DA* 16-50mm Serial Number Database.

[PentaxScott]

Serial 9019218 purchased from Adorama on 4/28/08.

After extensive testing and questions on the forum, I found this lens to be a good copy.

[ericc]

Good in terms of focus. Had to send it in for a mechanical failure.

Purchased 3/17/08 from Keeble and Shuchat in Palo Alto, CA

[hhallman]

Originally Posted by cafinator

Serial 9021117 is good

Wow, that's so cool!
@cafinator, I could hardly beleive my eyes, when I saw I have the exact one just before yours!! 9021116. Just got it from B&H Photo (ordered three weeks ago.)
So far, it seems good. Focusing seems a tad off, but I'll try and fix that in the week end.

[PentaxPoke]

Serial Number 9024876

Bad! See below.

[SayK]

SN 9017473, bought from local story in Canada. Spot-on focus except in several instance, no decentering issues. Very good !

[PentaxPoke]

I noticed that the right side of several of my photos are out of focus relative to the left, even at infinity focus. Decentering. I returned the lens.

[amoringello]

9013269 - other than a little squeaking, it works just fine.
ACE Photo - Northern Virginia.

[Reuben0]

9023236 is a good one.

Unfortunately, this is the 4th one I've tried

I can't remember the exact serial numbers of the previous 3, but my tale of woe is as follows:

First one (first UK batch, 9014xxx), had slight de-centering and trouble focussing at 50mm. Was great stopped down though.

Second one (latest UK batch, 90233xx), was total rubbish in the corners unless stopped down to F16! Focussing was good though.

Third one (latest UK batch, 90244xx), seemed same as second one, although I only tested it briefly in the shop.

Fourth one (latest UK batch, 9023236) is a good one. Better in the corners at F2.8 than the second one was at F5.6

Fortunately, the shop where I bought it (the excellent and highly recommended SRS Microsystems), displayed great patience while I worked through all the problems

Cheers,
Reuben0

[morfic]

I consider 9019284 a good copy (Got it from Adorama). Having said that i shot all day at a -5 AF adjustment on the K20D, and based on results thought i could get closer, -7 shot under artificial light at ISO1600 seems about as spot on as it can get, will need daylight to verify.

Based on how this went i will retest the 40/2.8 as well since i stopped at -3 there and seeing how i thought -4 was it for the 16-50 i may not be spot on. (Test charts would tell me i back focus already, real use shows i am on at -7 a little in front at -5)

I need to find that one chart again that you mount at 45 deg and has a target parallel to focal plane, that way no matter how off the focus point is from where i think it is, it won't be causing any kind of skew. Any time we focus on a 45deg plane, the amount the center focus point is off from the center in the viewfinder will skew the result.

If all my lenses keep coming in at -7 i may need to ask Pentax to tweak the body or i soon run out of wiggle room with -7s everywhere I'm just glad i have the capability at all.

[filorp]

my is 9018176, bought in adorama, beginning of the may: monstruos distortions at the very corners, assimetric to boot, decentering, apart from this... spotless... i'm going to send it to the local service in uk... why is that?

[filorp]

Originally Posted by Reuben0

... had slight de-centering and trouble focussing at 50mm. Was great stopped down though.

i would like to ask you what you mean "slight decentering" ill show you my samples if you could judge them and tell me if there is any problem, those are very corner crops..
this is the link: Fotoalbum.eu - Stwórz swój fotoalbum online

[Richard3550]

9018946 - good

[benjikan]

9016531...GOOD!

Here is a sample shot at f6.3 at 28mm.

Ben

[Reuben0]

Originally Posted by filorp

i would like to ask you what you mean "slight decentering" ill show you my samples if you could judge them and tell me if there is any problem, those are very corner crops..
this is the link: Fotoalbum.eu - Stwórz swój fotoalbum online

I presume that photo 1 has the chimney pot in one corner and in photo 2 it was the opposite corner?

If so, then yes yours is decentered, as one corner is a lot better than the other corner. Mine cleaned itself by F4, which is why I described it as "slightly" decentered.

It is important to have reasonable expectations though - a wide-angle zoom is never going to be pin-sharp in the extreme corners, particularly at F2.8

HTH
R

[emaruyama]

hey folks, got mine last XMas, from Henry's... I'm pretty happy with it...
Regards from the north,
Ed
Iqaluit - NU
Canada