Question on lens specs...

When a manufacturer states the minimum focal distance, is that as
measured from the end of the lens or, as I've assumed, from the focal
plane (film/sensor)?

I'm looking at the Pentax DA 35mm f/2.8 Macro Limited.
http://www.pentaxwebstore.com/produc...p?T1=PTX+21730

Thanks!

On 2009-09-04 07:20:22 -0700, John A. said:

When a manufacturer states the minimum focal distance, is that as
measured from the end of the lens or, as I've assumed, from the focal
plane (film/sensor)?

I'm looking at the Pentax DA 35mm f/2.8 Macro Limited.
http://www.pentaxwebstore.com/produc...p?T1=PTX+21730

Thanks!

It is from the focal plane. It is the reason there is a little symbol
marking the focal plane on your camera -- so you can measure focus
distance manually, if necessary.

--
Waddling Eagle
World Famous Flight Instructor

On Fri, 4 Sep 2009 08:09:45 -0700, C J Campbell
wrote:

On 2009-09-04 07:20:22 -0700, John A. said:

When a manufacturer states the minimum focal distance, is that as
measured from the end of the lens or, as I've assumed, from the focal
plane (film/sensor)?

I'm looking at the Pentax DA 35mm f/2.8 Macro Limited.
http://www.pentaxwebstore.com/produc...p?T1=PTX+21730

Thanks!

It is from the focal plane. It is the reason there is a little symbol
marking the focal plane on your camera -- so you can measure focus
distance manually, if necessary.

That's what I thought. I haven't been able to spot the mark (like the
Greek letter phi) on my K20D, but I do recall seeing it on my dad's
old Exacta and in pics of the K7, and I seem to recall seeing it on my
old SF1.

Bob G wrote:
It is the reason there is a little symbol
marking the focal plane on your camera -- so you can measure focus
distance manually, if necessary.

I know it's there and I know it's at the same level (what's the
tolerance, anyway?) as the focal plane, but I've never ever seen
anyone use it and, with the advent of computers controlling every
function of a camera, I don't see what its purpose is anymore. Maybe
in some scientific applications or in closeup work. Anybody?

I use it rarely, usually for tabletop macros. I could live without it.

On Fri, 04 Sep 2009 14:51:45 -0700, Bob G wrote:

It is the reason there is a little symbol
marking the focal plane on your camera -- so you can measure focus
distance manually, if necessary.


I know it's there and I know it's at the same level (what's the
tolerance, anyway?) as the focal plane, but I've never ever seen anyone
use it and, with the advent of computers controlling every function of a
camera, I don't see what its purpose is anymore. Maybe in some
scientific applications or in closeup work. Anybody?

It's useful for dpreview.com to see if the tripod mount is in line with
the focal plane. :-)

--
Regards, Robert http://www.arumes.com