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Thread: I must be doing something wrong....

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    Default I must be doing something wrong....

    I see so many fabulous BIF images here, and I usually note that the shutter speed is often as fast as 1/2000, even at ISOs as low as 400.

    I'm using a Canon 50D (which I just got used) with a 500L f4.5 and a non-reporting 1.4x, so I still have AF.

    Even at nearly wide-open apertures, in anything other than blinding light, I can't seem to get anywhere near that fast a shutter speed at anything close to that low an ISO. (Most of the time, I'm lucky to be shooting as fast as 1/800 at ISOs approaching 1000, at or nearly wide open.)

    The converter should only cost me 1 stop, so I can't figure out why my techs are so different from so many images here.

    What could causing this, and what should I check?

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    Something doesn't sound right Allen.

    Going back to basics --> the Sunny-16 rule: On a sunny day, set aperture to f/16 and shutter speed to the reciprocal of the ISO setting for a subject in direct sunlight. If you are shooting at ISO 400, then the correct exposure in direct sunlight would be 1/400 @ f/16. This would yield the same exposure at settings of 1/800 @ f/11 -or- 1/1600 @ f/8 -or- 1/3200 @ f/5.6 -or- 1/6400 @ f/4.

    Your f/4.5 lens with a 1.4x teleconverter becomes effectively an f/6.3 lens - interpolating from the Sunny-16 rule, with your camera set to ISO 400 with your lens + 1.4x combo opened wide, you should be able to get a good exposure at 1/2000 in direct sunlight.

    Edit - couple things to check:

    Any chance you left a polarizing filter in the drop-in?
    Do you still have the same problem when you take off the 1.4x TC?
    Last edited by Jeff Dyck; 01-24-2011 at 09:59 PM.

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    BPN Member Chris Ober's Avatar
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    Which TC do you have? I'd love to get AF back with mine for the few occasions I use the TC.
    Chris


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  4. #4
    Roman Kurywczak
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    Hey Allen,
    Jeff covered my sunny 16 lesson......so unless ther is a serious issue with the TC or the polariser is in......no othere possible reason I can think of.......so Jeff is on the right track!

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    Roman: I ditched the polarizer right away because it killed light.

    Chris: I have the Tamron TC.

    I went out in bright light, set f/16, ISO 200, 1/200 shutter speed, shot a green street sign in sunlight - and it's at least 2 stops underexposed. In fact, it took f/7.1 to get proper exposure, at both ISO 200/ss 1/200 and ISO 400/ss 1/400.

    I then tried a power line high voltage sign in bright yellow, blue clear sky BG. At ISO 500, f/5.6, the proper shutter speed was 1/2000.

    Next, I guess I'll try the 500L without the converter and see if that's the light-killer, or if the 50D is off somehow (I never noticed this problem with my 500L + 1.4x on my 40D).

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    BPN Member Chris Ober's Avatar
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    Maybe a silly question but did you make sure there wasn't any exposure comp dialed in by mistake?
    Chris


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    Yes, I did check that. I can't think of any other settings on the 50D that could be doing this.

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    You likely already thought of this but...make sure the sun is behind you and make sure the sun is low enough to be at a good angle to light the side of the bird you need lit, if its too high your light may be above the bird. Finally are you using manual exposure or aperture preferred?

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    Quote Originally Posted by Nick Palmieri View Post
    You likely already thought of this but...make sure the sun is behind you and make sure the sun is low enough to be at a good angle to light the side of the bird you need lit, if its too high your light may be above the bird. Finally are you using manual exposure or aperture preferred?

    Manual exposure for about the last 7-8 months; aperture priority before that.

    I got very similar techs using my 40D, so it's not the camera body. So I think it must be the converter - still have to test without it.

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    BPN Member Chris Ober's Avatar
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    moved to photo gear forum
    Chris


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    OK - it's definitely the Tamron converter.

    With the 50D and just the 500L, the "sunny 16 rule" is spot on exposure-wise, in the same light with the same subjects as previously.

    Now I know to give up the 200mm extra reach of the converter if I need light and/or faster shutter speed for situations like BIF.

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    Have you tried Canon's EF 1.4x TC-II? It's not 2x, but shooting at 700mm isn't all bad.

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    Quote Originally Posted by David Stephens View Post
    Have you tried Canon's EF 1.4x TC-II? It's not 2x, but shooting at 700mm isn't all bad.

    Not with my 500L f4.5, because with any Canon TC, I lose AF on that lens (unless I pin-tape). I use a Canon 1.4x on my 300L f4.

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    BPN Viewer Charles Glatzer's Avatar
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    If resulting exposure is correct, my guess is you are shooting at the high shutter speed, but the camera is not showing this as per miscommunication with the converter in use. Your camera should not AF past f/5.6 (f/4.5 w/ 1.4x). Did you check meta data in another program?

    Chas

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    Steven Kersting
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    I tend to get about 1 stop underexposure w/ a non-reporting 1.4 TC. I believe this is because the metering/focusing is done w/ the lens wide open, but it's calculated for the "target aperture" and the camera doesn't "know" the actual "target aperture."

    But I have no problem getting fast SS's.

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    Quote Originally Posted by Steven Kersting View Post
    I tend to get about 1 stop underexposure w/ a non-reporting 1.4 TC. I believe this is because the metering/focusing is done w/ the lens wide open, but it's calculated for the "target aperture" and the camera doesn't "know" the actual "target aperture."

    But I have no problem getting fast SS's.
    You can use +1EV, but you'll cut your SS.

  17. #17
    Steven Kersting
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    Quote Originally Posted by David Stephens View Post
    You can use +1EV, but you'll cut your SS.
    Of course. I probably should have said "if I don't compensate"....

  18. #18
    Steven Kersting
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    Quote Originally Posted by David Stephens View Post
    You can use +1EV, but you'll cut your SS.
    Of course (or bump ISO).
    I probably should have said "if I don't compensate"....

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