shutter speed question

[seashoreCM]

I suggest startting with the same shutter speed rules for DSLR's as for (film) SLR's given the same angle of view in degrees.

If the camera has one stop of image stabilization, that means on average you can have twice the shutter open time (e.g. 1/30'th second instead of 1/60'th second) for the same sharpness when hand-holding the camera. Two stops of IS means 4 times the shutter open time.

Crop factor is one number to help derive the 35mm film camera equivalent focal length, when the lens was taken from a different camera body to put on the body you are using. Shutter speed rules are the same for a DSLR versus a SLR each with lens of (or zoomed to) the same 35mm film camera equivalent focal length (which translates to the same angle of view in degrees) and all other things being equal.

I find it hard to believe someone got a great sharp shot at 1/10'th second without a tripod or a lot of luck.

Digital camera hints: http://www.cockam.com/digicam.htm

 

[Gdad]

I have always just used the reciprocal of the focal length I am shooting at (50mm = 1/50th) for a basic guideline/benchmark and I try not to drop too many stops below that for best consistent results. Everyone has their own abilities and tolerances- and everyone has their own idea of what is an acceptable ‘keeper’ and what’s a throw-away. Like a lot of people I have ‘pulled off’ a couple 1/4 second handheld miracles here and there but it’s not a setting I would consider trying except in a pinch (or more likely a happy accident.)

I know what I have read but I don't really buy into the whole crop factor adjustment thing either- 50mm is 50mm cropped or full frame- you are just grabbing light from a smaller part of the image circle. I could be shooting with my daughters 6mp D40 which is 'cropped' or using a full frame 24mp D3x and crop it myself to the same view- what's the difference? SLR’s shooting crop sensors, full frame sensors, and even film, I find what I can do and what I can’t do to be about the same.

 

[boBQuincy]

I know what I have read but I don't really buy into the whole crop factor adjustment thing either- 50mm is 50mm cropped or full frame- you are just grabbing light from a smaller part of the image circle. I could be shooting with my daughters 6mp D40 which is 'cropped' or using a full frame 24mp D3x and crop it myself to the same view- what's the difference? SLR’s shooting crop sensors, full frame sensors, and even film, I find what I can do and what I can’t do to be about the same.

I completely agree! The lens is the same, the distance from the focal point to the sensor is the same, and given the same amount of vibration the movement of the image on the sensor will be the same. If anything has changed it is our definition of what is sharp, and that has become more critical as we pixel-peep at 100% and routinely make enlargements of 13x19 and more from a "35mm" camera.

 

[DisneyGrampa]

I'm an old SLR guy, who never tried to hand-hold below 1/30 sec. But with my stabilized new D5000, I can easily do better than that. I spent a few days practicing low speed shooting with it, and I found that if I took three shots in a row-I'm not talking about a multi mode-I got much better results on the third shot. Has anyone ever tried this?

 

[Chikabowa]

I'm an old SLR guy, who never tried to hand-hold below 1/30 sec. But with my stabilized new D5000, I can easily do better than that. I spent a few days practicing low speed shooting with it, and I found that if I took three shots in a row-I'm not talking about a multi mode-I got much better results on the third shot. Has anyone ever tried this?

Definitely. I shoot on Continuous Low quite frequently, and I have that set to 7fps. When in low-light situations, I'll often pull off three frames of the same shot and usually the middle one is the sharpest.

 

[VVFF]

I have always just used the reciprocal of the focal length I am shooting at (50mm = 1/50th) for a basic guideline/benchmark and I try not to drop too many stops below that for best consistent results. Everyone has their own abilities and tolerances- and everyone has their own idea of what is an acceptable ‘keeper’ and what’s a throw-away. Like a lot of people I have ‘pulled off’ a couple 1/4 second handheld miracles here and there but it’s not a setting I would consider trying except in a pinch (or more likely a happy accident.)

I know what I have read but I don't really buy into the whole crop factor adjustment thing either- 50mm is 50mm cropped or full frame- you are just grabbing light from a smaller part of the image circle. I could be shooting with my daughters 6mp D40 which is 'cropped' or using a full frame 24mp D3x and crop it myself to the same view- what's the difference? SLR’s shooting crop sensors, full frame sensors, and even film, I find what I can do and what I can’t do to be about the same.

The reasoning behind it is that it could effectively be considered a "digital zoom" of sorts. It's a crop of the original frame resulting in a smaller portion of the light being displayed the same size on screen as the full frame would have been. This makes slight blurring more apparent in the crop shot. Not to mention that the more densely packed sensor on a crop camera will have blur that extends for more pixels. Similar to how chromatic aberration can "appear" larger at 100% than on a less pixel dense sensor. In the end it doesn't matter though as all that matters is that the photographer decide a good rule for him.

 

[VVFF]

I suggest startting with the same shutter speed rules for DSLR's as for (film) SLR's given the same angle of view in degrees.

If the camera has one stop of image stabilization, that means on average you can have twice the shutter open time (e.g. 1/30'th second instead of 1/60'th second) for the same sharpness when hand-holding the camera. Two stops of IS means 4 times the shutter open time.

Crop factor is one number to help derive the 35mm film camera equivalent focal length, when the lens was taken from a different camera body to put on the body you are using. Shutter speed rules are the same for a DSLR versus a SLR each with lens of (or zoomed to) the same 35mm film camera equivalent focal length (which translates to the same angle of view in degrees) and all other things being equal.

I find it hard to believe someone got a great sharp shot at 1/10'th second without a tripod or a lot of luck.

Digital camera hints: http://www.cockam.com/digicam.htm

Provided nothing is moving I can easily shoot at 17mm and get a sharp shot with my 17-55mm F2.8 IS @ less than 1/10th a second.

Even if you use the "conservative" approach of multiplying by the crop factor and only assuming 2 stops of IS(advertised 3) then you'll get 1/6th a second as the "safe" limit. Indeed, I can use this and things turn out just fine.

Here's an example with the above lens at 44mm F2.8 1/10th a second exposure. I pushed this one a bit farther than normal but I was in a good position for less camera shake but still no tripod.

http://www.flickr.com/photos/purduery/3979156378/meta/

 

[GrillMouster]

I completely agree! The lens is the same, the distance from the focal point to the sensor is the same, and given the same amount of vibration the movement of the image on the sensor will be the same. If anything has changed it is our definition of what is sharp, and that has become more critical as we pixel-peep at 100% and routinely make enlargements of 13x19 and more from a "35mm" camera.

The amount of camera movement would be the same regardless of whether the sensor is full frame or crop, but how much of the frame that motion affects would be greater on the crop sensor than it would be on the full frame sensor. It's all about relativity. Vibration that would cause a point in the scene to sway from the center of the frame to the edge of the frame on a 35mm-equivalent sensor would cause the point to sway from edge to edge (or completely off frame) of a crop sensor.

Here's an experiment to try: hold your arm straight out in front of you, close one eye, and use your thumb and index finger to frame a person standing down the hall from head to toe. In other words, from your perspective it would appear that the person is standing on top of your thumb and your index finger is touching the top of the person's head. Your arm will have a certain amount of vibration, but, not enough to lose the "frame". Now, pinch your thumb and index finger together so that only the person's nose and mouth are visible between your fingers. You'll find that even though your arm has the same amount of vibration that it did when you framed the person's entire body, the effect of the vibration is much greater when a smaller portion of the scene is in frame. That's because the amount of vibration, is greater in relation to the second scene, even though it is the same, as a raw measurement, to the first.

It's the same as a picture appearing sharp when viewed at 25% on your screen, but blurry at 100%. It's also the same as capturing a car going 120 miles per hour from a distance of 500 yards vs capturing that same car at the same speed from 10 feet away. Even though the car is traveling the same speed, it moves faster across the frame the closer you are to it.

 

[boBQuincy]

The amount of camera movement would be the same regardless of whether the sensor is full frame or crop, but how much of the frame that motion affects would be greater on the crop sensor than it would be on the full frame sensor. It's all about relativity. Vibration that would cause a point in the scene to sway from the center of the frame to the edge of the frame on a 35mm-equivalent sensor would cause the point to sway from edge to edge (or completely off frame) of a crop sensor.

Exactly. And when we enlarge the images 10x we find *exactly* the same amount of blur in the images! It is completely a function of how much the lens moved multiplied by the magnification of that lens.

If we look through a FF and a 1.6x crop camera with a 50 mm lens (both with 100%, 1.0x viewfinders) the images look about the same size as if we looked with our eyes. If we mount a 200mm lens the image is now 4x *on both cameras*. We just see less of the frame on the 1.6x camera but the magnification is exactly the same!

A 200mm lens is a 200mm lens and will never appear as a 320mm lens on a 1.6x crop camera.

 

[GrillMouster]

But since the crop sensor camera is packing roughly the same number of pixels than the full-frame sensor, the images would not have the same amount of blur if you enlarged them both 10x. The blur would extend over more pixels in the crop sensor camera. The amount of subject motion blur present in an image is influenced primarily by how quickly the subject moves from one edge of the frame to the other. That's why you can photograph an extremely fast-moving object, like a jet plane, with a low shutter speed when it's very far away, but you'd need a much faster shutter speed if you photographed the same object traveling at the same speed up close. The reason you need a faster shutter speed in the latter scenario is not (just) because it's closer, but because it moves across the frame faster.

I understand your point that a 50mm lens (which closely approximates the field of view of the human eye, and, thus, why it's referred to as a "normal lens) is a 50mm lens regardless of the size of the sensor. Yes, the crop-sensor just receives light from a smaller portion of the lens. However, because a moving subject would traverse the frame of a crop sensor faster than it does the frame of a full-frame sensor, a faster shutter speed would be required for the crop sensor camera. If the crop sensor were able to capture the same framing as the full-frame sensor (which I guess would no longer mean it's a crop sensor), then the subject would move across the frame at the same speed, and THEN the shutter speed could be the same.

I think it's hard to grasp this, because the logical mind says "the subject is moving at the same speed, at the same distance to the camera, so the shutter speed required to freeze the action should be the same", but it's all about the relative size.

The only other thing I can think to compare it to is how the relative size of a light source affects whether it gives soft or hard shadows. A small light bulb that would create hard shadows on a person's face would create soft shadows on a miniature toy, because to that toy the light is relatively large. I know, it's a weird example, but it's photography related.

 

[seashoreCM]

Not exactly on topic but I do not think it is meaningful to compare the images from two cameras or two camera/lens combinations unless the subject matter in each image is the same and both are presented as finished pictures of the same size.

So in the case of the same 200mm lens used on different cameras, the image from the larger frame camera needs be cropped so as to have identical subject matter the other camera delivered (You can do this during postprocessing). Now both images will be the same size. Both could then be enlarged the same amount if desired. The amount of blur from a slow shutter speed coupled with less than steady hand holding will still on average be the same in terms of microns or millimeters.

If we put a lens with an actual focal length of 200mm on a 1.6 crop frame camera, the lens focal length needed to fill a full (35mm film) frame with the same content would be 320mm. To compare the results we need to at the very least enlarge the smaller image (during postprocessing) to be the same size as the larger image. After this is done, the amount of blur from a slow shutter speed coupled with less than steady hand holding will on average be the same in terms of microns or millimeters, all other things, including amount of image stabilization, being equal.