Quote Originally Posted by puketronic View Post
And if it matters this is a DR Summicron and a Contax RF Sonnar (not the new ZM one).
It does rather the abberations and the contrast are different.

The abberations for the contax lens would differ between the pre WWII, post WWII and late production CZ Contax lens, as the glass catalogue has new glass and withdrawn glass(, for quarantine). The later lenses would be better off axis, a little or a lot depending on the glasses selected for the recomputations.

But if you are not using Pan F on a clamp, set into a 1m block of concrete you might not detect any difference other than at wide apertures.

The Contax lens will be lower contrast then the ZM cause of the multi coating (if you were using colour the mid tones and shadows would be more pastelled) in mono the contrast will be lower cause the shadows will be filled in. The pastel and the fill in are dependent on the contrast of the sceane, a high contrast sceane has most compensation.

The Summicron double Gauss style design offers more degrees of freedom for correction and was computed of a 56-57 glass catalogue, so is very well corrected, (by comparison) but it has more air to glass surfaces (compared to the CZ triplet), so is lower contrast, more pastel and more shadow fill in.

The adaptive contrast is not a big secret Cosina offered the 40mm /1.4 M lens in single or multi coated and did a short run of the SC (as they thought) for the Ja home market (mnochrome people) , the short run was snapped up so they made lots of batches in SC and later also offered the 35mm /1.4 in SC and MC...

I normally do a day shoot from large GBag three or four bodies with three of four lenses, cause I can only carry one set, all the lenses either SC or MC dependent on the weather forcast ikons for sunny or overcast, note MC for overcast. The SC lenses are from 60s. the MC from this decade, the abberation (correction) differences are irrelevant cause I am shooting quickly and get a lot of blurrr...

Keep the most ergonomic oldster bye a modern one.