15-inch lens recommendations ?

[Ken Lee]

I already have a 300 and a 450, and would like to find a lens which is mid-way between them, for use with 5x7 and 4x5.

The midpoint is 375mm, or 14.7 inches.

I don't want a 355 or 360, and I don't want a portrait lens. The lens can be in shutter, or in barrel.

Thanks as always for your help !

[erie patsellis]

Ken, have you looked at the Apo Artars? I use both the 16 1/2" and 19" RD quite a bit lately.


erie

[Paul Fitzgerald]

Ken,

There are plenty of 14" or 16" but 15" is a bit limited:

381/5.6 (15") Tele- Optar
15" f/10 APO Raptar
375 /6.3 Ilex Paragon

Why the specific focal length?

[Ken Lee]

I already have a 300 and a 450, and would like to find a lens which is mid-way between them, for use with 5x7 and 4x5.

[Paul Fitzgerald]

Ken,

the 'angle of view' does not step off in a linear fashion, sorry but I don't have a formula for this. You could doodle it out on paper and see it if you wish.

[Oren Grad]

I already have a 300 and a 450, and would like to find a lens which is mid-way between them, for use with 5x7 and 4x5.

The midpoint is 375mm, or 14.7 inches.

I don't want a 355 or 360, and I don't want a portrait lens. The lens can be in shutter, or in barrel.

Thanks as always for your help !

If you want the angle of view to be halfway in between, and if this gentleman got his trigonometry right, the desired focal length will actually come out around 362.

Nothing wrong with going longer, of course, if you've tried 360 and it doesn't appeal...

[Ken Lee]

Aha ! You really gotta ask "them that knows" !

Wikepedia has a nice article which discusses the geometry entitled Angle of View.

So when choice of lenses is discussed, and people tell us that they like to space them out according to some ratio, like 150/300/450 or 120/240/360... those are nice numbers, but they aren't really linear in terms of coverage. They're linear in terms of focal length only.

To what extent does this matter ?

[Turner Reich]

Ken, you are looking for a 14" Kodak Commercial Ektar lens.

[Oren Grad]

To what extent does this matter ?

Not at all. Any trick that helps you find the lenses that best suit the way you see is fair game.

[neil poulsen]

I have a Wollensak 15 inch Raptar telephoto f5.6 single-coated lens. I believe the flange focal length is about 9 inches.

I haven't used this lens yet, but plan to. Check out the following link for more information.

http://www.largeformatphotography.in...ad.php?t=26489