180mm + 50mm reversed: Magnification?

[scot079]

I'm toying w/ the idea of purchasing another MP-E 65 because it's just so fun!:-) However in the interest of saving about $800 (!) I might try to reverse a 50mm on my 180mm macro lens.

My main question is what is the magnification of a 1:1 180mm macro lens + reversed 50mm? Secondly, do the experts think this will give me image quality on par w/ the MP-E 65mm at same magnification?

[LordV]

You should get a max magnification of 4.6:1. Not sure about IQ - shouldn't be amazingly different to the MPE-65. I didn't notice a huge jump in IQ from my sigma 105 + ext tubes + reversed 50mm when I changed to MPE-65. The MPE-65 is just a whole lot more conveniant to use esp as you have a smooth "zoom" from 1:1 to 5:1

Brian v.

[scot079]

Thanks for the reply Brian. 4.6:1? Wow that's pretty crazy! Is there a way to get less say around 3:1 w/ a different focal length lens reversed? Thanks :-)

[LordV]

Thanks for the reply Brian. 4.6:1? Wow that's pretty crazy! Is there a way to get less say around 3:1 w/ a different focal length lens reversed? Thanks :-)

Tim - the formula for mag for a reversed lens on another

M= Existing Mag + (focal length main lens/focal length reversed lens)

So in your case you would need a 90mm lens reversed

ie M = 1+ 180/90 for 3:1.
I suspect this would get a bit unwieldy to use in practice.

You may be better off thinking about an add on dioptre (filter lens) but you would need around +10 for 3:1 or a combo of TC and Dioptre
eg a 1.4X TC and a canon 500D diopter would give you around 2:1.
Brian V.

[scot079]

You're awesome Brian. Thanks for the formula, I couldn't find it to save my life. :-)

A 90mm lens on the end would make the whole rig unmanageable...it's already front heavy anyhow. I'll take a look at the TC/diopter solution. Thanks again:-)