DA* 16-50mm Serial Number Database. - Page 9

suro · 07-24-2008, 12:19 AM

For example (about soft border):

Center and corner, full frame fix focal 20mm lens on the crop body. Line 2 - by center, line 3 - by corner

leadbelly · 07-24-2008, 07:17 AM

I just got my 16-50, and after a few test shots, it seems like a good copy. a few questions though...

1) Is the zoom ring really a little stiff, especially around 28-35mm? Unlike the 50-135 that's smooth? (Is it because of the weathersealing in the front part of the barrel where the lens extends?)

2) Focusing wide open is sharp at 50mm, but when I focus at 16mm, it's a little soft. Is this normal when used with the K10? (as with my 50-135, focusing is soft at the wide end, whereas focusing at the long end is hella sharp... but when I tried the 50-135 on a k20, it was sharp all the way.) Is this a K10D only issue?

Thanks!

suro · 07-24-2008, 07:33 AM

Originally Posted by leadbelly

I just got my 16-50, and after a few test shots, it seems like a good copy. a few questions though...

1) Is the zoom ring really a little stiff, especially around 28-35mm? Unlike the 50-135 that's smooth? (Is it because of the weathersealing in the front part of the barrel where the lens extends?)

2) Focusing wide open is sharp at 50mm, but when I focus at 16mm, it's a little soft. Is this normal when used with the K10? (as with my 50-135, focusing is soft at the wide end, whereas focusing at the long end is hella sharp... but when I tried the 50-135 on a k20, it was sharp all the way.) Is this a K10D only issue?

Thanks!

1. I think is a temporally problem (silicone greasing). Your lens will work better after few times use. I'm not have this problem.

2. I think you must try to use your lens on K20D and watch the result. Probably it's problem K10D.

You're welcome!

leadbelly · 07-24-2008, 09:22 PM

Some real world shots from my 16-50, is this a good copy? Serial number is 9024618...

I also just did a BF/FF issue test awhile ago, and at 50mm, it sightly back focuses. AF at 16mm though suffers from moderate BF... just like the 50-135, I'll just make it a habit to focus while zoomed in first, then zoom out to compose. Is this problem evident with the K20D? Or only with the K10D?

I also did a quick newspaper test (no tripod, not sure if its parallel), and it seems ok. With corner softness (as expected from a zoom), but not much. Center is sharp. Will do a more "scientific" newspaper test later though.

In all I think I got a good copy cept for slight back focusing. IQ is very much comparable with my 50-135 when sharp, and suffers from the same AF issues as its big brother (soft focus at wide end, have to focus zoomed in). Should I exchange my copy?

to add: with the K100D, it is just perfect. Is SDM really this inaccurate? Or should I learn to live with it?

leadbelly · 07-25-2008, 12:19 AM

A couple of wall shots of my 16-50, is my copy any good?
Focused on "mushroom" for both...

Here's on focused at 16mm

Another this time, focused at 50mm then zoomed out to 16mm

Keep or replace?

suro · 07-25-2008, 12:50 AM

Originally Posted by leadbelly

Keep or replace?

I think is pretty well!

Can you post link on the full-size of newspaper picture?

suro · 07-25-2008, 12:55 AM

Originally Posted by leadbelly

Is SDM really this inaccurate? Or should I learn to live with it?

SDM works more well on the K10D after you flash v.1.3 bios. On the K20D its work good

leadbelly · 07-25-2008, 12:57 AM

here...

http://farm4.static.flickr.com/3032/...26c009e1_b.jpg

http://farm4.static.flickr.com/3046/...64c6b6db_b.jpg

any good?

What do you mean flash v.1.3 bios?

suro · 07-25-2008, 01:44 AM

Originally Posted by leadbelly

any good? What do you mean flash v.1.3 bios?

Will see your photos after work (in my homeplace I have unlimited internet traffic)

Flash v.1.3 bios... I mean... Pentax releases firmware update version 1.30 for the K10D digital SLR camera.

With this latest firmware version the support for Pentax DA lenses with a built-in Supersonic Drive Motor (so called SDM lenses) has been implemeted.

Support for the Pentax SDM lenses has recently also been introduced with the announcement of Pentax's latest digital SLR camera, the K100D Super.

Update 1.30 for K10D you can download from PENTAX official site:

Software Downloads : Support & Service : PENTAX

suro · 07-25-2008, 01:47 AM

Link to firmware 1.30 for K10D (English):

http://www.pentax.jp/english/support...e/k10e130w.exe

leadbelly · 07-25-2008, 03:51 AM

ahh the firmware, yep. I already upgraded to 1.30. will try with the k20 latr to see if it backfocuses as well...

suro · 07-26-2008, 04:17 AM

Originally Posted by leadbelly

well...

Your lens is good by my opinion

leadbelly · 07-28-2008, 11:25 PM

I did a brick wall test, and I think mine has decentering defects

The center is sharp, the left side is soft, but the right side is softer... I know there will will be corner softness, but both corners aren't the same, with the right side showing extreme softness...

I was initially fine with my copy's output, but after taking portraits, I found that people on the right side always looked soft. So I did the test. Is this reason enough for me to have it replaced or repaired?

edit: BTW, this is only one of many shots, all shots had the right side being soft. Parallel to the wall as well. Tried it with the 50-135, to see if maybe I wasn't parallel, the 50-135 was sharp across the frame...

little laker · 07-28-2008, 11:41 PM

leadbelly,
I tend to agree with you on the right side being way to soft.
However I'm just wondering if it might not be quite perfectly parallel to the wall.
If I was doing the test I'd also aim it a little to the left, and then to the right. And see how it changes the image.

Plus I don't have access to the Image Data. To me it looks like this shot was taken around the 16mm mark.
If it was how about trying it around 18 and 20mm. And see if the problems still exist.

I know that at that price a lens should be perfect. But the reality is that it's still a zoom, so there's usually a compromise in IQ on one end or the other

leadbelly · 07-29-2008, 08:32 AM

It was on a tripod and i made sure it was perfectly parallel, but still it came out soft... I'll try that tomorrow, the thing about aiming a little to the left and right...

It was taken at 16mm. I also shot at 50mm, it was still soft... what bugs me is that even in real world shots, the right side looks obviously soft...