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07-18-2010, 02:19 PM   #1
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Magnification Question: Reversed 50mm vs. Raynox 250

I have a DFA100/2.8 WR macro, and I've also got a Raynox 150. I've read that the 150 won't add much to the DFA100's magnification and that a Raynox 250 should be used in this case. But I also have an FA50/1.4, and I'm wondering how the magnification of the 50mm reversed (via macro coupler) on the front of the DFA100 would compare to the Raynox 250.

Would the magnification of the DFA100 with the reversed 50mm be greater than with the Raynox 250? Would the reversed 50mm affect the effective aperture? As I understand it, only rear adapters affect aperture.

Also, is the reversed 50mm likely to yield better IQ than the Raynox 250?

TIA!

07-18-2010, 03:10 PM - 1 Like   #2
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QuoteOriginally posted by twokatmew Quote
I have a DFA100/2.8 WR macro, and I've also got a Raynox 150. I've read that the 150 won't add much to the DFA100's magnification and that a Raynox 250 should be used in this case. But I also have an FA50/1.4, and I'm wondering how the magnification of the 50mm reversed (via macro coupler) on the front of the DFA100 would compare to the Raynox 250.

Would the magnification of the DFA100 with the reversed 50mm be greater than with the Raynox 250? Would the reversed 50mm affect the effective aperture? As I understand it, only rear adapters affect aperture.

Also, is the reversed 50mm likely to yield better IQ than the Raynox 250?

TIA!
The focal length of the Raynox 250 is 125mm.

Magnification of stacked lenses (with primary lens focused at infinity) is:

m= primary_lens_focal_length/stacked_lens_focal_length

For the Raynox on the 100, m=100/125=0.8x
For the 50 on the 100, m=100/50=2.0x

2x is an awfully strong minimum magnification & you may well be happier with the Raynox; it'll almost double the maximum magnification you get with the bare 100mm macro lens.
07-18-2010, 04:15 PM   #3
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Thank you!

How did you determine the focal length of the DCR-250? I don't see it in the specs anywhere. And what's the focal length of the DCR-150? Is there really no point in using the 150 with my 100mm macro, or is that a matter of opinion?

Edit:

Hmm, I just found some notes I'd taken previously that the focal length of the Raynox 150 is ~208mm, which means the magnification of the 150 on my 100mm macro is 0.48x. Seems to me that an additional almost 50% magnification is not insignificant. I guess I'll give the 150 a try before springing for the 250. Thanks!

Last edited by twokatmew; 07-18-2010 at 04:22 PM.
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