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Old Dec 24, 2007, 12:56 AM   #1
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I'm using my 70-210 (4-5.6) Sigma Manual Focus lens for my K100 that I used for my old K1000 back in 1992. I've been lucky that it still takes excellent photos and as far as I can tell there has been no purple fringing (I was kinda expecting that).

Anyway, the lens says its macro. It looks like however that it's macro when used at its max length. The thing is that I dont know exactly how to switch the lens to macro. It has no "switch" that I can see. I'd have to be at least 7ft away from my subject for it to come into focus. I'd figure that I'd be able to come in close for it to be considered macro. Am i missing something? I could use my Canon PowershotS3 up to 2 inches from the subject in its macro mode.

Thanks.

Merry Christmas Eve! :-)


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Old Dec 24, 2007, 3:35 AM   #2
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Hi,
Strictly speaking these lenses are not true macro lenses, at full zoom and nearest focus you'll probably get 1:4 at best ie. 1/4 lifesize. Occasionally you get one that gives 1:3. Ideally the macro range extends from 1:1 to 10:1, anything less is really just a close-up shot. Hope this helps ... Jack.
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Old Dec 24, 2007, 3:56 AM   #3
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Hi again,
You can make an estimate of the magnification you're getting ... set your camera to it's nearest focus distance, and shoot a picture of a millimetre ruler ... juggle the camera distance to subject by moving in and out until you have correct focus, and take the shot. The sensor in the K100D is known to be 23.5mm X 15.7mm , so if you get an image that is 23.5mm wide then you've got 1:1 anything wider is then in proportion to 23.5 divided by whatever width you see in your image ie. 1:4 = 23.5/94. ... Jack
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Old Dec 24, 2007, 10:14 AM   #4
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Ah, so Im gonna have to by a "true" macro lens. Ok, there are worse things.

Thanks for your help.
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Old Dec 24, 2007, 10:29 AM   #5
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JBoyde wrote:
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Ah, so Im gonna have to by a "true" macro lens. Ok, there are worse things.

Thanks for your help.
OK You're welcome, you could try adding dioptres, Screw in close up lenses that fit the filter ring to improve your magnification, and good results can be had that way, but the best way is obviously a dedicated macro lens. ... Jack.
Edit ... Just out of interest my avatar was done with dioptres on a point and shoot model.
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Old Dec 24, 2007, 10:57 AM   #6
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jachol wrote:
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JBoyde wrote:
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Ah, so Im gonna have to by a "true" macro lens. Ok, there are worse things.

Thanks for your help.
OK You're welcome, you could try adding dioptres, Screw in close up lenses that fit the filter ring to improve your magnification, and good results can be had that way, but the best way is obviously a dedicated macro lens. ... Jack.
Edit ... Just out of interest my avatar was done with dioptres on a point and shoot model.
A better bet is an achromatic filter such as a Sigma version which halfs the distance at which lens can close focus. They have a curved surface and give better image quality than add on close up filters which can introduce ca and distortion. You might find one on ebay were i got my 2 from.
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Old Mar 1, 2012, 12:35 AM   #7
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Default Macro Lens

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Originally Posted by jachol View Post
Hi,
Strictly speaking these lenses are not true macro lenses, at full zoom and nearest focus you'll probably get 1:4 at best ie. 1/4 lifesize. Occasionally you get one that gives 1:3. Ideally the macro range extends from 1:1 to 10:1, anything less is really just a close-up shot. Hope this helps ... Jack.
Hi I have a Nikon D5100 and am dying to get a Macro Lens but don't want to pay and arm and leg for it....and not sure which one to get....can you advice me on a good one? Thanks a bunch! God bless you!
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Old Mar 2, 2012, 3:21 AM   #8
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Hi I have a Nikon D5100 and am dying to get a Macro Lens but don't want to pay and arm and leg for it....and not sure which one to get....can you advice me on a good one? Thanks a bunch! God bless you!
Hi,
One of the cheapest you'll find is the Cosina 100mm/f3.5, it has rather cheap construction (plastic), but is capable of excellent very sharp results. there are two versions one manual focus, and the second auto ... most people prefer to use manual focus for macro work.
The lens on it's own give 1:2 shots (half life size), it comes with a matched dioptre close up that gives 1:1.
Rebadged versions exist under several different marks, Vivitar, Phoenix, Promaster, Soligor and voightlander.

There's a good review here. ...
http://www.dyxum.com/columns/article...cro_review.asp

Hope this helps. ... Jack
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