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06-16-2012, 08:03 AM   #61
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QuoteOriginally posted by normhead Quote
Here's the issue with the 12-24s. My kit lens and my 18-135 cover it's range in zoom, and I already have the 21 in prime. Neither of them have the stellar CA numbers the 15 or 8-16. The 15 has F5.6 and F8 both of which have "you can't take this picture better with any lens you can buy" appeal, for two different types of images. That's just rare. The 8-16 would actually extend my range beyond 10 as well as provide a nice compliment to the two zooms that start at 18.

The Tammy 10-24, Sigma 10-20 and 12-24 and Pentax 12-24 are all kind of overlap lenses for me. I'm assuming that if I ever want to cover the range around 25 , one of that host of lenses that cover 16-50 will do sInce my current zooms cover that range.There are some very good lenses in that range. How many lenses can you use that cover 18-24?
No offense but I really don't understand this thread. You've been going on and on about all of these test chart numbers but then you try to dismiss the excellent WA zooms because they overlap with kit lenses. If you're making a decision based on test charts then you should not even consider the overlap with your kit lenses as a factor.

All of the WA options are excellent. Your decision should be based on your particular usability needs. I need a light lens because all I do is walk around and I strongly prefer not to buy an additional filter kit (yet). So the DA15 was a slam dunk since I have a 49mm filter kit. If weight and filters isn't a concern then one of the 3 zooms would be a better option imo. The Sigma 8-16 is a unique lens that from what I recall hearing has more distortion especially at the wide end (it's really, really wide) and I don't think it takes filters at all. I think the Sigma 8-16 is a wide angle complement for some very creative shots instead of a stand alone wide. Perhaps someone that uses the 8-16 has a different opinion but I would the other 4 lenses discussed as my primary usage WA.

06-16-2012, 08:03 AM   #62
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QuoteOriginally posted by normhead Quote
The Sigma doesn't really match the 15 ltd. at 5.6 or 8 according to photozone. That's the thing that bothers me most about the Sigma. Solid numbers, but not spectacular numbers.
Question is do you see it back in your photos?
06-16-2012, 08:09 AM   #63
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QuoteOriginally posted by Laurentiu Cristofor Quote
I did not find the DA15 as sharp as I expected a Limited lens to be. Even at f/8 it doesn't feel very sharp. I used it on the K-7 - I wonder how it will look on photozone once it gets retested on a higher resolution camera. Lack of barrel distortion and CA are very nice though.
No reason to expct that a lens that blows away all all other lenses on a 10MP camera won't continue to do so on a bigger resolution camera. Either you got a defective copy, or your testing was perhaps not sufficiently well controlled, or perhaps you jus just have unreasonable expectations for what is possible for an ultra-wide lens - clearly, it is rendering objects very small, so more enlargement is necessary to see them at a similar size to whatever other longer lenses you might have been comparing against. But compared to other ultra wides, it is objectively speaking the sharpest lens available for Pentax, as evidence by Photozone numbers, with the only weakness being the corners at large apertures, which are rarely if ever in focus anyhow. Not that there is normally a reason to shoot an ultra wide at large apertures when looking for corner to corner sharpness anyhow - usually, the point of large apertures is for the shallow DOF you can obtain throug proximity effects - sharp subject, OOF background.
06-16-2012, 08:12 AM   #64
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QuoteOriginally posted by selar Quote
If you are carrying a 16-50 might as well stop that down instead at 16mm o get very nearly the same shot.
I don't think the 15 is intended for people who are already carrying a large heavy zoom that is the same range. What would be the point?

06-16-2012, 08:37 AM   #65
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QuoteOriginally posted by stormtech Quote
In case not everyone has seen it, Adam has just done a very nice in-depth review of the 15ltd
The review calls the DA 15mm a pancake. No one has ever called the FA 50 1.4 a pancake, and it's virtually the same length as the 15mm. Neither is a pancake, pancake are 1" long or less (DA 21, 40, 70, FA 43).

Strange that the review never mentions the DA 15's exceptional contrast.
06-16-2012, 08:44 AM   #66
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QuoteOriginally posted by audiobomber Quote
The review calls the DA 15mm a pancake. No one has ever called the FA 50 1.4 a pancake, and it's virtually the same length as the 15mm. Neither is a pancake, pancake are 1" long or less (DA 21, 40, 70, FA 43).

Strange that the review never mentions the DA 15's exceptional contrast.
Considering the size of the DA 14, I would call the DA 15 a pancake too. It's a matter of perspective (no pun intended) but I get your point. I suppose that there is no definition of pancake lens.


One thing is certain, five pages on the DA 15 means that a lot of people are interested in the lens. If I were to post something about my old DA 17-70 you would not see it reach five - so far - pages.

The DA 15 is my favourite lens and I even like the screw on on cap because it never falls off. It is the only lens cap I own that never falls off (although in truth, the cap on my DA18-125 is pretty good).
06-16-2012, 08:52 AM   #67
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QuoteQuote:
I don't think the 15 is intended for people who are already carrying a large heavy zoom that is the same range. What would be the point?
For me the issue is, apart from the Sigma 8-12 none of the zooms control CA as well.

Hell I might as well throw an image out here.



We've found in images like this we feel the barrel distortion detracts from the image. The lighting conditions are harsh.. if we did a crop we could show you some serious purple fringing because of back lighting in the tree leaves. The CA issues pretty much rule out the zooms, except for the Sigma 8-16. We take a lot of shots like this. Shots taken from the forest floor with a bright sky behind the canopy. We want the best lens for this type of image.

Here's a crop of one of the problem areas.



My feeling is, we can find a lens that does better than the 10-17 this was taken with. While I'd love to think a zoom could handle the CA etc. I really think I have more chance with a prime. I don't want perfect, not in this kind of lighting conditions, but, I do want the best possible. If that means shooting F8 with a 15 then for us, it's worth it, just to have this type of shot under control. But I'd love to see images from any other lens that might be able to handle it.
06-16-2012, 08:59 AM   #68
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QuoteOriginally posted by Marc Sabatella Quote
I don't think the 15 is intended for people who are already carrying a large heavy zoom that is the same range. What would be the point?
There is no point in carrying both, but there are reasons for owning both. I never carry the 15mm if I'm carrying the 16-45mm. I choose one or the other to throw in the bag. I never pack the 16-45 when I'm bringing the 18-135, but the 15mm is a nice complement to the superzoom. The little 15mm always goes in the bag if I'm carrying only primes.

06-16-2012, 10:59 AM   #69
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Where as I'm at the point where I could see carrying the Sigam 8-16 (aspherical and heavily corrected), the Pentax 10-17 ( a wild and wacky fisheye) and the 15 Ltd. If I could get that super sharp 5.6 and edge sharpness, in the excellent range in a zoom, it would make the 15 redundant. As long as the 15 will give me superior images at some settings to the zooms I'm carrying... it's going to come along. To me, that's what you buy primes for.
06-16-2012, 11:08 AM   #70
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What kind of stuff are you doing that requires f5.6 at 15mm's? I rarely shoot that big unless I don't have my tripod.
06-16-2012, 11:12 AM   #71
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I tend to shoot to IQ. If that's where the lens is sharpest, I shoot there. The above images was taken at F4. Some places you just need light. Under the canopy, there isn't a lot of light even on a sunny day. Most lenses are at their sharpest from 5.6 to 8.
06-16-2012, 11:29 AM   #72
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I usually try to increase the DOF to keep everything sharp and use a tripod if necessary.
06-16-2012, 11:49 AM   #73
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QuoteQuote:
I usually try to increase the DOF to keep everything sharp and use a tripod if necessary.
I still shoot multiple images of every scene when possible at different F-stops. You'd be amazed how often, especially with a WA lens, you have depth of field and extreme sharpness at 5.6. We actually find , based on a combination of sharpness and DoF , F8 and F11 are usually the winners, but if you can creep down into 5.6, it doesn't happen all that often that you can use and F5.6 image over an F8, but when you can, usually the 5.6 is sharper. Every now and then an F16 picture come out on top and sometimes a 22 because sometimes over all sharpness of the image is worth more than a razor sharp centre. The whole sharpness thing is way more complicated than just assuming DoF will give you abetter picture and a higher F stop gives you more DoF.

Here's an example of an image shot at F5, right in the super sharp range for a Tamron 90 that has both amazing sharpness, but also perfect DoF. The image is far enough from the camera that DOF covers the full range from where the picture starts to infinity. It would actually be less sharp if we shot at F16, because of diffraction.


Last edited by normhead; 06-16-2012 at 12:03 PM.
06-16-2012, 12:17 PM   #74
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QuoteOriginally posted by normhead Quote
To me, that's what you buy primes for.
I'd disagree. The difference between contemporary zooms and primes is minimal, both will give fantastic shots. You buy primes because they're smaller, faster and/or cheaper for a specific focal length.

In general.

Last edited by Mareket; 06-17-2012 at 09:35 AM.
06-16-2012, 12:49 PM   #75
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Looking at the test scores for the various WAs I looked at, not one of them matched the test score of the 15 ltd at 5.6 or F8?

We did a similar comparison of the DA* 60-250 @ 90mm and the Tamron 90. Despite the DA* costing us 2K and the Tamron costing us $250 second hand, and despite the fact that their MTF numbers were very similar, we judged the Tamron images to be better. We found the difference to be noticeable, not minimal. Same with our comparison of the DA*16-50 @16 and 15 Ltd. The control of CA and distortion, I'm guessing have way more affect on IQ than most people give them credit for. The 60250 should have more CA control than the Tamron... it's hard to figure this out in the real world. We know they are testing something. We're just not sure what.

There's no sense in doing well on a test pattern 6 feet away, if CA messes up your images that are taken of subjects that are distant from the camera. The Sigma 8-16 apparently has good CA control, but still lacks the initial sharpness of the 15ltd . So , I'm really interested to find out. Will the 8-16's CA control mean that the MTF number becomes as meaningless as it theoretically should be? It's quite possible it was the lack of control of CA that made zooms less "pop off the page" sharp looking. I don't know. I can't really find anything definitive.

But these two lenses offer an interesting test.
QuoteQuote:
You buy primes because they're smaller, faster and cheaper for a specific focal length.
You can buy a DA*16-50 for about the same money you can buy an FA 31. You still need the 21 and and a 50 as a bare minimum.

Anyone have an example of a zoom that out performs a prime at a given focal length and F-stop or even somewhere in it's range of F-stops.?
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