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Lens equivilents, a different perspective?
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RichS
Joined: 18 Oct 2001
Posts: 1468
PostPosted: Fri Mar 01, 2002 6:17 am

Okay, it's late at night and my mind has wandered (and wondered).
I've been trying to figure out a way to duplicate the lens coverage I have in 35mm with my 4x5. A 500mm tele is as close as I've been able to think of (but not afford) so far on the tele range for the 4x5. Then I wandered (and wondered) about true differences. The 35 is 24x36mm and the 4x5 is 101x127 (roughly). Close to a 3.5:1 ratio. Now if I can explain this so somone else can uderstand it...
If I use a 380mm lens on the 4x5 (my longest lens), shoot a neg and crop out a 24x36mm section. Wouldn't that be the same as using a 1340mm lens on the 35mm? If I use tri-x in both wouldn't the resolution be pretty much the same? If I was happy with the 35mm neg, wouldn't the cropped section of 4x5 be just about the same? Am I searching for a long lens for nothing? (discounting the benefits of LF). Am I making sense or way off the mark? I'll re-think this tomorrow, but for now it sounded interesting to me and I never heard anyone do a comparison like this before. Right now it makes my 380mm lens seem a whole lot better :wink:
Les
Joined: 09 May 2001
Posts: 2682
PostPosted: Fri Mar 01, 2002 12:54 pm

everyting sounds good until you get to the resolution part.

I don't know why, but my gut reaction says that an 8x enlargement from a shot taken with say a 1400mm non-cat Nikkor or Minolta will blow the pants off a cropped 8x enlargement from a 380mm Wollensak telephoto. You might not see it as much with Tri-X but you would with Tech Pan or Tmax.
RichS
Joined: 18 Oct 2001
Posts: 1468
PostPosted: Fri Mar 01, 2002 5:53 pm

To tell the truth, I really thought the other way around. I figured any tele that long in 35mm wouldn't be that good and it would be stretched all the way to the edges of it's coverage. Even though the 380 is a wollensak (or optar), it's much simpler in design (good or bad?) and would be operating in a very small section of it's center of coverage. So I thought the cropped 380 might actually be sharper?
True about tri-x. I used it only as an example because it was my favorite B&W in 35mm. I did plus-x in 120 and some 35. Haven't yet made up my mind in 4x5...
I'm going to have to give this a test as close as I can. I can only get to 500mm in 35 (unless I want to use an extender) and that would be pretty close to a 150mm on 4x5 cropped. But I'd have to use comparable films. Then there's the question of comparable lenses... Although in that category "comparable" means what I can afford :wink:
45PSS
Joined: 28 Sep 2001
Posts: 4081
PostPosted: Sat Mar 02, 2002 2:36 am



<font size=-1>[ This Message was edited by: 45PSS on 2005-12-24 20:15 ]</font>
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