Confused about 300mm lens vs. 150mm lens

[Kelli]

Hello everyone,

I am just starting out in LF, and I am trying to determine which focal length lens is right for me. I know this much: 150mm lens are standard for LF and that a normal lens for LF has more focusing flexibility than a camera with a static back.

I have found a used camera that I like, but it comes with a 300mm lens...which leads me to my question: So what is the defining characteristic of a 300mm lens? What is it most often used for? How close and far away can I move from my subject and still be able to get things in focus? What can't you do with a 300mm lens? I really just do not understand the significance of the lens measurement...

Any insight will be greatly appreciated!! Thank you very much for your time. Bye, Kelli

[Donald Brewster]

Well it depends. What is the size of the camera? 150mm is in the "standard" range for a 4x5 camera, and 300mm is in the "standard" range for an 8x10 camera, roughly comparable to a 50mm lens on a 35mm camera. 300mm could be used as a portrait lens for a 4x5 camera. The other parameters you seek differs among lenses based upon their design. You need to be more specific with the size of the camera and the name of the lens.

[Nick Morris]

Hello Kelli;

The 150mm lens is generally though of as a normal lens for a 4x5 camera (like the 50mm lens for a 35mm camera), though 135mm to 200mm can function in that capacity. The normal focal length for a camera lens is a function of its relationship to the film size. You do not give the film size of the camera. Is it a 4x5, 5x7, 8x10, or one of a number of other film sizes? A 300mm lens is though of as a normal lens for the 8x10 film size, but like the 150mm for 4x5, there is a range of focal lengths that can function as normal. Typical with the LF camera, focus is made by adjusting the bellows: extending the bellows for close focusing and compressing the bellows for distance. Important aspects of focal length are angle of view and perspective. A longer focal length will narrow the field of view and extend the sense of depth; a shorter focal length will widen the field of view and compress the sense of depth; the normal focal length will more reflect the field of view and depth perspective of human vision. I think you would find a book covering the basics of LF equipment and use very helpful. Steve Simmons and Jim Stone have both written good introductory texts about LF equipment and use.

[Tim Curry]

Kelli, If you go to the Schneider site, they have a good list of large format lenses and tables showing depth of field. These should give you an idea of what the trade offs are with respect to field of view, depth of field, format size and practical applications. Whatever lens you are most familiar with in 35mm would be a logical place to start in large format. Start with the basics and go from there. Good luck.

[Kelli]

Hello again-

Thanks for all the replies! I will definitely check out the sites suggested. To be more specific- I plan on using 4x5 film and the 300mm lens in question is a Scneider.

-Kelli

[Ralph Barker]

Unless the 300mm lens is a telephoto design, Kelli, I think you'd find it inconvenient for most 4x5 applications. A conventional 300mm lens requires 300mm of bellows extension to focus at infinity, and even more bellows extension for closer work. Depending on the design of the camera (monorail vs. "field"), it may not have sufficient bellows extension to make the 300mm lens practical. Using front focus, there's also a point that one simply runs out of arm. ;-)

[Jim Galli]

Good answers all and I will try to over simplify. If you use a 35mm camera and never find a need for anything but an 85mm lens, Then your way of seeing might translate very well to 4X5 with a 300mm. If however you like a 35-70mm lens and find yourself between 35 and 50 somewhere for a lot of your shooting, that translates to a 150mm lens on a 4X5. If you are comfortable between 50 and 70 on that 35-70 zoom, you might enjoy a 4X5 with a 210 mm lens. For a conversion from 35mm thinking to 4X5, use 3.3. So a 50mm lens on 35mm system times 3.3 = about a 165mm lens on a 4X5 system. There's no right answer except to try to translate what you enjoy the most on a small camera to the bigger one.

[Ernest Purdum]

Kelli, if you email me your mailing address, I'll send you a booklet on view camera lens choice.