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04-24-2016, 07:26 AM   #31
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Panasonic id's actually combining ois and ibis together in the latest systems, however the reports on the efficacy of this are really mixed. The gx7 I have has fairly primitive ibis compared to The latest cameras, but is useful for adapted lenses.

So I see room for both approaches.

04-24-2016, 07:36 AM   #32
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QuoteOriginally posted by UncleVanya Quote
Panasonic id's actually combining ois and ibis together in the latest systems, however the reports on the efficacy of this are really mixed. The gx7 I have has fairly primitive ibis compared to The latest cameras, but is useful for adapted lenses.

So I see room for both approaches.
Sony also combines OIS with IBIS. My A7II has IBIS and my FE 90mm F/2.8 has OIS. The body will handle certain types of movement and the lens with handle others. Seems to work pretty well.
04-24-2016, 08:26 AM   #33
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QuoteOriginally posted by Simen1 Quote
You mention stabilized viewfinder as if it was an advantage. I have to disagree with that. Stabilization can be done within certain limits of sensor or lens movemens (1,5mm in all directions for Pentax IBIS). That means that if the camera is held less stable by the photographer, its more likely that more shots are out of reach for the stabilizer (OIS or IBIS). Now, why do I assume OIS causes the camera to be shaken more? The human body uses two sensory systems to hold the balance. A balance unit in each ear (I donít know the English name), and two eyes. If the impression for those two systems conflict, lets say if you are reading while being a passenger in a car on a bumpy road, or staying inside a boat, the conflicting sense between the eyes and the balance units will make you dissy and carsick or seasick. Different people are constructed differently. Some people rely more on the balance unit then the eyes. Some the other way around. Some quite equal. Its almost like someone being left handed and some right handed. thats why some people easily get seasick and others donít. Those people that rely on the visible image to hold the balance (almost all people do to some extent), will get a confusing image when they view through a stabilized viewfinder (OIS). They will keep their balance worse compared to using a non stabilized viewfinder (IBIS).

In short, OIS confuses the brains balancing sense and results in more physical camera shake. That may result in more images that exceed the stabilizers capability.
Sorry, but this seems just too far-fetched for me. I know about the ear/eye balance system, but this is meant to keep your body in balance so you don't fall over, not to reduce the minute vibrations that occur when holding a camera and lens in your hand.

QuoteOriginally posted by Simen1 Quote
For the second point, stabilized image at the AF and metering unit, sounds like a positive advantage. I don't know if makes a real life difference in some cases, but if so, its a positive real life advantage. IF this is a real advantage for OIS, I still doubt that its important enough to compete with the long list of IBIS advantages. Astrotracing, horizon correction, composition correction, pixel shift resolution, AA filter simulator and more.
Well, that depends on your usage I guess. If you use a long tele and want to track a fast animal, I can see a stabilized AF array providing far better tracking performance (and thus more keepers) than IBIS ever could. That's also what I meant by saying OIS is better at stabilizing.

OTOH I don't use all the features that IBIS can offer, but I will say that it is definitely more versatile than OIS. Except maybe at video.
04-24-2016, 01:39 PM   #34
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QuoteOriginally posted by starbase218 Quote
Sorry, but this seems just too far-fetched for me. I know about the ear/eye balance system, but this is meant to keep your body in balance so you don't fall over, not to reduce the minute vibrations that occur when holding a camera and lens in your hand.
Far fetched? Its the same thing, and the frequency spectrum of human body vibrations/balance is a continuous spectrum. This should be fairly easy to test in real life. Take 100 shots of a test sheet with a OIS system in challenging conditions and compare to 100 shots from a IBIS system (alternate to make sure its as fair as possible). The images should be interpreted by some sort of machine vision analysis system with the slanted edge method to avoid human systematic errors.

QuoteOriginally posted by starbase218 Quote
Well, that depends on your usage I guess. If you use a long tele and want to track a fast animal, I can see a stabilized AF array providing far better tracking performance (and thus more keepers) than IBIS ever could.
That should also be tested in real life. Does it just do a difference when using tracking focus? Only for fast moving objects? Only when the light is poor? A thorough test should answer these questions.

04-24-2016, 01:53 PM   #35
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04-24-2016, 04:35 PM   #36
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QuoteOriginally posted by jatrax Quote
Talks about the development of the DFA series of lenses
Interesting read. Esp.
QuoteQuote:
When I looked into the causes, it turned out that the spherical precision of the large-aperture, special-glass lens was slightly off. The error was beyond the level detectable by measuring instruments, so it was impossible for us to anticipate this in advance.
triggered my attention. Is this the explaination why the 70-200/2.8 was delayed?

Anyway, it is interesting. It highlights how computer-aided lens design cannot automate the design process as much as we (in the forums) tend to believe. One naively would have thought that error propagation analysis in the design software with the quality-inspection tolerance parameters as input values would have predicted the problem. It obviously didn't and experience of lens designers remains key to the success of optical companies.
04-25-2016, 05:34 AM   #37
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QuoteOriginally posted by falconeye Quote
Interesting read. Esp.

triggered my attention. Is this the explaination why the 70-200/2.8 was delayed?

Anyway, it is interesting. It highlights how computer-aided lens design cannot automate the design process as much as we (in the forums) tend to believe. One naively would have thought that error propagation analysis in the design software with the quality-inspection tolerance parameters as input values would have predicted the problem. It obviously didn't and experience of lens designers remains key to the success of optical companies.
I've just spent half the night reading up on f1's technical progress, of recent times. The advancements in CFD (computational fluid dynamics) that are even remotely attainable (over half-billion $ budgets for the top teams allow for almost anything, especially when it can be used back in the road car segment) have increased dramatically. The complexity doesnt just lie in the software itself but also what to calculate for. So in cases like lens design, that has a much longer turn around then 'the next race' and can run into years, I'd imagine it has a way to go yet. This is where the experienced designers can help both in modern product and for future development of software.

And lets remember the leading aerodynamicist in f1 still uses pencil and paper...
04-25-2016, 08:23 AM   #38
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QuoteOriginally posted by Winder Quote
Sony also combines OIS with IBIS. My A7II has IBIS and my FE 90mm F/2.8 has OIS. The body will handle certain types of movement and the lens with handle others. Seems to work pretty well.
Some of the test results for the Panasonic's with OIS and IBIS have not been as successful. OIS alone and IBIS alone both beat the combined version. However the number of tests run and the breadth of lenses tested is small. It could be an issue with a specific combination or a bad sample camera or lens.

04-25-2016, 10:21 AM   #39
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QuoteOriginally posted by bibz Quote
And lets remember the leading aerodynamicist in f1 still uses pencil and paper...
I remember a statement of Sir Sydney Camm's (Hawker Hurricane designer, among other things). When asked to incorporate a certain modification into the rear fuselage of the Hawker Hunter, he demurred; when the design they eventually tested failed, he's reported to have said "I could have told them it wouldn't work - when you've been designing airplanes for as long as I have [he started in the biplane era and finished with transonic jets], you can see the airflow."

I wonder if lens designers have a similar sense.
04-25-2016, 12:42 PM   #40
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QuoteOriginally posted by pathdoc Quote
I remember a statement of Sir Sydney Camm's (Hawker Hurricane designer, among other things). When asked to incorporate a certain modification into the rear fuselage of the Hawker Hunter, he demurred; when the design they eventually tested failed, he's reported to have said "I could have told them it wouldn't work - when you've been designing airplanes for as long as I have [he started in the biplane era and finished with transonic jets], you can see the airflow."
Many people, myself included, think that the Hawker Hunter was the most beautiful looking jet aircraft ever designed. I'm a great believer in "if it looks right, it is right!" The K-1 looks right to me.
04-25-2016, 01:04 PM   #41
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It's a pleasure to see an article that explains parameters, decisions, reasoning and as free of obfuscation as Marketing will allow. May it continue.
04-25-2016, 03:31 PM   #42
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QuoteOriginally posted by Cynog Ap Brychan Quote
"if it looks right, it is right!"

Nevertheless, I guess intuition can be fooled.

The Bulbous Bow of tankers comes to my mind ...
04-25-2016, 04:11 PM - 1 Like   #43
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QuoteOriginally posted by falconeye Quote

Nevertheless, I guess intuition can be fooled.

The Bulbous Bow of tankers comes to my mind ...
Fluid dynamics is a dark art.
04-25-2016, 04:22 PM   #44
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QuoteOriginally posted by Cynog Ap Brychan Quote
Many people, myself included, think that the Hawker Hunter was the most beautiful looking jet aircraft ever designed.
I have a weak spot for the English Electric Lightning (the final, F.6 mark). Variety is the spice of life. (Though I will grant you, I'm not sure Sydney Camm really knew how to design an ugly airplane. Perhaps the Typhoon - the prop fighter - comes closest.)
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