close-up work maximum depth of field

[robc]

N.B. if image in previous post is not visible then email me and I will send it to you.

[robc]

It's an example but of course what you need depends on the enlargement you want in the print and we haven't been told that.

However, one of the original responses gives a link to another dof calculator which quotes
coc for 4x5 = .094mm Only 6 thou of a mm difference.

Another oft used figure is focal length /1720 = 0.122mm

take your pick.

[John Cook]

Serge, to reduce all this great information as you requested: put on the 210mm lens, fill the frame and shoot at f/64. (It was good enough for Ed Weston)

If you can't hold enough depth of field to suit you, back out a little bit and shoot with a smaller image on the ground glass.

If you find you haven't enough bellows to get the thing in focus at all, switch to the 150 as a last resort.

As someone who has always had a too short commercial deadline and a too small budget, that is exactly my approach to this type of practical problem. Those with more time and money to study, re-study and theorize about all aspects of every issue tend to approach things differently, of course.

[Dan Fromm]

John, whether Serge is practical and just shoots or theorizes and then shoots, basically he's toast. Can't get where he wants to go from here, practically or in theory.

Cheers,

[Serge J-F. Levy]

laugh... well, toast may be a bit strong. I feel that the abundance of thought that went into all of these answers have given me some very strong ideas of how to proceed without having to reinvent the... studio camera... per se.

cheers,
Serge

[robc]

I think the question was what is the optimum achievable.
if Serge would tell us what he is photographing and/or how much dof he needs then maybe we could give a more explicit answer.

[paul stimac]

I agree with all the math/physics talk here but there's one thing that I don't get. I remember seeing a Brett Weston picture of a barrel cactus shot from the top, it filled the frame except it trails off at an angle - all of it was sharp - all of it... maybe my memory is bad... but I'm pretty sure that all of it is in focus. How did he do it? I'll look for the pic and get back to you. ..,.. OK i just found it. I'll post it when I get home.

[paul stimac]

Here's that Brett Weston shot:
http://www.artnet.com/artwork/424202860/brett-weston-santa-barbara.html

Looks like he somehow cheated physics to me. Maybe it's a really small cactis? Maybe get a small orange? Or maybe there is another secret technique?

[Leonard Evens]

Weston didn't cheat physics. The spines are in fact in a fairly narrow range close to a single plane of focus. You can see that by looking at the lower right and left and also the "hole". The image is clearly going out of focus as you move a small distance from the plane of focus.

[Paul H]

I'm sure this is not a route that you want to take, but I thought I'd mention it anyway.

There is another option which involves using several images taken at different focal points, and then combining the resulting image stack with some software.

http://www.heliconfilter.com/pages/focus_overview.html

I have absolutely no idea if this will work for your situations, but it may be worth exploring.

Paul