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12-29-2013, 08:20 PM   #1
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New da21 with loose barrel

Checking out a new da21mm. At infinity focus, just gently shaking with lens facing up gives a knocking sound and the barrel is a bit loose with gentle jiggling. At close focus still evident but less so; anyone -- is this normal for this lens?

IQ seems fine -- very sharp in center. Lateral edges are a bit soft, left more than right.

12-29-2013, 08:22 PM   #2
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I don't think that's normal. A loose barrel/ring is a rare but not unseen manufacturing defect, so I'd recommend that you get the lens replaced.

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12-29-2013, 09:14 PM   #3
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That is not normal. Probably needs a lens alignment as well. Figure $150 to get it fixed.
12-30-2013, 12:52 PM   #4
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I had the same concern and sent the lens to Pentax Canada for repair. They told me that no repair is necessary--it's loose by design. However, I would be concerned about the uneven sharpness you describe.

12-30-2013, 04:30 PM   #5
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Thanks to everyone for comments. Has anyone else heard that the lens is "loose by design"?
01-04-2014, 06:38 AM   #6
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QuoteOriginally posted by Adam Quote
I don't think that's normal. A loose barrel/ring is a rare but not unseen manufacturing defect, so I'd recommend that you get the lens replaced.
I am still trying to get a handle on how much barrel wobble or play is acceptable. I have all of the limiteds except the 21 mm and noticed the 40 mm and 70 mm have a slight wobble especially when focused to maximum closeness fully extended. if you grasp the inner barrel with two fingers and gently jiggle it there is a slight but noticeable clicking sound where the barrel just does not seem tight. You cannot see the wobble but can feel and hear it. Optically the pictures seem fine. I have checked both new and used versions at B&H and Adorama in the stores and noticed this with all of them. Is this OK or a problem with the lenses? My 15 mm and 35 mm limiteds do not have this issue. Inner barrels are tight. Could this be where the larger versions are easier to build to a tighter tolerance? I checked my DFA 100 macro and noticed on that lens there is no play in the barrel side to side but when fully extended the barrel has a slight play or wobble up and down.
01-04-2014, 03:53 PM   #7
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QuoteOriginally posted by jddwoods Quote
I am still trying to get a handle on how much barrel wobble or play is acceptable. I have all of the limiteds except the 21 mm and noticed the 40 mm and 70 mm have a slight wobble especially when focused to maximum closeness fully extended. if you grasp the inner barrel with two fingers and gently jiggle it there is a slight but noticeable clicking sound where the barrel just does not seem tight. You cannot see the wobble but can feel and hear it. Optically the pictures seem fine. I have checked both new and used versions at B&H and Adorama in the stores and noticed this with all of them. Is this OK or a problem with the lenses? My 15 mm and 35 mm limiteds do not have this issue. Inner barrels are tight. Could this be where the larger versions are easier to build to a tighter tolerance? I checked my DFA 100 macro and noticed on that lens there is no play in the barrel side to side but when fully extended the barrel has a slight play or wobble up and down.
A bit of play in the part that moves when focusing is perfectly normal, but a loose outer barrel/trim is not.

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01-04-2014, 05:55 PM   #8
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QuoteOriginally posted by Adam Quote
A bit of play in the part that moves when focusing is perfectly normal, but a loose outer barrel/trim is not.
Thanks Adam this clears it up for me. On all of my lenses, even the DA 40 LTD and 70 LTD with the slight play in the inner barrels, the outer barrels and focus rings feel very solid and smooth with no play, wobble or looseness at all. If a slight play in the inner barrel which moves in and out when focusing is normal then I am OK with it. I just bought a used DA21 mm in like new condition and it has no wobbles or looseness in either the inner or outer barrels.

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