View Full Version : Dumb question - crown graphic 2 lenses

5-Mar-2011, 00:11
:o My Crown Graphic Special came with 2 lenses, a Xenar 100mm and a Xenar 135mm. There are two rear elements. One seems a bit more zoomed in. How do I know which front element goes with which rear element?


Brian C. Miller
5-Mar-2011, 01:05
If the lenses focus correctly, then the elements are paired correctly. If not, swap the rear elements.

5-Mar-2011, 02:29
You might get some interesting effects by swapping them

5-Mar-2011, 02:53
Well all combos seem to focus fine that is why I am confused. One set focuses closest at 5". The other combinations focus further.

Jack Dahlgren
5-Mar-2011, 08:00
5 inches is about 100mm so that would seem to correspond to the 100mm lens. The 135 should focus at a bit over 6 inches.

John Koehrer
5-Mar-2011, 10:34
25.4mm = 1"
100/25.4 = 3.93"
135/25.4 = 5.31"
at infinity

19-Mar-2011, 01:07
Hmmm......would the 'wrong' combo vignette incredibly bad at infinity? :D

Jack Dahlgren
19-Mar-2011, 02:06
The 100mm xenar is a lens for 6cm x 9cm format. It would vignette badly at infinity on a 4x5. If that is what you are seeing it is likely the "right" combo.

19-Mar-2011, 02:15
Well I had the 135mm front element on with what I had previously thought was the correct rear element. The corners on the negative are nonexistent. And the fov is much wider than I would expect the 135 to be. I can see the rails of the camera O_o. I'll get a scan up.

Disregard crappy photo:

I guess I wasn't at infinity either....

Dan Fromm
19-Mar-2011, 05:51
large with large, small with small