Photoclubalpha

When you reverse this lens, do you get 1: to 1: macro or not? Also, has anybody else tried the lens cap trick to control aperture with the reversed lens? I've put one together but I'm still expiermenting with it. Thanks.

-----Nod----- wrote:When you reverse this lens, do you get 1: to 1: macro or not?

Huh!? What is "1: to 1: macro" supposed to mean?

Anyway—when a lens is designed for subject distances that are longer than the lens-to-image distance then reversing it means optimising it for the use at subject distances that are shorter than the lens-to-image distance. The turning point is the magnification of 1:1, or 1.0×. Here, subject-to-lens distance is always equal to lens-to-image distance. At smaller magnifications, the subject-to-lens distance is longer. At greater magnifications, the lens-to-image distance is longer. The front element of most lenses should always face the longer of the two distances for best image quality. So at magnifications greater than 1:1, you'd reverse them. As simple as that.

In reversed mode, non-AF lenses are easier to use. Get an old MC or MD Rokkor 50 mm, or M42 lens, or whatever for a couple of bucks from eBay ... the kind of lens mount doesn't matter. Or better yet, get an enlarger lens because these are optimised for short distances. For yet greater magnifications, use a wide-angle lens in reversed mode.

Thanks for the info 01af. 1:1 was what I meant.

-----Nod----- wrote:1:1 was what I meant.

I see. So if the particular magnification of 1:1 is what you're interested in then you need the right amount of extension. For a 50 mm lens in normal mode, that will always be 50 mm. In reversed mode, it formally will be 50 mm, too, but the actual length of the extension tubes (or bellows unit) required may be slightly longer or shorter according to the lens' physical length and asymmetry of the design.

To arrive at 1:1 magnification with a regular 50 mm standard lens, you may also combine a close-up lens and extension tubes. This way, you'd need less extension (say, 30 mm rather than 50 mm, depending on the strength of the close-up lens), and you'd get better image quality. Achromatic (i. e. double-element) close-up lenses yield better image quality than simple (single-element) ones.

At 1:1 exactly, it doesn't matter whether the lens is reversed or not, so I'd recommend not to reverse it so it will be easier to use. Remember—reversing the lens is recommended above 1:1 only, not at 1:1.

01af wrote: In reversed mode, non-AF lenses are easier to use. Get an old MC or MD Rokkor 50 mm, or M42 lens, or whatever for a couple of bucks from eBay ... the kind of lens mount doesn't matter. Or better yet, get an enlarger lens because these are optimised for short distances. For yet greater magnifications, use a wide-angle lens in reversed mode.

Why are they easier to use reversed rather than mounted normally on say 50mm tube combination?

artington wrote:

01af wrote:In reversed mode, non-AF lenses are easier to use. [...]

Why are they easier to use reversed rather than mounted normally on say 50 mm tube combination?

Of course, they aren't.

Reversed non-AF lenses are easier to use than reversed AF lenses.