Flange to focus?

[MattKing]

[looks like they don't allow links to Amazon. Fair enough. Go to amazon and search this term:
DSLRKIT Lens Focus Calibration Tool Alignment Ruler Folding Card ]

There should be no problem with most Amazon links.
Here is a link to the Amazon Canada version:

 

[Dan Daniel]

There should be no problem with most Amazon links.
Here is a link to the Amazon Canada version:

Interesting, my browser is again showing nothing. I'll assume that it is Firefox or an add-on that is killing off the link. No problems, of course- I'd rather not see one or two links of interest than see four hundred sixty three spam pop-ups.

 

[grain elevator]

sure what the issue is with what Steve wrote. I don’t see a problem with it. He clearly indicated image space when discussing Depth of Focus. It is, btw, directly proportional to the Depth of Field times the system magnification.

The issue is that he appears to insist that absolutely nothing will be in focus when the film is out of the ideal plane of focus, whereas in many situations with 3d subjects, it just means focus is on something else. This makes it harder for the OP to understand the issue, as the answer to his question can be deduced from what he already knows once he realises that placement of film relative to lens = focusing.

 

[wiltw]

The issue is that he appears to insist that absolutely nothing will be in focus when the film is out of the ideal plane of focus, whereas in many situations with 3d subjects, it just means focus is on something else. This makes it harder for the OP to understand the issue, as the answer to his question can be deduced from what he already knows once he realises that placement of film relative to lens = focusing.

I fail to see that point of view expressed in OP. He asked if changing aperture would put things into better focus, if the film was not placed at the ideal plane of focus...we answered that the Depth of Focus zone does get deeper with smaller aperture, just as Depth of Field gets deeper. So the tolerance for error in the focus plane gets better for Depth of Focus at smaller aperture setting.
However, the amount of allowable error in the Depth of Focus is microns deep, and can be exceeded by film curl. For example, large format shooters who detect focus error at f/16 will often find an acceptable photo if taken at f/22 or f/32 instead.

 

[BJC0000]

I fail to see that point of view expressed in OP. He asked if changing aperture would put things into better focus, if the film was not placed at the ideal plane of focus...we answered that the Depth of Focus zone does get deeper with smaller aperture, just as Depth of Field gets deeper. So the tolerance for error in the focus plane gets better for Depth of Focus at smaller aperture setting.
However, the amount of allowable error in the Depth of Focus is microns deep, and can be exceeded by film curl. For example, large format shooters who detect focus error at f/16 will often find an acceptable photo if taken at f/22 or f/32 instead.

Quite right. As the OP my question has been answered and thanks to all who replied.
Thanks especially to Monopix who came up with that excellent post and some serious reading.
It just shows that you don't know what you don't know until someone who does know comes along ;-)

 

[grain elevator]

I fail to see that point of view expressed in OP. He asked if changing aperture would put things into better focus, if the film was not placed at the ideal plane of focus...we answered that the Depth of Focus zone does get deeper with smaller aperture, just as Depth of Field gets deeper. So the tolerance for error in the focus plane gets better for Depth of Focus at smaller aperture setting.
However, the amount of allowable error in the Depth of Focus is microns deep, and can be exceeded by film curl. For example, large format shooters who detect focus error at f/16 will often find an acceptable photo if taken at f/22 or f/32 instead.

I replied to a post about someone other than the OP