Bronica lens test results

[Greg Erker <erker@xxxxxxxxxxxxxx>]

  I did some test shots with my new Bronica
80mm f2.4 lens vs my old Nikkor-P 75mm f2.8
vs the Tominon 127mm f4.7 lens. I used some
out of date 400 speed fuji negative film.

  The first six shots were maximum bellows
extension macros (~80mm ext.) of the back
side of a 25 cent Canadian Tire Money bill.
(For those in the US they are coupons/money
that you can spend at the CT hardware store.
They are really nicely engraved just like real
money plus the 25 cent one is purple so the
engraved lines are fairly high contrast relative
to the white paper.)

  I took two shots with each lens: Bron and Nik
at f4 and f5.6 marks (=~f8 and f11 actual). And
the Tominon at f4.7 and f6.8.

  At f4 the Bron and Nik were both very sharp
in the centers but soft at the corners. The Nikkor
was slightly better. At f5.6 they both improved
at the edges but still not super sharp. In real
world shooting at f11 or smaller both would likely
be excellent.

  The Tominon didn't give as much magnification
but center and edges were sharp at both apertures.
Definitely the winner for flat field shooting.

---

  With the second half of the roll I took some
star photos. The Bronica and Nikkor were shot
wide open (2.4/2.8) and at f4.  Again both were
good in the center. I didn't have bright enough
stars to judge the corners really well but the
the Nikkor was slightly better wide open. At f4
both appeared equal. Had I taken a shot with the
Bronica at f2.8 I suspect it would match the Nikkor
at f2.8.

  The wide open Tominon shot was a bit soft in
the center. I suspect my homemade spacer ring
(that is supposed to space the lens out to give
infinity focus when the focusing mount is at inf)
is not quite the right thickness. The shot at f6.8
was sharp center and corner, though again, I didn't
have any really bright stars in the corner.

---

  I had been hoping that the extra element in
the Bronica lens would make it better for flat
field macro shooting, but it looks like I have
the Tominon for that.

Greg