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04-23-2010, 02:39 AM   #16
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Strange behavior - soft and front focus. Nothing in common with my FA31 (MIJ). I've noticed to some FA31 much improved results in f2.0 instead of f1.8.
Test again from f2.0 to f2.8. The photos should be super sharp with some Chromatic aberrations in out of focus areas. From f4.0 to f8, CAs are 99% disappeared.

04-23-2010, 04:46 AM   #17
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Japan vs. Vietnam

Bellow are two shots showing my experience with a 31mm Limited lens assembled in Vietnam and my second 31mm Limited lens made in Japan:

Due to the enormous size I added the links to the images in quotes. Copy the two separate links without including the quotes and paste them in your browser.


Vietnam:
"http://farm3.static.flickr.com/2691/4162111759_4cbc1ccea7_o.jpg"

Japan
"http://farm3.static.flickr.com/2719/4162868642_ac89ebf3f0_o.jpg"

The point of focus is in the center, just bellow the non smoking sign. Feel free to pixelpeep across the whole image.

Forgot to mention that both images are shot at f/1.8

Last edited by Voe; 04-23-2010 at 04:53 AM.
04-23-2010, 06:01 AM   #18
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oh wow!

Thanks Voe for those two photos.
Now I really know that the FA 31mm can be sharp at 1.8 which I've being trying to find - I really do think (know) that my lens is very similar to your AIV lens. I get similar results wide open on brick walls at a similar angle... nothing really sharp!
04-23-2010, 08:31 AM   #19
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QuoteOriginally posted by Voe Quote
Bellow are two shots showing my experience with a 31mm Limited lens assembled in Vietnam and my second 31mm Limited lens made in Japan:

Due to the enormous size I added the links to the images in quotes. Copy the two separate links without including the quotes and paste them in your browser.


Vietnam:
"http://farm3.static.flickr.com/2691/4162111759_4cbc1ccea7_o.jpg"

Japan
"http://farm3.static.flickr.com/2719/4162868642_ac89ebf3f0_o.jpg"

The point of focus is in the center, just bellow the non smoking sign. Feel free to pixelpeep across the whole image.

Forgot to mention that both images are shot at f/1.8
that makes a big difference
mine has got a "Made in Japan" sticker on the box - so it is really made in japan?
or do they label the vietnam-made one the same?

04-23-2010, 08:31 AM   #20
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QuoteOriginally posted by Voe Quote
If you can contact CRK and ask them to send it back to Japan for adjustment as it appears that the lens has a decentered optics.
Yes mine was one of these 'bad' ones, I told CRK to send it back to Japan after they said it was just minor BF. In Japan they replaced an 'optical group' they didn't say which one. But it is much better now, I guess it was decentered?

Personally though I find it hard to believe it is a 'assembled in Vietnam' vs 'made in Japan' issue as ALL Pentax lenses are now assembled in Vietnam..

For the OP: I'm curious what your lens is like stopped down, as mine had terrible problems at certain distances (2-4m) even at 5.6 (looked like your 1.8 shots) but at infinity mine was stellar... Make CRK send it to Japan for testing, they'll fix it there even if CRK think it is OK.

Last edited by joele; 04-23-2010 at 08:45 AM.
04-23-2010, 01:17 PM   #21
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QuoteOriginally posted by joele Quote
Personally though I find it hard to believe it is a 'assembled in Vietnam' vs 'made in Japan' issue as ALL Pentax lenses are now assembled in Vietnam..
Hi Joele,

Just a note I'm not saying that it applies for other lenses assembled in Vietnam. My and few other people's experience applies to the the 31mm Limited, which before was unheard of anyone having an optical de-centering issue with it as they were built and checked to a what I believe a higher standard. I also don't think it applies for all 31mm assembled in Vietnam.
04-23-2010, 05:20 PM   #22
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Hey Voe,

Maybe CRK got a bad batch? somehow banged around in shipment or something like that.. As most of the bad examples I have seen on the net don't just come from Vietnam but are directly from CRK.. Is this your experience? I did see one from Canada (I think) but his was fixed with AF adjustment so not the same issue.

With mine (from CRK too) the Japan service centre said they replaced an element group and realigned the lens. I haven't seen what other people have had on their service reports after having them fixed? It would be interesting to compare!
04-23-2010, 08:05 PM   #23
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QuoteOriginally posted by joele Quote
Hey Voe,

Maybe CRK got a bad batch? somehow banged around in shipment or something like that.. As most of the bad examples I have seen on the net don't just come from Vietnam but are directly from CRK.. Is this your experience? I did see one from Canada (I think) but his was fixed with AF adjustment so not the same issue.
I don't think that only CRK got a bad batch as I purchased both 31mm Limiteds from B&H. Also there are a few more complaints on dpreview from non-Australian forum members.

I think there could be many others who didn't realise yet that they have a decentered copy.

04-24-2010, 06:29 AM   #24
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Image Stab on a wrong setting maybe? (havn't read other posts in this thread)
04-24-2010, 08:49 AM   #25
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QuoteOriginally posted by Voe Quote
I don't think that only CRK got a bad batch as I purchased both 31mm Limiteds from B&H. Also there are a few more complaints on dpreview from non-Australian forum members.

I think there could be many others who didn't realise yet that they have a decentered copy.
Ohh ok I thought you got yours locally.. wow, strange for it to be so widespread with one model.. is the 31 harder to calibrate correctly?
04-24-2010, 09:08 AM   #26
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QuoteOriginally posted by Voe Quote
Bellow are two shots showing my experience with a 31mm Limited lens assembled in Vietnam and my second 31mm Limited lens made in Japan:

Due to the enormous size I added the links to the images in quotes. Copy the two separate links without including the quotes and paste them in your browser.


Vietnam:
"http://farm3.static.flickr.com/2691/4162111759_4cbc1ccea7_o.jpg"

Japan
"http://farm3.static.flickr.com/2719/4162868642_ac89ebf3f0_o.jpg"

The point of focus is in the center, just bellow the non smoking sign. Feel free to pixelpeep across the whole image.

Forgot to mention that both images are shot at f/1.8
So, what's wrong with the pic using FA31 AIV, I cannot see it...
04-24-2010, 09:23 AM   #27
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Morning,

Since you just purchased the lens apparently new from CRK, (and this is not an inexpensive, cheap lens) I would give them a call indicating that the lens has major problems and in that your going on holiday, you will be returning it and want an instant replacement. I would also suggest that maybe that they could check out the ones in inventory and send the best one available. They should take care of repairing it and not you having to send it in, wait - dealing with all the uncertainly and the like.

I have read that CRK has somewhat of a monopoly in Pentax down under, but you just put a major dent in your checking account, and should have received a first rate lens. I do not know how far that will go, but it should be worth a try...

I have one that I was able to pick up second hand 6 months ago, but in mint condition and it is perfect as far as I can tell - takes wonderful fanatically sharp images.

Just my 2 cents worth.....
04-24-2010, 09:35 AM   #28
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Your example photos indicate something much worse than missed focus. I have seen this sort of thing when internal elements were badly misaligned. I would suggest a replacement from the store and would test the replacement lens before leaving the store.


Steve
04-24-2010, 03:13 PM   #29
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QuoteOriginally posted by joele Quote
Hey Voe,

Maybe CRK got a bad batch? somehow banged around in shipment or something like that.. As most of the bad examples I have seen on the net don't just come from Vietnam but are directly from CRK.. Is this your experience? I did see one from Canada (I think) but his was fixed with AF adjustment so not the same issue.

With mine (from CRK too) the Japan service centre said they replaced an element group and realigned the lens. I haven't seen what other people have had on their service reports after having them fixed? It would be interesting to compare!
This is certianly a possibility, but I wanted to share my experience. I bought a FA31 from B&H about 4 months ago, and was sent a AIV copy. (Despite B&H telling me twice prior to the sale they had only MIJ copies.) The AIV FA31 did not have problems like the above, but was not as sharp as sample shots from other FA31's. So I sent it back.

Then I got a FA31 (and FA77) from a craigslist add, both MIJ. I am embarassed about this, but I did not perform due dillagence during the purchase. My baby girl was with me and screaming so I hurried the transaction. I did take some test shots, but every lends needs AF adjustment on my K20D, so I could not dial it in compleately on the spot. So I get home and I notice the 31 has clearly been droped from a decent height. One of the lower corners of the hood is bent in some and the tip of top of the hood is a little scuffed. So I had a huge sinking feeling in the pit of my stomach. Well, I dialed in the AF adjustment properly, and the 31 takes wonderfully sharp pictures, so I decided not to worry about it. I guess the point of the above rambling is that the FA31 is a tough lens and if that many are having problems I would guess that maybe something in the manufacturing process is to blame.
04-24-2010, 03:48 PM   #30
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some more interesting comments...

here in Adelaide no shops have any stock of FA31s and there were only 2 in stock at CRK (Melbourne supplier) when I ordered mine... thus a bit hard to test etc.

I have been doing some more testing and have found that I can get a focus lock (beep sound and all) at 12cm! Can a 31 focus this close?

Also I've been doing my eyebrow test (just taking a portrait approx. 1 - 1.5m away and pixel peeping the results and I can't get a sharp image of eye lashes at f4 or f5.6 at any focus adjustment (K20). ****can anyone point me to or show me a full size or 100% crop with a eyebrow/eye lashes at any aperture (just collecting ammunition when I ring CRK next tuesday)****
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