• Please use real names.

    Greetings to all who have registered to OPF and those guests taking a look around. Please use real names. Registrations with fictitious names will not be processed. REAL NAMES ONLY will be processed

    Firstname Lastname

    Register

    We are a courteous and supportive community. No need to hide behind an alia. If you have a genuine need for privacy/secrecy then let me know!
  • Welcome to the new site. Here's a thread about the update where you can post your feedback, ask questions or spot those nasty bugs!

My World: Which lens for Macro?

Doug Kerr

Active member
I will take this opportunity to remind us that the infamous "1:1" image magnification, often used as the criterion of "real macro performance" for a lens, is not very definitive with regard to our actual photographic needs.

Almost always, what we are really interested in is what sized object (or object field) will fill our frame. At the "1:1" benchmark, that is a field whose size equals the fame size. For a camera with a four-thirds sensor, that would be an object less than 13.5 mm in diameter (about 2/3 the diameter of an American dime coin).

For an 8" × 10" format camera, that object might be a ladies' shoe.

Best regards,

Doug
 

Dr Klaus Schmitt

Active member
I will take this opportunity to remind us that the infamous "1:1" image magnification, often used as the criterion of "real macro performance" for a lens, is not very definitive with regard to our actual photographic needs.

Almost always, what we are really interested in is what sized object (or object field) will fill our frame. At the "1:1" benchmark, that is a field whose size equals the fame size. For a camera with a four-thirds sensor, that would be an object less than 13.5 mm in diameter (about 2/3 the diameter of an American dime coin).

For an 8" × 10" format camera, that object might be a ladies' shoe.

Best regards,

Doug
Ehemm Doug, sorry, but at 1:1 the object size is identical to the size on the sensor, i.e. a 1mm object will be exactly 1mm on the sensor. It has nothing to do with sensor size nor field size, it is a parameter of the lens only.
 

Asher Kelman

OPF Owner/Editor-in-Chief
Klaus, is he starting from the standpoint "where we have no units of measurement", just some camera. In that world one could say that a 1:1 image that fills sheet of film is that size too.

Asher
 

Doug Kerr

Active member
Hi, Klaus,
Ehemm Doug, sorry, but at 1:1 the object size is identical to the size on the sensor, i.e. a 1mm object will be exactly 1mm on the sensor.. . .
Quite so.

It has nothing to do with sensor size nor field size . . .
Quite so.

. . .it is a parameter of the lens only.
Quite so.

Now, all that having been said, if we are operating at a magnification of 1:1, and our frame size is 36 mm × 24 mm, then the size of the object field (at the object distance for which the magnification is 1:1, at which distance we presumably are focused) will be 36 mm × 24 mm, for the very reasons you cite. If our frame size is 11 in. × 14 in., then the size of the object field is 11 in. × 14 in.

And my point is that if macrophotography is to be thought of as the photography of small (but not microscopic) objects, I don't consider an object that occupies most of an 11 in. × 14 in. region "small".

Best regards,

Doug
 

Dr Klaus Schmitt

Active member
Absolutely Doug, I just wanted to be clear. Surely, there were lenses built for shipbuilding drawings which copied 1:1, not what I woudl call "m,acro" rather than "repro"
 
Top