150mm APO Sironar W -- Wow!

[Kerry L. Thalmann]

" it doesn't cover 5x7 at all. That's the one area where the 150mm APO Sironar-W is "superior" to the smaller, lighter, less expensive 135mm APO Sironar-N."

The Apo Sironar N 150mm most certainly does cover 5x7. The factory specifies it as covering a 214mm circle which just allows 3mm and 2mm of shift on 5x7.

Bob,

If you read what I actually wrote, you'll notice I specifically said the 135mm APO Sironar-N doesn't cover 5x7. I never mentioned the 150mm APO Sironar-N.

The Apo Sironar S 150mm that replaced the W covers a 231mm circle which allows for 17mm of rise and 13mm of shift on 5x7 in a relatively small and light lens.

The Apo Sironar/Apo Sironar W 150mm covered a 252mm circle allowing for 33mm of rise and 26mm of shift.

Which is exactly what I wrote above when I stated: "The extra fve degrees of coverage provided twice as much front rise on 5x7 as the 150mm APO Sironar-S I had been using."

While the 150mm APO Sironar-N technically covers 5x7, if you want to use movements forget it. 2 - 3mm of front rise is insignificant. Even the 13-17mm of front rise provided by the 150mm APO Sironar-S, as I stated above, was insufficient for my needs on 5x7.

Finally, the 150mm APO Sironmar-S did not replace the 150mm APO Sironar-W. Both lenses coexisited for 5 - 6 years. Perhaps slow sales of the 150mm APO Sironar-W compared to the more popular 150mm APO Sironar-S lead to the eventual discontinuation of the 150mm APO Sironar-W, but it was not replaced by the 150mm APO Sironar-S.

Kerry