Are all lenses softer wide open?

Discussion in 'Photography Beginners' Forum' started by PhotoXopher, Dec 26, 2009.

  1. PhotoXopher

    PhotoXopher TPF Noob!

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    EDIT
    Samples here:
    http://picasaweb.google.com/cwnauman/70200F28Samples#

    Just curious (I really don't know), but is it normal for a lens to be softer wide open (f/2.8 in this case).

    I'd post some samples but I really haven't had time to with Christmas and all. If possible I'll take some tonight on a tripod (only real fair way to do this).

    Anyway, what would be a realistic expectation vs being too picky?
     
    Last edited: Dec 26, 2009
  2. Goontz

    Goontz TPF Noob!

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    Yes, I believe that any lens will tend to be sharper at f/8 than it will wide open. I suppose the exact difference in sharpness will vary, and it's probably more personal choice and what you view as acceptable. Looking at charts vs. real world will be hugely different as well.
     
  3. gsgary

    gsgary Been spending a lot of time on here!

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    No Canon 300mmF2.8L is sharp

    [​IMG]

    [​IMG]


    [​IMG]
     
    Last edited: Dec 26, 2009
  4. DScience

    DScience No longer a newbie, moving up!

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    No no no no...Some lenses, I can't say what %, will be softer at it's widest aperture. However this is lens specific. There are GREAT lenses out there that perform very sharp at wide open apertures, just as sharp as other f stops.

    However what you should keep in mind, is that when a lens is wide open it's DOF is a lot smaller, so I think a lot of times people think it's soft simply because much of the picture is soft and out of focus. But the focal point can still be tack sharp. As an example lens I would say look at the 85mm f/1.4. It is insanely sharp wide open at 1.4
     
  5. PhotoXopher

    PhotoXopher TPF Noob!

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    I've found if I underexpose the f/2.8 shot by one stop it's better and actually more on par with the other f/stops exposure.

    Samples here (for some reason Picasa doesn't work so well when posting photos on the forum) and my flickr account is maxed for the month:

    All shot at 200mm on tripod in aperture priority mode. -.5 exposure compensation on the second to last one and -1 exposure compensation on the last one at f/2.8
    Picasa Web Albums - cwnauman - 70-200 f2.8 S...

    Full exif available by clicking 'more info' on the right hand panel.

    After doing this the only real difference I see cycling through them is the depth of field... (other than 100% views).

    Thanks for any input!
     
    Last edited: Dec 26, 2009
  6. chip

    chip TPF Noob!

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    Usually you get what you pay for. Cheap lenses are usually terrible wide open. Even expensive lenses may get a little softer wide open but still more than acceptable.
     
  7. PhotoXopher

    PhotoXopher TPF Noob!

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    I guess that's why I'm asking... I don't have anything to compare it to.
     
  8. Shockey

    Shockey TPF Noob!

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    Yes lenses are softer wide open and get soft again on the other end starting generally at f14.
    Having said that there are several Very Expensive lenses that are quite sharp wide open but even they are sharper a few stops into the range typically lenses are sharpest around f5.6 or f8.

    Inexpensive lenses are typically quote soft wide open but two stops into the range they will be sharp.
    If you have an f2.8 lens that is not sharp stop it down to F4 and it should be sharp by then, this is quite normal.
     
  9. PhotoXopher

    PhotoXopher TPF Noob!

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    OK, I guess I kind of figured as much but wanted to make sure I wasn't beeing too picky.
     
  10. Goontz

    Goontz TPF Noob!

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  11. cliffy13

    cliffy13 TPF Noob!

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    The majority of lenses do get better as you stop them down but it does not apply to all lenses old and new,I have a 30 year old Vivitar 300mm f 5.6 that is as pin sharp wide open as it is at f11
     
  12. PhotoXopher

    PhotoXopher TPF Noob!

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    Has anyone looked at the examples I posted?

    Just wondering what the general concensus is of this particular example.

    Thanks
     

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