X-T10 + 35/2 issue

[peperr]

Using the new 35/2 on my X-T10, I noticed this issue (watch the ball distortion). Can somebody explain this? Just to know, X-T10 was in mechanical shutter 

 

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[quincy]

Very high shutter speed maybe? Ball moving upwards, very narrow shutter slit moving downwards, ball gets compressed. maybe. Very high shutter speeds are like line-scanning where the whole frame overall is still captured at the flash-sync speed (close to 1/250th of a second with older Fujifilm cameras, 1/250th of a second with the X-Pro 2).

There are two ways of getting rid of it: Using a camera with a leaf shutter (X100 series, for example), or a highspeed flash.

 

/edit: or using a slower shutter speed and accepting some motion blur.

Edited May 1, 2016 by quincy

[darknj]

Question, are you certain the ball wasn't physically distorted when the picture was taken ?

 

It would seems weird that only the ball would be distorted but nothing else around it.

The boy's leg on the background are fairly straight, and I couldn't see anything weird about the girl's fingers either.

[peperr]

Guys thanks for your notes, look at this now

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[quincy]

Can you provide some EXIF data for the two images?

 

The second one looks exactly like the results I get when panning with the electronic shutter.

[peperr]

Dear friends, this is no panning, there is no electronic shutter 

[milandro]

I concur this is exactly what the electronic shutter might do.

[peperr]

This is a photo taken with electronic shutter, so we probably have to face rolling shutter issue

But what about previous two? I should note that I put the lens on another body X-T10 and did not appear the phenomenon!

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[milandro]

which portion of the picture is this?

[peperr]

its the full picture if you mean this

[milandro]

then I am baffled.

 

I have no idea what is going on but whatever it is is not normal.

[darknj]

What was the speed ? If it was above  1/4000, it could shift automatically to Electronic Shutter instead of the mechanical one.

[milandro]

if the option Manual + ES is enabled.

[darknj]

If I remember correctly, that is the default shutter after one of the FW 4.x update.

 

The second shots look a lot like a Rolling Shutter effect from Electronic shutter, the third shot is a bit inconclusive to me, it seems that the shot was just taken skewed.

[milandro]

it looks almost like the sensor is hanging lose and is twisted 

[vladand]

Even mechanical shutter is rolling, at a speed of 1/180 s (as opposed to electronic shutter which is rolling at a speed of 1/15 s).

 

When shutter speed is (say) 1/2000 s, the first curtain is released and it will take 1/180 s to reach the other end. 1/2000 s after the first curtain is released, the second curtain is released, and now there is a slit that travels at a constant speed, taking 1/180 s to complete, but as the curtains are pretty close, any part of the image is exposed for 1/2000 s (time from first to second curtain passing a given point on the sensor).

 

If a ball is moving during exposure, it will be distorted. As shutter is travelling bottom to top, and the lens projects the image upside down, the travel direction of shutter on the image when it is upright is top to bottom. If a ball is travelling downwards, it will be stretched vertically as it travels in the same direction as the shutter. If the ball is travelling upwards, it will be squished as it travels in the opposite direction. If the ball is travelling horizontally, it will be stretched diagonally, as shutter slit moves across the frame (because the ball also travels, but horizontally).

 

Interestingly, the electronic shutter reads sensor top to bottom, and the direction of distortion will be reversed from the one with mechanical shutter. If camera is panned left to right, vertical structures lean to the right with electronic shutter, and to the left (but 12x less so) with mechanical shutter.

 

This has always been the case with any focal plane shutter.

 

Distortion of moving objects is less visible if mechanical shutter is used, since it is 12x faster than electronic shutter, but if the object is moving fast enough across the frame, it will still show to some extent.

 

The easiest way to show this is to pan the camera horizontally when taking a picture of a vertical object (such as a street light post). If camera is panned fast enough, even at 1/4000 s it will still show the distortion.

Edited May 9, 2016 by vladand