FZ200 Diffraction Limit - Panasonic Tech Service

Started Aug 27, 2013 | Discussions
LTZ470
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FZ200 Diffraction Limit - Panasonic Tech Service
Aug 27, 2013

Received a reply back from Panasonic Tech's on the FZ200 and where the Diffraction limit begins:

Dear Valued Customer
Case Number:30742743

Thank you for your inquiry, the diffraction (FZ200) starts 3.5 to 4.0.
We hope this information is helpful.Thank you for contacting Panasonic.

Experience is a funny thing, it is hard to beat...so don't believe all the Diffraction Calculators and so called camera experts on the internet...we ourselves can easily determine it from our user experiences...

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Ron Tolmie
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Re: FZ200 Diffraction Limit - Panasonic Tech Service
In reply to LTZ470, Aug 27, 2013

Panasonic's lens designers would be aghast to hear what Panasonic's "tech" staff are claiming.

All lenses are subject to diffraction at all f/ stops - it doesn't "begin" at any f/ stop. There may be some other factor that is more damaging to the performance of the lens - optical design faults or sensor problems, for example, so lenses/cameras differ with respect to what settings are optimal, but the diffraction contributions (more than just resolution is affected) are simply determined by the physical diameter of the diaphragm. That assumes that the resolution is measured in arc sec, not lines per mm.

The FZ200 has an aperture diameter of only 1.6 mm at its shortest focal length and maximum aperture. The consequence is that its resolution degradation attributable to diffraction is substantially worse than, say, that of the LX7. At its maximum focal length the maximum aperture diameter is 38.6 mm for the FZ200. Since the diffraction is inversely proportional to the diameter the diffraction effects are much less significant at long focal lengths. Optical aberrations are usually the limiting factor at the long focal lengths of lenses that have big zoom ratios.

Although the FZ200 has an unusually large f/ stop (and aperture diameter) at its longest focal length the advantage that confers to the resolution is quite small so other cameras that typically have smaller apertures at their maximum focal length may be just as sharp. The large f/ stop is of course very desirable because it permits faster shutter speeds and lower ISO settings.

Ron

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J C Brown
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Re: FZ200 Diffraction Limit - For Ron tolmie
In reply to Ron Tolmie, Aug 27, 2013

Ron Tolmie wrote:

Panasonic's lens designers would be aghast to hear what Panasonic's "tech" staff are claiming.

All lenses are subject to diffraction at all f/ stops - it doesn't "begin" at any f/ stop. There may be some other factor that is more damaging to the performance of the lens - optical design faults or sensor problems, for example, so lenses/cameras differ with respect to what settings are optimal, but the diffraction contributions (more than just resolution is affected) are simply determined by the physical diameter of the diaphragm. That assumes that the resolution is measured in arc sec, not lines per mm.

The FZ200 has an aperture diameter of only 1.6 mm at its shortest focal length and maximum aperture. The consequence is that its resolution degradation attributable to diffraction is substantially worse than, say, that of the LX7. At its maximum focal length the maximum aperture diameter is 38.6 mm for the FZ200. Since the diffraction is inversely proportional to the diameter the diffraction effects are much less significant at long focal lengths. Optical aberrations are usually the limiting factor at the long focal lengths of lenses that have big zoom ratios.

Although the FZ200 has an unusually large f/ stop (and aperture diameter) at its longest focal length the advantage that confers to the resolution is quite small so other cameras that typically have smaller apertures at their maximum focal length may be just as sharp. The large f/ stop is of course very desirable because it permits faster shutter speeds and lower ISO settings.

Ron

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Hi Ron,

Ron Tolmie / 3mm minimum sensor size

As you haven't yet replied to Sherm's original post or any of the subsequent responses it seems that you may have missed the above thread.

For my own benefit and that of other forum members who may be interested I would be very grateful if you could provide a more detailed explanation of the origin of the "3mm" aperture and its relation to the F/No, which as I understand it is simply the focal length of the equivalent single element lens divided by its effective aperture.

Thanks in advance

Jimmy

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sherman_levine
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Re: FZ200 Diffraction Limit - Panasonic Tech Service
In reply to LTZ470, Aug 27, 2013

LTZ470 wrote:

Received a reply back from Panasonic Tech's on the FZ200 and where the Diffraction limit begins:

Dear Valued Customer
Case Number:30742743

Thank you for your inquiry, the diffraction (FZ200) starts 3.5 to 4.0.
We hope this information is helpful.Thank you for contacting Panasonic.

Experience is a funny thing, it is hard to beat...so don't believe all the Diffraction Calculators and so called camera experts on the internet...we ourselves can easily determine it from our user experiences...

Interesting that the response was so brief - but it's consistent with your posting yesterday that your images start getting soft at apertures narrower than 4-4.5.

It's consistent also (albeit with a different absolute) with Ian's ZS19 results, where the resolution varies only with aperture, and is independent of zoom.

http://www.dpreview.com/forums/post/51807115

I suspect their answer is more to "When does diffraction become the limiting factor in resolution" than "When does diffraction start"....since diffraction is of course always with us.  The zoom lens is far more complex than the thin single lenses for which Airy discs are calculated, and it's not trivial (at least for me) to extract the relationships among the physical iris diaphragm diameter, the distance from the sensor, and the magnification of the zoom mechanism by the front lens as the zoom is changed.

Sherm

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LTZ470
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Re: FZ200 Diffraction Limit - Panasonic Tech Service
In reply to sherman_levine, Aug 27, 2013

From what I can tell they are doing some tricks with the zoom lens now...how does your FZ200 lens work?

When you zoom wide what does the lens actually do? Does it zoom all the way in and then back out slightly?

I noticed that the RX100 does this and I think its to do with diffraction limit and avoiding it too soon with the new lens/cameras...when you zoom the RX100 out wide the lens zooms all the way in then back out a few MM...if you zoom it back to point where it is the most retracted on the camera the frame is actually narrower than when it moves out a few mm...so there is some serious technology going into these cams, and of course you can see it in the prices as well...

They are doing something to offset the diffraction and the old calculation that everyone is using are wrong when utilised for the newly designed zoom lens?

Would like to know myself...

The also why does Panasonic use f/4 when you switch to Teleconversion Mode on the FZ200? Which is also a tell-tale sign. Panasonic have been designing cameras and making lens for sometime, and there is a Method to their Madness...

Interesting to say the least...

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Detail Man
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Re: FZ200 Diffraction Limit - Panasonic Tech Service
In reply to sherman_levine, Aug 27, 2013

sherman_levine wrote:

LTZ470 wrote:

Received a reply back from Panasonic Tech's on the FZ200 and where the Diffraction limit begins:

Dear Valued Customer
Case Number:30742743

Thank you for your inquiry, the diffraction (FZ200) starts 3.5 to 4.0.
We hope this information is helpful.Thank you for contacting Panasonic.

Interesting that the response was so brief - but it's consistent with your posting yesterday that your images start getting soft at apertures narrower than 4-4.5.

It's consistent also (albeit with a different absolute) with Ian's ZS19 results, where the resolution varies only with aperture, and is independent of zoom.

http://www.dpreview.com/forums/post/51807115

I suspect their answer is more to "When does diffraction become the limiting factor in resolution" than "When does diffraction start"....since diffraction is of course always with us. The zoom lens is far more complex than the thin single lenses for which Airy discs are calculated, and it's not trivial (at least for me) to extract the relationships among the physical iris diaphragm diameter, the distance from the sensor, and the magnification of the zoom mechanism by the front lens as the zoom is changed.

I can tell you from plenty of actual "experience" that the kids who work at Panasonic's "Technical Support" facility in Virginia are universally clueless in the extreme - and so are their "stupervisors".

For those who like to read, you might find yourself ruminating on the non-trivial details involved:

http://www.dpreview.com/forums/thread/3475094

When DIWA Labs was still around, they used DxOMark's testing rig to test (JPGs) from Pansonic stuperzooms. For the most part, MTF(50%) and Lens-Blur (in BxU) was highest at the lower F-Numbers (2.8-4.0), reducing somewhat after that. So, the "sweet spot" was more of a "sweet band" located near the bottom of the F-Number adjustment range.

It is important to understand that numerous factors affect the composite system spatial frequency response - lens-system diffraction is only one of them (and tends to be a relatively minor factor, until F-Numbers are reached where "extinction" of the lens-system (only) MTF begins to result in some (gradual, not "sudden") losses at the very highest spatial frequencies.

Details surrounding what happens (and how it happens) given various different parameters involved are discussed in the thread that I provide a reference link to above. These are complex matters.

DM ...

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Ianperegian
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Re: FZ200 Diffraction Limit - Panasonic Tech Service
In reply to Ron Tolmie, Aug 27, 2013

Ron Tolmie wrote:

Since the diffraction is inversely proportional to the diameter the diffraction effects are much less significant at long focal lengths.

Hi Ron,

I agree that the Panasonic "tech" staff response is misleading because what does "begin" mean in practical terms?  Also, it depends on the criteria used for calculating the Airy disk and the acceptable circle of confusion.

I don't agree with what you said above though.

For a given lens/sensor system the Airy disk diameter depends on the f number, and is independent of the focal length. As explained on the Cambridge site (here ), quote:

"Technical Note: Independence of Focal Length
Since the physical size of an aperture is larger for telephoto lenses (f/4 has a 50 mm diameter at 200 mm, but only a 25 mm diameter at 100 mm), why doesn't the airy disk become smaller? This is because longer focal lengths also cause light to travel further before hitting the camera sensor -- thus increasing the distance over which the airy disk can continue to diverge. The competing effects of larger aperture and longer focal length therefore cancel, leaving only the f-number as being important (which describes focal length relative to aperture size)."

I found that to be the case when I tested the variation of resolution at different apertures and focal lengths on my ZS20 (and earlier on my FZ38).  At f/8, where diffraction was decidedly the limiting factor, the resolution was similar at all focal lengths.

Ian

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LTZ470
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Re: FZ200 Diffraction Limit - Panasonic Tech Service
In reply to Ron Tolmie, Aug 27, 2013

Ron Tolmie wrote:

Panasonic's lens designers would be aghast to hear what Panasonic's "tech" staff are claiming.

All lenses are subject to diffraction at all f/ stops - it doesn't "begin" at any f/ stop. There may be some other factor that is more damaging to the performance of the lens - optical design faults or sensor problems, for example, so lenses/cameras differ with respect to what settings are optimal, but the diffraction contributions (more than just resolution is affected) are simply determined by the physical diameter of the diaphragm. That assumes that the resolution is measured in arc sec, not lines per mm.

The FZ200 has an aperture diameter of only 1.6 mm at its shortest focal length and maximum aperture. The consequence is that its resolution degradation attributable to diffraction is substantially worse than, say, that of the LX7. At its maximum focal length the maximum aperture diameter is 38.6 mm for the FZ200. Since the diffraction is inversely proportional to the diameter the diffraction effects are much less significant at long focal lengths. Optical aberrations are usually the limiting factor at the long focal lengths of lenses that have big zoom ratios.

Although the FZ200 has an unusually large f/ stop (and aperture diameter) at its longest focal length the advantage that confers to the resolution is quite small so other cameras that typically have smaller apertures at their maximum focal length may be just as sharp. The large f/ stop is of course very desirable because it permits faster shutter speeds and lower ISO settings.

Ron

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Emailed the designers at Panny, will revert with their response when received...

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LTZ470
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Re: FZ200 Diffraction Limit - Panasonic Tech Service
In reply to Detail Man, Aug 27, 2013

Detail Man wrote:

sherman_levine wrote:

LTZ470 wrote:

Received a reply back from Panasonic Tech's on the FZ200 and where the Diffraction limit begins:

Dear Valued Customer
Case Number:30742743

Thank you for your inquiry, the diffraction (FZ200) starts 3.5 to 4.0.
We hope this information is helpful.Thank you for contacting Panasonic.

Interesting that the response was so brief - but it's consistent with your posting yesterday that your images start getting soft at apertures narrower than 4-4.5.

It's consistent also (albeit with a different absolute) with Ian's ZS19 results, where the resolution varies only with aperture, and is independent of zoom.

http://www.dpreview.com/forums/post/51807115

I suspect their answer is more to "When does diffraction become the limiting factor in resolution" than "When does diffraction start"....since diffraction is of course always with us. The zoom lens is far more complex than the thin single lenses for which Airy discs are calculated, and it's not trivial (at least for me) to extract the relationships among the physical iris diaphragm diameter, the distance from the sensor, and the magnification of the zoom mechanism by the front lens as the zoom is changed.

I can tell you from plenty of actual "experience" that the kids who work at Panasonic's "Technical Support" facility in Virginia are universally clueless in the extreme - and so are their "stupervisors".

For those who like to read, you might find yourself ruminating on the non-trivial details involved:

http://www.dpreview.com/forums/thread/3475094

When DIWA Labs was still around, they used DxOMark's testing rig to test (JPGs) from Pansonic stuperzooms. For the most part, MTF(50%) and Lens-Blur (in BxU) was highest at the lower F-Numbers (2.8-4.0), reducing somewhat after that. So, the "sweet spot" was more of a "sweet band" located near the bottom of the F-Number adjustment range.

It is important to understand that numerous factors affect the composite system spatial frequency response - lens-system diffraction is only one of them (and tends to be a relatively minor factor, until F-Numbers are reached where "extinction" of the lens-system (only) MTF begins to result in some (gradual, not "sudden") losses at the very highest spatial frequencies.

Details surrounding what happens (and how it happens) given various different parameters involved are discussed in the thread that I provide a reference link to above. These are complex matters.

DM ...

So it could very well be at where we are seeing the sudden degradation at f4.5 and higher? And the f/3.5 to f/4.0 holds true as it is the sharpest?

Now when you use EZ Zoom how does that affect Diffraction? as it crops the sensor, but then it's only 8mp...same lens though...

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LTZ470
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Re: FZ200 Diffraction Limit - Panasonic Tech Service
In reply to Detail Man, Aug 27, 2013

DM wrote:

"In addition, lens-system aberrations will also reduce the magnitude of the composite system MTF, and increasing the F-Number to the point where the composite system MTF response is maximized makes sense (regardless of any other factors, such as calculated Airy disk diameters). At F-Numbers above that point (for any given Focal Length), the system is "diffraction limited".

So the FZ200 is diffraction limited regardless of focal length? and the f/4 sharpness just comes from lens characteristics? Nothing to do with diffraction because it is already in the lens from when you turn it on?

Once past f/4 I see a degradation quickly on the FZ200, but could be related to shutter speed as well...

All the scientific lingo is a bit much for my old brain…and I am reading work related programs for now...

I emailed Panasonic Japan to see how they respond…If panasonic doesn't know their own camera and lens then we are definitely in trouble! Leica's next...

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rcjim
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Re: FZ200 Diffraction Limit - Panasonic Tech Service
In reply to LTZ470, Aug 27, 2013

Regarding the so called experts you mention...please also allow me to count my own pixels.  

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Ron Tolmie
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Re: FZ200 Diffraction Limit - For Ron tolmie
In reply to J C Brown, Aug 27, 2013

Jimmy:

I had posted the equation for calculating the effect of diffraction in my original note. Most people assume that it is proportional to the f/ stop but it is not. It is simply (inversely) proportional to the diameter of the aperture. The tiny lens in a ZS20, the much bigger lens in a full frame camera, and the enormous lens in a big process camera will all suffer from the same resolution loss (in angular resolution terms) if they have the same aperture size, and in practical applications the smallest diameter that is capable of yielding really sharp images is about 3 mm for all of those lenses. Cameras (like the FZ200 and ZS20) that have smaller aperture diameters are not capable of producing what a critical photographer would consider to be a really sharp image at their shortest focal length. The same is true of an 800mm process camera lens that has been stopped down so that its diaphragm is under 3mm in diameter.

One of the interesting implications is that these small cameras could produce very sharp images at their longer focal length settings if the optical aberrations are very well controlled. At 100mm focal length an f/8 aperture corresponds to a 12.5mm aperture diameter, for which the diffraction effects are very small. That means that there is still room for substantial improvements in these tiny cameras if you are willing to live with softer images at the extreme WA setting. In that case the statistics for the number of photons captured per pixel tends to become the limiting factor for IQ.

Ron

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Ron Tolmie
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Resolution at long focal length settings
In reply to Ianperegian, Aug 27, 2013

Ian:

In my own experience with the ZS20 the resolution at the maximum focal length is substantially worse than at shorter focal lengths. You need to put the camera on a solid tripod and use the timer delay for such shots. Even with the smallest f/ stop the aperture diameter is still nearly 11mm at the longest FL so the image softness cannot be blamed on diffraction.

The objective of the lens designers was to control the optical aberrations so that the resolution is approximately the same at all focal lengths. Your tests show that the designers did a pretty good job. However, for most of the focal length range there is still a lot of room for improvements in resolution before diffraction becomes the limiting factor.

I think that future small-sensor cameras will be significantly sharper at most focal lengths. Most people do not really need better sharpness but they tend to buy the cameras that have a good reputation for sharpness.

Ron

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LTZ470
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Re: FZ200 Diffraction Limit - Panasonic Tech Service
In reply to rcjim, Aug 27, 2013

rcjim wrote:

Regarding the so called experts you mention...please also allow me to count my own pixels.

Alright Jim, shucks...those guys are legends...in their "own" minds...;-)

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Erik Ohlson
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Re: FZ200 Diffraction Limit - Panasonic Tech Service
In reply to LTZ470, Aug 27, 2013

LTZ470 wrote:

From what I can tell they are doing some tricks with the zoom lens now...how does your FZ200 lens work?

When you zoom wide what does the lens actually do? Does it zoom all the way in and then back out slightly?

I noticed that the RX100 does this and I think its to do with diffraction limit and avoiding it too soon with the new lens/cameras...when you zoom the RX100 out wide the lens zooms all the way in then back out a few MM...if you zoom it back to point where it is the most retracted on the camera the frame is actually narrower than when it moves out a few mm...so there is some serious technology going into these cams, and of course you can see it in the prices as well...

They are doing something to offset the diffraction and the old calculation that everyone is using are wrong when utilised for the newly designed zoom lens?

Would like to know myself...

The also why does Panasonic use f/4 when you switch to Teleconversion Mode on the FZ200? Which is also a tell-tale sign. Panasonic have been designing cameras and making lens for sometime, and there is a Method to their Madness...

Interesting to say the least...

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Hi,

I think you may be reading too much into the "....zoom all the way in and then back out slightly." that we notice on these cameras.

As a lens zooms, the proportional spacing of the internal lens elements varies and I believe that the spacing isn't quite "linear", so the little "back out slightly" correction may be a way of finalizing the positions of some elements as well as refining the focus.

At least that is how the internal workings of zoom lenses was explained back when they were being introduced in regular consumer cameras. [And didn't work very well  ]

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LTZ470
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Re: FZ200 Diffraction Limit - Panasonic Tech Service
In reply to Erik Ohlson, Aug 27, 2013

Erik Ohlson wrote:

LTZ470 wrote:

From what I can tell they are doing some tricks with the zoom lens now...how does your FZ200 lens work?

When you zoom wide what does the lens actually do? Does it zoom all the way in and then back out slightly?

I noticed that the RX100 does this and I think its to do with diffraction limit and avoiding it too soon with the new lens/cameras...when you zoom the RX100 out wide the lens zooms all the way in then back out a few MM...if you zoom it back to point where it is the most retracted on the camera the frame is actually narrower than when it moves out a few mm...so there is some serious technology going into these cams, and of course you can see it in the prices as well...

They are doing something to offset the diffraction and the old calculation that everyone is using are wrong when utilised for the newly designed zoom lens?

Would like to know myself...

The also why does Panasonic use f/4 when you switch to Teleconversion Mode on the FZ200? Which is also a tell-tale sign. Panasonic have been designing cameras and making lens for sometime, and there is a Method to their Madness...

Interesting to say the least...

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Hi,

I think you may be reading too much into the "....zoom all the way in and then back out slightly." that we notice on these cameras.

As a lens zooms, the proportional spacing of the internal lens elements varies and I believe that the spacing isn't quite "linear", so the little "back out slightly" correction may be a way of finalizing the positions of some elements as well as refining the focus.

At least that is how the internal workings of zoom lenses was explained back when they were being introduced in regular consumer cameras. [And didn't work very well ]

Erik you would have to see it to understand that it is more exaggerated than just a little on the RX100 it's significant...

I couldn't remember if the FZ200 was the same way...

IF you do zoom the RX100 all the way wide, then it zooms inside then goes back out quite significant if I remember right...

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Detail Man
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Re: FZ200 Diffraction Limit - Panasonic Tech Service
In reply to LTZ470, Aug 27, 2013

LTZ470 wrote:

DM wrote:

"In addition, lens-system aberrations will also reduce the magnitude of the composite system MTF, and increasing the F-Number to the point where the composite system MTF response is maximized makes sense (regardless of any other factors, such as calculated Airy disk diameters). At F-Numbers above that point (for any given Focal Length), the system is "diffraction limited".

So the FZ200 is diffraction limited regardless of focal length?

The net composite effect at the photosite level (the "RAW" level) of lens-system diffraction, combined together with lens-aberrations, optical filter-stack characteristics, photosite aperture, shape, and "pitch" ...

... which then is also "filtered" by the (potentially non-limear) spatial frequency response of the de-mocaiscing algorithm that readies a RAW-level image for (in-camera, or external) further processings, many of which will (themselves) "filter" the image-data further.

Then (on some particular viewing medium at some particular physical size in some given ambient light environment at some distance), depending somewhat on mood (perhaps), and that final end-product is what viewers then gaze at - typically through all kinds of varying fideltiy monitor-screens as well as browser color-management. No one single unifrom "elephant to be seen" there.

We are assuming zero focus-error (or the MTF becomes more complicated still, and not in simple ways), zero net camera-motion (or the perfect cancellation of such), of course. In real life, these tangible and oft-present annoyances very likely completely "swamp-out" any significant "diffraction" concerns, anyway ...

.

Diffraction itself is (solely) a characteristic of the lens-system. It is measured in spatial frequency units (using MTF curves).

"Diffraction Limited" describes a range of lens-system F-Numbers where the (essentially linear) net-decrease of the numerical magnitude of the MTF curve (also described as the "contrast" amount) as spatial frequency increases dominates over the (also present) optical aberrations.

This is complex, in that "stopping-down" only reduces (some) aberrations (some by direct divisions of the effects of the aberrations, some by division proportional to the square of the F-Number). But those optical aberrations are still there - only somewhat lessened from "stopping" down.

At some particular F-Number (for a given lens-camera combination), the measured (spatial frequency) resolution will exist at a maximum numerical value. Or, perhaps not in this case (below).

and the f/4 sharpness just comes from lens characteristics?

See above explanation.

Nothing to do with diffraction because it is already in the lens from when you turn it on?

Diffraction effects occur on their own within the lens/aperture system only.

Once past f/4 I see a degradation quickly on the FZ200, but could be related to shutter speed as well...

Not in Aperture Priority mode. I am assuming that you would be in Aperture Priority shooting mode, and then control the Shutter Speeed to some comfortably higher level via (negative direction) adjustment of the manual Exposure Compensation control (so as to achieve a constant Live Histogram reading) ? All of the above optical/electronic effects are independent of the time of the exposure (of the image-sensor surface to incoming light).

All the scientific lingo is a bit much for my old brain…and I am reading work related programs for now...

I emailed Panasonic Japan to see how they respond…If panasonic doesn't know their own camera and lens then we are definitely in trouble! Leica's next...x

Well, there you go ...

So it could very well be at where we are seeing the sudden degradation at f4.5 and higher? And the f/3.5 to f/4.0 holds true as it is the sharpest?

What you see is what you get (but nobody else can ever know or understand what your own perceptual mind envisions). The FZ28 lens (x18) was best at it's minimum F=2.8 F-Number. Things only got (slowly, gradually) worse above minimum F-Number.

"Stopping-down" only reduces (some) optical lens-system aberration effects (at any F-Number).

It (may) be that rather than think in terms of a certain and well defined peak "sweet spot" (of F-Number) here, it (may, in actual behavior) be more like a gradual reduction of resolution (measured usig MTF curves) starting (at or near) the lowest F-Numbers. At which point, there is no (other base F-Number setting-value) "point" (in the value of F-Number) to call some (reasoned to be a well-defined peak "maximum").

Now when you use EZ Zoom how does that affect Diffraction? as it crops the sensor, but then it's only 8mp...same lens though...

Indeed. The resolution will be reduced by the fraction of the original image-dimension (used in calculations) that the sensor-cropping comprises. There is absolutely no free-lunch on that. There still (may) be some particular F-Number that you might want to be at - but not so if the FZ200's lens-system is similar to the FZ18's (18x) telephoto zoom lens-system. I do not know.

At longer lens-system Focal Lengths, it would seem to my (near zero understanding of optical lens-system design) likely (some) optical aberrations must allowed to exist in order for a lens-system to achieve a constant F-Number over such a wide range of multiples of Focal Length.

But I should let others much better speak to the various trade-offs of optical lens-system designs.

DM ...

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sherman_levine
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Re: FZ200 Diffraction Limit - Panasonic Tech Service
In reply to LTZ470, Aug 27, 2013

LTZ470 wrote:

Erik Ohlson wrote:

LTZ470 wrote:

From what I can tell they are doing some tricks with the zoom lens now...how does your FZ200 lens work?

When you zoom wide what does the lens actually do? Does it zoom all the way in and then back out slightly?

I noticed that the RX100 does this and I think its to do with diffraction limit and avoiding it too soon with the new lens/cameras...when you zoom the RX100 out wide the lens zooms all the way in then back out a few MM...if you zoom it back to point where it is the most retracted on the camera the frame is actually narrower than when it moves out a few mm...so there is some serious technology going into these cams, and of course you can see it in the prices as well...

They are doing something to offset the diffraction and the old calculation that everyone is using are wrong when utilised for the newly designed zoom lens?

Would like to know myself...

The also why does Panasonic use f/4 when you switch to Teleconversion Mode on the FZ200? Which is also a tell-tale sign. Panasonic have been designing cameras and making lens for sometime, and there is a Method to their Madness...

Interesting to say the least...

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Hi,

I think you may be reading too much into the "....zoom all the way in and then back out slightly." that we notice on these cameras.

As a lens zooms, the proportional spacing of the internal lens elements varies and I believe that the spacing isn't quite "linear", so the little "back out slightly" correction may be a way of finalizing the positions of some elements as well as refining the focus.

At least that is how the internal workings of zoom lenses was explained back when they were being introduced in regular consumer cameras. [And didn't work very well ]

Erik you would have to see it to understand that it is more exaggerated than just a little on the RX100 it's significant...

I couldn't remember if the FZ200 was the same way...

IF you do zoom the RX100 all the way wide, then it zooms inside then goes back out quite significant if I remember right...

There's a lot of movement in the innards as the lens zooms - and it's not anything like linear. The bottom of this page shows one example.

http://www.adaptall-2.org/articles/InsideZoomLens/InsideZoomLens.html

FZ200 pulls in about 4mm as you go from full wide to about 2x. I think every small sensor I've owned has the same behavior.

Sherm

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Erik Ohlson
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Re: FZ200 Diffraction Limit - Panasonic Tech Service
In reply to sherman_levine, Aug 27, 2013

sherman_levine wrote:

LTZ470 wrote:

Erik Ohlson wrote:

LTZ470 wrote:

From what I can tell they are doing some tricks with the zoom lens now...how does your FZ200 lens work?

When you zoom wide what does the lens actually do? Does it zoom all the way in and then back out slightly?

I noticed that the RX100 does this and I think its to do with diffraction limit and avoiding it too soon with the new lens/cameras...when you zoom the RX100 out wide the lens zooms all the way in then back out a few MM...if you zoom it back to point where it is the most retracted on the camera the frame is actually narrower than when it moves out a few mm...so there is some serious technology going into these cams, and of course you can see it in the prices as well...

They are doing something to offset the diffraction and the old calculation that everyone is using are wrong when utilised for the newly designed zoom lens?

Would like to know myself...

The also why does Panasonic use f/4 when you switch to Teleconversion Mode on the FZ200? Which is also a tell-tale sign. Panasonic have been designing cameras and making lens for sometime, and there is a Method to their Madness...

Interesting to say the least...

-- hide signature --

--Really there is a God...and He loves you..
FlickR Photostream:
www.flickr.com/photos/46756347@N08/
Mr Ichiro Kitao, I support the call to upgrade the FZ50.
I will not only buy one but two no questions asked...

Hi,

I think you may be reading too much into the "....zoom all the way in and then back out slightly." that we notice on these cameras.

As a lens zooms, the proportional spacing of the internal lens elements varies and I believe that the spacing isn't quite "linear", so the little "back out slightly" correction may be a way of finalizing the positions of some elements as well as refining the focus.

At least that is how the internal workings of zoom lenses was explained back when they were being introduced in regular consumer cameras. [And didn't work very well ]

Erik you would have to see it to understand that it is more exaggerated than just a little on the RX100 it's significant...

I couldn't remember if the FZ200 was the same way...

IF you do zoom the RX100 all the way wide, then it zooms inside then goes back out quite significant if I remember right...

There's a lot of movement in the innards as the lens zooms - and it's not anything like linear. The bottom of this page shows one example.

http://www.adaptall-2.org/articles/InsideZoomLens/InsideZoomLens.html

FZ200 pulls in about 4mm as you go from full wide to about 2x. I think every small sensor I've owned has the same behavior.

Sherm

Thanks for the details, Sherm. The clarification is much appreciated.

I didn't want to over-explain this as it may be that the latest zooms might not have quite as complex movements but we should all understand that a whole lot more is going on in these marvelous cameras than simply "meets the eye" 

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Jerrich
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Re: FZ200 Diffraction Limit - Panasonic Tech Service
In reply to LTZ470, Aug 27, 2013

LTZ470 wrote:

When you zoom wide what does the lens actually do? Does it zoom all the way in and then back out slightly?

I just checked and my Canon G11 does this also.
JR
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