RobertS
accidental monkeycammer
I love to use my OLD 90'cron. I think it was one of the first 2000 or so made in M mount. It is old (like I said), BIG, and Heavy. It has some chunks inside and even a fingerprint smudge cemented between elements. BUT...but despite all of these drawbacks it is a super lens when you get it focused***
And I DO mean 'when'. Stopped down is easy, and using the 1.25x mag. eyepiece helps alot... but wide open it has a TINY DOF. Cool effects... but only if you have what you were hoping for inside of that sharp area. It is an extreme twister of a lens: very long throw from close to infinity. That is part of the problem, I guess.
QUESTION:
Does someone know of an online source/ chart that helps calculate DOF at various f stops/ distance for 90 mm focal length??? Maybe one of you lens-heads knows offhand what the dof is at f2 HAHA!
I know some folks like the "thin" 90/2.8 better... does it focus with less of a twist??
Comments please!
And I DO mean 'when'. Stopped down is easy, and using the 1.25x mag. eyepiece helps alot... but wide open it has a TINY DOF. Cool effects... but only if you have what you were hoping for inside of that sharp area. It is an extreme twister of a lens: very long throw from close to infinity. That is part of the problem, I guess.
QUESTION:
Does someone know of an online source/ chart that helps calculate DOF at various f stops/ distance for 90 mm focal length??? Maybe one of you lens-heads knows offhand what the dof is at f2 HAHA!
I know some folks like the "thin" 90/2.8 better... does it focus with less of a twist??
Comments please!
jlw
Rangefinder camera pedant
Here's one:
http://www.dofmaster.com/dofjs.html
And here's another, written in Javascript. The one on the page doesn't include the 90mm focal length -- but it DOES include the source code, so you can easily add it and then run it in a web browser whenever you want to calculate DOF.
http://javascript.internet.com/calculators/field-depth.html
Incidentally, DOF for a 90mm lens on 35mm film at f/2 and a focusing distance of one meter is about +/- 0.01 meter... that means the total depth is less than one inch! So you definitely want to twist focusing ring with care...
http://www.dofmaster.com/dofjs.html
And here's another, written in Javascript. The one on the page doesn't include the 90mm focal length -- but it DOES include the source code, so you can easily add it and then run it in a web browser whenever you want to calculate DOF.
http://javascript.internet.com/calculators/field-depth.html
Incidentally, DOF for a 90mm lens on 35mm film at f/2 and a focusing distance of one meter is about +/- 0.01 meter... that means the total depth is less than one inch! So you definitely want to twist focusing ring with care...
Wayne R. Scott
Half fast Leica User
Roger Hicks
Veteran
The trouble is that DoF isn't an absolute. It depends on how big the final picture is and what you regard as 'acceptable'.
Cheers,
Roger
Cheers,
Roger
jlw
Rangefinder camera pedant
That's the nice thing about the calculators that include source code. You can plug in your own circle-of-confusion value based on your own parameters.
Personally, I hardly ever worry about it. I have to shoot at full aperture almost all the time, so the way I calculate depth of field is that I just assume there ain't any!
Personally, I hardly ever worry about it. I have to shoot at full aperture almost all the time, so the way I calculate depth of field is that I just assume there ain't any!
VictorM.
Well-known
Source code with a 90mm Summicron?!! Better to buy a Leica manual with dof tables at the back.