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09-21-2010, 11:33 AM   #1
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Sigma 105mm EX DG

I have just purchased a Sigma 105mm EX DG lens to fit on my K20D
Can anyone give me a few tips with focusing at 1:1
and general macro tips

Thanks Gary

09-21-2010, 11:40 AM   #2
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Usually manual focusing is easier at 1:1, at least in my experience. A tripod is always a good idea, but i would be lying if I said I always use one. I rarely do, but getting sharp photos at such high magnifications can be tough and will take a lot of practice. That is a great lens and I am certain you will love it. Congrats on the new lens!!
09-21-2010, 11:48 AM   #3
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QuoteOriginally posted by Ducatigaz Quote
I have just purchased a Sigma 105mm EX DG lens to fit on my K20D
Can anyone give me a few tips with focusing at 1:1
and general macro tips

Thanks Gary
incase you don't already know... choose the magnification for the subject and move yourself/the camera back and forth to focus.
09-21-2010, 11:55 AM   #4
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Ha. It's funny you mention that. That is usually my problem when using my macro lens. I am moving back and forth too much.

QuoteOriginally posted by yeatzee Quote
incase you don't already know... choose the magnification for the subject and move yourself/the camera back and forth to focus.


09-21-2010, 12:08 PM   #5
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Original Poster
If I place a Sigma 1.4x convertor behind the lens what will be the effect, ie bigger than 1:1
or just a longer focal length?
09-21-2010, 12:38 PM   #6
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You would get a scratched rear element - the Sigma 1.4 converter won't fit the 105 EX DG - the rear lens element isn't recessed far enough (the front element on the converter protrudes) - I've got both and have just checked.
09-21-2010, 12:53 PM   #7
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I think the best way to get good macro images is to use MF mode and serial shooting.

basically you start continuous shooting and while it's taking images, slowly either move the lens to/from the subject (so it'd be in focus) or turn focus ring over possible excellent focus range.

latter is useful if you're using tripod since you can't move the camera.

this is useful since you can't tell if it's in focus from the viewfinder (well at least I can't). Also the shaking might interfere with perfect shot so you need to take a few dozen of chances to get a single good shot.

also make sure that aperture is small enough, since DoF will be less than millimetre if you set max aperture in macro mode. also you need very fast shutter speed to avoid movement blur. so as you see, you will need a lot of light for this. It's still doable if it's a sunny day and the subject is not in the shadow,

But otherwise you will probably need some kind of artificial light... which is a problem since if you mount a flash onto the camera's hot shoe then the lens will probably cover the subject from flash .. so you will need an external flash... but i myself don't know if there are any cheap solutions for this (which would also shoot for each of the continuous shots). I'd appreciate suggestions though.
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