Is this tyical difference between zoom and prime?

Discussion in 'Digital SLR' started by Chris Stolpe, Jan 21, 2005.

  1. Chris Stolpe

    Chris Stolpe Guest

    I was looking at:

    Sigma 70-200mm f2.8 HSM photodo.com rating 3.9 B&H price $800
    Canon 70-200mm f2.8 USM photodo.com rating 4.1 B&H price $1140
    Canon 135mm f2.0 L USM photodo.com rating 4.5 B&H price $900
    Canon 200mm f2.8 L II USM photodo.com rating 4.1 B&H price $660

    But I have no feel for what the difference between 3.9 and 4.1 (Canon vs
    Sigma zoom) or 4.1 and 4.5 (Canon zoom vs Canon 135mm).

    The Canon 100-400mm f4.5-f5.6 L IS USM mention in the article is rated at
    3.6 by photodo.com
    They didn't have a rating for the 400mm f5.6 L so I can't get a sense from
    that.
    But it is the only visual comparison I have come across so far.

    I'm looking at these focal length based on the asumption I will by an
    inexpensive film body (Canon T2) with an eye to getting a digital body in a
    couple of years. The 135 fixed would be 200mm on a digital body and f2.0 to
    boot.. I'd have to get the extender (another $280) for a film body. But it
    woudn't go to waste either. My thinking is invest more into the lens at this
    point.

    But:
    The Canon 70-200mm f4.0 L you mentioned is rated at 4.1, B&H price $580.
    On a digital body I could use higher ISO to compensate for the 1 stop
    difference in speed.
    That with a digital rebel kit is in the same ballpark as the Canon 2.8 zoom
    lens (especially with the rebates).
     
    Chris Stolpe, Jan 21, 2005
    #21
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  2. Chris Stolpe

    Frank ess Guest

    I wonder if photodo.com's note that the Canon lens list hasn't been
    updated in mosdre than four years is accurate. If it is, do you suppose
    the ratings would be the same if done on current equipment? Any
    quantified "ratings" that don't give the reader a "feel for what the
    difference..." is probably suspect if recent, doubly so if ancient.
     
    Frank ess, Jan 21, 2005
    #22
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  3. Chris Stolpe

    Colin D Guest

    I dunno about the performance of the zoom here. It looks even worse
    than the MTF graph suggests.

    I notice that almost every time somebody does a lens test they do not
    say how they focused the lens. The worst possible thing to do - apart
    from not focusing at all - is to rely on AF when testing a lens. That
    comparison in the link looks very much to me like the zoom was actually
    out of focus. The blur looks too smooth to be the result of
    aberrations. I would like the tester to state whether he accurately
    focused the lens manually, or whether he used AF; and if AF, whether the
    focus was actually on the enlarged subject area. If MF, how are his
    eyes - are they able to accommodate the apparent VF distance, or is his
    view of the viewfinder not quite sharp?

    In fact, using AF when testing a lens will invalidate the test. AF
    relies on DOF to an extent. It has to accept a degree of unsharpness to
    prevent constant hunting, so some degree of hysteresis is built in to
    the focusing algorithm, which simply means that if the focus is within
    the hysteresis parameter, the camera accepts it as focused. With 3D
    subjects - ordinary scenes, etc. it doesn't matter, but with 2D, or
    flat, targets, it can be off enough to produce the results we have seen.

    These observations might seem nitpicking, but when one sets out to
    evaluate the performance of a lens, rigorous attention to these matters
    is essential if the results are to be meaningful.

    Last, he tested one example. 'nuff said.

    Colin.

    PS: I don't have the lens, so I'm not biased here.
     
    Colin D, Jan 21, 2005
    #23
  4. Chris Stolpe

    Alan Browne Guest

    Well said Colin. It does come up from time to time but people do need
    continuous reminders.

    Cheers,
    alan
     
    Alan Browne, Jan 21, 2005
    #24
  5. Chris Stolpe

    brian Guest

    Although I appreciate that Lieca do make some shit hot camera's and lenses,
    He has decided to go for Canon, and as far as I know Leica do not make
    lenses to fit Canon, neither do they do a "starter" SLR kit, within most
    people's budget, I could buy a couple of Canon kits for the price of one
    Leica Lens.

    Brian..................
     
    brian, Jan 21, 2005
    #25
  6. Chris Stolpe

    Chris Stolpe Guest

    I overlooked that that. June of 2000. Their links to their MTF charts are
    broken as well. I have had to download their MTF charts seperately. I guess
    I can't take a hint. The Canon site displays MTF and a sample image but it
    is not a high res image nor do they indicate what apeture or focal length
    the took they picture at. Anyone know of a place to download or buy a series
    of high res digital or 4000 dpi scans of Fuji Velvia shot at different
    apetures and focal lengths from various lenses? Any place to buy such a
    thing? That is what I liked about how http://www.imaging-resource.com/ did
    their digital camera tests. They shoot the same scene with different cameras
    under similar circumstances and I can view it at full resolution.

    Any other accurate independent source to compare lenses?
    Only other information I have found is:
    http://www.popphoto.com/article.asp?section_id=2&article_id=351&page_number=1
     
    Chris Stolpe, Jan 21, 2005
    #26
  7. Chris Stolpe

    JPS Guest

    In message <>,
    MTF alone does not determine the sharpness of the lens in the context of
    its use. The size of the recording medium must be factored in, too. If
    you were to look at the inverse of MTF, in terms of resolution at a
    given contrast, you would have to halve the practical resolution for a
    18*12mm sensor, compared to 35mm film.
    --
     
    JPS, Jan 22, 2005
    #27
  8. Chris Stolpe

    brian Guest

    Rather than say it is a photography term, I should have said it was a term
    used by most Photographers to describe a fixed focal length lens, the fact
    that the manufacturers use this term in a different context is neither here
    nor there. For the purposes of this question a prime lens in a lens of fixed
    focal length, simple as that. In days gone by, before the introduction of
    zooms, a photographer would have a lens that he would use first and
    foremost, his "prime" lens, basically his "preferred" lens.Just because a
    word means something in a dictionary, it doesn't mean it MUST always be used
    in that context, If you look up the word "train" in the dictionary, it's
    literal meaning is to betray, also if you want to go down that road, its
    not a "lens", its a series of lenses combined to create a device that
    concentrates and focuses light, as a lens is a singular piece of glass, so
    should we be asking for a Canon 70-200mm lenses?, the context used by the
    manufacturers may be correct for them , but its not for photographers.
    Neither use or definition is incorrect. It's all about context.

    Brian...................
     
    brian, Jan 22, 2005
    #28
  9. Chris Stolpe

    Mike Kohary Guest

    Why, does Leica make any lenses that fit this poster's Canon camera(s)?
     
    Mike Kohary, Jan 22, 2005
    #29
  10. Chris Stolpe

    Mike Kohary Guest

    This is a sound strategy. The technology for digital camera bodies is
    changing rapidly, but your lenses will be interchangeable for a long time to
    come. Invest in great lenses and you'll never be sorry.
    I chose the f4 over the f2.8 version precisely because it was half the
    price. The lenses are otherwise virtually identical, and it just wasn't
    worth it to me to pay $800 for one more stop. :) For the record, I'm using
    the Digital Rebel myself, and yes, it is easy to compensate on the fly by
    adjusting ISO. I used this lens for a wedding this last summer, moving
    indoors and outdoors and adjusting as I went, with spectacular results that
    pleased my clients to no end.
     
    Mike Kohary, Jan 22, 2005
    #30
  11. Chris Stolpe

    Stacey Guest


    Isn't that what I just said in the part you sniped out??

    " I'm assuming that 100-400 is from
    pre-digital days and was designed with the limits of 35mm film in mind."

    This is why people have to be careful choosing lenses to use on something
    like a 20D. Some of the lenses that were fine on 35mm film aren't good
    enough for a smaller sensor camera or one that can resolve more than 35mm
    film could.
     
    Stacey, Jan 22, 2005
    #31
  12. Chris Stolpe

    Stacey Guest

    This same site did this exact thing comparing the contax 35mm to the arsat
    fisheye. The had one focused at infinity, the other about 20 feet from the
    camera then compared crops at infinity, guess which one won? After seeing
    that and then the author ARGUED that he had focused correctly when you
    could obviously see it wasn't, I ignore much of what is posted there as far
    as "tests"..
     
    Stacey, Jan 22, 2005
    #32
  13. Chris Stolpe

    Lionel Guest

    Kibo informs me that stated that:
    On a Canon 20D? - I don't think so. ;)
     
    Lionel, Jan 22, 2005
    #33
  14. Chris Stolpe

    Crownfield Guest

    does that presume full color pixels?
     
    Crownfield, Jan 22, 2005
    #34
  15. Chris Stolpe

    Carl Guest

    Actually "prime" is a photographic term and owes its antecedents to the
    cinematographic industry, from which 35mm photography was derived.
     
    Carl, Jan 22, 2005
    #35
  16. Chris Stolpe

    brian Guest

    Meanings of Prime form just ONE dictionary, I don't see even one definition
    here that includes anything photographic :-

    Main Entry: 1prime
    Pronunciation: 'prIm
    Function: noun
    Etymology: Middle English, from Old English prIm, from Latin prima hora
    first hour
    1 a often capitalized : the second of the canonical hours b : the first hour
    of the day usually considered either as 6 a.m. or the hour of sunrise
    2 a : the earliest stage b : SPRING c : YOUTH
    3 : the most active, thriving, or successful stage or period <in the prime
    of his life>
    4 : the chief or best individual or part : PICK <prime of the flock, and
    choicest of the stall -- Alexander Pope>
    5 : PRIME NUMBER
    6 a : the first note or tone of a musical scale : TONIC b : the interval
    between two notes on the same staff degree
    7 : the symbol ´
    8 : PRIME RATE

    ALSO

    Main Entry: 2prime
    Function: adjective
    Etymology: Middle English, from Middle French, feminine of prin first, from
    Latin primus; akin to Latin prior
    1 : first in time : ORIGINAL
    2 a : of, relating to, or being a prime number -- compare RELATIVELY PRIME b
    : having no polynomial factors other than itself and no monomial factors
    other than 1 <a prime polynomial> c : expressed as a product of prime
    factors (as prime numbers and prime polynomials) <a prime factorization>
    3 a : first in rank, authority, or significance : PRINCIPAL b : having the
    highest quality or value <prime farmland> c : of the highest grade regularly
    marketed -- used of meat and especially beef
    4 : not deriving from something else : PRIMARY

    AND

    Main Entry: 3prime
    Function: verb
    Inflected Form(s): primed; prim·ing
    Etymology: probably from 1prime
    transitive senses
    1 : FILL, LOAD
    2 a : to prepare for firing by supplying with priming b : to insert a primer
    into (a cartridge case)
    3 : to apply the first color, coating, or preparation to <prime a wall>
    4 : to put into working order by filling or charging with something <prime a
    pump with water>
    5 : to instruct beforehand : COACH <primed the witness>
    6 : STIMULATE
    intransitive senses : to become prime
    - prime the pump : to take steps to encourage the growth or functioning of
    something
     
    brian, Jan 22, 2005
    #36
  17. Chris Stolpe

    JPS Guest

    In message <>,
    Only if you're looking at chromatic resolution. It has little effect on
    the perception of sharpness.

    You can take a very sharp color image which has been downsampled to
    guarantee mostly-measured values for each channel of each pixel, and
    view it at 100%, and blurring the hue a few pixels without blurring the
    luminance is harldy noticeable.
    --
     
    JPS, Jan 22, 2005
    #37
  18. Chris Stolpe

    JPS Guest

    In message <[email protected]>,
    I always like to slant the test pattern or subject slightly, so that
    some part of it has to be in focus if I am off, and I focus manually on
    the center. The sharpest strip is where the lens is focused (unoless it
    is at an edge).
    --
     
    JPS, Jan 22, 2005
    #38
  19. Chris Stolpe

    Stacey Guest


    Another point no one mentioned, do you plan on always using a large tripod?
    If not, you'll NEVER see the difference posted here.
     
    Stacey, Jan 22, 2005
    #39
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