Front focus vs. rear focus

[stradibarrius]

Is there a rule of thumb as to when you should use front vs. rear focus? Or...is it just to try to keep the cameras mass balanced over the tripod?

[Jay DeFehr]

A couple other things; when using long extensions it can be hard to reach the front focus while using a loupe on the GG (8x10+), and front focus changes magnification/ the size of the image on the GG, while rear focus does not, which can be important with subjects close to the lens.

[E. von Hoegh]

Mainly the length of ones arms, but it's nice to keep the camera balanced on the tripod, too. For long extensions, you can set the focus roughly with the front, and make final adjustments with the rear.

[Bob Salomon]

Are you trying to shoot to a specific image scale?

[stradibarrius]

No, just trying to learn some specifics. Jays comment of adjust the front changes magnification and adjusting the rear does not is exactly the type of info I was looking for.

[Greg Lockrey]

If you use rear focus your relative position to the subject stays the same... with that you can do focus stacking where the front object will be as sharp as at infinity. I once seen a macro of a toad stole where the Grand Tetons in the background were all sharp....

[Matus Kalisky]

I did shoot a few close-up shots with my Tachihara 4x5 and can just tell you that front focusing makes it so hard to get correct focus and framing at the same time. Problem is - the more you focus in with the front standard you keep moving the lens towards the subject - at some point this distance will start to change faster than the focus plane so in the effect you will see (during focusing "in') that your focus plane first changes as you would expect (getting "closer"), will stop at some point (at 1:1 I guess, would have to compute it to be sure) and than will start to move backwards. At the same time the magnification changes wildly. Rear focusing does not give you this issue.

[Doremus Scudder]

The practical considerations, like ease of use, etc. are most important for general (subject relatively far from the camera) shooting, where it doesn't really make a difference whether you use front or rear focusing.

For close-up work, as Jay mentioned, moving the front moves the lens (and therefore, the viewpoint) closer or farther from the subject, which changes the magnification, while focusing with the rear does not.

It is often helpful to use both front and rear focusing to simply move the entire camera to the correct distance from the subject (you can use shift and rise/fall too, so you don't have to fool with the tripod at all). Once you have the lens positioned correctly, then use the rear focus and appropriate movements to place the plane of focus where you want it.

Best

Doremus

[johnielvis]

depends on the equipment for me....usually the closer you are to the subject, rear is best....but then I find it easier to move the whole camera at the bigger magnifications for focus than actually focusing the camera...the more towards infinity you are the less it matters except for where the focus knobs are like others have said....this is something I think that is individual preference for the equipment used.....and environment

[stradibarrius]

Thanks for the great information. Obviously for a manufacturer to make the camera where you have two ways to basically do the same thing there is usually a reason.

[ic-racer]

Front focus changes the position of your camera. Rear focus does not. Of course, both cause the projected image to change in size as the image is focused.

[Andrew O'Neill]

I usually focus from the back of the camera as it is easier to do so.

[Vaughn]

Whichever standard loosens up and tightens up (and fine-focuses) the easiest!

And when I used a 28" lens on My Zone VI 8x10, I put both standards at the very ends of the geared rails and could just focus at infinity. A 24" lens gives me a little wiggle room, but I have to focus via the back as I can barely see the GG and front focus at the same time.