BigD Loc: The LEFT Coast

HaHa, High Speed Slip
:roll:

ShakyShutter Loc: Arizona

Trick photography sort of like the JFK film going around.

Archangel

I took this at 1/3200 shutter speed.
It froze the action of the bird.

ThomasS Loc: Colorado

You are way over analyzing this. It doesn't really matter why we see things the way we do, it is just the way it is. When I use a high enough shutter speed, I can appear to stop the blades on a helicopter. Are they really stopped? No! But that high speed shutter makes it look like it is, and that's what counts. What is your point in all this?

evandr Loc: Tooele, Utah

Amazing isn't it, a stop action shot of a bird taken at a very fast shutter speed that has almost no perceptible blur (there is some at the extreamities of the one wing but I never would have given it any thought if it were not the point of this thread, in fact a shutter speed of 1/4000 may have eliminated that also) even though the laws of physics demand that there has to beeee...well...you know....the dreaded roll that causes blur. For me it is a moot point as long as I know what I want and how to get it; I am quite frankly surprised that it has given way to this much debate; it is a valid question with a simple answer -

A: "Don't worry about it, the perceptible distortion you speak of at that shutter speed will happen so rarely that you should not give it a second thought outside the reality that the faster the shutter speed the faster an object can be moving and still be froze in the photograph without distortion and/or motion blur. A more likely happening at that speed is a shot that is badly underexposed where nothing can be seen at all, blur or no blur.”

photosbysexton Loc: Knoxville, TN

KG, I think you have been given some bad information. There are not two physical curtains in your shutter. 1st curtain refers to the opening of the shutter, 2nd curtain refers to the closing of the shutter. So, when you are setting your flash to 2nd curtain, you are actually forcing the flash to activate just before the shutter closes. This is very effective when using slower shutter speeds to blur the action but freeze one subject in the image. Try taking a shot of someone walking towards you in the evening with a 1 second shutter speed using 2nd curtain flash. You will see the them nice and clear with an action blur behind them. Or try first curtain and you will see the blur in front of the clear image. This is what I've perceived from the turorials that I've read.

M

KG

I was afraid that me mentioning the sync speed would steer the thread in the direction of discussing flash. And sadly it did. Even though I stated that this is not about flash at all.

So it's especially weird that someone would reference my explanation of how flash works with fast shutter speed. I didn't post any such explanations to begin with :)

The only reason I even mentioned flash was because the highest shutter speed a body can achieve -- while completely uncovering the sensor --- is called the flash sync speed.

Aside from that, the discussion was never meant to be about flash or available light.

notnoBuddha

Frankly looking back over the thread many seem to be confused what his thread is about. To me it seems be a debate about what are absolutes as opposed to the practical - as does anything occur in zero time or do many of them happen so fast the human eye / mind is not aware of the duration. In which case it is a moot point unles wants to argue for the sake of arguement - in which case it worked out well.

BigD Loc: The LEFT Coast

"So it seems that higher shutter speed is a mechanism for controlling the amount of light that gets onto each photosite of the sensor to control overall exposure settings, but it won't work for freezing motion."

No we did not move into discussing HSS just to argue. The above part of the OP postulates that a fast Shutter won't "work for freezing motion" and then asks if he is right or wrong. That was answered in about a second (he was wrong).

Then we went off to try and explain that his understanding of 1st and 2nd curtain and how "mechanically" it worked trying to pass along some information that was absolutely pertinent to the topic if you want to begin a serious discussion about how the Shutter freezes motion. HSS came into it because some reply's thought that a strobe was the thing that froze the motion. The difference between the Eye and the Shutter came in because some didn't understand how the Flash worked with HSS (because it worked for their eye to see fast things). The OP was basically correct about the Shutter controlling the amount of light that reaches the Sensor but the topic (some of us felt) could stand a little expanding. My original reply answered the question that was asked and then tried to quantify my reply, the resulting frenzy occurred when certain other people disagreed with some of my point and we discussed them, BIG DEAL.

Like I said in my earlier reply after some people started to basically argue with what is generally an accepted fact (that a high speed Shutter does stop motion), if we cannot expand on a topic and hear from those that might be more informed why have a forum? Is this site like a court where certain "facts" are not allowed because they were not part of this exact topic? Even though they might just take the topic in a direction where people can pickup some good information? Then there are those that feel it necessary to post a reply about people that posted a reply so they can accomplish what? And within their "sensible" reply they draw the same conclusion we did but provide nothing additional. Seems to me those are the people that just want to bicker.

I actually thought that by exploring the topic of freezing motion in its entirety we might have some really cool input from people but that is far from what I got. So I apologize for trying to go too deep and trust me it won't happen again. I have to prepare for a big shoot now and It just might involve a fast Shutter so wish me luck.

evandr Loc: Tooele, Utah

Wrong, wrong, wrong - there are two curtains, you cannot now, nor is it possible to get an even exposure with only one nor will one be able to open and close at the speeds that a DSLR will go to (1/8000+).

Consider, the curtain begins to open and those first pixels start to expose; as the curtain continues each successive vertical line of pixels start to expose so through the whole process of opening each line starts to expose at a different time; when the curtain is fully open that last line of pixels has just started to expose while the first line has been exposing for a long time (relatively speaking); now, if what you say is true and there was only one curtain it would have to start its closing cycle and that would mean stopping the last row of pixels that started during the opening cycle from exposing while the first is still exposing. Can you see what I am saying, in such a case the end result would be a picture that would be properly exposed on that first row of pixels while each successive row of pixels would be progressively underexposed until, on the other side of the picture, there would be nothing but black. It takes a shutter speed of less than 1/250th of a secont to achieve a fully exposed sensor (first curtain fully open before the second starts to close) at which time the flash can fire without shutter shadows.

You must also consider the mechanical limitations, there is no way that a physical shutter can open and close in 1/8000th of a second, it is just not possible, that is why the Iris shutter in a hasselblad can only reach speeds of 1/800th of a second and that is a camera with technology costing $20,00+.

To achieve an even exposure at the speeds a DSLR can attain the first curtain has to be opening followed closely by the second curtain closing behind it. That is why the concept of Flash sync is important, so important that most cameras will not allow you to set shutter speeds above 250 to 350 because only a narrow vertical line of the picture will be exposed because the flash is much faster than the curtains leaving the only part of the picture exposed to the flash being that part that was open between the front physical curtain and the second physical curtain.

At exposures of 1/8000th of a second the opening between the two curtains would be extremely thin and moving as fast as the physical properties of the camera will allow leaving each column of pixels to have the exact same exposure time.

BigD Loc: The LEFT Coast

BigD Loc: The LEFT Coast

Evandr I was trying to agree with you but I replied wrong. I'm gonna stop watching this thread its getting silly.

photosbysexton Loc: Knoxville, TN

After much digging I did discover that I was wrong, somewhat anyway. Yes there are 2 curtains, one opening, the other closing. My deepest apologies, but yet, my sincere thanks as well. It seems that I learned something again tonight. Now I can go rest. Now, back to the original question; what was it again?

wilsondl2 Loc: Lincoln, Nebraska

Take a look at pictures of race cars taken with focal plain shutters on the old Graphic cameras in the 1920's. They had a slit in the curtain that went across the film so that bottom of the picture was taken before the top. The tires looked oblong and not round. This gave the look that the cars were leaning forward. Todays shutters do not have 4 inches to travel so you can't do it with them. While you can't stop a bullet with the fast shutter speed you will be able to "stop" most sport action. - Dave

wilsondl2 Loc: Lincoln, Nebraska

Take a look at pictures of race cars taken with focal plain shutters on the old Graphic cameras in the 1920's. They had a slit in the curtain that went across the film so that bottom of the picture was taken before the top. The tires looked oblong and not round. This gave the look that the cars were leaning forward. Todays shutters do not have 4 inches to travel so you can't do it with them. While you can't stop a bullet with the fast shutter speed you will be able to "stop" most sport action. - Dave