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Unsharp autofocus image using stabilised Sony lens


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My weapons of choice are normally all manual focus, with the exception of the Sigma 19mm f2,8. Yesterday, however, I took the camera out for a bike ride and chose to carry the NEX 6 16-50 kit lens to minimise weight. With the camera set to auto ISO and the lens to f8 I expected everything to be tolerably sharp. Most were,  but the one shot that I took that might have had legs here was blurred. Checking the details, the lens was at 28 mm and the shutter speed 320th. I can hand hold a manual  28mm lens at 1/30th never mind 1/320th!

 

Could this be a result of the image stabilisation system  causing problems?   It looks like camera shake, but at 1/320??

 

Another good reason to continue to shoot using ancient glass.....

 

Happy Luddite.

 

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Did you have the AF area set to "multi"? I find that the camera sometimes chooses unexpected AF points. In which case, I usually refocus -- i.e. I keep re-pressing the shutter release button -- until relevant points are selected.

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Did you have the AF area set to "multi"? I find that the camera sometimes chooses unexpected AF points. In which case, I usually refocus -- i.e. I keep re-pressing the shutter release button -- until relevant points are selected.

Thanks for the suggestion but I don't think that anything is sharp John, looks like shake rather than out of focus.

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Did you have the AF area set to "multi"? I find that the camera sometimes chooses unexpected AF points. In which case, I usually refocus -- i.e. I keep re-pressing the shutter release button -- until relevant points are selected.

Thanks for the suggestion but I don't think that anything is sharp John, looks like shake rather than out of focus.

 

That's odd. I use the 18-55mm most of the time with the NEX-6. Haven't had problems with IS, and the 6's hybrid AF definitely seems faster and more accurate than the NEX-3's AF. Still have the occasional problem with IS when using the 55-210, though. It just doesn't seem to be as effective as with the other Sony lenses.

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Yesterday, however, I took the camera out for a bike ride and chose to carry the NEX 6 16-50 kit lens to minimise weight. With the camera set to auto ISO and the lens to f8 I expected everything to be tolerably sharp. Most were,  but the one shot that I took that might have had legs here was blurred. Checking the details, the lens was at 28 mm and the shutter speed 320th. I can hand hold a manual  28mm lens at 1/30th never mind 1/320th!

 

 

Were you riding the bike when you shot the unsharp photo?

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Yesterday, however, I took the camera out for a bike ride and chose to carry the NEX 6 16-50 kit lens to minimise weight. With the camera set to auto ISO and the lens to f8 I expected everything to be tolerably sharp. Most were,  but the one shot that I took that might have had legs here was blurred. Checking the details, the lens was at 28 mm and the shutter speed 320th. I can hand hold a manual  28mm lens at 1/30th never mind 1/320th!

 

 

Were you riding the bike when you shot the unsharp photo?

 

Bryan didn't mention any broken bones, so my guess is that he wasn't.

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:)

 

No broken bones, fortunately, and not riding bike!

 

Checked the data again and found that it was at 49 mm not 28 mm so more chance of shake, but disappointing that IS did not handle it at 1/320th. Auto focus set to centre and image stabilisation on. Subject, a building, dead centre. Don't think focus confused. 

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If the OSS causes unsharpness, which it certainly can, the normal pattern is that one side of the image (usually the left) shows a lateral blur and the other side is sharper. The new OSS lenses don't seem to be as simple and robust as the 18-55mm, perhaps because they cover wider angles, but my 10-18mm seems 100% reliable - no unsharpness ever seems to result from OSS.

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If the OSS causes unsharpness, which it certainly can, the normal pattern is that one side of the image (usually the left) shows a lateral blur and the other side is sharper. The new OSS lenses don't seem to be as simple and robust as the 18-55mm, perhaps because they cover wider angles, but my 10-18mm seems 100% reliable - no unsharpness ever seems to result from OSS.

I agree, the IS on my older 18-55mm e-mount lens is really effective (think I got a good one), as good as my Sony DSLR's sensor-shift image stabilization. The newer 55-210 is another matter, though. I'm not convinced that the IS works at all at longer focal lengths. Guess it's about time I did some proper tests.

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If the OSS causes unsharpness, which it certainly can, the normal pattern is that one side of the image (usually the left) shows a lateral blur and the other side is sharper. The new OSS lenses don't seem to be as simple and robust as the 18-55mm, perhaps because they cover wider angles, but my 10-18mm seems 100% reliable - no unsharpness ever seems to result from OSS.

 

Hmm. I had (still have) a Nikon 24-85 f/2.8-4 that would produce that "effect," an out of focus left side of the image. It did not do it all the time, just every ten frames or so. At this point, I can't see that it would be cost effective to send it to Nikon for repair. When it's sharp. it's very very sharp. 

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I don't have a NEX, but do have a Sony SLT A-33. I use mostly old Minolta AF film lenses and personally keep the IS turned off all the time. If this was happening with all images I'd say a back focusing issue in camera, but that's not the case. Then again take what I say with a grain of salt. ;)

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I don't have a NEX, but do have a Sony SLT A-33. I use mostly old Minolta AF film lenses and personally keep the IS turned off all the time. If this was happening with all images I'd say a back focusing issue in camera, but that's not the case. Then again take what I say with a grain of salt. ;)

I used several Minolta AF lenses with my Sony DSLR (pre-SLT) and found that Sony's sensor-shift stabilization (such as that in the a33) works extremely well. I never turned "steady shot" off except when using a tripod and had no sharpness issues. With the NEX cameras, IS is built into the lens, not the body, and it is not always as effective IME. I'm currently debating whether or not I should look around for a used SLT camera or get an adapter so that I can use my remaining Minolta lenses with the NEX-6 (no IS, of course, in this case).

Edited by John Mitchell
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