Motion vs. Clarity

I really appreciate this forum. Hearing other experiences and opinions helps me get exposed to new information and reminds me of the variety of human experiences and variety of perspectives and how we share with others.

Everything that follows in this post is based on my own experiences and opinions. YMMV.

There was recent thread that talked about motion blur. Initially there was some ambiguity (for some, but not for others) about what "motion blur" meant. Was it "camera motion" or "subject motion"? (That distinction came to light over time.)

In my mind, it was totally about "camera motion". In fact, camera motion is (for me) the only motion to worry about. When camera motion is NOT a factor and subject motion is visible, it's intentional. In such cases, the photographer has experience and knowledge to control motion and get the desired result. Or... sometimes we just get lucky.

When motion is not fully controlled, and when there is a question about "what happened?" it seems to be caused by camera motion. It is often referred to as "camera shake", but shake has some connotations that are sometimes emotional ("you can't hold a camera steady") or sometimes doesn't reflect a smooth panning motion (which is "different" than "shake").

So how important is camera motion? Camera motion, or cancelling it out, is the whole reason that IBIS exists! IS, VC, VR? Same thing: cancelling out camera motion. None of these technologies has any effect on subject motion.

I took a few pictures of a test chart and sharing those images here. Basically, higher numbered groups are better clarity. In the images below, the group numbers ranged from -1 to +1 (and enclosed in a green box). Within each group, higher numbered elements are better clarity. The pictures below are scaled down because the full-resolution pictures are too big!

Using a focal length of about 160mm (actually ranging from 165mm - 168mm), the "1/focal length" says that I should be able to get a clear shot with about 1/160 second shutter. At 1/1600 (ten times faster) it should be sharp every time, right? For me, no. My worst shots were handheld with a fast sweeping motion. The best shot? On a tripod.

Continuing...

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Last one...

You seem to have omitted the EXIF from the images, that makes them meaningless.
Define a fast sweep and a slow sweep.
The subject to camera distance is also an integral part of the equation.

john crossley wrote in post #19026705
You seem to have omitted the EXIF from the images, that makes them meaningless.
Define a fast sweep and a slow sweep.
The subject to camera distance is also an integral part of the equation.

Sorry. I was meaning to share my own experiences and thoughts, and was only emphasizing shutter speed. I described at the top the 1/160 sec and the "1 over focal length rule" and that 1/1600 (ten times that) should be sharp. Any further details about EXIF would probably also need a measurement of light, which I didn't not capture.

All shots are:
70-200 @ 165mm
1/1600
f/2.8
ISO 100

Distance to subject ~15ft.
I have no metrics for slow vs. fast.

If I understand your test, in all cases you were assessing the ability of the stabilization system to neutralize horizontal sweep motion, off tripod, and at 10*Rule of Thumb. Then you also took tripod-mounted as the 'control' shot by which to compare the others.

I find it puzzling that, in all cases, the degree of motion blur in the Vertical seems about the same as in the Horizontal, even though the induced motion was in the horizontal direction?!
This is evidenced that the width of the white spaces between horizonal target lines is generally 'the same' as the white spaces between vertical target lines. And knowing there is induced horizontal motion, one would think that the horizontal lines and spaces are pretty well preserved (with some apparent lengthing of the line lengths!), and photo 1 in Post 3 presents what one would be expecting to happen. Yet the other photos taken during sweep do not exhibit this same expected result.

So then, in puzzling thru what I am and am not seeing, I start to wonder:

• did the lens used HAVE a 'tripod mode', and
  
• was it turned on or turned off?
  

Wilt wrote in post #19026791
If I understand your test, in all cases you were assessing the ability of the stabilization system to neutralize horizontal sweep motion, off tripod, and at 10*Rule of Thumb. Then you also took tripod-mounted as the 'control' shot by which to compare the others.

I find it puzzling that, in all cases, the degree of motion blur in the Vertical seems about the same as in the Horizontal, even though the induced motion was in the horizontal direction?!
This is evidenced that the width of the white spaces between horizonal target lines is generally 'the same' as the white spaces between vertical target lines. And knowing there is induced horizontal motion, one would think that the horizontal lines and spaces are pretty well preserved (with some apparent lengthing of the line lengths!), and photo 1 in Post 3 presents what one would be expecting to happen. Yet the other photos taken during sweep do not exhibit this same expected result.

So then, in puzzling thru what I am and am not seeing, I start to wonder:

• did the lens used HAVE a 'tripod mode', and
  
• was it turned on or turned off?
  

I was sweeping diagonally from UR to LL. I had no particular reason for diagonal vs. horizontal vs. vertical. I was just easier to hold in the immediate circumstances. I should go back and stick to one dimension...

The lens was Canon's 70-200/2.8 IS II. The IS was on except for the tripod (control) shot and the one image that was explicitly labeled "no IS". I found it interesting that one of my slow sweep (with IS) was sharper than the handheld (nominally not moving) w/ IS.

And yeah, it's not scientifically controlled. The inspiration for me to do this was my understanding that subject motion blur could be described by 1x or 2x focal length rule, but camera shake is more sensitive.

dasmith232 wrote in post #19026676
Basically, higher numbered groups are better clarity. In the images below, the group numbers ranged from -1 to +1 (and enclosed in a green box). Within each group, higher numbered elements are better clarity.

I don't understand what you mean by that.

I don't understand what the Green and Blue boxes indicate.

dasmith232 wrote in post #19026810
I was sweeping diagonally from UR to LL. I had no particular reason for diagonal vs. horizontal vs. vertical. I was just easier to hold in the immediate circumstances. I should go back and stick to one dimension...

The lens was Canon's 70-200/2.8 IS II. The IS was on except for the tripod (control) shot and the one image that was explicitly labeled "no IS". I found it interesting that one of my slow sweep (with IS) was sharper than the handheld (nominally not moving) w/ IS.

And yeah, it's not scientifically controlled. The inspiration for me to do this was my understanding that subject motion blur could be described by 1x or 2x focal length rule, but camera shake is more sensitive.

Thanks for clarification of the axis of motion not being purely horizontal; so the question of 'tripod mode' becomes irrelevant to your test.
And seeing 'the same' effect in both horizontal and vertically spaced lines is now explained.

dasmith232 wrote in post #19026810
The inspiration for me to do this was my understanding that subject motion blur could be described by 1x or 2x focal length rule, but camera shake is more sensitive.

Subject motion blur is controlled by the shutter speed. A fast shutter speed will freeze all the movement in the subject and background. A slow shutter speed will create motion blur in the subject.

The reciprocal of the focal length rule is to counteract camera shake when photographing static subjects.

I do a lot of motorsport photography and I use shutter-speeds way below the reciprocal of the focal length of the lens. You don't get camera shake in this situation because the panning action cancels it out.


Also are the images that posted cropped, and if so by how much?

Interesting. Thanks for posting

john crossley wrote in post #19026811
I don't understand what you mean by that.

I don't understand what the Green and Blue boxes indicate.

I was describing how to read the AF-1951 resolution chart. Each group of lines has a number with the lower numbers (like -2) having larger lines and gaps than the higher numbers (like +1) which are finer resolution. Within each group, the elements are numbered from 1 to 6, with the higher numbers having finer resolution. I used the green boxes to mark the group that I thought showed where the ability to resolve broke down and the blue boxes showed at which element the resolution broke down.

john crossley wrote in post #19026817
Subject motion blur is controlled by the shutter speed. A fast shutter speed will freeze all the movement in the subject and background. A slow shutter speed will create motion blur in the subject.

Yes, I totally agree with that and have experienced that over many years.

john crossley wrote in post #19026817
The reciprocal of the focal length rule is to counteract camera shake when photographing static subjects.

That has been the rule of thumb for many, many years. I have a "cheat sheet" from Kodak from (idunno) the 1950's that says that same thing. Over the years, resolutions have gone up, pixel peeping has become more common, pictures are being enlarged more commonly (not just the pros), and long lenses have become more available to the masses. In my opinion, the reciprocal rule doesn't always hold up for all cases.

john crossley wrote in post #19026817
I do a lot of motorsport photography and I use shutter-speeds way below the reciprocal of the focal length of the lens. You don't get camera shake in this situation because the panning action cancels it out.

And that's where skill like yours comes in. Tools like IBIS and IS/VC/VR help too, especially with the ability to select a mode (I vs. II in Canon vernacular).

john crossley wrote in post #19026817
Also are the images that posted cropped, and if so by how much?

They are cropped by a lot! The horizontal dimension on the original CR2 file is 5760 pixels. The cropped samples are on the order of 800 pixels. That's a 7.2x factor.