Vibration of the A7R shutter compared to D3 and NEX-7 using a seismometer

Started Dec 20, 2013 | Discussions
fotowbert
fotowbert Veteran Member • Posts: 3,052
Yes it was too harsh

Keit ll wrote:

fotowbert wrote:

Keit ll wrote:

These results are interesting & it would be nice to see what happens at a range of different shutter speeds. Some caution in interpreting the data is needed however because these vibrations are being measured at the periphery of the camera body & do not necessarily reflect what is happening at the sensor.

These measurements may not even be accurately representing the behavior at the camera body when you consider the attachment of the iphone to the camera body. The OP's description has the flat side of the iphone held against the hot shoe with rubber bands. Accurate vibration measurements require the accelerometers to be rigidly attached (like bolts or epoxy perhaps) otherwise the data is likely being influenced by the iphone vibrating relative to the camera body.

How the sensor moves will depend on how well it is isolated from the rest of the vibrating body & on any inherent resonance frequencies of the sensor itself.

The a7r 1/2 sec Z channel data show about a 40 Hz resonance superimposed upon a much slower event which damps out after 1/3 of the exposure. Something is definitely resonating but what that is is unclear.

There could well be some designed in isolation of the shutter mechanism from the rest of the camera body since it is the source of the vibration. However with the exception of IBIS there should be absolutely no movement of the sensor relative to the lens mount as this would seriously degrade image quality. This is in addition to any movement during exposure of the lens mount relative to global space which is what we generally think of as "camera shake". Image blur is the sum of both movements.

One way of sorting this out would be to correlate the measured vibrations with a critical examination of the images obtained from individual cameras.

Yes indeed. This is crucial. Without some proof of concept there can be no confidence in any conclusions made from these measurements.

So while many may note that the 1/2 sec data seems to show either the NEX 7 or D3 (with mirror lock-up) are similar with the least vibration, followed by the D3 (without mirror lock-up) and the a7r worst of the bunch, this conclusion is meaningless.

While I agree with most of your comments , your conclusion is a little harsh ? The conclusion should be that these results are highly suggestive & require further investigations to confirm a vibration issue which is affecting IQ

Yes I was too harsh in how I phrased it. To all readers please accept my apology.

After a career in product design I am acutely aware of the consequences of drawing conclusions and making decisions based upon data from an unproven process and got carried away with my response. I still occasionally get on that soap box.  Sorry.

  • John
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Paul Richman
Paul Richman Veteran Member • Posts: 4,526
Lloyd Chambers
1

He thinks there is a real problem, and has documented it carefully. Has me worried as I love my A7r. Personally, I have not seen the problem yet, but Lloyd's a keen observer and I'm afraid I will.
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ferrellmc
OP ferrellmc Regular Member • Posts: 106
Re: Yes it was too harsh

fotowbert wrote:

Keit ll wrote:

fotowbert wrote:

Keit ll wrote:

These results are interesting & it would be nice to see what happens at a range of different shutter speeds. Some caution in interpreting the data is needed however because these vibrations are being measured at the periphery of the camera body & do not necessarily reflect what is happening at the sensor.

These measurements may not even be accurately representing the behavior at the camera body when you consider the attachment of the iphone to the camera body. The OP's description has the flat side of the iphone held against the hot shoe with rubber bands. Accurate vibration measurements require the accelerometers to be rigidly attached (like bolts or epoxy perhaps) otherwise the data is likely being influenced by the iphone vibrating relative to the camera body.

How the sensor moves will depend on how well it is isolated from the rest of the vibrating body & on any inherent resonance frequencies of the sensor itself.

The a7r 1/2 sec Z channel data show about a 40 Hz resonance superimposed upon a much slower event which damps out after 1/3 of the exposure. Something is definitely resonating but what that is is unclear.

There could well be some designed in isolation of the shutter mechanism from the rest of the camera body since it is the source of the vibration. However with the exception of IBIS there should be absolutely no movement of the sensor relative to the lens mount as this would seriously degrade image quality. This is in addition to any movement during exposure of the lens mount relative to global space which is what we generally think of as "camera shake". Image blur is the sum of both movements.

One way of sorting this out would be to correlate the measured vibrations with a critical examination of the images obtained from individual cameras.

Yes indeed. This is crucial. Without some proof of concept there can be no confidence in any conclusions made from these measurements.

So while many may note that the 1/2 sec data seems to show either the NEX 7 or D3 (with mirror lock-up) are similar with the least vibration, followed by the D3 (without mirror lock-up) and the a7r worst of the bunch, this conclusion is meaningless.

While I agree with most of your comments , your conclusion is a little harsh ? The conclusion should be that these results are highly suggestive & require further investigations to confirm a vibration issue which is affecting IQ

Yes I was too harsh in how I phrased it. To all readers please accept my apology.

After a career in product design I am acutely aware of the consequences of drawing conclusions and making decisions based upon data from an unproven process and got carried away with my response. I still occasionally get on that soap box. Sorry.

  • John

A possible way to test shutter vibration and eliminate the variables would be to take an image with shutter vibration and then compare it to an image without shutter vibration.

To take the image with NO shutter vibration have the camera set up in a dark studio, open the shutter for say 10-20seconds. While the shutter is open fire a strobe(s) off camera to expose the image. This exposure will have no vibration from a shutter release.

Then take an image normally but don't use the strobes their duration is too short, use hot lights or similar.

If everything is the same: lens, focus, ISO, tripod mount, distance etc. the difference in the two images is shutter vibration. Then do the MTF mapper (I've never worked with it).

This could be done at different shutter speeds.

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Rod McD Veteran Member • Posts: 6,653
Re: Vibration of the A7R shutter compared to D3 and NEX-7 using a seismometer

Hi,

Thanks for the test and your post. Whilst I agree that the results raise some questions, I think we need to be mindful of how significant this may or may not be.....

1)  There are now a great many posts across the internet which show that the A7r delivers wonderfully sharp and detailed images.

2)  Reviewers seem happy to compare the output of their tests favorably with a D800, the reigning DSLR king of resolution.

3)  The test of hand-holding shows a lower frequency vibration or shake that is as big and sometimes bigger in amplitude than the shutter induced vibration of the camera mounted on the desk.  To me, this really invites the question of whether the shutter shock is worth worrying about if you're a hand-holder.

I used to shoot medium and large format.  I once tested my ability to hand-hold a medium format camera in good light by comparing side by side tripod and handheld shots of a test chart or bank notes.  I thought I was pretty steady as a hand holder at "reasonable" shutter speeds, but that simple test soon provided an education....... A tripod is always better.  I learned to reach for one at shutter speeds I previously though were good for hand-holding.  It's a pity they're such a long gangly thing to carry all the time and so inconvenient in many contexts.

Cheers, Rod

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jpr2 Forum Pro • Posts: 15,554
re: the power of investigating mind - congratulations !!!

there was a long, but pretty convincing writeup on SAR about the vibration issue

by Joseph Holmes

"Unfortunately, Sony has a problem with the A7R which is serious for a significant segment of uses, involving longer lenses on a tripod, and especially lenses which are connected via a lens foot or adapter foot to the tripod. The first curtain shutter shake is too great to avoid motion blur in many longer-lens situations. A firmware update to provide an option to add a delay between the two motions of the first curtain would be a big help, but might not be enough to solve the problem entirely.

Lloyd Chambers at DigLloyd.com, and two more of us (including myself), in separate series of carefully done experiments, have found consistent, clear and certain proof of a serious issue with the camera bouncing too much during exposures at various speeds, typically 1/100th of a second being the worst. The shutter shake seems, if anything, to be worse than when the same lens is connected to a Canon 5D II with full mirror slap. The motion is primarily in the direction of the shutter: up and down with a horizontal image and side to side with a vertical image (see samples below).

This happens more with longer lenses and more with lenses where the camera itself is not mounted directly to the tripod, rather the lens is mounted via its own foot, or its mounted to the foot of an adapter, so the camera is at the end of a “branch” sticking out in space, unsupported so that it is more readily made to shake. The further the mounting point is from the camera’s sensor plane, the worse the motion blur in the capture. And it is also highly dependent on the shutter speed, with longer exposures like 1/4 and longer being unaffected and the worst blur usually occurring at 1/100th of a second (strangely). Lloyd also observed a sudden up-tick in motion blur at 1/500th with a Leica 280 mm lens. I have been seeing the problem at focal lengths between 120 and 160mm (the longest lens I have which will work on the camera at the moment), as has my friend Mike Schultz, with exposures between 100 mm and 280 mm. Our results and observations are in close agreement.

I just tried a series of hand-held exposures with a fairly light weight, f3.5 150mm non-native lens at both 1/100th and 1/160th, in both horizontal and vertical position, and there was no clear pattern of shutter vibration causing movement in the direction of shutter movement, at either shutter speed. Some where sharp, some obviously moved. So that’s good, as this implies that the self-induced vibration is not necessarily affecting hand-held cameras, for whatever reason.

It has also been conclusively shown by Lloyd’s testing that the electronic first curtain of the A7 eliminates all of this pernicious camera shake. (Unless there is another important difference between the two shutters, where the second curtain of the A7R blurs the exposure as it’s closing and that of the A7 other does not, which seems very unlikely.)

Further, Mike and I have shown that attaching a certain amount of weight to the camera can solve the problem completely. We are building 24-ounce weights (including the weight of a small, Arca-Swiss type screw-knob clamp, the L-plate and a metal block) to connect to the base of the camera when using longer lenses, especially when they are not native lenses with the camera connected directly to the tripod. I tested a 26-ounce weight, screwed to the bottom of the camera for horizontal exposures and found it highly effective. Mike tested a 24-ounce metal weight screwed directly to the base of the camera and it was highly effective for both horizontal and vertical camera position. If an L-plate such as the new one from Really Right Stuff, and a compact screw clamp are combined with a block of metal, the metal would need to weigh only about 17 ounces and can therefore be a piece of brass or stainless steel about 1 x 1.25 x 3″ long with simply a hole drilled through the middle in the short direction, or drilled through, up to a quarter inch behind the middle, because the shutter is about 1/4″ ahead of the tripod screw hole of the camera and moving the bar forward a bit would center it right beneath the shutter for optimal effect. Such a piece of stainless will weigh about 17 oz, so combined with the L-plate and clamp, the total is 24 ounces. A piece of brass would, depending on the alloy chosen, probably weight 1 or 2 ounces more. 13 ounces doesn’t work very well at all. We have not tried a series of several different weights, owing to the inconvenience of performing such tests, but a total weight of 24 ounces is looking at least close to ideal

I suspect that when the Sony G 70-200 f4 OSS lens appears, we will find that even at 200mm on a tripod, it is little affected by this malady, because the shake is well prevented by the Arca-Swiss style clamp on the tripod head with the camera directly connected via the base of an L-plate to the tripod. When mounting the same lens on its tripod foot for better weight balance and less strain on the lens mount (the 70-200 lens is only 840 grams so it’s not too heavy to mount directly and have the camera support it), the vibration issue is very likely to be worse, and may show motion at speeds close to 1/100th, especially when closer to 200 mm, or they may not be bad enough to notice. We’ll see.

But Sony needs to address this critical issue, which is preventing many uses of the camera from allowing us to get sharp pictures, except by using the dead weight. Notice that of all the samples published on the web, there have been few, if any, longer lens captures, and the method of connection to the tripod and use of adapters can have a big impact on the result.

In no case have I seen motion at focal lengths of 85 mm and below, even when adapting the lens to the camera and supporting the assembly by the adapter’s foot. Native lenses may be fairly safe from obvious movement out to 150mm when the camera is mounted directly to the tripod, at all shutter speeds, horizontal or vertical camera, but only testing them will tell. Vertical is apt to be worse, however.

We very much hope that Sony changes the firmware so as to allow an option to introduce a delay between the closing of the first curtain and the opening of the first curtain, to begin the exposure. It would appear that this delay would be very effective at diminishing the additional effect of the first motion of the first curtain to nearly nothing if it is only as long as 1/10th of a second, and would be a substantial improvement if it were even a delay of just 1/40th of a second, as evidence shows that this vibration is dampened very quickly. Or they could, with a new soft shutter option, require a double push of a remote to trip the shutter in this special mode. About half the vibration would remain, but it would be a big help to reduce it by half.

Leica did provide a special solution, something very much like this with the M240, I gather. It is certainly unfortunate that we didn’t get an electronic first curtain option with the A7R, and it remains mysterious why it didn’t happen. Hopefully a follow on camera will not omit this vital feature for tripod work with a very light weight camera. But in the meantime a modest firmware update could solve the problem ABOUT half way and help a lot. All of my tripod-shooting photographer friends care about this issue a great deal. The whole point of the camera is defeated if its fine detail is ruined by shutter shake.

Here are two examples made by Mike (100% sections). The first is the Nikkor 70-200 f4 VR lens at 1/100th and 800 ISO at 180 mm, the A7R turned vertical, and the lens connected to a sturdy tripod via the lens’ foot. The second is with the 24-ounce brass weight screwed directly into the tripod hole of the camera (no L-plate or clamp). These results (the one with the shake) are typical of what all three of us are seeing. Shorter lenses are better, longer are worse. And this lens, if the camera+lens had been mounted directly to the tripod, might have given a fine result, or a least a much less damaged result.

When the camera is hanging out on the end of the camera-lens mass, it is very readily moved by small forces!

Addendum:
As an addendum to my letter about the shutter vibration issue, I wanted to mention that my friend Mike and I have discussed what would be an optimal solution for Sony to allow the two movements of the first curtain to be separated in time, so as to cut vibrations during the exposure by roughly half.

After considering various options, we prefer a mode which would work exactly like a conventional MUP (mirror up) mode. When this “Delayed Shutter” mode is enabled, the first press of the shutter release (on a remote or on the camera) would cause the first shutter curtain to close, ending live view. The second press would then begin the exposure sequence by opening the first curtain, which is then followed by the second curtain closing, then re-opening to again begin live view.

I think we would find that even with a shutter speed of 1/100th of a second and the camera turned to vertical (portrait) position, that a delay between the two presses of as little as 1/4 second would still achieve the full benefit of the Delayed Shutter mode. Click, click. Simple, fast, and familiar to all of us tripod users. This would still be faster than the traditional process, where we wait 2 to 6 seconds after mirror up for the camera to calm down before starting an exposure where fine detail matters a lot. This approach, rather than inserting a fixed delay, would also allow us to choose precisely when we want the exposure to begin, which is important in many cases. It just wears out the shutter button on the remote twice as fast, along with the battery of a wireless remote.

Fully sharp results with longer lenses may still require the use of a dead weight as described, but only testing will tell. The weight seems to be highly effective, but cameras can wiggle lots of different ways and some setups may not even work just right with the weight at some shutter speeds, after a firmware fix. I sure hope they do as I really like this camera. I’ve been waiting a very long time for a camera that can do what it does".

jpr2

DavieK Contributing Member • Posts: 708
Re: Vibration of the A7R shutter compared to D3 and NEX-7 using a seismometer

There is a second issue to this, the reaction of certain OS/OSS lenses to the shake. I've just acquired a 28-70mm OSS - the one NOT being sold with the A7R - split off from an A7 kit and on initial tests I'd say the OSS is either not able to cancel out the brief vibration, or it is reacting at the wrong time.

All these new tests just confirm what I found almost immediately when checking lenses on the A7R, that there is a shutter speed zone (I said 1/60th to 1/160th approx) which is liably to produce shake.

The only conditions I do not get the shake are not below 70 or 80mm focal length, but below 20mm. The 10-18mm OSS seems to have reliable OSS with the A7R, but checking for example Min 17-35mm or Sigma 18-250 at 18mm, either the shake is so fine I can't see it.

In communication with Gary Friedman over this. I suggest that Sony has disabled the OSS function in the A7R with specific E-mount lenses, but not with others, because their engineers found the OSS reinforced rather than cancelled this brief shutter-shock reverberation. Gary doubts it. I've said that I bet Sony issues a firmware fix 1-2 months from now, and I also speculate that the delay in launching the 24-70mm CZ OSS is for the same reason - they saw problems and decided to launch the A7R as body only, or with 35 and 55mm primes only, rather than have quantities retailed with an OSS kit lens that produced image blur under certain very common conditions.

David

user_name Veteran Member • Posts: 3,134
Vibration at Sensor

D Cox wrote:

What we really want to see is the vibration of the sensor relative to the lens and subject.

Exactly.

As clever as this test was, we can only guess/assume that the hotshoe vibration is representative of the vibration seen at the sensor.

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cosmonaut
cosmonaut Senior Member • Posts: 2,223
Re: Vibration of the A7R shutter compared to D3 and NEX-7 using a seismometer

I still dont understand the big deal with the shutter vibration. In the old days I had cameras with mirror slap that was really bad and never caused blurred pictures unless it was a long exposure, hence mirror up feature.

If the sensor is fixed unlike one with IBIS the shutter shock issue is a mood point and the only cause for blur would be camera movement by the photographer. With that it depends on technique and shutter speed.

I had a Mamiya 645 and the mirror slap was horrible but it was never an issue hand held at faster shutter speeds. Now if you are comparing shutter noise that's a different issue. Yes it's loud.

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creeker Senior Member • Posts: 1,450
Re: Vibration of the A7R shutter compared to D3 and NEX-7 using a seismometer

Thanks for sharing your interesting test results. The proof of the pudding will come when we get feedback from users as more people buy the camera. What has to be noted is the better the cameras get the more they show flaws in our photographic techniques. Time will tell if there is a real problem with the A7r. BTW, your site has some really beautiful stunning images.

regards

Ed

sassenach74
sassenach74 Regular Member • Posts: 376
Re: Vibration of the A7R shutter compared to D3 and NEX-7 using a seismometer

DavieK wrote:

There is a second issue to this, the reaction of certain OS/OSS lenses to the shake. I've just acquired a 28-70mm OSS - the one NOT being sold with the A7R - split off from an A7 kit and on initial tests I'd say the OSS is either not able to cancel out the brief vibration, or it is reacting at the wrong time.

All these new tests just confirm what I found almost immediately when checking lenses on the A7R, that there is a shutter speed zone (I said 1/60th to 1/160th approx) which is liably to produce shake.

The only conditions I do not get the shake are not below 70 or 80mm focal length, but below 20mm. The 10-18mm OSS seems to have reliable OSS with the A7R, but checking for example Min 17-35mm or Sigma 18-250 at 18mm, either the shake is so fine I can't see it.

In communication with Gary Friedman over this. I suggest that Sony has disabled the OSS function in the A7R with specific E-mount lenses, but not with others, because their engineers found the OSS reinforced rather than cancelled this brief shutter-shock reverberation. Gary doubts it. I've said that I bet Sony issues a firmware fix 1-2 months from now, and I also speculate that the delay in launching the 24-70mm CZ OSS is for the same reason - they saw problems and decided to launch the A7R as body only, or with 35 and 55mm primes only, rather than have quantities retailed with an OSS kit lens that produced image blur under certain very common conditions.

David

Yet you can buy the 28-70 FE without a body.

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Neil.

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Bob Janes
Bob Janes Veteran Member • Posts: 3,189
Harmonics?

Do you think that the problem of the excess vibration might be due to harmonics between the vibration of the initial closing of the shutter prior to exposure and the impact of the first curtain hitting the other side of the shutter when fully open?  I notice the big peak on the Z axis occurs at about the 4th phase after the initial vibration... makes me wonder if the vibration would be minimised if the two impacts were out of phase rather than in phase with each other...

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DavieK Contributing Member • Posts: 708
Re: Harmonics?

Bob Janes wrote:

Do you think that the problem of the excess vibration might be due to harmonics between the vibration of the initial closing of the shutter prior to exposure and the impact of the first curtain hitting the other side of the shutter when fully open? I notice the big peak on the Z axis occurs at about the 4th phase after the initial vibration... makes me wonder if the vibration would be minimised if the two impacts were out of phase rather than in phase with each other...

I think you may have something there Bob. Elsewhere I've quoted the transit speed of the shutter (4.8 metres per second) based on 24mm traversed in 1/200th - the time it takes for the first curtain to fully uncover the sensor, equal to the flash sync speed (where the second curtain starts travel after 1/200th).

The seismic readings indicate that the peak/tail occupies half of a 1/100-1/125 or similar exposure time, which would be commensurate with two vibrations ending in in phase - one from the capping action of the first blind, the second from its closing end of travel.

David

DavieK Contributing Member • Posts: 708
Re: Vibration of the A7R shutter compared to D3 and NEX-7 using a seismometer

Yet you can buy the 28-70 FE without a body.

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Neil.

Only very recently and not in all markets - and not listed at all in Sony's original offering.

David

Horshack Veteran Member • Posts: 7,971
Re: Yes it was too harsh

ferrellmc wrote:

A possible way to test shutter vibration and eliminate the variables would be to take an image with shutter vibration and then compare it to an image without shutter vibration.

To take the image with NO shutter vibration have the camera set up in a dark studio, open the shutter for say 10-20seconds. While the shutter is open fire a strobe(s) off camera to expose the image. This exposure will have no vibration from a shutter release.

Then take an image normally but don't use the strobes their duration is too short, use hot lights or similar.

If everything is the same: lens, focus, ISO, tripod mount, distance etc. the difference in the two images is shutter vibration. Then do the MTF mapper (I've never worked with it).

This could be done at different shutter speeds.

I actually considered this a while back but then realized it's not a valid test because the duration of the flash strobe is only a handful of milliseconds, so its effective shutter speed is very high.

ferrellmc
OP ferrellmc Regular Member • Posts: 106
Re: Yes it was too harsh
1

Horshack wrote:

ferrellmc wrote:

A possible way to test shutter vibration and eliminate the variables would be to take an image with shutter vibration and then compare it to an image without shutter vibration.

To take the image with NO shutter vibration have the camera set up in a dark studio, open the shutter for say 10-20seconds. While the shutter is open fire a strobe(s) off camera to expose the image. This exposure will have no vibration from a shutter release.

Then take an image normally but don't use the strobes their duration is too short, use hot lights or similar.

If everything is the same: lens, focus, ISO, tripod mount, distance etc. the difference in the two images is shutter vibration. Then do the MTF mapper (I've never worked with it).

This could be done at different shutter speeds.

I actually considered this a while back but then realized it's not a valid test because the duration of the flash strobe is only a handful of milliseconds, so its effective shutter speed is very high.

I did the test here: http://beforethecoffee.com/sony-a7r-vibration-comparison-with-nikon-d3-and-sony-nex-7/

I took 30+ sample images, one set with no shutter vibration and one set with normal shutter vibration exposures. Then I compared the results. I used a Nikon 85mm 1.4 and the Sony FE 35mm 2.8.

I am very pleased to find no visible evidence of shutter vibration in images from the A7R when mounted on a good tripod.

Horshack - Could you please elaborate on why shutter speed in the "no shutter vibration" image matters. The idea is to obtain the "purest" form of an image with no vibration. Although I don't think it's relevant, the fast strobe duration works toward that goal. If you thought a fast strobe might bias the image you could always change methods and turn a light on for a split second to expose the image.

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Horshack Veteran Member • Posts: 7,971
Re: Yes it was too harsh

ferrellmc wrote:

Horshack wrote:

ferrellmc wrote:

A possible way to test shutter vibration and eliminate the variables would be to take an image with shutter vibration and then compare it to an image without shutter vibration.

To take the image with NO shutter vibration have the camera set up in a dark studio, open the shutter for say 10-20seconds. While the shutter is open fire a strobe(s) off camera to expose the image. This exposure will have no vibration from a shutter release.

Then take an image normally but don't use the strobes their duration is too short, use hot lights or similar.

If everything is the same: lens, focus, ISO, tripod mount, distance etc. the difference in the two images is shutter vibration. Then do the MTF mapper (I've never worked with it).

This could be done at different shutter speeds.

I actually considered this a while back but then realized it's not a valid test because the duration of the flash strobe is only a handful of milliseconds, so its effective shutter speed is very high.

I did the test here: http://beforethecoffee.com/sony-a7r-vibration-comparison-with-nikon-d3-and-sony-nex-7/

I took 30+ sample images, one set with no shutter vibration and one set with normal shutter vibration exposures. Then I compared the results. I used a Nikon 85mm 1.4 and the Sony FE 35mm 2.8.

I am very pleased to find no visible evidence of shutter vibration in images from the A7R when mounted on a good tripod.

Horshack - Could you please elaborate on why shutter speed in the "no shutter vibration" image matters. The idea is to obtain the "purest" form of an image with no vibration. Although I don't think it's relevant, the fast strobe duration works toward that goal. If you thought a fast strobe might bias the image you could always change methods and turn a light on for a split second to expose the image.

If the only goal of using the strobe was to obtain the "control" image that demonstrates no vibration effects then sure, it doesn't matter. But the same control image could be obtained by just adding more ambient light and using a faster shutter speed (or removing the light and using a very long exposure). My point was that a strobe'd image couldn't be used as an experiment to prove the vibration effects go away when dragging the shutter (ie, using say a 5 second exposure in a dark room, manually strobing during that time, and comparing to a non-strobed image).

fotowbert
fotowbert Veteran Member • Posts: 3,052
re: a7r shutter shake test

ferrellmc wrote:

I did the test here: http://beforethecoffee.com/sony-a7r-vibration-comparison-with-nikon-d3-and-sony-nex-7/

I took 30+ sample images, one set with no shutter vibration and one set with normal shutter vibration exposures. Then I compared the results. I used a Nikon 85mm 1.4 and the Sony FE 35mm 2.8.

I am very pleased to find no visible evidence of shutter vibration in images from the A7R when mounted on a good tripod.

Well done ferrellmc!

This test data directly addresses the issue, ie image blur. No need to be concerned how some intermediate type of measurement relates to the issue.

After having put forth this amount of effort it would seem appropriate to extend it to determine your own min shutter speed rule of thumb. If you have not already done so, consider shooting some hand held comparison shots to establish just how steady you are.

  • John
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jpr2 Forum Pro • Posts: 15,554
David: the issue of possible coupling the most adverse effects from SShock & from IS/OSS...

DavieK wrote:

In communication with Gary Friedman over this. I suggest that Sony has disabled the OSS function in the A7R with specific E-mount lenses, but not with others, because their engineers found the OSS reinforced rather than cancelled this brief shutter-shock reverberation. Gary doubts it. I've said that I bet Sony issues a firmware fix 1-2 months from now, and I also speculate that the delay in launching the 24-70mm CZ OSS is for the same reason - they saw problems and decided to launch the A7R as body only, or with 35 and 55mm primes only, rather than have quantities retailed with an OSS kit lens that produced image blur under certain very common conditions.

...is of course crucial here:

  • and given how much more widespread and popular are the topmost EF L lenses with IS in comparison to a really frugal selection of the OSS ones,
  • the attention given to the former will certainly pay off handsomely;
  • tTo say nothing about ability to test them here and now, instead in some rather fuzzily defined future in case of road-mapped OSS'es

jpr2

shawnfb Contributing Member • Posts: 612
Re: Vibration of the A7R shutter compared to D3 and NEX-7 using a seismometer

I have a 28-70 FE new out of a kit for sale..

$600.00

-- hide signature --

shawn

Petroglyph
Petroglyph Veteran Member • Posts: 6,085
Re: Vibration of the A7R shutter compared to D3 and NEX-7 using a seismometer

Rod McD wrote:

Hi,

Thanks for the test and your post. Whilst I agree that the results raise some questions, I think we need to be mindful of how significant this may or may not be.....

1) There are now a great many posts across the internet which show that the A7r delivers wonderfully sharp and detailed images.

2) Reviewers seem happy to compare the output of their tests favorably with a D800, the reigning DSLR king of resolution.

3) The test of hand-holding shows a lower frequency vibration or shake that is as big and sometimes bigger in amplitude than the shutter induced vibration of the camera mounted on the desk. To me, this really invites the question of whether the shutter shock is worth worrying about if you're a hand-holder.

From what I've read from other sources, and the ones linked to off of SAR, there may be a visible issue with longer lenses mounted via the lenses tripod collar on a tripod.  It seems the blur is across the short axis of the shot and begins at 100mm as visible in shots taken on a tripod using the tripod collar of the lens to mount the cam.  It may have something to do with the camera being off-axis and a fulcrum effect setting up a standing wave.  The testers suggested Sony could fix via firmware with a certain delay in one of the curtain traverses.  They also recommended adding (24 grams?) of mass below the camera mount socket.  They said it the camera was mounted via its own mount socket there was no visible vibration effect in the image.  They posted some of the effects and I clearly saw what they were talking about.  Don't think hand holding with a 55mm would see any effect or mounting via the tripod socket in the camera.

Cheers

I used to shoot medium and large format. I once tested my ability to hand-hold a medium format camera in good light by comparing side by side tripod and handheld shots of a test chart or bank notes. I thought I was pretty steady as a hand holder at "reasonable" shutter speeds, but that simple test soon provided an education....... A tripod is always better. I learned to reach for one at shutter speeds I previously though were good for hand-holding. It's a pity they're such a long gangly thing to carry all the time and so inconvenient in many contexts.

Cheers, Rod

 Petroglyph's gear list:Petroglyph's gear list
Sony a7R II Zeiss Batis 85mm F1.8 Rokinon 135mm F2.0 Samyang 20mm F1.8
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