarters of soft sale going to hurt most? There's two ways of looking at that.
If you borrow money to expand too fast one of two things inevitably happens:
  1. Global economy expands, driving interest rates up (and your debt servuice with them) - then economy contracts for 3 - 6 quarters (average recession duration over the last 60 years) -- but your debt service doesn't. Implosion!!
  2. Global economy contracts, banks tighten lending standards, you look to non-bank lenders (Junk Bonds) at high rates to continue expansion (because you need more cash flow to service existing dent) -- but your cash flow isn't sufficent to maintain loan covenants. Hedge funds corner your junk bonds as entire junk MARKET collapses (happens every time), banks and/or hedgies call your loans for convenant violations (which you cannot meet), force you into bankruptcy "reorganization" wiping out equity holders (that's you) and liquidate your remaining assets at a nice fat profit (or alternatively take debtor-in-possesion benefits and operate the company for profit, eventually selling it off to a competitor).
The LESSON - do not ever leverage more than 35% debt to total capital; grow at a sustainable rate; plow back 35% ot net profit into self-financed expansion; pay dividends to your shareholders (to maintain the stock price). Patient, long-term growth strategies win once every 7 years - at ever higher lows and ever higher highs. If this is Ricoh's plan - well OK then.
06-11-2012, 03:37 PM   #30
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QuoteOriginally posted by Anvh Quote
Really just try them out and see which one you like, hands on experience is what counts if you ask me
This. You seem to be getting way too obsessed with numbers, and much as I love numbers, they don't have anything to do with how much I like a lens. The DA 35 f/2.4 is cheap, and that has all the resolution you'll need if you want sharp. Sharp isn't that expensive. Building a lens that's nice to use? That costs a fair bit more.

GO and try these lenses out, or buy second hand and re-sell. Prices are very stable, so if you go for second hand and don't like it you can do away with it. I got a DA 15 new and sold it for a 40 loss I think.
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