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11-04-2014, 04:17 AM   #121
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QuoteOriginally posted by macTak Quote
I seem to recall that some people were even shimming it with paper to, like your finger, support the barrel.
Forgive me for my ignorance. Can anyone help me how to test if my lens is decentered?


Last edited by totsmuyco; 11-04-2014 at 05:16 AM.
11-04-2014, 05:49 AM   #122
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QuoteOriginally posted by totsmuyco Quote
Forgive me for my ignorance. Can anyone help me how to test if my lens is decentered?
Typical symptoms is softness on only one side of the picture. For instance, if I take a picture of a brick wall in portrait mode with my 16-45 set to 16-18 mm, with the camera perpendicular to the wall and with the center in focus, the upper part of the picture will typically look more out of focus than the lower part. Sometimes, if I'm unlucky, I can see slightly more softness on the right side than on the left side when used in landscape mode, too.
11-04-2014, 06:03 AM   #123
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QuoteOriginally posted by gazonk Quote
Typical symptoms is softness on only one side of the picture. For instance, if I take a picture of a brick wall in portrait mode with my 16-45 set to 16-18 mm, with the camera perpendicular to the wall and with the center in focus, the upper part of the picture will typically look more out of focus than the lower part. Sometimes, if I'm unlucky, I can see slightly more softness on the right side than on the left side when used in landscape mode, too.
If you hold near the end and it's decentring, that implies that the lens + camera weight is enough to cause that. Does that mean that the weight of the lens alone, when fully extended, wouldn't be enough to provoke the problem? With the camera on a tripod, for example.
11-04-2014, 06:27 AM   #124
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Thanks. I'll give that a try. By the way, which Pentax lenses are prone to being decentered?

11-04-2014, 08:17 AM   #125
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QuoteOriginally posted by Clothears Quote
If you hold near the end and it's decentring, that implies that the lens + camera weight is enough to cause that. Does that mean that the weight of the lens alone, when fully extended, wouldn't be enough to provoke the problem? With the camera on a tripod, for example.
I'm not sure what you mean, but I'm not holding near the end, just pushing with a finger to prevent the lens from "falling down". The wobbliness of a wobbly DA16-45 fully extended @16mm is certainly enough for it to get decentered by its own weight only. The wobbliness of my copy is mostly in the horizontal direction, thus the problem is worse when the camera is held in the portrait direction.
11-04-2014, 08:30 AM   #126
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QuoteOriginally posted by totsmuyco Quote
By the way, which Pentax lenses are prone to being decentered?
Typically, wide-angle lenses.

And it's not just a Pentax thing.
11-04-2014, 09:38 AM   #127
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QuoteOriginally posted by gazonk Quote
The wobbliness of a wobbly DA16-45 fully extended @16mm is certainly enough for it to get decentered by its own weight only.
Ouch. OK, that's what I was afraid of. Is it as bad as that for the 55-300?
11-04-2014, 02:18 PM   #128
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I'm afraid that, despite the "newer" technology, this lens won't be any better than the 17-70 I assume it is supposed to replace. The weight is about the same (488 vs 485 g) and just one size greater filter diameter (72 vs 67 mm), which leads me to believe that it will have the same type of construction (i.e. plastic barrel).

The MTF doesn't look like the increase in diameter has resulted in sharper corners or lower distortion, maybe sharper/better bokeh, but at the expense of a non-fixed aperture. Of course it's difficult to tell without better samples, but it doesn't seem like an improvement so far on paper. Plus the MTFs posted are duplicates, usually they post two sets based on wide open and stopped down... Is anyone paying attention to these details???

11-04-2014, 02:29 PM   #129
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QuoteOriginally posted by thigmo Quote
Plus the MTFs posted are duplicates, usually they post two sets based on wide open and stopped down... Is anyone paying attention to these details???
It's been discussed elsewhere.

The Japanese page has differing MTF charts,
but not for distinct apertures,
just one geometric, and the other accounting for diffraction.
11-04-2014, 03:21 PM   #130
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QuoteOriginally posted by thigmo Quote
I'm afraid that, despite the "newer" technology, this lens won't be any better than the 17-70
It's not SDM................
11-04-2014, 05:12 PM   #131
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Are there any user photos with the lens yet?
11-04-2014, 05:29 PM   #132
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QuoteOriginally posted by Clothears Quote
Is it as bad as that for the 55-300?
With my all-plastic DAL 55-300, the issue only arises when I apply some pressure on the tip of the extended lens by resting it on a hard surface. Otherwise, no issues.

I wouldn't overstate the problem. The plastic of a lens isn't really an issue. Even the most solidly built lenses can get de-centred because they may have taken a knock. And the more complex the design of a lens (23 elements in 19 groups etc), the harder it becomes to ensure perfect optical performance even straight from the factory, let alone over time, as wear, heat, the loosening of screws etc take their toll.
11-04-2014, 06:23 PM   #133
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QuoteOriginally posted by Mikesul Quote
Are there any user photos with the lens yet?
It will be released end of November, how could there be any user photos yet?

Unless Ricoh is handing out models to trusted reviewers early - which I doubt.
11-04-2014, 07:13 PM   #134
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QuoteOriginally posted by Sam N. Quote
Good question. Is anyone out there thinking to get the 16-85mm. I am thinking to get it, I presently use 16-50mm DA* lens as all purpose
Not me, but if you decide to replace your DA* 16-50, I'll be happy to give it a good home. You would be going from a constant f2.8 to f3.5-5.6 for starters, and from "*" optics to similar IQ as the much maligned (unfairly in my opinion) DA 18-135. If you are good with 50mm as the long end of your all purpose lens, you probably won't use 51-85mm that much, either. The only advantage to you getting the new 16-85 is the DC autofocus motor compared to SDM in your 16-50. Makes no sense to me, but it's your money.
11-05-2014, 05:46 AM   #135
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QuoteOriginally posted by Clothears Quote
Ouch. OK, that's what I was afraid of. Is it as bad as that for the 55-300?
My own 55-300 isn't wobbly at all.
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