More on lens reversing

[erb_duchenne]

I understand that when a 50mm lens is reversed on a 100mm I'll get 2x

magnification. But what does 2x mean? Is it 2 x 'life-size?' (2:1)?

Does it also mean that if I reversed a 50mm onto a 50mm I'd get 'life-

size?'

 

For the reversed 50mm lens, would there be a difference if I used a

50mm f/2.5macro or 50mm f/1.4? Is the difference significant and

which would be the better one?

 

How would a 14mm reversed on a 28mm fare? (probably nobody has tried

it, but wondering what the difference is as this config is also 2x

but both are wide-angles.)

 

Currently my only 50mm is the f/2.5macro and I'm wondering if it's

actually worth getting yet another 50mm to add to my gear.

[jackflesher]

"I understand that when a 50mm lens is reversed on a 100mm I'll get 2x magnification. But what does 2x mean? Is it 2 x 'life-size?' (2:1)? Does it also mean that if I reversed a 50mm onto a 50mm I'd get 'life- size?' "

 

YES.

 

"For the reversed 50mm lens, would there be a difference if I used a 50mm f/2.5macro or 50mm f/1.4? Is the difference significant and which would be the better one?"

 

The ratio will still be 1:1, but the WIDER the aperture on the REVERSED lens, the LESS chance for vignetting.

 

"How would a 14mm reversed on a 28mm fare? (probably nobody has tried it, but wondering what the difference is as this config is also 2x but both are wide-angles.)"

 

Probably not too well as reversed wides tend to vignette more than normal lenses and the wider the main lens the more the chance for vignetting. My guess is you'd end up with a tiny circular image on sensor/film.

 

 

"Currently my only 50mm is the f/2.5macro and I'm wondering if it's actually worth getting yet another 50mm to add to my gear. "

 

Sure it is worth a try as there are many cheap, used 50's available. But IMO a tube behind your current macro is a MUCH better alternative, and I think you can buy an entire set of Kenko tubes pretty cheaply -- probably not too different than what another 50 would cost.

 

Cheers,

 

Jack