On Sharpness, ISO and Shutter Speed

[Jack Hogan]

Some of this information has appeared in recent posts, but I thought it deserved its own thread.

DPR's improved technique in capturing images for its new Studio Scene includes focus bracketing and controlled lighting, resulting in one of the better databases of systematically collected raw files available for downlonad online. Nevertheless there have been reports of inconsistencies and unexpectedly blurry images which most people (including myself) have almost subconsciously ascribed to either faulty equipment or operator error. Given the vast number of variables, pieces of equipment and information collected there are bound to be some of those. On the other hand, if we take the information for good, we may be able to gain some interesting insights on our gadgets, their performance and testing at large. As some of you know I've been playing with MTF Mapper recently, so in this post I am going to concentrate on MTF50 as an imperfect but convenient indicator of Spatial Resolution quality in the captured information (aka sharpness).

I used the slanted edges in DPR's new Studio Scene's raw files to derive vertical and horizontal MTF50 readings at base ISO in order to get the cleanest reading possible. AFAIK the captures are taken on a tripod, mirror up (where there is one), delayed release, typically at a lens' sharpest aperture, at whatever shutter speed is appropriate for the desired Exposure. The few times that I checked ISOs just above base I saw a tendency for the MTF50 readings to creep up, which I assumed was increased noise messing with MTF Mapper's algorithms. Upon further inspection, it turns out I was wrong.

Here for instance is how the MTF50 readings vary with ISO on a Nikon DF whose sensor has a 'traditional' antialiasing filter:

It doesn't vary much. Here are two more with sensors by a different manufacturer (the D800 applies digital scaling after ISO1600)

Shutter Speeds Correspond to ISO 200-6400

And since we are at it here is a more recent camera with a sensor by the same manufacturer as the last two, Sony's A7

The vertical and horizontal readings in previous graphs were within what I think would be the expected accuracy of measurements from different setups (say +/-3% from the average), but obviously something is very different in this case compared to the previous ones - most likely the AA as explained by The_Suede here . It is also clear that MTF Mapper deals with the increasing noise with aplomb, so taking the data for good it is worth investigating some of the imperfections in it.

For instance the dip in performance of the EM5 at base ISO. There have been suggestions that some cameras suffer from obvious shutter shock. Could this be it? Let's take a look at its younger brother, which reportedly shows the issue more clearly

Shutter Speeds correspond to ISO 100-6400

Whoa. Looking at the relative images in the comparometer confirms these results: below 1/320th the EM1's images are definitely blurrier. Shutter Shock, changed lighting, changed positions, changed hardware, misfocus, operator error? And what do we make of that vertical/horizontal crossover?

Steen Bay wondered how the AAless Sony A7r would look next to the AAful A7 above, because the A7 has an electronic shutter while the A7r has a mechanical one.

Interesting. This confirms reports that the A7's images look sharper than the A7r's at some ISOs in the Studio Scene - I (probably incorrectly) thought the A7r's focus had not been peaked properly. And there's that dip again.

I also wondered how the D610 (mechanical shutter) would do against the A7, since its sensor is the same size, it is made by the same manufacturer and it has the same resolution.

The first set of ISOs come from the 'Dim' Studio Scene Setting. The seond from the 'Daylight' setting

Still interesting. The large difference in horizontal and vertical readings is similar to what it was in the A7 - but here we see the inconsistent 'dip' near base ISO and few subsequent stops, which is not there in the A7 with its electronic shutter. The slower shutter speeds are from 'dim light' Studio Scene raw files, to see whether a change in lighting/WB would make a difference. It apparently doesn't.

So I have two initial questions, assuming that the data is valid:

1) What are the practical implications for a photographer of the large spatial resolution differences in the V+H directions seen in the newer sensors measured here ? Will it make a difference whether we look at the final image in portrait vs landscape orientation?

2) Are the dips we see in MTF50 around 1/10th of a second to about 1/300th possibly due to shutter shock - or something else? What implications does this have for people choosing a high resolution camera today?

Everybody's thoughts are welcome.

Jack

 

[Steen Bay]

Very interesting, thanks for posting. Wondering why the D800 resolution (or 'sharpness') is so relatively low (about the same as the 24mp A7)? Another mFT camera with a serious shutter shock issue (I assume) in the new comparison tool is the Panasonic G6. Seems to be even worse than on the E-M1. Could probably have been avoided if DPR had used the optional electronic shutter on G6. Olympus E-P5 and E-PL5 are affected too, but it doesn't seem to be a problem on the (also mirror less) Fuji X-E2 and X-Pro1. Can't spot any problems on Canon and Nikon DSLRs, except maybe a bit with the D5300.

 

[Austinian]

Very interesting, thanks for posting. Wondering why the D800 resolution (or 'sharpness') is so relatively low (about the same as the 24mp A7)?

Seeing this data raises a number of questions in my mind; unfortunately I lack the technical background to even begin to answer them. I will be watching what you gentlemen and the other experts discover with great interest. There may be implications for everyone in this.

Another mFT camera with a serious shutter shock issue (I assume) in the new comparison tool is the Panasonic G6. Seems to be even worse than on the E-M1. Could probably have been avoided if DPR had used the optional electronic shutter on G6. Olympus E-P5 and E-PL5 are affected too, but it doesn't seem to be a problem on the (also mirror less) Fuji X-E2 and X-Pro1. Can't spot any problems on Canon and Nikon DSLRs, except maybe a bit with the D5300.

One thing that concerns me; if this is shutter shock vibrating the sensor, external damping (heavier tripod, draping the camera body on the tripod with weights, etc.) may not be of much help.

I do wonder; how could high-end camera manufacturers, with vast resources for testing, possibly miss an engineering problem like this with a potential for degrading the value of their premium products?

More data!

 

[Anders W]

Very interesting, thanks for posting. Wondering why the D800 resolution (or 'sharpness') is so relatively low (about the same as the 24mp A7)?

Seeing this data raises a number of questions in my mind; unfortunately I lack the technical background to even begin to answer them. I will be watching what you gentlemen and the other experts discover with great interest. There may be implications for everyone in this.

Another mFT camera with a serious shutter shock issue (I assume) in the new comparison tool is the Panasonic G6. Seems to be even worse than on the E-M1. Could probably have been avoided if DPR had used the optional electronic shutter on G6. Olympus E-P5 and E-PL5 are affected too, but it doesn't seem to be a problem on the (also mirror less) Fuji X-E2 and X-Pro1. Can't spot any problems on Canon and Nikon DSLRs, except maybe a bit with the D5300.

One thing that concerns me; if this is shutter shock vibrating the sensor, external damping (heavier tripod, draping the camera body on the tripod with weights, etc.) may not be of much help.

External damping does help. Put the camera on a heavy and perfectly rigid surface (like for example a stone floor) and you won't see any sign of shutter shock even with lenses far more sensitive to the problem than a short tele. I have tried it with my Oly E-M5 and Pany 100-300 at 300 mm (600 mm EFL) and see no problem at all under those conditions. When shooting the same combo from a reasonably sturdy tripod, however, I can't get blur-free images in the critical range of shutter speeds (about 1/25 to 1/250 with the peak about 1/100 or slightly higher).

That said, I am surprised to see the problem appear (if that's what it is in DPR's studio samples; we don't know that yet) with what is supposedly a heavy studio tripod and a much shorter FL (about 100 mm EFL). I can't remember seeing any problems of this kind with the old DPR studio samples, which makes you wonder if they have some special problems with the support gear they are using for some or all cameras.

I do wonder; how could high-end camera manufacturers, with vast resources for testing, possibly miss an engineering problem like this with a potential for degrading the value of their premium products?

A so-called good question.

More data!

 

[Anders W]

Some of this information has appeared in recent posts, but I thought it deserved its own thread.

DPR's improved technique in capturing images for its new Studio Scene includes focus bracketing and controlled lighting, resulting in one of the better databases of systematically collected raw files available for downlonad online. Nevertheless there have been reports of inconsistencies and unexpectedly blurry images which most people (including myself) have almost subconsciously ascribed to either faulty equipment or operator error. Given the vast number of variables, pieces of equipment and information collected there are bound to be some of those. On the other hand, if we take the information for good, we may be able to gain some interesting insights on our gadgets, their performance and testing at large. As some of you know I've been playing with MTF Mapper recently, so in this post I am going to concentrate on MTF50 as an imperfect but convenient indicator of Spatial Resolution quality in the captured information (aka sharpness).

I used the slanted edges in DPR's new Studio Scene's raw files to derive vertical and horizontal MTF50 readings at base ISO in order to get the cleanest reading possible. AFAIK the captures are taken on a tripod, mirror up (where there is one), delayed release, typically at a lens' sharpest aperture, at whatever shutter speed is appropriate for the desired Exposure. The few times that I checked ISOs just above base I saw a tendency for the MTF50 readings to creep up, which I assumed was increased noise messing with MTF Mapper's algorithms. Upon further inspection, it turns out I was wrong.

Here for instance is how the MTF50 readings vary with ISO on a Nikon DF whose sensor has a 'traditional' antialiasing filter:

It doesn't vary much. Here are two more with sensors by a different manufacturer (the D800 applies digital scaling after ISO1600)

Shutter Speeds Correspond to ISO 200-6400

And since we are at it here is a more recent camera with a sensor by the same manufacturer as the last two, Sony's A7

The vertical and horizontal readings in previous graphs were within what I think would be the expected accuracy of measurements from different setups (say +/-3% from the average), but obviously something is very different in this case compared to the previous ones - most likely the AA as explained by The_Suede here . It is also clear that MTF Mapper deals with the increasing noise with aplomb, so taking the data for good it is worth investigating some of the imperfections in it.

For instance the dip in performance of the EM5 at base ISO. There have been suggestions that some cameras suffer from obvious shutter shock. Could this be it? Let's take a look at its younger brother, which reportedly shows the issue more clearly

Shutter Speeds correspond to ISO 100-6400

Whoa. Looking at the relative images in the comparometer confirms these results: below 1/320th the EM1's images are definitely blurrier. Shutter Shock, changed lighting, changed positions, changed hardware, misfocus, operator error? And what do we make of that vertical/horizontal crossover?

Steen Bay wondered how the AAless Sony A7r would look next to the AAful A7 above, because the A7 has an electronic shutter while the A7r has a mechanical one.

Interesting. This confirms reports that the A7's images look sharper than the A7r's at some ISOs in the Studio Scene - I (probably incorrectly) thought the A7r's focus had not been peaked properly. And there's that dip again.

I also wondered how the D610 (mechanical shutter) would do against the A7, since its sensor is the same size, it is made by the same manufacturer and it has the same resolution.

The first set of ISOs come from the 'Dim' Studio Scene Setting. The seond from the 'Daylight' setting

Still interesting. The large difference in horizontal and vertical readings is similar to what it was in the A7 - but here we see the inconsistent 'dip' near base ISO and few subsequent stops, which is not there in the A7 with its electronic shutter. The slower shutter speeds are from 'dim light' Studio Scene raw files, to see whether a change in lighting/WB would make a difference. It apparently doesn't.

So I have two initial questions, assuming that the data is valid:

1) What are the practical implications for a photographer of the large spatial resolution differences in the V+H directions seen in the newer sensors measured here ? Will it make a difference whether we look at the final image in portrait vs landscape orientation?

Why would it make a difference if we look at it this way or that way? Blur is blur and to my knowledge, the human visual system isn't differently sensitive to blur in one dimension than in the other. Besides, we wouldn't normally want to look at something shot in landscape orientation in portrait mode or vice versa, for pretty obvious reasons.

2) Are the dips we see in MTF50 around 1/10th of a second to about 1/300th possibly due to shutter shock - or something else? What implications does this have for people choosing a high resolution camera today?

Hard to say without knowing more about what's going on in DPR's studio. But the shutter speed range affected and the fact that the blur is largely vertical makes shutter shock the likely culprit. The problem is known to occur in that range, with a peak at about 1/100 s or slightly higher. The point where the problem disappears at the upper end of the range may be related to the max sync speed of the camera (disappearing later the higher that speed is). At the lower end, it disappears more gradually, without much of a clear cut point.

That said, it surprises me to see the shutter-shock problem (if that's what it is) appear so clearly in the DPR studio scene samples. Presumably, they use a heavy studio tripod and the focal length is not all that long (about 100 mm EFL). Furthermore, one would at least have expected DPR to take the precaution of using anti-shock delay with Oly bodies and the electronic shutter option with Pany bodies. But I certainly wouldn't have expected any clear shutter-shock problems even if they didn't, provided that my assumption about good tripod support is correct.

Everybody's thoughts are welcome.

Jack

 

[Jack Hogan]

So I have two initial questions, assuming that the data is valid:

1) What are the practical implications for a photographer of the large spatial resolution differences in the V+H directions seen in the newer sensors measured here ? Will it make a difference whether we look at the final image in portrait vs landscape orientation?

Why would it make a difference if we look at it this way or that way? Blur is blur and to my knowledge, the human visual system isn't differently sensitive to blur in one dimension than in the other. Besides, we wouldn't normally want to look at something shot in landscape orientation in portrait mode or vice versa, for pretty obvious reasons.

Yes, I saw that did not come out right but only after having used up my two corrections already. Let me rephrase the question:

If in the A7 and D610 there is really such a large difference in horizontal vs vertical captured resolution, is that an issue in practice? Or should we be preferring capturing in landscape vs portrait orientation to maximize, say, vertical detail in the center of an image? Many of us spend thousands of dollars on better lenses to typically gain less than the 20% difference shown.

2) Are the dips we see in MTF50 around 1/10th of a second to about 1/300th possibly due to shutter shock - or something else? What implications does this have for people choosing a high resolution camera today?

Hard to say without knowing more about what's going on in DPR's studio. But the shutter speed range affected and the fact that the blur is largely vertical makes shutter shock the likely culprit. The problem is known to occur in that range, with a peak at about 1/100 s or slightly higher. The point where the problem disappears at the upper end of the range may be related to the max sync speed of the camera (disappearing later the higher that speed is). At the lower end, it disappears more gradually, without much of a clear cut point.

That said, it surprises me to see the shutter-shock problem (if that's what it is) appear so clearly in the DPR studio scene samples. Presumably, they use a heavy studio tripod and the focal length is not all that long (about 100 mm EFL). Furthermore, one would at least have expected DPR to take the precaution of using anti-shock delay with Oly bodies and the electronic shutter option with Pany bodies. But I certainly wouldn't have expected any clear shutter-shock problems even if they didn't, provided that my assumption about good tripod support is correct.

The A7r and the D610 show signs of dips around there as well, and they are the lighter of the four FF bodies shown. Possibly some of this is surfacing now exactly because the better technique and smaller sensors are no longer hiding imperfections that before were below the 'noise' floor. I wonder if anybody ever put a camera through such rigorous scrutiny 30 years ago

 

[Austinian]

External damping does help. Put the camera on a heavy and perfectly rigid surface (like for example a stone floor) and you won't see any sign of shutter shock even with lenses far more sensitive to the problem than a short tele. I have tried it with my Oly E-M5 and Pany 100-300 at 300 mm (600 mm EFL) and see no problem at all under those conditions. When shooting the same combo from a reasonably sturdy tripod, however, I can't get blur-free images in the critical range of shutter speeds (about 1/25 to 1/250 with the peak about 1/100 or slightly higher).

Interesting. I'm guessing the camera isn't actually attached to the stone floor (as it would be for a tripod), so I wouldn't think it would provide much internal damping. Perhaps the vibrations really are causing whole-camera movement, rather than my original notion of sensor-only movement.

Your info opens up a good deal of speculation on my part; would the problem be minimized by hand-gripping the tripod and camera (with consequent damping), and/or by leaving the IBIS on even when using a tripod?

 

[Jack Hogan]

Very interesting, thanks for posting. Wondering why the D800 resolution (or 'sharpness') is so relatively low (about the same as the 24mp A7)?

Yes, I wondered that too. Could be AA strength (the D800 is the oldest model in this sample). And/or the lens difference.

FWIW Figure 6 here shows the D800+24-70 @50mm at 2161 lw/ph, so the figures are at least iin the ballpark.

 

[rubank]

Jack Hogan wrote:

If in the A7 and D610 there is really such a large difference in horizontal vs vertical captured resolution, is that an issue in practice? Or should we be preferring capturing in landscape vs portrait orientation to maximize, say, vertical detail in the center of an image? Many of us spend thousands of dollars on better lenses to typically gain less than the 20% difference shown.

It´s interesting (and surprising) to see that the vertical and horisontal readings has swapped places between the two cameras. I wonder what´s with this?

And then a question: does MTFmapper take readings from the "raw" RAW files or from processed files. If the latter, how are they processed?

Side note: I once downloaded the D800 RAW file from DPR, and developed it with my preferred settings in ACR; the result was quite different vs the DPR conversion (i.e. mine was much better), so I wouldn´t make too much of the "weak" D800 performance in DPR's comparison. That is at it should be, maybe, but should be remembered regarding whatever camera is tested.

 

[rubank]

Thanks for this.

Your analysis makes it clear that the studio tests must be taken with some grains of salt.

BTW, the sometimes much critisized IR test shots doesn´t show the same variations, AFAICT.
I´ve downloaded a vast number of IR's RAW files during the years and for more cameras than I can remember, but I haven´t seen this kind of difference between exposures (ISO's). Differences in focussing between cameras is a wellknown fact, but that is something else.

 

[exdeejjjaaaa]

Shutter Speeds Correspond to ISO 200-6400

For instance the dip in performance of the EM5 at base ISO. There have been suggestions that some cameras suffer from obvious shutter shock. Could this be it? Let's take a look at its younger brother, which reportedly shows the issue more clearly

Shutter Speeds correspond to ISO 100-6400

Whoa. Looking at the relative images in the comparometer confirms these results: below 1/320th the EM1's images are definitely blurrier. Shutter Shock, changed lighting, changed positions, changed hardware, misfocus, operator error? And what do we make of that vertical/horizontal crossover?

E-M1 has faster x-sync than E-M5 - so shutter blades impact (higher speed) affects suspended sensor more... as as result I use only manual (non TTL) flashes @ 1/400 xsync now, that allows me to move futher away out of shutter shock prone exposure speeds...

 

[Jack Hogan]

Jack Hogan wrote:

If in the A7 and D610 there is really such a large difference in horizontal vs vertical captured resolution, is that an issue in practice? Or should we be preferring capturing in landscape vs portrait orientation to maximize, say, vertical detail in the center of an image? Many of us spend thousands of dollars on better lenses to typically gain less than the 20% difference shown.

It´s interesting (and surprising) to see that the vertical and horisontal readings has swapped places between the two cameras. I wonder what´s with this?

Perhaps in Sony cameras the AAs are laid down in one orientation, and in Nikon cameras in another 90 degrees off Sony's.

And then a question: does MTFmapper take readings from the "raw" RAW files or from processed files. If the latter, how are they processed?

I believe these are the least processed files used for this type of analysis on the net: the raw data is just clipped to black and white balanced. That's it.

 

[Jack Hogan]

Thanks for this.

Your analysis makes it clear that the studio tests must be taken with some grains of salt.

BTW, the sometimes much critisized IR test shots doesn´t show the same variations, AFAICT.
I´ve downloaded a vast number of IR's RAW files during the years and for more cameras than I can remember, but I haven´t seen this kind of difference between exposures (ISO's). Differences in focussing between cameras is a wellknown fact, but that is something else.

Imho IR is not a good source for this type of information: they admit that they do not have time to meet Imatest's focusing standards, so they do not focus peak properly. The few images of theirs that I have tested (e.g. D800) confirm this.

 

[rubank]

Thanks for this.

Your analysis makes it clear that the studio tests must be taken with some grains of salt.

BTW, the sometimes much critisized IR test shots doesn´t show the same variations, AFAICT.
I´ve downloaded a vast number of IR's RAW files during the years and for more cameras than I can remember, but I haven´t seen this kind of difference between exposures (ISO's). Differences in focussing between cameras is a wellknown fact, but that is something else.

Imho IR is not a good source for this type of information: they admit that they do not have time to meet Imatest's focusing standards, so they do not focus peak properly. The few images of theirs that I have tested (e.g. D800) confirm this.

Yes, as I noted but as I also said that is something else. And at least some part of their studio scene tends to be in good focus....
They don´t show the vaying behavior with changing ISO (i.e. varying shutter speeds), which was my point.

But of course, would it turn out that the DPR setup is so good that it just reveals manufacturers shortcomings then we know who to blame

 

[Jack Hogan]

But of course, would it turn out that the DPR setup is so good that it just reveals manufacturers shortcomings then we know who to blame

Wouldn't that be ironic...

 

[Anders W]

External damping does help. Put the camera on a heavy and perfectly rigid surface (like for example a stone floor) and you won't see any sign of shutter shock even with lenses far more sensitive to the problem than a short tele. I have tried it with my Oly E-M5 and Pany 100-300 at 300 mm (600 mm EFL) and see no problem at all under those conditions. When shooting the same combo from a reasonably sturdy tripod, however, I can't get blur-free images in the critical range of shutter speeds (about 1/25 to 1/250 with the peak about 1/100 or slightly higher).

Interesting. I'm guessing the camera isn't actually attached to the stone floor (as it would be for a tripod), so I wouldn't think it would provide much internal damping.

Correct. That's the point of the test. It rules out displacement of the body as a whole but it does not rule out what we might refer to as bell-type vibration.

Perhaps the vibrations really are causing whole-camera movement, rather than my original notion of sensor-only movement.

The tests I am aware of suggest that bell-type vibration isn't involved at all, at least not as a rule (exceptions may exist with certain specific pieces of equipment). Rather, the blur occurs because of displacements of the body in direct response to the way the shutter blades move and stop inside the camera. When these displacements are completely prevented, as they are with the camera on a very heavy and rigid surface, there is no blur.

Your info opens up a good deal of speculation on my part; would the problem be minimized by hand-gripping the tripod and camera (with consequent damping),

No, since the mechanism is not that of bell-type vibration.

and/or by leaving the IBIS on even when using a tripod?

Based on my testing, there is no evidence that IBIS (of the type used in the E-M5 and some later Oly bodies) misbehaves as a result of vibration when used on a tripod. While the manual recommends that you turn it off when shooting from a tripod, I have seen no ill effects from forgetting to do so, as I sometimes have, even in cases where I was shooting specifically for the purpose of sharpness testing.

On the other hand, I have seen no evidence that IBIS helps against shutter shock either. Regardless of whether you shoot hand-held or on a tripod, the evidence I have suggest that IBIS doesn't exacerbate the blur due to the shock but doesn't help against it either. The reason why it does not help is in all likelihood that the displacements involved are faster than the range the IBIS system can handle.

I have found one instance where the stabilization system is indeed able to counteract the shock: the OIS on my Panasonic 14-45/3.5-5.6. Since the OIS on this lens is also about as effective as the E-M5 IBIS, shutter-shock aside, I use OIS rather than IBIS when I have this particular lens mounted.

This appears to be a rather special case, however. I have found no evidence that the OIS on the other two OIS lenses I have (Pany 45-200/4-5.6 and 100-300/4-5.6) help against shutter shock. Rather, just like IBIS, it neither hurts nor helps.

Shutter-shock issues aside, there may be instances where it is a good idea to leave the stabilization system on in tripod-based shooting. If you have trouble with the wind, for example, the displacements involved may well be slow enough for the stabilization to cope with them. This is not something I have tried to test however.

 

[Austinian]

External damping does help. Put the camera on a heavy and perfectly rigid surface (like for example a stone floor) and you won't see any sign of shutter shock even with lenses far more sensitive to the problem than a short tele. I have tried it with my Oly E-M5 and Pany 100-300 at 300 mm (600 mm EFL) and see no problem at all under those conditions. When shooting the same combo from a reasonably sturdy tripod, however, I can't get blur-free images in the critical range of shutter speeds (about 1/25 to 1/250 with the peak about 1/100 or slightly higher).

Interesting. I'm guessing the camera isn't actually attached to the stone floor (as it would be for a tripod), so I wouldn't think it would provide much internal damping.

Correct. That's the point of the test. It rules out displacement of the body as a whole but it does not rule out what we might refer to as bell-type vibration.

Perhaps the vibrations really are causing whole-camera movement, rather than my original notion of sensor-only movement.

The tests I am aware of suggest that bell-type vibration isn't involved at all, at least not as a rule (exceptions may exist with certain specific pieces of equipment). Rather, the blur occurs because of displacements of the body in direct response to the way the shutter blades move and stop inside the camera. When these displacements are completely prevented, as they are with the camera on a very heavy and rigid surface, there is no blur.

Your info opens up a good deal of speculation on my part; would the problem be minimized by hand-gripping the tripod and camera (with consequent damping),

No, since the mechanism is not that of bell-type vibration.

and/or by leaving the IBIS on even when using a tripod?

Based on my testing, there is no evidence that IBIS (of the type used in the E-M5 and some later Oly bodies) misbehaves as a result of vibration when used on a tripod. While the manual recommends that you turn it off when shooting from a tripod, I have seen no ill effects from forgetting to do so, as I sometimes have, even in cases where I was shooting specifically for the purpose of sharpness testing.

On the other hand, I have seen no evidence that IBIS helps against shutter shock either. Regardless of whether you shoot hand-held or on a tripod, the evidence I have suggest that IBIS doesn't exacerbate the blur due to the shock but doesn't help against it either. The reason why it does not help is in all likelihood that the displacements involved are faster than the range the IBIS system can handle.

This is all rather a surprise to me. I wouldn't have thought that the forces involved in shutter opening/closing would have been enough to physically move the entire camera, since I understood that shutters themselves were quite light. The forces in the rest of the mechanism must be considerable though, I guess.

I have found one instance where the stabilization system is indeed able to counteract the shock: the OIS on my Panasonic 14-45/3.5-5.6. Since the OIS on this lens is also about as effective as the E-M5 IBIS, shutter-shock aside, I use OIS rather than IBIS when I have this particular lens mounted.

This appears to be a rather special case, however. I have found no evidence that the OIS on the other two OIS lenses I have (Pany 45-200/4-5.6 and 100-300/4-5.6) help against shutter shock. Rather, just like IBIS, it neither hurts nor helps.

Shutter-shock issues aside, there may be instances where it is a good idea to leave the stabilization system on in tripod-based shooting. If you have trouble with the wind, for example, the displacements involved may well be slow enough for the stabilization to cope with them. This is not something I have tried to test however.

Thank you for all this info.

Turning off the stabilization on my A57 requires a menu change which I seldom remember to make. I have not noticed any problems yet on test shots.

Jack Hogan has brought up some really interesting issues in this thread, but I'm clearly out of my depth here as far as figuring out what's actually happening is concerned.

I wish I wasn't, because some of the possibilities (less vibration with smaller sensors/shutters for a given camera weight?, strange manufacturer inattention to this issue?, need for electronic first-curtain?) have some fascinating implications for our cameras.

And that's without even thinking about the horizontal/vertical differences on the A7 and D610...

I'll be lurking and learning with great interest.

 

[Anders W]

External damping does help. Put the camera on a heavy and perfectly rigid surface (like for example a stone floor) and you won't see any sign of shutter shock even with lenses far more sensitive to the problem than a short tele. I have tried it with my Oly E-M5 and Pany 100-300 at 300 mm (600 mm EFL) and see no problem at all under those conditions. When shooting the same combo from a reasonably sturdy tripod, however, I can't get blur-free images in the critical range of shutter speeds (about 1/25 to 1/250 with the peak about 1/100 or slightly higher).

Interesting. I'm guessing the camera isn't actually attached to the stone floor (as it would be for a tripod), so I wouldn't think it would provide much internal damping.

Correct. That's the point of the test. It rules out displacement of the body as a whole but it does not rule out what we might refer to as bell-type vibration.

Perhaps the vibrations really are causing whole-camera movement, rather than my original notion of sensor-only movement.

The tests I am aware of suggest that bell-type vibration isn't involved at all, at least not as a rule (exceptions may exist with certain specific pieces of equipment). Rather, the blur occurs because of displacements of the body in direct response to the way the shutter blades move and stop inside the camera. When these displacements are completely prevented, as they are with the camera on a very heavy and rigid surface, there is no blur.

Your info opens up a good deal of speculation on my part; would the problem be minimized by hand-gripping the tripod and camera (with consequent damping),

No, since the mechanism is not that of bell-type vibration.

and/or by leaving the IBIS on even when using a tripod?

Based on my testing, there is no evidence that IBIS (of the type used in the E-M5 and some later Oly bodies) misbehaves as a result of vibration when used on a tripod. While the manual recommends that you turn it off when shooting from a tripod, I have seen no ill effects from forgetting to do so, as I sometimes have, even in cases where I was shooting specifically for the purpose of sharpness testing.

On the other hand, I have seen no evidence that IBIS helps against shutter shock either. Regardless of whether you shoot hand-held or on a tripod, the evidence I have suggest that IBIS doesn't exacerbate the blur due to the shock but doesn't help against it either. The reason why it does not help is in all likelihood that the displacements involved are faster than the range the IBIS system can handle.

This is all rather a surprise to me. I wouldn't have thought that the forces involved in shutter opening/closing would have been enough to physically move the entire camera, since I understood that shutters themselves were quite light. The forces in the rest of the mechanism must be considerable though, I guess.

You are right that the shutter blades are very light (probably no more than a gram or so). But they are accelerated up to considerable speed (on the order of 10 meters per second) within an extremely short time and the force responsible for this acceleration as well as the momentum passed on to the body when the blades come to a sudden halt (even more sudden than the very brief acceleration phase) must by physical necessity affect the entire camera body. The only case in which we can be sure that their impact is too small to cause any displacement worth worrying about is when the camera is placed on a very heavy and rigid surface, like the one I mentioned.

I have found one instance where the stabilization system is indeed able to counteract the shock: the OIS on my Panasonic 14-45/3.5-5.6. Since the OIS on this lens is also about as effective as the E-M5 IBIS, shutter-shock aside, I use OIS rather than IBIS when I have this particular lens mounted.

This appears to be a rather special case, however. I have found no evidence that the OIS on the other two OIS lenses I have (Pany 45-200/4-5.6 and 100-300/4-5.6) help against shutter shock. Rather, just like IBIS, it neither hurts nor helps.

Shutter-shock issues aside, there may be instances where it is a good idea to leave the stabilization system on in tripod-based shooting. If you have trouble with the wind, for example, the displacements involved may well be slow enough for the stabilization to cope with them. This is not something I have tried to test however.

Thank you for all this info.

Turning off the stabilization on my A57 requires a menu change which I seldom remember to make. I have not noticed any problems yet on test shots.

Jack Hogan has brought up some really interesting issues in this thread, but I'm clearly out of my depth here as far as figuring out what's actually happening is concerned.

I wish I wasn't, because some of the possibilities (less vibration with smaller sensors/shutters for a given camera weight?, strange manufacturer inattention to this issue?, need for electronic first-curtain?) have some fascinating implications for our cameras.

And that's without even thinking about the horizontal/vertical differences on the A7 and D610...

I'll be lurking and learning with great interest.

 

[Anders W]

So I have two initial questions, assuming that the data is valid:

1) What are the practical implications for a photographer of the large spatial resolution differences in the V+H directions seen in the newer sensors measured here ? Will it make a difference whether we look at the final image in portrait vs landscape orientation?

Why would it make a difference if we look at it this way or that way? Blur is blur and to my knowledge, the human visual system isn't differently sensitive to blur in one dimension than in the other. Besides, we wouldn't normally want to look at something shot in landscape orientation in portrait mode or vice versa, for pretty obvious reasons.

Yes, I saw that did not come out right but only after having used up my two corrections already. Let me rephrase the question:

If in the A7 and D610 there is really such a large difference in horizontal vs vertical captured resolution, is that an issue in practice? Or should we be preferring capturing in landscape vs portrait orientation to maximize, say, vertical detail in the center of an image? Many of us spend thousands of dollars on better lenses to typically gain less than the 20% difference shown.

OK. Then I understand what you have in mind. I am not sure how much of an issue it is or if better performance in the one dimension is bought at the expense of worse in the other. However, it seems preferable to have an equal amount of blur in all directions and I don't readily see why that shouldn't be possible or why it should come at the expense of something else.

2) Are the dips we see in MTF50 around 1/10th of a second to about 1/300th possibly due to shutter shock - or something else? What implications does this have for people choosing a high resolution camera today?

Hard to say without knowing more about what's going on in DPR's studio. But the shutter speed range affected and the fact that the blur is largely vertical makes shutter shock the likely culprit. The problem is known to occur in that range, with a peak at about 1/100 s or slightly higher. The point where the problem disappears at the upper end of the range may be related to the max sync speed of the camera (disappearing later the higher that speed is). At the lower end, it disappears more gradually, without much of a clear cut point.

That said, it surprises me to see the shutter-shock problem (if that's what it is) appear so clearly in the DPR studio scene samples. Presumably, they use a heavy studio tripod and the focal length is not all that long (about 100 mm EFL). Furthermore, one would at least have expected DPR to take the precaution of using anti-shock delay with Oly bodies and the electronic shutter option with Pany bodies. But I certainly wouldn't have expected any clear shutter-shock problems even if they didn't, provided that my assumption about good tripod support is correct.

The A7r and the D610 show signs of dips around there as well, and they are the lighter of the four FF bodies shown.

Yes, there seems to be a correlation with body weight. How strong that correlation really is (if it is shutter shock we are actually talking about) and why it is there is not yet clear to me. Sure, a heavy FF camera has more weight to "absorb" the forces and momentum associated with the acceleration and deceleration of the shutter blades than a light MFT camera. However, an FF camera is also likely to have heavier shutter blades (four times heavier than an MFT camera everything else equal) and these blades also have to be nearly twice as fast to reach the same sync speed (since they have to traverse an opening that is nearly twice as high). So if we start relating the forces and momentum associated with shutter action, an FF camera is not necessarily better off in this regard than an MFT camera. If anything, it might be the other way around.

Possibly some of this is surfacing now exactly because the better technique and smaller sensors are no longer hiding imperfections that before were below the 'noise' floor. I wonder if anybody ever put a camera through such rigorous scrutiny 30 years ago

Better opportunities to see what's going on probably plays a part here. So does the fact that there is currently so much talk about the problem of shutter shock (if that is what we are seeing here), at least in the MFT forum. More talk generates more attention which in turn generates more talk.

 

[Anders W]

So I have two initial questions, assuming that the data is valid:

1) What are the practical implications for a photographer of the large spatial resolution differences in the V+H directions seen in the newer sensors measured here ? Will it make a difference whether we look at the final image in portrait vs landscape orientation?

Why would it make a difference if we look at it this way or that way? Blur is blur and to my knowledge, the human visual system isn't differently sensitive to blur in one dimension than in the other. Besides, we wouldn't normally want to look at something shot in landscape orientation in portrait mode or vice versa, for pretty obvious reasons.

Yes, I saw that did not come out right but only after having used up my two corrections already. Let me rephrase the question:

If in the A7 and D610 there is really such a large difference in horizontal vs vertical captured resolution, is that an issue in practice? Or should we be preferring capturing in landscape vs portrait orientation to maximize, say, vertical detail in the center of an image? Many of us spend thousands of dollars on better lenses to typically gain less than the 20% difference shown.

OK. Then I understand what you have in mind. I am not sure how much of an issue it is or if better performance in the one dimension is bought at the expense of worse in the other. However, it seems preferable to have an equal amount of blur in all directions and I don't readily see why that shouldn't be possible or why it should come at the expense of something else.

2) Are the dips we see in MTF50 around 1/10th of a second to about 1/300th possibly due to shutter shock - or something else? What implications does this have for people choosing a high resolution camera today?

Hard to say without knowing more about what's going on in DPR's studio. But the shutter speed range affected and the fact that the blur is largely vertical makes shutter shock the likely culprit. The problem is known to occur in that range, with a peak at about 1/100 s or slightly higher. The point where the problem disappears at the upper end of the range may be related to the max sync speed of the camera (disappearing later the higher that speed is). At the lower end, it disappears more gradually, without much of a clear cut point.

That said, it surprises me to see the shutter-shock problem (if that's what it is) appear so clearly in the DPR studio scene samples. Presumably, they use a heavy studio tripod and the focal length is not all that long (about 100 mm EFL). Furthermore, one would at least have expected DPR to take the precaution of using anti-shock delay with Oly bodies and the electronic shutter option with Pany bodies. But I certainly wouldn't have expected any clear shutter-shock problems even if they didn't, provided that my assumption about good tripod support is correct.

The A7r and the D610 show signs of dips around there as well, and they are the lighter of the four FF bodies shown.

Yes, there seems to be a correlation with body weight. How strong that correlation really is (if it is shutter shock we are actually talking about) and why it is there is not yet clear to me. Sure, a heavy FF camera has more weight to "absorb" the forces and momentum associated with the acceleration and deceleration of the shutter blades than a light MFT camera. However, an FF camera is also likely to have heavier shutter blades (four times heavier than an MFT camera everything else equal) and these blades also have to be nearly twice as fast to reach the same sync speed (since they have to traverse an opening that is nearly twice as high). So if we start relating the forces and momentum associated with shutter action, an FF camera is not necessarily better off in this regard than an MFT camera. If anything, it might be the other way around.

In the penultimate sentence above, I meant to add "to camera weight" after "relating the forces and momentum".

Possibly some of this is surfacing now exactly because the better technique and smaller sensors are no longer hiding imperfections that before were below the 'noise' floor. I wonder if anybody ever put a camera through such rigorous scrutiny 30 years ago

Better opportunities to see what's going on probably plays a part here. So does the fact that there is currently so much talk about the problem of shutter shock (if that is what we are seeing here), at least in the MFT forum. More talk generates more attention which in turn generates more talk.