OIS with teleconverters?

rondeann said:

Do you know if a haze filter is worth the trouble to help with
atmospheric haze and if yes what brand do you recommend. Anyone
else with an opinion is welcome to comment.

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A so-called "haze" filter is actually a filter designed to absorb a certain amount of UV light. UV reflects off particles in the atmosphere causing a certain amount of UV scatter. This causes 'haze' to image on older B&W film emulsions which had a high sensitivity at the blue and of the spectrum.

The sensor in your FZ camera is not particularly sensitive to UV light and moreover has white balance as part of the image processing algorithm, so a filter designed to absorb UV scatter does nothing to reduce this kind of haze. Atmospheric haze in the visible light spectrum caused by large amounts of water and dust in the air are also not reduced by a 'haze' or UV filter.

What can help reduce this kind of haze in some circumstances is a polarizing filter, but at the cost some light transmission. For an FZ10 or FZ20, you only need a linear polarizer. It won't take out all the haze but it can help to some degree if used correctly.

Godfrey

The more atmosphere you are shooting through, the greater the amount of light scatter, aka haze, you will see in your photos.

Remember: the gases of the atmosphere are really real... This is what limits the resolution with an astronomical telescope, at the limit. ;-)

Godfrey

John_Reed said:

I take a lot of shots of small subjects (like birds) that are
within maybe 30-40 feet of my camera, with and without my
telextender. My cat shot posted the other day was at 432mm zoom, at
a subject distance of 15 feet, no telextender. I don't think that
haze has much effect on these photos.

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I would say if you put anything in between the camera and the excellent clarity of the Leica glass there will in fact be a loss of quality. Whether you can see it with the eye or not is irrelevant.
This isn't the ISIE.
I'm not that smart and I don't really want to be.

I don't design these things and I don't really understand what you're really getting at anymore.
Harlan

Alan Martin said:

Harlan Saperstein said:

I can answer the first part of your question simply.
Yes.The more magnification you use the more your camera or
binoculars will be prone to hand shake. The IS will compensate for
this very effectively.
The IS technology in my experience begins to deteriorate after 10X
optical zoom, although at 12 it it still very good and even at 3X
digital is still usable.
This is perhaps why 420mm is where they called it.
Using a teleconverter will add to the IS burden but will still be
clearer then going into digital.

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This is why I specified to compare at the same effective zoom,
i.e., the same focal length. So the FZ20 alone at 12x zoom would
be compared with FZ20 + 2.2x teleconverter at 5x zoom. Of course,
this may cause vignetting and kind of defeats the purpose of using
a teleconverter in practice, but it does help to determine if OIS
performance is degraded by the mere use of a teleconverter, even
without increasing the focal length.

--
Alan Martin

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--
http://www.pbase.com/harlanjs

Here's my guess at how OIS works:

From the picture on the Panasonic sight, the gyro-sensor appears to be a relatively small chip on a circuit board. If this is the case, and there are no "moving parts", then it's a "gyro" in name and function only, as opposed to little rotating gizmos that those with better hearing than I have reported hearing.

I think that what this chip does is read an area (or areas) of the sensor, then calculate the motion of the deflection of light as it moves across the sensors, then translates this data to move the lens element to make this motion as little as possible. In other words, it "sees" that a consistent "shape" is moving across the CCD with a deflection of x number of sensor cells in direction y and moves the corrective lens element in the opposite (?) direction in real time, until the "shape" is as close to stationary on the CCD as the system allows.

If this is the case, then a couple of things are explained.

1. The addition of teleconvertors, WA converters, or closeups, or any other image modifiers will not effect OIS performance (it'll only do what it does to the extent that it can), and the user does not have to tell the camera that it has added anything because the system doesn't need to know. It's still just sensing the motion of light across the CCD. Since the telephoto setting only allows for 6x an up zoom, the assumption is that this is a static setting to help prevent vignetting and make the process faster for the user.

2. Mode 2 is theoretically more effective because the corrective element, in most cases, has to move less from a stationary centered position (as opposed to from full left to full right or any permutation of such positions) and can more effectively reach the position needed to damp movement at the point of shutter release.

3. It doesn't use much battery power. Spinning little doodads, then sensing that, then correcting the motion of a movable lens element would, I would think, use a lot more power. There would also be a problem with long term reliability.

I'll easily stand corrected if I'm totally off base here.

Scott

Alan Martin said:

Does use of a teleconverter (especially one such as the Raynox
DCR-2020 Pro which has a higher magnification than the Panasonic
one) reduce the effectiveness of the FZ20's OIS, even at the same
effective zoom setting?

It seems to me that the camera needs to know the actual focal
length to properly compensate for camera shake. Indeed, the FZ20
has a setting to inform it of the use of a tele or wide converter
(see pp. 79-80 of the user manual at
http://service.us.panasonic.com/OPERMANPDF/DMCFZ20PP.PDF ).

So, a question for FZ20 owners (and other FZ owners, presuming it
works the same way) with teleconverters: Do you use this setting?

Also, could you please try OIS mode 1 at the same effective zoom
setting (i.e., with the picture composed the same way) with and
without teleconverter (and with and without informing the camera of
it), and see if there is a noticeable difference in viewfinder
steadiness? Actual photo tests in OIS mode 2 would be even better,
but it would probably be a lot more effort because a meaningful
comparison would require many tries in each condition.

I have seen anecdotal reports that OIS is still at least partially
effective with teleconverters, but I would appreciate some hard
data on this.

--
Alan Martin

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All,

--Good try to all but here is an explaination.. it is simple and it does not matter if a teleconverter is attached. There are two solid state (nothing spinning) accelerometers (probably made by Analog devices) located inside the camera on a circuit card and perpendicular to each other(two axis). The motion of the camera (and lens) is sampled , position calculated and hence known. A control system applies "opposite" motion to a floating lens element which keeps the image "stabilized" with respect to the CCD. The IS modes deal with when the control is applied (all the time or when the shutter is depressed). This determines the response of the control system and hence the performance differences. The response of the lens element from "zero correct" or motion to correct position is faster than trying to get it(the lens) to the proper position when it may have been moving opposite that what was desired, i.e it must stop and then reverse.
Hope this puts the discussion to bed.

John Y
'you never know what you CAN see'