Mirror Lockup and sharpness test with Canon 300D

Discussion in 'Digital Photography' started by Siddhartha Jain, Dec 14, 2004.

  1. Siddhartha Jain, Dec 14, 2004
    #1
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  2. Siddhartha Jain

    Todd H. Guest

    Todd H., Dec 14, 2004
    #2
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  3. Dave knows who, Dec 14, 2004
    #3
  4. "Todd H." <> wrote in message news:...
    > "Siddhartha Jain" <> writes:
    >
    >> Nothing very scientific - just a small test.
    >> http://www.geocities.com/losttoy2000/MLU-Test.html

    >
    > Wow. Cool. Thanks for doing that.


    For those of us without time to download the raw data and analyze it
    ourselves -- What did you conclude?
     
    Michael A. Covington, Dec 14, 2004
    #4
  5. Siddhartha Jain

    Colin D Guest

    Siddhartha Jain wrote:

    > Nothing very scientific - just a small test.
    > http://www.geocities.com/losttoy2000/MLU-Test.html
    >
    > - Siddhartha


    As the owner of a 300D, and considering the Wasia hack, I was very
    interested in your test, Siddartha.

    I have some downstream questions, though, that you might be kind enough
    to answer for the enlightenment of interested people.

    1. How rigid was the tripod? Was it lightweight, or a pro or semi-pro
    tripod?
    2. Was the centre column raised, and/or was it properly tightened up
    with the screw?
    3. Was the pan-tilt head secure, and was the rotate bearing under the
    head tight, to prevent rotary motion?
    4. Were the tripod legs firmly set on the ground, with no play where
    they support the centre yoke?
    5. Were the shots indoor or outdoor? if outdoor, was there any wind?
    6. What were the actual shutter speed and aperture settings used, and
    was it the same for both shots?
    7. Looking at the original images, the blurring seems to me to be more
    like slight out-of-focus, rather than camera shake initiated by the
    mirror. Was the camera set on autofocus, or was it critically focussed
    manually? I presume the lens was the 18-55mm kit lens (which is pretty
    good).

    Questions 1 to 5 basically ensure that tripod movement is ruled out as a
    cause of loss of sharpness; q.6 could be interesting, as higher speeds,
    say 1/200 upwards tend to be too quick for the shake to be apparent, and
    slow speeds of 1/2 sec or slower tend to mask any movement that might
    happen in a 1/10 second or thereabouts.

    Question 7 is the most interesting one. If autofocus was used, slight
    errors in focussing and refocussing can easily cause loss of definition,
    specially with wide-aperture shots. I have found there seems to be some
    hysteresis built-in to autofocus systems, to avoid having the lens
    constantly hunting for focus. Repeated focussing on a subject without
    moving the camera results in the lens stopping at slightly different
    points each time. With normal subject matter, depth of field usually
    masks any slight misfocus, but when shooting a flat surface where DOF
    doesn't apply, slight misfocus can be all too apparent.

    I mention all of this because, as I said in q.7, the blur looks very
    much like out-of-focus blur, and not like the blur one gets with camera
    movement - a sharp image smeared in one direction.

    Colin
     
    Colin D, Dec 15, 2004
    #5
  6. Colin D wrote:
    []
    > I mention all of this because, as I said in q.7, the blur looks very
    > much like out-of-focus blur, and not like the blur one gets with
    > camera movement - a sharp image smeared in one direction.


    That was very much my impression as well.

    David
     
    David J Taylor, Dec 15, 2004
    #6
  7. Siddhartha Jain

    Ryadia Guest

    "David J Taylor" <> wrote in message
    news:...
    > Colin D wrote:
    > []
    > > I mention all of this because, as I said in q.7, the blur looks very
    > > much like out-of-focus blur, and not like the blur one gets with
    > > camera movement - a sharp image smeared in one direction.

    >
    > That was very much my impression as well.
    >
    > David
    >

    I carried out some intensive focus tests with a 20D and initially got
    variable results, thinking it was mirror slap that caused it. later, when I
    begain using an extremely ridged mount and an electronic cable release, the
    differences were much less.

    There is an old established rule of thumb about shutter speed and sharpness
    which goes along the lines of 125% of the focal length should be the minium
    speed. If you use a 100 mm lens then the shutter speed should be 1/125th of
    a second minimum. The longer the lens, the faster the shutter to avoid out
    of focus from hand and mirror movement.

    When I applied this rule to my tests, there was no focus difference between
    mirror up and normal exposures. I suggest the tests this fellow did were in
    low light and with slow shutter speeds. These rather than the mirror shudder
    itself are probably the cause of the focus variations.

    The unclear part of my rule of thumb is with the 1.6 X of DSLRs. Should we
    presume a 75mm lens to be 100 for the purpose of that rule? My tests in this
    area are inconclusive. None the less, since being more aware of the shutter
    speeds, my photographs are much sharper... The resulting shallow depth of
    field is OK with some subjects and not with others.

    Doug
     
    Ryadia, Dec 15, 2004
    #7
  8. Colin D wrote:
    > As the owner of a 300D, and considering the Wasia hack, I was very
    > interested in your test, Siddartha.
    >
    > I have some downstream questions, though, that you might be kind

    enough
    > to answer for the enlightenment of interested people.
    >
    > 1. How rigid was the tripod? Was it lightweight, or a pro or

    semi-pro
    > tripod?

    Its a light-weight. I bought it for about $25.

    > 2. Was the centre column raised, and/or was it properly tightened up
    > with the screw?

    Yes, the centre column was raised and tightened up well.

    > 3. Was the pan-tilt head secure, and was the rotate bearing under the
    > head tight, to prevent rotary motion?

    Yes, that was secured well as well.

    > 4. Were the tripod legs firmly set on the ground, with no play where
    > they support the centre yoke?

    Yes, it was on a level floor with no play.

    > 5. Were the shots indoor or outdoor? if outdoor, was there any wind?

    Indoors with not even the fan ;-)

    > 6. What were the actual shutter speed and aperture settings used, and
    > was it the same for both shots?

    Yes, both were at:
    Focal length: 37mm
    ISO: 200
    Aperture: f5
    Shutter: 1/5 sec

    The EXIF info is there in all the photos on the webpage.


    > 7. Looking at the original images, the blurring seems to me to be

    more
    > like slight out-of-focus, rather than camera shake initiated by the
    > mirror. Was the camera set on autofocus, or was it critically

    focussed
    > manually? I presume the lens was the 18-55mm kit lens (which is

    pretty
    > good).


    Good point. I used the "P" mode and AF. Will repeat the test with MF. I
    plan to do the test at three different focal lengths and will post
    four crops of each, MLU and non-MLU.
    Thanks for the input,

    Siddhartha
     
    Siddhartha Jain, Dec 15, 2004
    #8
  9. Dave knows who wrote:
    > "Siddhartha Jain" <> wrote in message
    > news:...
    > > Nothing very scientific - just a small test.
    > > http://www.geocities.com/losttoy2000/MLU-Test.html

    >
    > On the D-Rebel were you using the timer since you don't have a

    remote?

    Duh!! Stupid me ... will definitely keep that in mind alongwith using
    MF.

    Thanks,

    Siddhartha
     
    Siddhartha Jain, Dec 15, 2004
    #9
  10. "David J Taylor" <> wrote in message
    news:...
    > Colin D wrote:
    > []
    >> I mention all of this because, as I said in q.7, the blur looks very
    >> much like out-of-focus blur, and not like the blur one gets with
    >> camera movement - a sharp image smeared in one direction.

    >
    > That was very much my impression as well.


    Actually, my experience in astrophotography is that vibration blur looks
    *exactly* like poor focusing and has sent many of us on a wild goose chase
    looking for a focusing problem. After all, the camera has several
    milliseconds to vibrate in all directions - not just make a single linear
    movement - and it blurs the image. So I'll reserve judgment on this. I
    agree that the lens needs to be manually focused for the test.


    --
    Clear skies,

    Michael A. Covington
    Author, Astrophotography for the Amateur
    www.covingtoninnovations.com/astromenu.html
     
    Michael A. Covington, Dec 15, 2004
    #10
  11. "Ryadia" <> wrote in message
    news:...

    > I carried out some intensive focus tests with a 20D and initially got
    > variable results, thinking it was mirror slap that caused it. later, when
    > I
    > begain using an extremely ridged mount and an electronic cable release,
    > the
    > differences were much less.
    >
    > There is an old established rule of thumb about shutter speed and
    > sharpness
    > which goes along the lines of 125% of the focal length should be the
    > minium
    > speed. If you use a 100 mm lens then the shutter speed should be 1/125th
    > of
    > a second minimum. The longer the lens, the faster the shutter to avoid out
    > of focus from hand and mirror movement.
    >
    > When I applied this rule to my tests, there was no focus difference
    > between
    > mirror up and normal exposures. I suggest the tests this fellow did were
    > in
    > low light and with slow shutter speeds. These rather than the mirror
    > shudder
    > itself are probably the cause of the focus variations.


    But the *purpose* of mirror lock is to prevent vibration in long exposures
    (not short ones).


    > The unclear part of my rule of thumb is with the 1.6 X of DSLRs. Should we
    > presume a 75mm lens to be 100 for the purpose of that rule?


    Yes. But any exposure short enough to hand-hold will also be short enough
    to completely avoid problems with mirror slap. We have mirror lock for the
    sake of long exposures, not short ones.
     
    Michael A. Covington, Dec 15, 2004
    #11
  12. Michael A. Covington wrote:
    > "Todd H." <> wrote in message

    news:...
    > > "Siddhartha Jain" <> writes:
    > >
    > >> Nothing very scientific - just a small test.
    > >> http://www.geocities.com/losttoy2000/MLU-Test.html

    > >
    > > Wow. Cool. Thanks for doing that.

    >
    > For those of us without time to download the raw data and analyze it
    > ourselves -- What did you conclude?


    There is no raw data ;) Just a couple of pics and two crops, one with
    MLU and the other without MLU. MLU looks far sharper but as people
    above pointed out that it could be an AF issue and I did not use
    shutter timer. So I plan to do some more improved tests soon.
    - Siddhartha
     
    Siddhartha Jain, Dec 15, 2004
    #12
  13. "Siddhartha Jain" <> wrote in message
    news:...
    SNIP
    > I plan to do the test at three different focal lengths and
    > will post four crops of each, MLU and non-MLU.


    If I recall correctly, at about 1/15th of a second the mirror slap
    seems to be most noticable. You may test that on your setup and use it
    as the most sensitive shutterspeed to run tests with.

    Bart
     
    Bart van der Wolf, Dec 15, 2004
    #13
  14. Siddhartha Jain

    Guest

    Hm. The original posting isn't in google (!?).

    Todd H. wrote:
    > "Siddhartha Jain" <> writes:
    >
    >> Nothing very scientific - just a small test.
    >> http://www.geocities.com/losttoy2000/MLU-Test.html


    Was the camera manually focused? Did the focus change from one image
    to the next? I ask because the non-MLU version looks more defocused to
    me than motion-blurred. Compare the horizontal and vertical edges on
    some of the lettering; I would expect a directional smear than a
    roughly even fuzz-out.

    Anyways, even if the experiment was done "right", the conclusion comes
    as no particular surprise.
     
    , Dec 15, 2004
    #14
  15. Siddhartha Jain wrote:
    > Nothing very scientific - just a small test.
    > http://www.geocities.com/losttoy2000/MLU-Test.html


    Update
    ========

    I ran the tests again with manual focus, shutter timer and the camera
    in manual mode. I took 36 exposures in total. Three each at:
    - 18mm 1/8 F4 Non-MLU
    - 18mm 1/8 F4 MLU
    - 18mm 1/4 F5.6 Non-MLU
    - 18mm 1/4 F5.6 MLU

    - 35mm 1/6 F4.5 Non-MLU
    - 35mm 1/6 F4.5 MLU
    - 35mm 3/10 F6.3 Non-MLU
    - 35mm 3/10 F6.3 MLU

    - 55mm 1/4 F5.6 Non-MLU
    - 55mm 1/4 F5.6 MLU
    - 55mm 1/2 F8 Non-MLU
    - 55mm 1/2 F8 MLU

    Lens: Canon 18-55mm F4-5.6 on Canon 300D

    Well, I have yet to do a more careful analysis of the images but looks
    like I'll have to retract my earlier conclusion. This time, my eyes
    were hard pressed to find the difference in sharpness between Non-MLU
    and MLU!!
    Will post the results soon alongwith the images.

    - Siddhartha
     
    Siddhartha Jain, Dec 18, 2004
    #15
  16. "Siddhartha Jain" <> wrote in message
    news:...
    SNIP
    > Will post the results soon alongwith the images.


    Thanks for sharing.

    Bart
     
    Bart van der Wolf, Dec 19, 2004
    #16
  17. Siddhartha Jain

    Colin D Guest

    Siddhartha Jain wrote:

    > Siddhartha Jain wrote:
    > > Nothing very scientific - just a small test.
    > > http://www.geocities.com/losttoy2000/MLU-Test.html

    >
    > Update
    > ========
    >
    > I ran the tests again with manual focus, shutter timer and the camera
    > in manual mode. I took 36 exposures in total. Three each at:
    > - 18mm 1/8 F4 Non-MLU
    > - 18mm 1/8 F4 MLU
    > - 18mm 1/4 F5.6 Non-MLU
    > - 18mm 1/4 F5.6 MLU
    >
    > - 35mm 1/6 F4.5 Non-MLU
    > - 35mm 1/6 F4.5 MLU
    > - 35mm 3/10 F6.3 Non-MLU
    > - 35mm 3/10 F6.3 MLU
    >
    > - 55mm 1/4 F5.6 Non-MLU
    > - 55mm 1/4 F5.6 MLU
    > - 55mm 1/2 F8 Non-MLU
    > - 55mm 1/2 F8 MLU
    >
    > Lens: Canon 18-55mm F4-5.6 on Canon 300D
    >
    > Well, I have yet to do a more careful analysis of the images but looks
    > like I'll have to retract my earlier conclusion. This time, my eyes
    > were hard pressed to find the difference in sharpness between Non-MLU
    > and MLU!!
    > Will post the results soon alongwith the images.
    >
    > - Siddhartha


    Thanks for that, Siddartha. Will be pleased to see the images as and
    when.

    Colin
     
    Colin D, Dec 19, 2004
    #17
  18. Colin D wrote:
    >
    > Thanks for that, Siddartha. Will be pleased to see the images as and
    > when.


    A bit busy playing with my Pentax 50mm f/1.4 :) So here's what I could
    do in a hurry.

    At 18mm, shutter 1/4 sec, F5.6, ISO200. To your left is non-MLU and to
    the right MLU:
    http://www.geocities.com/losttoy2000/18mm-1by4-f5.6-compare.jpg

    At 35mm, shutter 3/10 sec, F6.3, ISO200. Left:Non-MLU, Right-MLU
    http://www.geocities.com/losttoy2000/35mm-3by10-f6.jpg

    At 55mm, shutter 1/2 sec, F8, ISO200, Top:Non-MLU, Bottom:MLU
    http://www.geocities.com/losttoy2000/55mm-1by2-f8-compare.jpg

    So going by these images, the difference is hard to see. I would very
    much like someone else to corroborate my conclusions or even dispute
    them.

    -Siddhartha
     
    Siddhartha Jain, Dec 21, 2004
    #18
  19. Colin D wrote:
    > Thanks for that, Siddartha. Will be pleased to see the images as and
    > when.


    Sorry for the delay, I am having fun with the Pentax 50mm f/1.4 :)
    Here's what I could do in a hurry:

    18mm, 1/4 sec, F5.6, ISO200. To your Left: Non-MLU, Right: MLU
    http://www.geocities.com/losttoy2000/18mm-1by4-f5.6-compare.jpg

    35mm, 3/10 sec, F6.3, ISO200, Left: Non-MLU, Right: MLU
    http://www.geocities.com/losttoy2000/35mm-3by10-f6.jpg

    55mm, 1/2 sec, F8, ISO200, Top: Non-MLU, Bottom: MLU
    http://www.geocities.com/losttoy2000/55mm-1by2-f8-compare.jpg

    So going by these, there doesn't seem to be any noticeable difference.
    I'd definitely like someone to corroborate this or even dispute this -
    but with some evidence.

    The original JPEGs are large, however if you want them for the EXIF
    info, mail me.

    - Siddhartha
     
    Siddhartha Jain, Dec 21, 2004
    #19
  20. Colin D wrote:
    > Thanks for that, Siddartha. Will be pleased to see the images as and
    > when.


    Sorry for the delay, I am having fun with the Pentax 50mm f/1.4 :)
    Here's what I could do in a hurry:

    18mm, 1/4 sec, F5.6, ISO200. To your Left: Non-MLU, Right: MLU
    http://www.geocities.com/losttoy2000/18mm-1by4-f5.6-compare.jpg

    35mm, 3/10 sec, F6.3, ISO200, Left: Non-MLU, Right: MLU
    http://www.geocities.com/losttoy2000/35mm-3by10-f6.jpg

    55mm, 1/2 sec, F8, ISO200, Top: Non-MLU, Bottom: MLU
    http://www.geocities.com/losttoy2000/55mm-1by2-f8-compare.jpg

    So going by these, there doesn't seem to be any noticeable difference.
    I'd definitely like someone to corroborate this or even dispute this -
    but with some evidence.

    The original JPEGs are large, however if you want them for the EXIF
    info, mail me.

    - Siddhartha
     
    Siddhartha Jain, Dec 21, 2004
    #20
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