Large Format Focusing architecture (focusing in a hangar)

Hi People,

before I am going to photograph I am studying, knowing more or less the scene, where to focus to keep the whole image in focus. I am going to a hangar where the main subject (big pillars about six meters large and four meter height) are placed all around the perimetry wall. My idea is to stop down at f32 using a 240mm lens. Now, to keep all in focus where I need to focus (keeping whole the pillar in the image. Tilt cannot be used (the roof will be not sharp). Can I use the 1/3 rule or it is better to focus on the subject and stop down at f 32, knowing that I will be at 8 or 10 meters from the pillar?

Linhot camera IV ( 5x4 ) / lens 240mm Fujinon

Thank you

Luigi

Good luck focussing in a dark hangar at f/32. I hope your night vision is good!

Focus where the main subject is and stop down more than f/32 if your lens will let you.

The 1/3rd distance guideline only works at landscape distances. As you focus closer, the depth-of-field split becomes increasingly 50:50, until at lifesize it is totally symmetrical fore and aft of the subject. So this is where a 'hyperfocal' or DoF calculator would be more than useful.

With a C-o-c suitable for 5"x4", my DoF calculator gives me figures of 6m near focus, and 29m far focus for a 240mm lens @ f/32 focussed at 10m.

Of course a wider lens will give you a lot more DoF for the same aperture, but not for the same field of view.

A 150mm lens gets you from 3m to near infinity when focussed at 6m at f/32.

Dear Joe,

thank you for your answer, very nice of you.

The hangar has roof windows so I might have a fair vision of the scene. 5x4 is the format.

I have the same figures made with Dof calculation. Yes, my lenses choice will be 240mm or 150mm. I need to try in loco. The important aspect I was worry (you help me a lot with it) is to focus on the subject. To increase the dof, do you think can I stop down more or you think f32 will be enough? I know it can cause disturbance.

Thank you

Luigi

Gigi, to assure focus just use a torch lamp.

You can always close the lens to get more DoF, the issue here is the size of the print and/or the viewing distance.

Diffraction causes blur, but if the print is not so large, sharpness could be right enough for the viewer.

You need to consider the final purpose of your image.

Dear Mr. Joe,

the final size it will be museum size, approx. 140 x 110 cm printed in color, film Kodak 160.

What do you think?

Again

Thank you very much

Gigi

Well, this is a big print. In a gallery, you'll need to move back to see it sharp.

Check any diffraction limit calculator, the one I have says you can shoot at f64 within the limits, if you are at one meter from the print. Closer inspection will reveal diffraction blur.

But all this is just maths... in real life you cannot distinguish the point where that "theoretical" limits are.

I'd shoot at f64 and be happy. And just in case, I`d shoot the other side of the holder at f32 :D

Generally - focus with a Large Format camera is a very different thing than small format in many ways.

The classic source is Leslie Stroebel's View Camera Technique (I have the 6th edition, 1993)

Some general discussion here at LINK Tilt / Shift movements for macro photography: a question

download various papers on the subject at LINK http://www.trenholm.org/hmmerk/FVC161.pdf

FWIW, I've seen 5 foot square exhibition prints taken with a Hasselblad on 120 film that are more than acceptably sharp. And the better recent digital cameras can exceed the sharpness of an old 500c and 120 film when fitted with the right lens.

It might be worth considering a smaller format if lens/back movements aren't helpful and a great depth-of-field is required.

Generally - focus with a Large Format camera is a very different thing than small format in many ways.

 

 

The classic source is Leslie Stroebel's View Camera Technique (I have the 6th edition, 1993)

 

Some general discussion here at LINK Tilt / Shift movements for macro photography: a question

 

download various papers on the subject at LINK http://www.trenholm.org/hmmerk/FVC161.pdf

I was lucky enough to take the class from Leslie Stroebel many years ago at RIT. Unfortunately, I sold the book to another student. Still have the 4x5 though!