Macro Teleconverter questions

bogiesbad · 12-12-2009, 06:24 PM

I have a Vivitar 2x Macro TC and a Panagor 3x Macro TC.

1) Does the TC value increase the minimum focus distance? Would a 50mm w/2x TC achieve the same magnification at the same distance as a 100mm macro?

2) Does the 2 or 3 stop reduction of light count as stopping down the aperture with regards to a lens' "sweet spot"?

I have not had much time to work with these TC's but I really like the results I have gotten thus far. I have read some good discussions concerning macro solutions but few mentions of TC's. They might be inferior to other methods but I found these two to be well worth the small price paid.

newarts · 12-13-2009, 01:58 AM

Originally posted by bogiesbad

I have a Vivitar 2x Macro TC and a Panagor 3x Macro TC.

1) Does the TC value increase the minimum focus distance? Would a 50mm w/2x TC achieve the same magnification at the same distance as a 100mm macro?

Yes, if you mean distance from the lens.

Quote:

2) Does the 2 or 3 stop reduction of light count as stopping down the aperture with regards to a lens' "sweet spot"?

Yes in principle, but the image may be degraded by the TC (at least the diffraction disk's diameter is also multiplied by the TC; depending on the sensor resolution this may shift the sweet spot to a wider aperture.)

Dave in Iowa

bogiesbad · 12-13-2009, 06:26 AM

Thank you Dave.

12-12-2009, 06:24 PM	#1
bogiesbad Veteran Member Join Date: Dec 2008 Location: Lower AL Photos: Albums Posts: 355	Macro Teleconverter questions I have a Vivitar 2x Macro TC and a Panagor 3x Macro TC. 1) Does the TC value increase the minimum focus distance? Would a 50mm w/2x TC achieve the same magnification at the same distance as a 100mm macro? 2) Does the 2 or 3 stop reduction of light count as stopping down the aperture with regards to a lens' "sweet spot"? I have not had much time to work with these TC's but I really like the results I have gotten thus far. I have read some good discussions concerning macro solutions but few mentions of TC's. They might be inferior to other methods but I found these two to be well worth the small price paid.

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12-13-2009, 01:58 AM	#2
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	Originally posted by bogiesbad I have a Vivitar 2x Macro TC and a Panagor 3x Macro TC. 1) Does the TC value increase the minimum focus distance? Would a 50mm w/2x TC achieve the same magnification at the same distance as a 100mm macro? Yes, if you mean distance from the lens. Quote: 2) Does the 2 or 3 stop reduction of light count as stopping down the aperture with regards to a lens' "sweet spot"? Yes in principle, but the image may be degraded by the TC (at least the diffraction disk's diameter is also multiplied by the TC; depending on the sensor resolution this may shift the sweet spot to a wider aperture.) Dave in Iowa

12-13-2009, 06:26 AM	#3
bogiesbad Veteran Member Join Date: Dec 2008 Location: Lower AL Photos: Albums Posts: 355 Original Poster	Thank you Dave.