40mm w/extension tubes - fun @ the dinner table

40mm w/extension tubes - fun @ the dinner table · 05:26 PM

It certainly isn't as easy as working with a dedicated macro lens - but hey, I don't have the money for that right now.

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taken with the DA40 with 72mm worth of extension tubes. woot!
C&C always welcome.

khardur · 11-28-2007, 02:17 PM

Tingchaleun:
you do lose stops of light with extension tubes - I saw a formula once, a long time ago. I believe you probably lose a little IQ as well, but my bet would be if you compared a teleconverter to adding an extension tube, IQ would be better using the extension tubes. #1 you're shooting through less air - with a teleconverter you're minimum focus distance is still the same. and #2 the extension tube adds no layers of glass in between the lens and the sensor.

as for #2, I don't know. I'm not well versed in optics, other than how to use them, but the specifics of the light paths and stuff like that - well that's not me. Someone else I'm sure knows the answer though.

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11-28-2007, 02:17 PM	#16
khardur Veteran Member Join Date: Feb 2007 Location: NW Massachusetts Photos: Gallery Posts: 1,560 Original Poster	Tingchaleun: you do lose stops of light with extension tubes - I saw a formula once, a long time ago. I believe you probably lose a little IQ as well, but my bet would be if you compared a teleconverter to adding an extension tube, IQ would be better using the extension tubes. #1 you're shooting through less air - with a teleconverter you're minimum focus distance is still the same. and #2 the extension tube adds no layers of glass in between the lens and the sensor. as for #2, I don't know. I'm not well versed in optics, other than how to use them, but the specifics of the light paths and stuff like that - well that's not me. Someone else I'm sure knows the answer though.