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06-13-2019, 01:10 PM   #1
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Teleconverter on macro lens

If I put a 2x tele converter behind my 105mm 1:1 macro lens what ratios would I be getting.

06-13-2019, 01:49 PM - 2 Likes   #2
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You'll get 2:1 when the lens is set to 1:1. It will also double the numerical value of the aperture so the image will be much darker and have more diffraction.

If you add extension tubes, adding them BETWEEN the teleconvertor and macro lens will have the biggest effect on magnification.

Last edited by photoptimist; 06-13-2019 at 02:38 PM. Reason: typos
06-13-2019, 03:11 PM - 2 Likes   #3
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QuoteOriginally posted by photoptimist Quote
also double the numerical value of the aperture
and bear in mind that at 1:1 your ?f2.8 macro lens is already has an effective f-stop close to f5.6 (see here). So add on a 2x tc and that makes near f11, before any stopping down !
06-13-2019, 03:53 PM   #4
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QuoteOriginally posted by photoptimist Quote
If you add extension tubes, adding them BETWEEN the teleconvertor and macro lens will have the biggest effect on magnification.
Fascinating! I did not know that.

06-13-2019, 04:06 PM - 4 Likes   #5
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I've used the Vivitar 2X Macro Focusing Teleconverter (V2XMFTC) on my Sigma 70mm f2.8 macro for higher magnification. It does get darker, though the actual degree of darkening was difficult for me to judge as I was shooting at night!



It combines a two times teleconverter with helicoid extension. I believe this shot might have had extension as well as the converter in play.

Last edited by Thagomizer; 06-13-2019 at 04:46 PM. Reason: Added information
06-13-2019, 11:48 PM   #6
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All I can say is the HD 1.4x works well with the D-FA 100 macro WR, with no loss of sharpness stopped down a stop or two.
06-14-2019, 04:34 AM   #7
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I'm not concerned about the loss of light as I use a flash for macro anyway. I always shoot manual using f16-f22 to maximize DOF. I adjust the light on my Sunpak DX-8R as needed. Thanks for the tip using the extension tube, I would not have thought about putting it in between the lenses.
06-14-2019, 07:48 AM   #8
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I'm assuming the working distance stays the same with just the 2x converter attached, correct? I know it changes if I use a extension tube.

06-14-2019, 10:48 AM   #9
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QuoteOriginally posted by bluestringer Quote
I'm assuming the working distance stays the same with just the 2x converter attached, correct? I know it changes if I use a extension tube.
Correct. The distance from the front of the lens to the subject does not change when adding a teleconvertor. The front lens stays put, the teleconvertor gets added to the back, and the camera goes on the back of that. Obviously, that does mean moving the tripod or yourself back by a distance equal to the thickness of the teleconvertor. You'll get 2:1 magnification with the convertor with the same working distance as 1:1 mag had without the 2X.

Or you can use the teleconvertor to get 1:1 with a longer working distance -- just set the lens to 1:2 (half of 1:1) and then add the teleconvertor.
09-12-2019, 08:23 AM   #10
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QuoteOriginally posted by marcusBMG Quote
and bear in mind that at 1:1 your ?f2.8 macro lens is already has an effective f-stop close to f5.6 (see here). So add on a 2x tc and that makes near f11, before any stopping down !
I was skeptical about that so I did a quick check. It appears to be reasonably accurate in terms of exposure values. Checked against grey siding.
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