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Old Aug 30, 2004, 1:09 AM   #1
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I've been eyeing the Sigma 70-200 2.8 lens for a while, as a step up from my current Sigma Macro APO Zoom II (70-300, 4-5.6). During the summer the lens hasn't been too bad since useable light lasts pretty late into the evening. Obviously for fall and winter a 2.8 lens would come in quite handy (not to mention the Norah Jones concert I'm going to next month). I shot softball last Tuesday evening (in the pouring rain) and for much of the game had to shoot with flash since even at ISO 1600 on my D70 and highest f-stop shutter speed was only about 100.
So my question is in a similiar situation, how much higher a shutter speed could I expect to use with a fixed 2.8 lens?
TIA :-)
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Old Aug 30, 2004, 8:06 AM   #2
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murphyc wrote:
Quote:
I've been eyeing the Sigma 70-200 2.8 lens for a while, as a step up from my current Sigma Macro APO Zoom II (70-300, 4-5.6). During the summer the lens hasn't been too bad since useable light lasts pretty late into the evening. Obviously for fall and winter a 2.8 lens would come in quite handy (not to mention the Norah Jones concert I'm going to next month). I shot softball last Tuesday evening (in the pouring rain) and for much of the game had to shoot with flash since even at ISO 1600 on my D70 and highest f-stop shutter speed was only about 100.
So my question is in a similiar situation, how much higher a shutter speed could I expect to use with a fixed 2.8 lens?
TIA :-)

Given the same lighting conditions, the new lensat an f/2.8 aperture will give you shutter speeds twice as fast as your existing lens using an aperture of f/4.0 at the 70mm wide angle setting.

At the maximum zoom setting, the new lens at an f/2.8 aperture will give you shutter speeds 4 times as fast as your existing lens would using an aperture of f/5.6

However, your old lens may not have stopped down as far as f/5.6 at it's 200mm setting, which is the maximum focal length of the new lens you are looking at. So, your new lenswill probably be around 3 times as fast at 200mm.

The aperture scale (in one stop increments) goes F/1.4, F/2.0, F/2.8, F/4.0, F/5.6, F/8.0, F/11, F/16, F/22... With each one stop move to a smaller aperture (represented by larger f/stop numbers), you will need shutter speeds twice as long for proper exposure.

Here is achart you can use to get anidea of the shutter speeds required for any EV and Aperture (but make sure to use your camera's metering, as lighting can vary -- this is only to give you an idea of how it works). It's based on ISO 100. So, each time double the ISO speed, you can use shutter speeds twice as fast:

http://home.earthlink.net/~terryleed...tes/tables.htm

If you shoot in aperture priority mode, selecting the largest aperture (smallest f/stop value), then your camera can usethe fastest possible shutter speed for proper exposure for a given ISO speed setting in any given lighting condition

Also, keep in mind that a larger aperture will give you a shallower depth of field (less of the image in focus as you get further away from your focus point). Select your camera model and use this handy DOF calculator to see how aperture impacts it. Use the actual focal length of your lens (not the 35mm Equivalent Focal Length):

http://www.dofmaster.com/dofjs.html


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Old Aug 31, 2004, 12:04 AM   #3
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Thanks for the excellent reply and links, JimC. I certainly do appreciate it.
I guess it's about time to start counting pennies.
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Old Sep 15, 2004, 12:18 PM   #4
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I've been reading about some quality issues with this lens and incompatibility issues with the D70 some have been having (due to the chipping). Does anyone have personal experience with the Sigma 70-200, and is there any way of assuring you get one from a "good" batch as far as serial numbers?
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Old Sep 15, 2004, 1:09 PM   #5
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There's no compatibility problem with any EX lenses, especially the 70-200 f/2.8 EX which also has the HSM (ie Silence Wave equivalent in Nikon). This ultrasonic drive is both fast and silent and allows full-time overide of the camera's AF!
http://www.pbase.com/nhl/back_focus_tests

The re-chipping applied only to some older and non-ultrasonic lenses made before 2000, and only to Canon's mount (and were re-chipped for free BTW). Some snob"ish" folks tend to poopoo any Sigma to justify their higher purchase price of the OEM that's my opinion...

Check out the Sigma's macros for example, they are 2nd to none :-):-):-)
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Old Sep 15, 2004, 2:52 PM   #6
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The reason I ask is I've seen posts from D70 users at DP review saying their 70-200 EX HSM lens were having compatibility issues (i.e. locking up the camera) and these seemed to be new or at least very recent lenses. :?:
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Old Sep 15, 2004, 5:52 PM   #7
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FYI http://forum.pbase.com/viewtopic.php?p=30785

I've also seen many D70 as well as other Nikon user's pictures over here: http://www.pbase.com/cameras/sigma/70-200_28_ex_apo

But if you are skeptical, by all means pay extra for the Nikkor as assurance...
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