Image Circle How Big do I need?

[Ulophot]

Sruddy, Doremus, as always, has stepped in with clear, concise advice. I would only add this:

You said you are just starting in 4x5 and have two lenses, looking for a third. You haven't mentioned whether you have previous photographic experience in film or what kinds of subjects may interest you. Regarding the latter, perhaps it's "all,"which is fine. However, depending on your experience, you may wish to stick with two lenses for a bit and concentrate on getting to know your camera and the new world of LF. It's not difficult to find that the extra considerations involved in making the view camera image present new challenges that need all your concentration until the mechanics become second nature and the movements with the different lenses become familiar. For instance, the amount of tilt or swing (front or back) needed with a 90mm will tend to be comparatively smaller than that with a longer moderate length such as your 150; and, the amount of tilt with the 150 may be less than you imagine in many situations.

There a tutorials on, and linked from, the home page here, and many other sources, including the extraordinary depth of knowledge and talent on this forum. My own favorite source, to which I find myself returning periodically for some bit of information or inspiration even after decades and having read them cover to cover repeatedly, include Ansel Adams's series, The Camera, The Negative, The Print. In any case, following advice found on the web comes with all the usual cautions.

Looking forward to seeing some of your work!

[John Layton]

Also...if you find yourself running out of coverage while using a forward axial tilt, you can often either use rear axial tilts if you have them (or rear base tilts if you have enough back focus) - or you can sometimes simply lower the lens vertically ("fall") as you tilt it forward "axially" on the front standard, which can work to keep your image circle more or less "centered" on the film area.