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Thread: Handshake

  1. #21

    Default Re: Handshake

    Quote Originally Posted by drake336
    Ok, we really need to confirm this... cos I am quite convince crop factor should be considered... here's my reasoning...

    Picturing how light passes through the lens and get focused on the back (film or CCD/CMOS).

    If we fit the same lens to both film and digital body and shoot the same object, light from the same point of an object will fall on the same position @ the back since focal length is the same.

    Ok, now if our hand shake an equal amount during both shots, the point of light focused @ back will also be shifted equally for both shots, let's say X mm.

    But when you consider, X mm on 35mm film and X mm on APS-size will mean different proportion of the entire image (i.e. smaller area = bigger proportion of blur), I really fail to understand how you can use the same guide line for 35mm film and smaller CCD/CMOS...
    Imagine a pin hole camera with a fixed focal length.

    For the same amount of handshake, does the image on the piece of paper at the back of the black box shake more if the piece of paper is bigger?

    Obviously, no.

  2. #22

    Default Re: Handshake

    That's what I mean... used to be your whole picture was 35mm film size, now your whole picture is only APS size, but the amount of shake is still the same...

    Won't the same shake on the APS sensor look like it's blur-er than than on a 35mm film when you print both out on the same size?

  3. #23

    Default Re: Handshake

    Quote Originally Posted by drake336
    That's what I mean... used to be your whole picture was 35mm film size, now your whole picture is only APS size, but the amount of shake is still the same...

    Won't the same shake on the APS sensor look like it's blur-er than than on a 35mm film when you print both out on the same size?
    Yes.. 1.5x bigger if you blow the whole frame up to the same size. However, if you blow the subject/object up to the same size, then there's no difference since the focal length is the same, you just get less surrounding area.
    Last edited by lsisaxon; 7th February 2006 at 05:43 PM.

  4. #24

    Default Re: Handshake

    Quote Originally Posted by Clockunder
    Agree that the guide is still 1/focal length and don't have to take the crop factor into account.

    For e.g., my Nikon Coolpix 5700 at max. 8x optical zoom has a focal length of 71.2mm which is equivalent to 280mm on the 35mm format. This is similar in calculation to how the focal lenght of lenses on DSLRs with APS sized sensors are multiplied by the crop factor to arrive at the 35mm format equivalent focal length. The crop factor on my camera is actually about 4x. I could easily shoot at 1/60 handheld fully zoom in since the actual focal is only 71.2mm. If the crop factor really needs to to taken into account, then the guide give 1/280 already at full zoom and shooting at 1/60 handheld at full zoom to get steady shots would be unthinkable already.

    The crop factor only affects how large the image will appear on the frame (i.e. because of the difference in FOV). How the rays of light in the camera and lens will vary to cause handshake-blur images is only affected by the amount of handshake and the focal length (how long light have to travel in the lens and camera to reach the sensor) but not the crop factor.
    T=1/(focal length number in mm) is just a guideline. There will still be a bit of blur and it will be more prominent on a 12mp DSLR because you can conveniently zoom beyond 100% pixel for pixel crop on the monitor.

    Having said that, my experience is that I can still get a blur when, say, I use a 50mm lens at 1/60s and whipping up the camera and shoot without waiting for my hands to get still first. On the other hand, it is also possible to handheld a 200mm lens to shoot at 1/60 if you become composed and very still before you release the shutter.

  5. #25

    Default Re: Handshake

    http://www.birdforum.net/showthread.php?t=50295

    It's a thread that discusses handshake also. So if FOV needn't be considered, then a compact camera with a 6mm lens can actually shoot at about 1/6 of a second safely?

  6. #26

    Default Re: Handshake

    Quote Originally Posted by drake336
    That's what I mean... used to be your whole picture was 35mm film size, now your whole picture is only APS size, but the amount of shake is still the same...

    Won't the same shake on the APS sensor look like it's blur-er than than on a 35mm film when you print both out on the same size?
    At the same focal length, the subject will appear smaller in the 35mm film size frame than on an APS size frame.

    For e.g. a moon which occupies 100% on an APS-sized sensor will occupy only about 66% of the 35mm film format frame. The guideline remains at 1/focal length. So if the focal length used is 100mm, the the guideline is 1/100 for both frame sizes.

    To have the subject appearing at the same relative size to the frame as an APS sized frame, then the focal length to be used on a 35mm film size format will have to be longer than the focal length used for an APS sized frame. Using the same example above, minimum shutter speed guideline for the 35mm film size format will of course be faster than the guideline for an APS-sized frame but it's not because the guideline formula has changed but because the focal length used for the 35mm format is now longer and therefore a faster shutter speed is required.

    In summary, the minimum shutter speed guideline remains the same but the actual shutter has to be faster on a bigger sensor because a longer focal length has to be used for bigger format in order to get the subject to be of the same relative size to the frame as a smaller format. Therefore the anormaly is just an illusion.

  7. #27

    Default Re: Handshake

    Quote Originally Posted by lsisaxon
    Yes.. 1.5x bigger if you blow the whole frame up to the same size. However, if you blow the subject/object up to the same size, then there's no difference since the focal length is the same, you just get less surrounding area.
    Oh... maybe this is the crux of the whole debate...

    Assuming I use same 50mm lens on both a 35mm camera and an APS camera (1.5x)...

    Now I shoot once at the same shutter speed with the same amount of handshake...

    Obviously the 35mm picture will have a wider FOV.

    1) I crop the 35mm picture to include the exact same area as the APS picture. Since the lens is same and perspective is same, the amount of handshake will be the same. If I print both cropped images at 8R the amount of handshake will be eaxctly the same

    1st case cropped 35mm => 8R
    2nd case APS => 8R
    same amount magnified, no apprent increase in handshake

    => in this case, I can say my crop factor does not affect my handholdable speed
    Last edited by drake336; 8th February 2006 at 01:32 AM.

  8. #28

    Default Re: Handshake

    however...

    2) I leave both pictures as they are and print both to 8R, the handshake visible on the APS picture will be more. Why?

    Again same lens, same perspective but the APS picture is a smaller, cropped version of the 35mm film one. In a manner of speaking, if I blow both the 35mm picture and a cropped version of the 35mm picture to 8R, any imperfection (in this case, blurring) will become more visible on the cropped one since it's magnified more... Why?

    bcos
    1st case: blowup 35mm => 8R
    2nd case: blow up APS => 8R

    Obviously to get the same size printout I will need to blowup image from APS sensor more, thus enlarging any flaw in the process.

    Bottomline is how fast (slow) you can handhold? This will be judged by the image be it on paper or on your monitor. Yes, the amount of shake is the same over the same subject area with the same lens, but the result when you view it or print it out will look different because your end result is one picture with 50mm perspective and the other one with a cropped 50mm perspective with magnified (I hate to use this word as the handshake is not magnified, but rather printing to the same size is what magnifies flaws) blurring.

    By logic I cannot say, "look at the nice and sharp half body shot of the couple with my 35mm film camera and the slightly blurred close up shot of a couple each with only half a face in the picture with the APS sensor" and conclude that I have successfully handheld both shot. Even if I were to blow up the 35mm one and they look identical.

    Cos with the 35mm, my picture is the couple and with the APS, my picture is the 2 half faces.

    So, I still believe handheld speed must be changed to reflect this...
    Last edited by drake336; 8th February 2006 at 01:41 AM.

  9. #29

    Default Re: Handshake

    This should be why also MF and LF shooters can handhold shots for much longer than 1/focal length since their film sizes are so damn huge!

  10. #30

    Default Re: Handshake

    What about compact cameras? Wouldn't it mean they can be handheld longer too since they have a smaller lens with smaller actual focal length?

  11. #31

    Default Re: Handshake

    It's the sensor / film size relative to the focal length that determines this, if you believe what I say...

    In general:

    Same film / sensor size, higher focal length harder to handhold

    Same focal length, smaller film / sensor size harder to handhold

    Or if don't believe my reasoning, then handhold at 1/focal length lor... anyway different people hand steadiness is different, do what works for you...

  12. #32
    Senior Member sammy888's Avatar
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    Default Re: Handshake

    YOu know...I have been reading most of this stuff with some interest hehe but there seem to be one thing no one mentioned that is also a culprit for camera shake in a way.

    YOUR SHUTTER FINGER.

    Get a friend to watch you press your shutter. You would be surprise how much you actually shift your camera when you press it down.

    In the early days of my shooting, when I get excited over a shot I tend to jam down directly my forefinger on the shutter button and my fingers around the grip tend to tighten at that moment thus there is some blurring in the shots when I am shooting even at 1/30 or 1/15 shutter speed with say a 70mm focal length.

    The right way as I learn it is to hold your camera firm but not tightly so that your muscle don't tense up especially if you have been shooting for a few hours. You notice tired muscle when you grasp tightly tend to shake unintentionally. Firm tend to hold the camera more steadily. And instead of pressing down on the shutter button with my tip of my finger, I use the top portion of my finger and I roll over the button. A roll over the button will still indent it deep enough to trigger it but as you roll, the force is roll over and forward but not downwards. And as I roll it, my other fingers gripping the body will not grasp tight at the last moment. Same goes for my left hand which cradle the bottom of the body and lens portion...firm but not tightly. To know that my left fist is not holding too tightly, I should still be able to easily change zoom length or manual focus with just my thumb and forefinger easily while cupping my camera.

    Well that's my two bits....

    also..I like heavy SLRS or DSLR..it helps steady my holding technique. I love my F4 and F5 with the intergrated motor drive. It was heavy like a brick but you get good balance and centre of gravity. It all help to make shots more sharp compared to the P&S NIkon and Sony I use to shoot with. The trade off being...lugging that brick while on holiday along with a heavy tripod hehe.. BUt hell..it builds good muscle and tone.
    Last edited by sammy888; 8th February 2006 at 11:50 PM.

  13. #33

    Default Re: Handshake

    Quote Originally Posted by drake336
    however...

    2) I leave both pictures as they are and print both to 8R, the handshake visible on the APS picture will be more. Why?

    Again same lens, same perspective but the APS picture is a smaller, cropped version of the 35mm film one. In a manner of speaking, if I blow both the 35mm picture and a cropped version of the 35mm picture to 8R, any imperfection (in this case, blurring) will become more visible on the cropped one since it's magnified more... Why?

    bcos
    1st case: blowup 35mm => 8R
    2nd case: blow up APS => 8R

    Obviously to get the same size printout I will need to blowup image from APS sensor more, thus enlarging any flaw in the process.

    Bottomline is how fast (slow) you can handhold? This will be judged by the image be it on paper or on your monitor. Yes, the amount of shake is the same over the same subject area with the same lens, but the result when you view it or print it out will look different because your end result is one picture with 50mm perspective and the other one with a cropped 50mm perspective with magnified (I hate to use this word as the handshake is not magnified, but rather printing to the same size is what magnifies flaws) blurring.

    By logic I cannot say, "look at the nice and sharp half body shot of the couple with my 35mm film camera and the slightly blurred close up shot of a couple each with only half a face in the picture with the APS sensor" and conclude that I have successfully handheld both shot. Even if I were to blow up the 35mm one and they look identical.

    Cos with the 35mm, my picture is the couple and with the APS, my picture is the 2 half faces.

    So, I still believe handheld speed must be changed to reflect this...

    With the same focal length, the following picture is an illustration of the difference in FOV and relative size between an APS size sensor and a 35mm full frame format sensor : (the bigger rectangle is the 35mm format (36mm x 24mm) while the small rectangle crop inside is the APS size sensor (about 22mm x 15mm) which is about 40% of the area of the 35mm full frame (i.e. APS size = 100%/ [(1.6)^2] of 35mm full frame, assuming that the crop factor is 1.6).



    The focal length is assumed to be 35mm. The images on the APS size sensor and the 35mm full format are exactly the same and the only difference is that the latter has a wider FOV simply because it has a bigger plane for the image to fall on. The image on the APS size sensor is in fact a centre crop of the large image of the 35mm format.

    1) For the same amount of handshake, both images will be affected equally since the APS sized image is actually a crop from the same image formed with the same lens at the same focal length. This means that if the image on the 35mm format is still sharp from any handshake, then the image on the APS size sensor will also be as sharp. If it suffers from handshake blur on the 35mm format, it will also be blurr on the APS size sensor.

    So the same minimum shutter speed guideline of 1/focal length applies to both format.


    2) Considering that the APS size is about 22mm x 15mm, the image on an APS size sensor needs to be blown up about 150 times to get 8R (i.e. 8 inches x 10 inches).

    To have a meaningful comparision between 35mm format and APS size sensor, you need crop the 35mm full frame image shown above to get the same FOV (i.e. same composition) as an APS size sensor. After cropping the full frame image to have exactly the same FOV, you would get exactly the same size (22mm x 15mm) as the APS size image. Again, you would need to blow it up about 150 times to get 8R, the same magnification as from an image from an APS size sensor. So there is no difference in magnification between the 2. (Actually, if the smaller sensor has a higher pixel density (i.e. no. of pixels per square area), the smaller sensor have an advantage. However, that's a separate issue).

    You can't simply compare the magnification needed without taking into account difference in FOV.


    3) If you want the 35mm full frame to have the same composition as the APS size sensor, then you would need to increase the focal length used to 35 x 1.6 = 56mm. Then the minimum shutter speed guideline would mean 1/56 instead of 1/35. It is therefore that the 35mm full format is more susceptible to handshake blur for the same composition as an APS size sensor and a faster shutter speed is required to avoid handshake blur. This is contrary to the belief that a faster shutter speed is required for a smaller format to avoid handshake blur. I'm actually side tracking as this is a separate issue from whether the same minimum shutter speed guideline applies to all formats.

    In conclusion : The minimum shutter speed guideline of 1/focal length applies to full frame as well as smaller sensors.
    Last edited by Clockunder; 9th February 2006 at 12:44 AM.

  14. #34

    Default Re: Handshake

    Quote Originally Posted by sammy888
    YOu know...I have been reading most of this stuff with some interest hehe but there seem to be one thing no one mentioned that is also a culprit for camera shake in a way.

    YOUR SHUTTER FINGER.

    Get a friend to watch you press your shutter. You would be surprise how much you actually shift your camera when you press it down.

    In the early days of my shooting, when I get excited over a shot I tend to jam down directly my forefinger on the shutter button and my fingers around the grip tend to tighten at that moment thus there is some blurring in the shots when I am shooting even at 1/30 or 1/15 shutter speed with say a 70mm focal length.

    The right way as I learn it is to hold your camera firm but not tightly so that your muscle don't tense up especially if you have been shooting for a few hours. You notice tired muscle when you grasp tightly tend to shake unintentionally. Firm tend to hold the camera more steadily. And instead of pressing down on the shutter button with my tip of my finger, I use the top portion of my finger and I roll over the button. A roll over the button will still indent it deep enough to trigger it but as you roll, the force is roll over and forward but not downwards. And as I roll it, my other fingers gripping the body will not grasp tight at the last moment. Same goes for my left hand which cradle the bottom of the body and lens portion...firm but not tightly. To know that my left fist is not holding too tightly, I should still be able to easily change zoom length or manual focus with just my thumb and forefinger easily while cupping my camera.

    Well that's my two bits....

    also..I like heavy SLRS or DSLR..it helps steady my holding technique. I love my F4 and F5 with the intergrated motor drive. It was heavy like a brick but you get good balance and centre of gravity. It all help to make shots more sharp compared to the P&S NIkon and Sony I use to shoot with. The trade off being...lugging that brick while on holiday along with a heavy tripod hehe.. BUt hell..it builds good muscle and tone.
    Thanks for the pointer.

    That is something I've often neglected.

  15. #35

    Default Re: Handshake

    For lack of a better way to express what I mean... I am speechless...

    You know what? If it works for you, great!
    Last edited by drake336; 9th February 2006 at 02:30 AM.

  16. #36

    Default Re: Handshake

    I don't quite agree with your conclusion that: In conclusion : The minimum shutter speed guideline of 1/focal length applies to full frame as well as smaller sensors.


    Since If I compare a smaller sensor camera to a larger sensor camera to want to achieve the same focal length, the smaller sensor camera can actually be handheld for longer, since it has the natural crop factor advantage to not need to use a longer focal length lens. Am I right?

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