SquareRoot Loc: southeast Missouri

Several times in my baseball pictures I have seen the bat seem to 'flex' or bend. But never as pronounced as in a pic Thursday night. In my younger days I would have tried to fully understand the physics or camera properties involved. But in my senior days now, guess I'll just relax & enjoy the Super Bowl!

bent bat

(Download)

flex in baseball bat

(Download)

redhogbill Loc: antelope, calif

this may be an optical illusion, I just watch a video on how a shutter works, watch the whole video, at the end he explains how taking a photo from a car window at speed makes the telephone pole"s look like they are bending..
just my thought
cut and paste link into browser

https://www.youtube.com/watch?v=CmjeCchGRQo

Erv Loc: Medina Ohio

Hi Wayne. Have you tried to up the shutter speed? You might has to Push the ISO up some too.
Erv

Erik_H Loc: Denham Springs, Louisiana

Bill nailed it. It is an optical effect caused by your camera's rolling shutter, where an image is not exposed on the whole sensor at the same time. here is a great article explaining this phenomenon.

rehess Loc: South Bend, Indiana, USA

According to the EXIF, this picture was taken using a Nikon d5200; does that camera not provide a mechanical shutter??

Erik_H Loc: Denham Springs, Louisiana

It is a mechanical shutter. However, it has two curtains that open at different times to expose the sensor a portion at a time. Check out the video that bill provided for a better demonstration of how a shutter works, iin it, you can clearly see both curtains of the shutter in action. http://www.youtube.com/watch?v=CmjeCchGRQo
(I took the s off to make it a hot link).

rehess Loc: South Bend, Indiana, USA

The reason I asked is that I have a little Pentax Q7. When I use just the electronic shutter, I'm in danger of getting the "rolling shutter" effect, but some of their lenses have mechanical shutters that are supposed to prevent the "rolling shutter" effect from happening. I was under the impression that "rolling shutter" happens only with cameras that depend solely upon the electronic shutter for exposure.

DirtFarmer Loc: Escaped from the NYC area, back to MA

There are several kinds of mechanical shutter. The real old style is located in the lens, and is two overlapping blades that are moved apart, then back together. That kind of shutter is not at a focal point, so the entire sensor (film, for those old shutters) is exposed at the same time.

That kind of mechanical shutter had speed limitations, so they didn't get much beyond 1/200-1/500 second exposure time. Focal plane shutters were invented to provide shorter exposures. They were built from a sheet with a slit in it that was moved rapidly across the film plane. The width of the slit determined the shutter speed, but the sheet took a fairly long time to get all the way across the film plane. I had an Exakta SLR back in the '50's that had that kind of a shutter. It was made of some kind of fabric with a metal or plastic edge so it wouldn't unravel. The slit was variable so the shutter speed could be changed.

Modern DSLR shutters are very similar to that one except that they are two thin metal sheets. They travel across the sensor plane independently. The time interval between when they start moving determines the shutter speed. The sheets typically take about 1/250 second to get all the way across. That's the reason for the 1/250 second flash sync limit. At that speed there's a time when the first sheet is all the way open and the second hasn't started moving. At faster speeds, the second sheet starts to move before the first is all the way across, so the sensor is not open all the way across. If you fire the flash then, you won't expose the entire frame.

PS: my old Exakta shutter travelled in the same direction as the film (in the long direction of the frame) wheras modern DSLR shutters travel across the short direction of the frame.

Photographer Jim Loc: Rio Vista, CA

Question: are these photos before or after contact with the ball? I ask because I have seen slow motion film that clearly shows the bat flexing after contact.

kavner58 Loc: Portland, Oregon

Your F number is 2.8. I suspect it is an illusion and if you would make the photo with longer DOF the bat could look as it should - not bent.

- AK

SteveR Loc: Michigan

Have you ever seen video taken from inside a prop plane? The straight propeller looks as though it's curved like a scythe. Same principle I suppose.

redhogbill Loc: antelope, calif

I know better!! thanks for fixing the link

:oops: :oops: :oops:

SquareRoot Loc: southeast Missouri

Thanks for your reply, Jim.
I'm thinking that the 'leading edge' of the object/ball/bat would be less blurred than the trailing edge in the pic. I decide that the ball is approaching the bat in the first photo, and leaving the bat in the second; but the difference is not too pronounced! What is your thinking?

SquareRoot Loc: southeast Missouri

Thanks, RedHogBill, for the link.
I like it.
Very instructive!

SquareRoot Loc: southeast Missouri

Yes, Erv, this past week I risked 'missing a shot' and tried to see how various settings would affect the pics. My preference in baseball pics is less blur; so I will increase the speed in my daylight shots and the ISO also. But seems there will be a limit to what my equipment will allow at night. I'll only be in a professional ballpark during playoffs (if then, ha!). So night-time lighting will be 'not great' at best and truly poor at worst. It seems apparent that 'sports mode' will not satisfy me at night.
Thanks for the suggestions.