hyperfocal distance/ tilt ????

[sammy_5100]

Hi, (beginner question)

I’m confused. I read some of the archives about hyperfocal distance when tilting, and basically came
to the conclusion that after tilting I just need to stop down until everything is in focus and forget about hyperfocal distance.

However, when reading here: http://largeformatphotography.info/how-to-focus.html, it suggests focusing on far, then tilting until near is sharp, then refocusing…etc…
Or focus on near, and tilt until far is sharp, and repeat …etc…

Then it says that if you have asymmetric tilt, you only need to tilt once.

Now here is the problem: if I have asymmetric tilt, I can either focus on far and tilt until near is in focus, then I’m done. (one iteration)

Or focus on near and tilt until far is in focus, then I’m done. (also one iteration)

But wait, if that’s the case, and both are correct…….in each case, the standards are different distances apart(!), right?

Is one more correct than the other, what’s the difference?

If I’m just using regular (non-asymmetric tilt), then I assume that weather I start by focusing on near or far, with the
Iterations, I’ll end up with the standards the same distance apart.

Thanx in advance,

sammy

[Ralph Barker]

Yeah, sure. Absolutely. But, not necessarily. ;-)

Assuming that all the variables aren't, that is, that camera position, lens, subject distances and placement of the plane of sharp focus are all held constant between the two scenarios, you should end up with the standards in about the same relative positions, and the same distance between the lens and the ground glass - if the same stuff is in the same focus.

What's missing from the concept, however, is that not all scenes are created equal, and with different subjects, you may want different parts of it critically sharp. The classic example, I think, is the situation where you tilt the plane of sharp focus down to the horizon to get "everything sharp" from the ground in front of the camera to those distant hills. Then, when you start to print the negative, you discover that the nifty foreground post you included to give depth to the composition extends out of the DOF wedge, making the negative worthless.

So, I think it's best not to forget about hyperfocal distances, or any other available focusing method, until you've determined what the scene requires to give you the image you want. There's no universal "solution" because the "problem" keeps changing.

[Doug Dolde]

With real asymetric tilt for instance like some Ebony and Sinar cameras have, you focus on the tilt axis then tilt the top of the back toward you (Ebony) until the foreground pops into focus. You should not have to worry about the background being in focus as it is gonna be close plus you have the hyperfocal to cover you assuming you stop down to at least f16.

If you are using a base tilt then it's more fiddly and you will have to just keep trying various degrees of tilt until you get it right. Usually though a few degrees say 2 or 3 should be sufficient.

Then there is center axis tilt which is more like asymetric tilt in that you focus first on the axis line then do your tilt until you get the in focus effect you are seeking.

Don't worry so much about the process but look at the gg with your lupe and take your time to get it right. No one ever said shooting large format was a fast process.

[sammy_5100]

>The classic example, I think, is the situation where you tilt the plane of sharp focus down >to the horizon to get "everything sharp" from the ground in front of the camera to those >distant hills

yes, this is what i want to do. can i so the following:

1) focus on the hyperfocal distance

2) (asymetric) tilt getting a flower (foreground) and mountain (backround) in focus - (one iteration)

3) stop down until everything is in focus

and shoot!!!

ps. what would the hyperfocal distance be for the 47 mm xl? i'll probably be shooting 6 x 9.

thanx

[Ralph Barker]

I might be wrong, and if so, I'm sure I'll be corrected, but the hyperfocal distance assumes a vertical plane of sharp focus and vertical near and far DOF planes, based on whatever Circle of Confusion assumptions are being made to arrive at the DOF at a given aperture. Once the lens is tilted, all of that changes, as the near and far DOF planes also get tilted into what roughly amounts to a wedge.

The real issue, I think, is to choose a focusing method that fits with the scene, and what you want in sharp focus. In some situations, tilting loses more than it gains. So, you might be better just using DOF, or you might need to choose a different composition. No focusing method will work for all possible objectives.

[Brian Ellis]

Maybe hyperfocal distances work well for some people, they never have for me. Tables of hyperfocal distances are all based on certain assumptions made by the person constructing the table (print size, acceptable size of the circles of confusion, print viewing distance, etc.) some or all of which may not be applicable to you. If you have a front base tilt camera and are in a situation where front tilts will be useful just focus on the farthest object that you wish to appear sharp, then tilt to bring the near into focus, refocus if necessary to bring the farthest object back into focus, etc. etc..until both are in focus or until you're as close to having both in focus as you can get, then stop down as needed. Do the opposite with an axis tilt camera (i.e. focus on the near, then tilt for the far etc.). The article you mention explains this better and in more detail than I can here but that's the basic idea.

Depending on the distance and angle of the near and far objects you may have to go through this a couple times, more so with base tilts than with axis tilts, but with some experience it's pretty simple. Many beginners make the mistake of thinking the tilt needs to be much greater than it usually needs to be so they "over tilt," everything gets out of whack, and frustration sets in. You can tell when you've tilted too much by observing what is happening as you refocus after a tilt. Normally moving a lens forward will tend to bring near objects into focus and moving it backward will tend to bring distant objects into focus. If the camera starts doing the opposite (i.e. moving the lens forward brings distant objects into focus and vice versa) then you've tilted too much.

[Ole Tjugen]

If you find you get poor results with hyperfocal focus, go here for some explanation of why.

Then throw away your hyperfocal distance table.

[sammy_5100]

thanx for the responses...but they still did *not* answer my question.

if i want a flower and mountains in focus using *asymetric* tilt, i can focus on near
and tilt until far is in focus or the opposite -- both in *one* iteration. but either way, the
standards are at different distances apart. when i'm finished, where should i focus?
I'm still lost! somebody help!!!!!

[Glenn Kroeger]

Sammy:

Your last statment is impossible... if you have the camera adjusted so that both the flower and the mountains are in focus, the lens and the groundglass are in the same relative positions regardless of what order of movements brought you there.

[sammy_5100]

yeah,

i guess thats whats confusing!

but Gelnn, can't i focus far, and tilt once (asymmetric) until near is
in focus?

if this is the case, then i could *not* do the same by focusing on near and tilting once until far
is in focus - because either way the standards are a different distances apart...

which way is correct?

boy am i confused...