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03-01-2012, 03:34 AM   #16
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i don't get why so many people think this is the result of panning too fast. if that were the case, the fence would be blurred more than the car, not less. it looks like the lens was actually moving right to left.

03-01-2012, 04:06 AM   #17
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QuoteOriginally posted by cmohr Quote
Average speed of these guys is 200mph, thats 300feet per second, and at 1/6000th of a second, thats car has travelled a few inches. So it will blur wil still occur if you are not panning correctly. It takes practice, so don't be so hard on the camera.

Also, maybe try taking pics at more of an approaching angle, rather than as they are almost parallel to you and you'll find greater success.
I worked out that at 200mph the car would have moved about 4" in 1/6000. That is about consistent witht he amount of blur on the advertising on the side. You held the camera steady - see the fence. Interesting - even at that shutter speed one still needs to pan. Who'd-a-thunk! - but the sums tell us.
03-01-2012, 04:45 AM   #18
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Then why is the blur on the wrong side of the car? It looks as if it were traveling backwards, which means it must be a case of panning too fast.

It's too bad that OP seems to have abandoned this thread without replying. More information would make this a lot easier to figure out.
03-02-2012, 02:53 AM   #19
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FWIW, if someone with shaky hands can freeze (normal) frames with a flash sync of say 1/125, panning with a shutterspeed of 1/6000 seems as useful as washing your car and then drive into a mudpool. With the speed of this car you would also have to jerk the camera, which might not be a good combination with SR, if good practice at all when releasing a shutter.

03-02-2012, 06:10 AM - 1 Like   #20
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Turn off SR off. It's been my experience that it doesn't play well with panning. F-stop between 8 and 11 for a decent Depth of Field and sharpness. Manual focus, don't depend on auto focus to keep up. Pick a spot on the track and prefocus in that area. Practice is the biggest key to shooting racecars and raceboats. With practice you'll find a technique that works for you.

These were taken with my K200D and a manual 300mm zoom.





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03-02-2012, 08:45 AM - 1 Like   #21
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QuoteOriginally posted by Twarp Quote
FWIW, if someone with shaky hands can freeze (normal) frames with a flash sync of say 1/125, panning with a shutterspeed of 1/6000 seems as useful as washing your car and then drive into a mudpool. With the speed of this car you would also have to jerk the camera, which might not be a good combination with SR, if good practice at all when releasing a shutter.
Flashes freeze action because the "flash" of high intensity light is very quick, 1/10000th or quicker, the Shutter speed is often irrellevant to freezing action with a flash.

The slower "shutterspeed" for Flash sync is generally the fastest speed that the complete sensor is completely exposed all at the same time, which is nessecary for flash photography to work correctly. IE when you take a picture regardless of the exposure time (IE what is generally called "Shutterspeed") the actual speed the shutter curtains themselves travel is always the same, the "shutter speed" is the amount of time the sensor is exposed to light. For slower exposure times the leading shutter curtain opens and travels all the way to the bottom exposing the sensor to light, after the correct exposure time IE 1/30 or 1/60th ect ect the trailing shutter curtain starts on its way down, shielding the sensor from light. There is a point (with Pentax around 1/180th second is the time it talks for the shutter curtain to travel the distance from top to bottom, so the moment the leading shutter curtain reaches the bottom the trailing curtain starts on its way down, so 1/180th of a second is the fastest "exposure time" that can be produced where the complete sensor is completely exposed to light all at the same time, thus maximum flash sync speed . To get faster exposure times, IE 1/250th, 1/1000th 1/5000th ect ect the leading shutter curtain starts on its way down, the trailing shutter curtain does not wait for the leading curtain to go all the way down to the bottom, it starts its way down exactly the "Shutter Speed" time after the leading started. So for a 1/1000th sec shutter speed, the leading curtain starts to open and then exactly 1/1000th of a second later the trail curtain starts to close, this actually creates a thin "band" of light that travels down the sensor, thus only giving 1/1000th of a sec light to the sensor as it travels down the sensor. the entire sensor at high shutter speeds is never completely open to light all at exactly the same time.

Sooooo, with flash photography, due to the flash of light being only say 1/50000th of a sec the entire sensor surface must be open for that 1/50000th of a second of light to hit the entire sensor , thus the 1/180th of a second maximum flash sync speed. This is why if you do use a higher shutter speed with a flash than 1/180th of a sec you will get the "letterbox" image where most of you image is very dark and blurred and there is just a small band with the correct exposure present which is when the 1/50000th sec of light was fired. A lot of people think that their equipment is faultly when they get this, but its just because they are not using a faster shutterspeed than the maximum flash sync speed.
Thats why a person with shaky hands can feeze action as they are actually shooting with the speed of the flash of light 1/50000th not the 1/180th of a second flash sync speed.

Still, doesn't explain what went wrong with the OP's picture as no more info has been given to the exact shooting style used when he took the picture, if he was panning or not, but as some say SR could have been working against him as well.
03-02-2012, 10:03 AM   #22
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I'm not sure what type of lighting they installed at Daytona. It's been too many years since I was there. Part of the problem could have been the frequency of the lights. That 60 Hz strobing can do some weird things with photography. Night race pictures from a distance can be challenging in that you are too far away for a flash to be effective and the ambient lighting is never the greatest.
03-02-2012, 11:59 AM   #23
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@cmohr: wow, that was the most comprehensive summary of shutter mechanics and the relation with flash I've seen till now! I'm aware of the fact that comparing flash with speed action is not very adequate. I was trying to say that since the overall picture was unsharp, from car till back- and foreground, something must have gone wrong and that a probable violent movement combined with SR and high shutter speeds (or any...) is not a good recipe.

Now for something mechanical (and off topic but related to the above), I was under the impression that the latest dslr's have an electronic shutter. Else why bother with dust on the sensor etc.?? With a mechanical shutter the sensor would be protected from the outside world when changing lenses right? Of course it doesn't rule out the accumulation of dust after all but it is a protective shield. I tried to have a look at the guts of my K-x but it doesn't let me lift the mirror to see what's behind. When selecting Bulb and fire, I see the sensor but stuff happens so fast that I can't see if any mechanical flips up&down. Before you start scolding, this is my first dslr after using only the good old metal ones without the d. Having a quick look at the manual of the K-5 (which I don't have) it states: choose mirror up and clean the sensor. Nothing about shutter curtains/leaves. But then there's still this 1/180 flash sync speed. This points to the mechanical one. Do you have an equally nice story on this?

03-02-2012, 01:28 PM   #24
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I increased the light in the picture and there are lots of short light streaks going in direction from down left to upper right corner. What could that be? Raindrops in bright light?
03-02-2012, 01:38 PM   #25
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QuoteOriginally posted by Twarp Quote
@cmohr: wow, that was the most comprehensive summary of shutter mechanics and the relation with flash I've seen till now! I'm aware of the fact that comparing flash with speed action is not very adequate. I was trying to say that since the overall picture was unsharp, from car till back- and foreground, something must have gone wrong and that a probable violent movement combined with SR and high shutter speeds (or any...) is not a good recipe.

Now for something mechanical (and off topic but related to the above), I was under the impression that the latest dslr's have an electronic shutter. Else why bother with dust on the sensor etc.?? With a mechanical shutter the sensor would be protected from the outside world when changing lenses right? Of course it doesn't rule out the accumulation of dust after all but it is a protective shield. I tried to have a look at the guts of my K-x but it doesn't let me lift the mirror to see what's behind. When selecting Bulb and fire, I see the sensor but stuff happens so fast that I can't see if any mechanical flips up&down. Before you start scolding, this is my first dslr after using only the good old metal ones without the d. Having a quick look at the manual of the K-5 (which I don't have) it states: choose mirror up and clean the sensor. Nothing about shutter curtains/leaves. But then there's still this 1/180 flash sync speed. This points to the mechanical one. Do you have an equally nice story on this?
We still have mechanical shutters. You can hear it, shoot the camera on 2s timer or 3s remote and you'll hear the mirror lock up on button press, followed by the shutter. And yes, strobe photography (and how flash freezes images) is associated with the speed of the flash image and the maximum shutter speed defines the speed at which the shutter will remain fully open at the time of the flash.

Higher end models of DSLRs will have faster sync speeds because they shutter mechanisms are better.
03-02-2012, 03:24 PM   #26
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QuoteOriginally posted by Gimbal Quote
I increased the light in the picture and there are lots of short light streaks going in direction from down left to upper right corner. What could that be? Raindrops in bright light?
That's probably the fencing reflecting the lighting for the track. The lighting they used is reflected onto the track from behind the drivers so as to not kill their vision.
03-02-2012, 03:26 PM   #27
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Here's another one.
I was using a K 105mm prime, wide open at f2.8. The light was better than I expected. I wasn't trying to pan at this speed, I didn't think it was necessary or possible.
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03-02-2012, 03:44 PM   #28
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QuoteOriginally posted by NeatKnight Quote
Here's another one.
I was using a K 105mm prime, wide open at f2.8. The light was better than I expected. I wasn't trying to pan at this speed, I didn't think it was necessary or possible.
F2.8 is going to give you a narrow DOF. It looks like you may have focused somewhere around the fence. Panning is necessary with anything moving this fast. Like I also said I've found SR doesn't play well with fast moving objects. I used to shoot film at Daytona with my ME Super and it only went to 1/2000 on the shutter.



I've found using my K200D like I did my ME Super and forgetting all the fancy stuff produces much better pictures.
03-02-2012, 03:58 PM   #29
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Well to look at it different is the amount of light passing true and meassuering EV.

So this picture taken at 1/8000the, f1.4 and iso160 (Dynamic Range ON).

E.V. calculation says 13,3

This (date is different, but same game, second camera) at 1/1250th, f5.6 and iso400

E.V. calculation says 13,3

So my guess is that your problem is user-error.
03-02-2012, 10:27 PM   #30
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Here's another example.
Image A was shot at 1/6000.
Image B was shot at the same time at 1/160 (more than 5 stops brighter!)
Image C is simply image B pulled 4 stops darker in LightRoom. It should be brighter than image A.
So it looks like either:
(a) There's reciprocity failure at high shutter speeds
(b) Camera increases the ISO without permission at high shutter speeds
or (C) The shutter just isn't moving at the nominal speed
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