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mosndup
23-Jan-2008, 08:09
I have here three lenses mounted on a Sinar plate, they have about the same functionalities.
Which one should I use for taking pictures on differents format 4x5, 5x7, 8x10.

Schneider Kreuznach Symmar S MC 5.6 240mm sn:14177306
Rodenstock Sironar-N 5.6 300mm MC sn:10802118
Rodenstock Sironar 6.8 360mm sn:9166831

Thanks.

Dan Fromm
23-Jan-2008, 08:33
You have the lenses, ask them. None of us has your lenses and our examples may not perform as well or badly as yours. Go to it!

By the way, since they all have different focal lengths, your lenses' angles of view differ and they don't have the same functionality. For example, the 240 is a .8 normal for 8x10, the 360 1.2 normal. And so on.

mosndup
23-Jan-2008, 08:36
You are right!

mosndup
23-Jan-2008, 12:48
You are right!

But the question I was trying to push here needs a little bit more data:

With these three lenses quoted

Schneider Kreuznach Symmar S MC 5.6 240mm sn:14177306
Rodenstock Sironar-N 5.6 300mm MC sn:10802118
Rodenstock Sironar 6.8 360mm sn:9166831

one can take the same picture if the subject is placed at 3 different distances from each lens. The three lenses above have about the same angle of view (72°) but a different circle of light. Do we get a better definition from an total image produced by a smaller focal or by the center of a larger one?

If this question asked by a newby (me) is not relevant, please excuse my ignorance, but tell me why.

Dan Fromm
23-Jan-2008, 13:08
You have the lenses. Ask them.

Ole Tjugen
23-Jan-2008, 13:35
... Do we get a better definition from an total image produced by a smaller focal or by the center of a larger one?...

Everything else being equal, the theoretical maximum resolution is higher with shorter focal lengths. But "everything else" is not equal, even if all three lenses were of the same make, age and focal length the individual differences would still be greater than the theoretical difference between a 240mm and a 360mm.

All three lenses will cover all three sizes. I have used all three focal lengths (but different lenses) on all three sizes myself, and the only reason I chose one over the other is to get the field of view I wanted.

The three lenses you name have similar construction, and the same angle of view. But they do not have the same field of view on any given format.