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05-23-2008, 04:16 AM   #16
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Drop the Sigma like a bad habit!

05-23-2008, 04:50 AM   #17
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rather off-topic

QuoteOriginally posted by cooldude14es Quote
Well, I notice you have been around Spain maybe last summer?!?!

I also have a FA35 and F28 and considering to buy a DA40... so I can understand brothereye on his LBA.
Actually I have never been to Spain because I think if I went there I would never leave. As far as LBA goes, I think I am developing an obsession with macros. My fourth one is on its way!
05-23-2008, 05:19 AM   #18
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QuoteOriginally posted by highyellow1 Quote
How about this? Sell all but the DA* and purchase 18-250 or a prime that would be the best focal length. Than you have the best lens for that range and a light walk around do it all lense as well.

Just a thought!
I've actually considered this, but I would feel obligated to sell my Tamron 28-200 XR. This was the fourth generation(I think, or maybe third) of that lens, and I was all prepared to sell it, since I don't use my P3 that much anymore. I had been happy with it already, but it seemed pointless to keep a lens that wasn't "digital compatible" or whatever when I was mostly using digital. But then I tried it out on my DSLR and was surprised (really! ) at how good it was. I don't know if it's just the lens I have, or if this particular generation performs so well, but even though it's kind of limited at 28mm, and it's not officially "digital" it's still sharp and contrasty. I had kind of been using the 16-45 (or 18-50) and the 28-200 as the equipment I took where I might need 200 or I might need 16, until the DA* came along. The other thing is, since I have a couple of DSLRs I can attach a tele and wide to each one and not have to switch lenses.
05-25-2008, 10:37 AM   #19
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Well for what it's worth, I decided to do an informal comparison before I sold anything. I'm not a lab, and frankly I don't have the patience to do a lot of painstaking tests, so I don't have any resolution charts or anything. But I figured I should do something to give me an idea of what these lenses are capable of.

I shot the same static subject from a couple of fixed distances at three focal lengths from wide-open and then stopping down one full stop a frame until I hit f11. I then compared the raw files on my pc to see how the lenses compared.

I used my K10D and the following lenses:
Pentax DA*16-50, Pentax DA 16-45, Sigma 18-50 f2.8 V1, Tamron 28-200(non-Di) and for comparison at 50mm(or 45mm in the case of the Pentax DA16-45). I also just latched onto a lightly used(seriously 500 frames, I checked in photoME) *ist DS kit on eBay. Why did I buy the *ist DS? It was pretty good deal, and I wanted the chance to use TTL flash when I can score a used flash that will support it(or if they ever made a ttl pentax module for my vivitar 3500 AND I can find one.) So I dug out the 18-55 kit lens, though I'm planning on selling it anyway, but I thought I would throw it in there for comparison sake.

And the overall sharpness (determined by my eyeballs) of the frames at 100% magnification(at the same focal length and fstop) rankings:

1)Pentax KA 50mm f2 - not a huge surprise, I'm sure, I know I wasn't surprised. It might not be fair, since this lens doesn't zoom, so while it's sharper, it doesn't offer the flexibility the others do.
2)Pentax DA* 16-50 f2.8 - only barely beaten by the KA 50mm, it was close, real close, there were frames where the only way the KA 50mm won was by very slightly better edge sharpness since the centers looked the same. This was not a surprise for me either.
3)Sigma 18-50 f2.8 - not as close as between the KA 50mm and DA* 16-50, still pretty good though.
3)Tamron 28-200 - this was so close I had to call it a tie between the Tamron and the Sigma, depending on which frames I looked at it could have gone either way.
4)Pentax DA 16-45 - this did surprise me. I expected this to beat the Sigma and Tamron or at least tie them, but it did not. At f8 and f11 it put up a good showing, but still came up short, center and edges.
5)Pentax DA 18-55 - again no surprise, but it wasn't as much worse than the DA16-45 as I expected, and if you compared only the centers wide open, there were frames where this lens could have probably tied the DA16-45.

So, I'm selling the DA16-45 and the DA18-55, though I don't think they are necessarily BAD, they just aren't as good as the others.

I'm not posting this to argue over my methodology(which was pretty simple and not very sophisticated and didn't involve the same sort of work that a testing lab would do, admittedly. It was fairly real world for the most part.) My idea was to compare them, so I could let the least sharp lenses go, and while I got a surprise, I'm still glad I did it.
Keep in mind of course, that you shouldn't make any decisions about what to buy or sell based on this. It was only a comparision of ONE lens of each model in an informal(although fair) way.
Also I'm not complaining about the DA16-45, it's a good lens, but my sample isn't as good as the two other similar lenses I have. I'm not upset or knocking Pentax about the DA16-45, in fact, I guess that I could take different sample of each lens, and the order might be some different. The real thing I've taken away is that you can't base your opinions on your lenses on what you might read in a magazine or online, you should try this yourself. Oh and I also re-learned something I learned a long time ago. I had always felt that primes were generally sharper than zooms, and when I tried this with 35mm film it was true, and I think it's still true today. If I was willing to change lenses more readily, I wouldn't have anything else, but it can be difficult in some situations(think perched on a scaffold that serves as a media center with limited room and limited time) to swap lenses, and I always seem to need to change lenses frequently when I'm using the few prime lenses I have. So I will continue to use both, being aware that I do give up some sharpness(a little or a lot depending on the lenses) when using a zoom, to get some convenience.

Now I've got to get an M42 adapter, I still have a couple of lenses left from my romance with the M42 system I built in the mid to late 1980's when everywhere you looked there was good, cheap screw-thread gear.


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