differences between enlarging lenses and camera lenses?

[Daniel Otranto]

Im building an 8x10 enlarger so I can make 16x20s and im trying to figure out how long of a lens to buy for the enlarger...is it possible to tell if the lens I use on my camera (nikkor 300mm 5.6) would cover enough to make 16x20s? And is there something special that makes an enlarging lens a enlarging lens or are they both applicable for using on an enlarger?

[MJSfoto1956]

enlarger lenses are optimized for approx 4:1 to 10:1 reproduction ratio. So a 4x5 "enlarged" to 16x20 to 40x50 is the sweet spot for such a lens. Macro lenses such as the Schneider Makro series are optimized for 2:1 to 1:2 ratio. Thus an 8x10 using such a lens would be in the sweet spot from 4x5 to 16x20 "enlargements".

Ordinary field lenses are optimized for focus at infinitiy. As such they are not optimal for enlargement purposes (although they *can* be used with very good results -- just not "optimal")

Make sense?

J Michael Sullivan

[Ernest Purdum]

A lens that will cover 8X10 on a camera should also be usable to enlarge 8X10 negatives,

Process lenses, despite their small apertures, do fairly well in enlarging use. Right now they are going at very low prices on eBay (frequently hiding in the enlarging category). The lesser known ones, AGFA for example, can be particularly inexpensive.

There is no reason not to try out your Nikkor, but it would be more convenient to have a dedicated lens on your enlarger.

[Jeff Scott]

IIRC, enlarging lenses (EL) are flat field where most taking lenses are not, and I believe ELs have higher resolution.

[ronald moravec]

There are two issues. One is you need a flat field lens and field lenses are not generally. Without flat field, you will not be able to fovus on the center and edges of the neg at the same time. Secondly the lens should be corrected for close work, not landscape work.

A 300 f9 Nikor will work as it is macro lens, not your 5.6.

Your 5.6 will cover the negative, but not provide optimum reproduction.

[robc]

making a print in an enlarger is the exact same as taking a macro image of a subject. In your case, the negative is the subject and the print is the object image.
The subject is 1 and the object will twice as big so you want a 1:2 macro lens. If you don't have a dedicated enlarging lens for this a suitable camera taking macro lens would suffice. i.e. one which is optimised for 1:2 or thereabouts. That would be one which covers 16x20 at a taking distance of half its focal length(I think).