New 20D needs lenses

Discussion in 'Digital SLR' started by Dale, Dec 26, 2004.

  1. Dale

    Colm Guest 20D images/Day at the Races&picture=21

    I would agree that it's not a piece of junk, but my experience of it (had
    one for a year or so) is that it's not the sharpest lens going. I was glad
    to get rid of mine.

    Lenses I've used and would recommend....
    Canon 50mm f1.8 - an absolute bargain.
    Canon 17-40L f4 - very good wide to standard zoom. Makes a good carry around
    lens for 10D or 20D
    Canon 70-200L f4 - A beauty of a lens. Light enough to handhold easily.
    Sharpness is excellent for a zoom and background blurs out beautifully.
    Canon 400L f5.6 - Tack sharp. I've had good results handholding this one.
    Great value long lens when used on 10D or 20D.
    Sigma 50mm f2.8 macro - I haven't used the Canon macros so I can't compare,
    but I've been happy with the results from this on. It's sharp.

    Hopefully I'll be able to add the 135L f2 to this list in the next few days

    Lenses to avoid imho...
    Canon 75-300 f4-5.6 - the greatest piece of junk I've ever had the
    misfortune to possess.
    Canon 28-135IS - not particularly sharp, build quality isn't great, IS is
    slow and not particularly useful given the focal range.
    Colm, Dec 29, 2004
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  2. Dale

    Ryadia Guest

    Just send 'em over to my place Frank, I don't mind sharing the beer!
    Sure. I go back to work on the 11th, I'll take a pic and post the link.

    Ryadia, Dec 29, 2004
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  3. Dale

    Ryadia Guest

    Once apon a time I owned a camera repair centre in a far away place. We
    repaired Bronica, Mamiya, Fuji and Toyo cameras. I once in a while worked on
    the odd (manual) SLR camera. The A1 Canon was the last SLR I bothered with
    due to their increasing complexity. I'm not sure if the focus issue is the
    big thing with lenses but it certainly is a big factor in their reputation.
    Plenty of cheap lenses become surprisingly good once you stop the internal
    reflections. Sigma lenses have a God awful method of killing stray light. I
    swear some of them actually generate their own. Just coating the edge of the
    elements on some of these lenses gives them spectacular performance but who
    will pay $100 an hour for a Tech to spend 4 hours rebuilding a lens? Easier
    and cheaper to just buy a good one up front.

    Ryadia, Dec 29, 2004
  4. SNIP
    Strange, I could have sworn that a 50mm lens focused at infinity
    produces focal points at exactly the same distance regardless of
    camera body used, but perhaps I misread you? Besides, your use of the
    term "back focus" is confusing, as you seem to mean rear focus
    distance. Backfocus is normally used to indicate focussing behind the
    subject that was focused upon.

    This will often result in wrong focus, because the sensor will focus
    anywhere within range of the entire sensor (so anywhere from the
    closest point to the most distant point covered by the sensor). The
    actual sensor is much larger than the indicator that is projected on
    the viewfinder screen!

    A better test is to autofocus on a flat (parallel to the sensor plane)
    target, switch to manual focus, and vary the camera to target distance
    by e.g. using a focus rail or copystand. A suitable target can be
    made, but the flat/parallel focus plane needs to be much larger than
    the focus sensor (indicator). Then, and only then, conclusions can be
    drawn about focus consistency and need for recalibration of either
    lens, camera, or both. You may also find optimal center focus to
    differ a bit from other areas in the image. A close to flat focal
    plane can only be expected in lenses designed for that, e.g. dedicated
    macro lenses.

    Also consider that only fast lenses allow critical autofocus, due to
    small DoF wide open. Slower and wide angle lenses have considerably
    larger DoF, and anything "close enough" will be within an acceptable
    range for the AF algorithm (either at the closer or more distant
    position within the "acceptable" range).

    Bart van der Wolf, Dec 29, 2004
  5. Dale

    Ryadia Guest

    Where you come from Bart there may be different descriptions of the distance
    between the sensor and the rear element. For 43 years it hss been called
    back focus in my vocalubary and I don't intend to change it anytime soon to
    accomodate you. I also don't intend to change other descriptions
    'tech-heads' in this group have pulled me up on either. Your version of how
    to check for 'back focus' variations may suit you but it never gave me any
    reliable results in the past. Your method is as prone to errors as mine.
    This is why I suggested making several shots.

    Now I pose the question:
    Are there actually any photographers lurking in this group or are you all
    tech-heads who take pictures? Maybe I made the wrong assumption about the
    name of the group. I thought photo in the first part meant it was a
    photographers group. I guess it is more for digital SLR followers after
    lurking here for a few weeks.

    (a Photographer)
    Ryadia, Dec 29, 2004
  6. Dale

    JPS Guest

    In message <>,
    That's a myth. There are much sharper lenses than it, though it is
    sufficient in many cases.
    JPS, Dec 29, 2004
  7. Dale

    Will D. Guest

    Rear focus distance instead of back focus sounds better. Isn't lens
    performance in general independent of the camera body?

    Will D.
    Will D., Dec 29, 2004
  8. Dale

    Will D. Guest

    So it seems. The problem here is that the adjustments mentioned are for
    the body, not the lens. On reflection, it makes sense that the primary
    focus difficulty is a lack of agreement between focus on the film/sensor
    plane, and 1) the viewfinder, 2) the autofocus mechanisms. This
    suggests that a problem with the camera body is what is responsible for
    some of the apparent fault of a lens, especially for autofocus.
    One wants the edges to be absolutely non reflective, I would think. Or
    is my understanding faulty here? WRT the $400, if the difference in
    price is in the $Ks, that might make good sense.


    Will D.
    Will D., Dec 29, 2004
  9. Please: What Canon lenses are much sharper, or even just sharper?
    John McWilliams, Dec 29, 2004
  10. Dale

    Ryadia Guest

    OK I'll call it rear focus.
    Once a camera has the correct distance setting for rear focus, then the lens
    performance is independent of the camera. Having said that, if the rear
    element to mount flange of the lens is not precise then the lens will still
    not focus properly. My experience tells me that apart from the optical
    variations, lenses are more closely manufactured than cameras.

    If you can satisfy yourself that the camera is correctly rear focusing, you
    can reasonably expect to get sharp photos from a variety of lenses. If you
    try one and it doesn't focus sharply, it's a fair bet it need to be
    calibrated or recalibrated. If it's new, don't buy it.

    Interestingly I tried several Canon f1.8, 50mm lenses on my adjusted 20D and
    got 2 that didn't focus correctly! When I think about it, probably the only
    reason my camera supplier puts up with me is because I buy a lot of stuff. I
    tried 3, Tokina lenses which are well reported in the media as 'good lenses'
    and none of them focused as sharply as either a Canon 24~70 f2.8 or the
    Sigma alternative yet the Sigma is not receiving the comments it deserves
    due to "poor focus" tests.

    At the end of the day, if you can't tell the difference and don't have a
    camera you know absolutely has correct rear focus, it's probably better to
    stick with a Canon lens. Plenty of people say some of them are soft focus
    but on a calibrated camera, none should be.

    Ryadia, Dec 29, 2004
  11. Dale

    JPS Guest

    In message <[email protected]_s04>,
    The 500mm f4L IS, 300mm f4L IS, 300mm f2.8L IS, 400mm f2.8L IS, 70-200mm
    f2.8L IS ... Tamron macros are sharper, the Sigmna 50mm f2.8 EX Macro is
    sharper ...

    Look at Caonon's MTF chart! It only approaches one for low-contrast,
    stopped down only:

    Some of the lenses I mentioned hug the 1 for all lines!
    JPS, Dec 29, 2004
  12. SNIP
    I can't speak for others, but I'm (amongst others) a certified pro
    photographer. For me it is important to know the limitations or strong
    points of my gear, ever since before my first Canon (original F1). I'd
    rather control the camera, than having the camera control me.
    The "digital" part means that one can suspect a certain level of
    technical interest/knowledge is present with some of the contributers,
    and photographs being the obvious final goal.

    Bart van der Wolf, Dec 30, 2004
  13. Dale

    Will D. Guest


    Thanks for the comments and information!

    I think I'll do focus tests on my gear now and see what I find. I've
    got a few fast lenses for each system, which is what I'll use, as slow
    lenses obviously provide little insight here. I've read through some of
    the available discussions, particularly by Bob Atkins, and it looks
    like this is not just a digital issue, although digital bodies are more

    I guess we've all known about this stuff, but it's often hard to tell
    just what is and is not really important until we read of the
    experiences of others. This thread has done that, and now off to set up
    a optical bench (of sorts). I have this table saw that has a POS motor
    but a very usable fence, and I've got clamps and stuff...

    Will D.
    Will D., Dec 30, 2004
  14. Dale

    Steve Dell Guest

    Care to elaborate on your comments about the 28-135 IS. I've been reasonably
    pleased with it thru-out all lengths and apertures.

    Steve Dell, Jan 2, 2005
  15. Dale

    nick c Guest

    One mans trash is another mans treasure. The 28-135 is a good lens to have.

    nick c, Jan 2, 2005
  16. Dale

    nick c Guest

    I have both Canon lenses (17-85 and 17-40) in addition to the 28-135 and
    I'm very pleased with them. AFAIC, these are keeper lenses. The 17-85
    lens is ideal with my 20D camera. I use the 17-40 and the 28-135 with my
    1D MkII and I pleased with the results from using those lenses with 1D
    MkII camera. I intend getting the 24-70 F-28L and either the 70-200 F-4L
    or 70-200 F2.8L lens. I like the 70-200 F-2.8L lens but I also like the
    weight of the 70-200 F-4L lens.

    nick c, Jan 2, 2005
  17. Dale

    Musty Guest

    Thankyou for your post. Its good to hear from people that have actually
    experienced these lenses. I am happy with my 17-85, except that it is a
    little on the soft side at 17mm. Do you see the same phenomenon? How does
    you 17-40 f/4L compare at the wide end? Do you feel that the L is sharper?

    Regarding the 70-200 f/4L it is a very practical lens due to its weight.
    Also I have yet to read a negative or "average" review of that lens. I have
    read even some posts of users who sold their IS or f/2.8 versions and bough
    the f/4L instead just because of the weight and the images were just as good
    (obviously IS would help a lot, but price is quite high).

    Musty, Jan 2, 2005
  18. Dale

    leo Guest

    I have 17-40/4L and 70-200/4L (and 300/4L IS). They are great but
    because they are slow, I have to crank up the ISO. I wish I had f/2.8
    but I won't spend that kinds of money.
    leo, Jan 2, 2005
  19. Dale

    Musty Guest

    Are you shooting with 20D? I am finding that cranking up the ISO on 20D is
    no issue. Noise @ 1600 ISO is similar to other cameras at much lower ISO.
    For example ISO 800 is very good. Ofcourse f/2.8 will also give very shallow
    DOP for portraits and other isolation shots.
    Musty, Jan 3, 2005
  20. Dale

    leo Guest

    I am waiting for a new 20D. I had used one for a week. I never tried
    anything about 800. Another thread stating 1600 is pushed, we shall see
    if it is proved.
    leo, Jan 3, 2005
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