Focus using rear -- or front -- standard first?

[Jon Warwick]

New to LF photography, I had a few questions:

1) Is there a general rule on whether one moves the rear? -- or front? -- standard first when you are focusing a LF camera ..... ie, for a subject that is fairly close, do i move the front standard until it reaches the best focus that the front standard can achieve .... prior to then moving the rear standard back to finish off the focusing? Or do most of you move the rear standard first? Or do you use a combo of the 2 to keep both standards more centralised over the base of the camera? Does it make any difference which combo of forward versus rear standard focusing one uses?

2) What is the point of the "focus lock knobs" on the left-side of the camera? ie, what is their purpose?

Many thanks

[Jack Flesher]

1) If you are trying to focus on something close, using the rear will cause you endless hours of grief So you generally want to use the front first to get good focus, then use the rear to adjust size if necessary, then front to re-focus. For distant subjects, it doesn't really matter.

2) To answer this question it would probably help to know which camera you are using... However, generally speaking, focus locks lock down the standards so focus doesn't move once set. Thus they are usually a good thing to use if you want crisp images.

Cheers,

[naturephoto1]

Focusing will be based upon the camera that you are using. It will be dependent in part upon whether there is geared focusing on the front or rear standard, whether the camera is a field/technical, monorail, etc. Generally you would set up the camera and extend the front standard and extend the bellows to some length to get a general focus (and then fince focus front or rear). As an example many monorail cameras such as my Linhof Technikardan 45S or my Toho Shimo FC-45X have rear geared rear focusing. Cameras such as a Linhof Technika on the other hand have front geared focusing.

What camera are you using?

Rich

[Glenn Thoreson]

Some cameras have only one moveable standard - i.e. tailboard and press cameras. That's when the fun starts. Follow Jack's advice. As a general rule, rear focus changes image size. Front focus changes focus. Experience - the great teacher.

[Patrik Roseen]

When doing close closeups, i.e macro, I only focus by moving the rear standard. Trying to focus with the front will cause hours of grief since the distance to the subject will change at the same time as the focus is changed.

An LF camera requires all sorts of locks (focusinglocks, tiltlocks, swinglocks etc) since moving the standard in one direction should not influence other directions. Also you will find that if you have not tighten all locks you will be sure to disturb your setup when inserting the filmholder, pulling the darkslide, cocking the shutter etc. Be sure to tighten your tripod as well for the very same reason.

[steve simmons]

If you are working outdoors with distant subjects use whichever is most convenient. It won't make a difference in terms of what is recorded on the film becuase the reproduction ratio is so small either way and moving the lens a few inches will not make a perceptable difference.

If you are doing closeup work then the position of the lens determines the reproduction ratio. If this is critical then position the lens the proper distance from the object (this becomes a math problem) and then focus with the back so as not to change this ratio. If you focus with the front/the lens then moving the lens will change this ratio.

If you will be doing both closeup and more distant work then get a camera that will allow you to at least focus with the back or both, not just the front.

steve simmons
publisher, view camera magazine

[cyrus]

...everything said above ...but also: since you're asking about keeping the balance, yes! good idea to make sure the camera remains balanced on the tripod head.

[Greg Lockrey]

Dittoes to the above, just keep in mind if you move the back, then you change the perspective.

[David Karp]

All of my cameras give me the choice of front or rear focus.

You have to use the front focus to rack out the bellows enough to get into rough focus in most situations.

Once I have gotten enough extension to see an image pretty clearly, I start moving the camera around to frame my photo. Unless I want to make some small changes to get something out or into the photo, I don't use the front focus any more. I use the rear so that the image size does not change.

Plus, it is easier to work at the back using long lenses, unless you have really long arms, and can reach the front focus knob!

[David A. Goldfarb]

For close objects, I concur with those who say focus with the rear, but would add that for cameras that don't have that option, you might use a focusing rail to focus by moving the whole camera. Focusing with the front standard for macro work is an exercise in frustration, but if it's the only option, getting rough focus by positioning the camera makes it easier to get fine focus using the front standard.

Moving the back changes the shape of objects in the frame, but not the perspective in the technical sense, which is determined by the distance between the lens and the subject.