Quote Originally Posted by Claire Senft
I agree that an enlarging lens is just like a camera lens. They are just designed to work at different magnification ratios.
Uh ... well I don't know if Magnification range would be the "best" way to describe what happens ... but .. OK. The more prominent difference is that between a "Capture" lens, and a "Projection" lens.

It is NOT my opinion that enlarging lenses that work well in the 4-5.6 range are poor at all other stops. In fact some of them work fairly nicely wide open.
I didn't take it that way, or did I say that either. I replied to the idea of a lens (of that approximate focal length) being "Diffraction Limited" at so large an aperture. I did "side comment" that some here are overly sensitive to enlarging lens "errors" - more than they are about camera lenses.

I would also imagine that many photographers that work with glassless carrriers may, when there is a goodly amount of detail at the edges and corners may prefer an aperture of at least f8. I neither fault no criticize anyone for whatever methodology they want to use.
How much difference f4, for instance, there is with f8, for the second instance, is going to also depend on other factors. How much details is in the negative, how well is the enlarger aligned, what is the light source, how big is the resulting print are some of the factors involved.
Agreed.

It is worth remembering that with an 8x magnification that the effective f stop is f 36 if the lens is set at f4.
Woof!! You just lost me. The f/stop is defined as the ratio of (I'll grind fine here) the aperture-to-film distance divided by the aperture diameter: f/stop = f/d. The magnification ratio has nothing to do with it directly. There are tables that indicate the "effective aperture" change from "marked" apertures (at infinity) due to the increase in aperture-to-film distance in close-up photography; using magnfication as a result of focal distance, but they are calculated on the original "f/d". I don't think that is as simple as "magnification ratio times marked f/stop."

So ... ???