how to determine the best working ratio for lenses

monk · Oct 20, 2015

Greetings All!
could somebody tell me how could i determine the best working ratio fom my large format lens?
and also i would need some light on the closeup photography subject..
as far as i know for example,if you make closeup-macro shots than your lets say f8 is f22,your f32 is f128 (where diffraction works too).the numbers i made up,but in theory is it something like this?am i right?
if so,what is the "limit" where this takes place?
i have a schneider 150 symmar convertible,a 300mm f8 nikkor,and a 65mm f8 schneider.
could some of you guys help me in this question?
Any help-idea is appreciated!
Thanks a Lot!

Have a good light everyone!

BrianShaw · Oct 20, 2015

Difficult question, monk... since aperture is only one factor to consider in exposure. Remember that aperture and time (shutter speed) and film speed (ASA/EI) all make up your given exposure. All this influenced by the amount of light available (or provided by artificial means). Aperture (in my opinion) should be selected to determine the depth-of-field that you desire. For close-up work there are tables that you can use to ensure that your chosen aperture has sufficient depth of field.

markbarendt · Oct 20, 2015

I don't think working ratio is the right descriptor.

https://en.wikipedia.org/wiki/F-number

https://en.wikipedia.org/wiki/Diffraction

BrianShaw · Oct 20, 2015

... and if your question is specific to diffraction, this may help you also:

https://www.google.com/#q=lens+diffraction

markbarendt · Oct 20, 2015

Yep Brian.

monk, diffraction isn't always bad, it imparts a certain look. Pinhole camera images are a classic example diffraction's effects.

Diffraction is also progressive and specific to the lens type and ...

Best way to find out if diffraction is a cure or a curse or even a factor is to force the issue on a few test shots. Get out there and shoot a few and see how bad you can make it.

monk · Oct 20, 2015

no Mark,i dont think it either,sorry for that,,i dont speak english that well..
how can i determine that my lens works best lets say from 120:1 to 1:1

markbarendt · Oct 20, 2015

Shoot photos using your camera and then print and decide.

monk · Oct 20, 2015

Brian,i did my google research before i wrote here.
im not asking about diffraction in general,im asking how it impacts my resolution,if i make closeups-macro shots..
in large format closeup macro work if you use f8 the result will be better as if you would shoot it on f22,because the 22 works as if it would be 128..the numbers i made up again,but is it like this?is this right?

monk · Oct 20, 2015

all this is on "normal lenses" not macro..
maybe im wrong on this apperture thing,if i am ,please tell me!
normally i would say the same,go out and shoot,but since 4x5 film is not so cheap,i considered a post here..
normally i wouldnt bother you guys with my stupid questions..

RobC · Oct 20, 2015

goto following and select "Pre Designer"/ Install

This free software will provide you with all the numbers you need once you have learnt how to use it. And that includes CoC, near far distances, lens extension for any maginfication factor, effective aperture after lens extension etc etc.

There is a learning curve but its worth it in the long run becaseu you'll learn a lot about lenses.

Play with it and good luck.

http://www.winlens.de/

Top Tips

1. As soon as you open software maximise window to full screen otherwise "Depth of Focus" tab doesn't always work properly.

2. Use depth of focus tab and adjust CoC size in there until it goes red. Then go back a fraction until it just stops being red. This tells you theoretical CoC according the settings on left of screen.
This tells you your resolution at effective aperture so you can work out ballpark enlargement you can use from that.

RobC · Oct 20, 2015

monk said:
all this is on "normal lenses" not macro..
maybe im wrong on this apperture thing,if i am ,please tell me!
normally i would say the same,go out and shoot,but since 4x5 film is not so cheap,i considered a post here..
normally i wouldnt bother you guys with my stupid questions..

Give example of on film magnifications required with each focal length then you might get some sensible answers. But you can do it yourself now you know about the Pre Designer software.

DREW WILEY · Oct 20, 2015

I simply judge with my eyes, first with a good loupe on the groundglass, then ultimately on the print, according to my own nitpicky expectations. This is all that really counts. If you enjoy endless tinkering with a calculator or redundant software, fine; but it won't tell you anything your own eyes won't in a fraction of the time and effort. A contact print will obviously tolerate a lot more diffraction than a big enlargement intended to be viewed at close range. So I also ignore all that "circle of confusion" and "normal viewing distance" nonsense too. It's all relative, and you set your own standard of what is acceptable.

Doremus Scudder · Oct 20, 2015

monk said:
Greetings All!
could somebody tell me how could i determine the best working ratio fom my large format lens?

Lenses are optimized to work best at certain distances. General purpose lenses are optimized from about 1:10 to infinity. There are macro lenses designed for more close-up work. That said, many general-purpose lenses work fairly well for close-ups up to 1:4 or even more. Process lenses like G-Clarons etc. are often a good compromise, being optimized for close(r) work but delivering excellent results at infinity as well. Google and search here for LF macro and process lenses and you'll uncover a ton of information.

monk said:
and also i would need some light on the closeup photography subject..
as far as i know for example,if you make closeup-macro shots than your lets say f8 is f22,your f32 is f128 (where diffraction works too).the numbers i made up,but in theory is it something like this?am i right? if so,what is the "limit" where this takes place?
i have a schneider 150 symmar convertible,a 300mm f8 nikkor,and a 65mm f8 schneider.
could some of you guys help me in this question?
Any help-idea is appreciated!
Thanks a Lot!

Have a good light everyone!

When you increase the amount of magnification (i.e., focusing on closer objects) than infinity, then the effective aperture of the lens changes. This change is negligible until you get fairly close. Most of us, however, don't work by figuring out our effective apertures; we simply add the correct bellows extension factor and stop down to get the desired depth of field.

FWIW, I use a regular plasmat 135mm lens (or a Wide Field Ektar 135mm) for most of my close up work, at ratios from 1:10 - 1:4 or even greater with good results. If you have enough bellows draw, your 150mm lens should get you fairly close. Try it and see if you like the results.

Best,

Doremus

AgX · Oct 20, 2015

monk said:
no Mark,i dont think it either,sorry for that,,i dont speak english that well..
how can i determine that my lens works best lets say from 120:1 to 1:1

I would use the term "optimum magnification"

For enlarging/repro lenses the manufacturer typically states an optimum magnification range. For other lenses such information typically is omittted.

Some lenses were intended to be be a workhorse on all fields, like the symmar. And in its early versions it was actually quite symmetric and thus useable at a large magnification range.

To determine that range yourself you would have to make a test pattern, filling the Image, and photograph it at varying magnifications, thus rearranging the targets. Than at enlargements you can mesure and calculate the Resolution and thus find an optimum range.

There were printed targets available with various line frequencies.

monk · Oct 20, 2015

Thanks Rob,installed,i will have a deeper look into it later,but im not so comfortable with this softwares..but thanks i will try to figure it out
im sure it would help me if i would understand it,but it would take me eternity to understand.
i think i will just do what (nearly)all you sadi will just go out and shoot

DREW WILEY · Oct 20, 2015

The original question is still a bit unresolved, because we don't know if he already owns certain lenses and is attempting to optimize their
performance, or is seeking something specifically for closeup work, which means a specialty lens could be recommended.

monk · Oct 20, 2015

optimum magnification!!!
Thanks AgX!
i think i will just put that symmar workhorse on work
so after all the stupid questions,the end result like nearly all the time:try it and see for yourself!

Thanks for all the answers Everyone!
monk

monk · Oct 20, 2015

thought i told the lenses im interested in i own in my first post,sorry,i got a 150mm symmar and a 300mm f9 nikkor,and a 65mm f8 super angulon.

RobC · Oct 20, 2015

monk said:
optimum magnification!!!
Thanks AgX!
i think i will just put that symmar workhorse on work
so after all the stupid questions,the end result like nearly all the time:try it and see for yourself!

Thanks for all the answers Everyone!
monk

True symmar designs are good for close ups but most LF Symmars aren't true symmars. Every lens is slightly different design and not all by far are symmars. (Symmars are Double Gauss types)

Nobody knows, except the lens manufacturers, what the design optimums are. Things like refractive index of each element, type of glass, coatings etc etc etc all play their part.

The software I pointed you at will give you some clues as to what type of lens design is good for what but you will need to learn and interpret what it is telling you. Clicking on the lens types in the "systems" tab gives you some clues. Then click on the magnifying button and you can see the typical lens element layout for that type of lens. You can set the refractive index of the glass if you know it but I doubt you ever would becasue its never published by the manufacturers.

So you see that your question is unasnswerable with any precision by anyone unless they happen to have all the facts about any particular lens which no one does. And then how well the lens has been put together affects its final performance. And many lens types require shimming between front and back elements for them to work properly (symmars less so). Buying used is problematic because shims are often missing or of the wrong thickness. In the long run you have to try it and see. It's no wonder that most people agree that the improvement between MF and LF is not much and may not be worth striving for unless you skip 4x5 and go straight to 8x10.

monk · Oct 20, 2015

RobC said:
True symmar designs are good for close ups but most LF Symmars aren't true symmars. Every lens is slightly different design and not all by far are symmars. (Symmars are Double Gauss types)

Nobody knows, except the lens manufacturers, what the design optimums are. Things like refractive index of each element, type of glass, coatings etc etc etc all play their part.

The software I pointed you at will give you some clues as to what type of lens design is good for what but you will need to learn and interpret what it is telling you. Clicking on the lens types in the "systems" tab gives you some clues. Then click on the magnifying button and you can see the typical lens element layout for that type of lens. You can set the refractive index of the glass if you know it but I doubt you ever would becasue its never published by the manufacturers.

So you see that your question is unasnswerable with any precision by anyone unless they happen to have all the facts about any particular lens which no one does. And then how well the lens has been put together affects its final performance. And many lens types require shimming between front and back elements for them to work properly (symmars less so). Buying used is problematic because shims are often missing or of the wrong thickness. In the long run you have to try it and see. It's no wonder that most people agree that the improvement between MF and LF is not much and may not be worth striving for unless you skip 4x5 and go straight to 8x10.

Thanks Rob!
as i sad,im sure it would help me if i could understand this software,but it would take me loads of time.but i will give another trys in hope of understanding.
yes Rob,i see your point
btw..i would love to go straight to 8x10,but i would have to face some factors what i cant face at the moment..price of a 8x10 camera-film-film holders-lenses..and i like enlarging my negatives..and to do so i would have to build an enlarger or let one built for me.
but i would love to..
time will tell..
first i would get optimum negatives on 4x5(that i can enlarge pretty big )
its all for the best resolution and overall sharpness..
Thanks Everyone!

RobC · Oct 20, 2015

Note:

LF cameras are also called view cameras and also, importantly, "technical" cameras. There's an awful lot to learn and know and that takes time.

For example, the very new schenider XL lenses are better performers than most older lenses so when you say you want maximum resolution and sharpness you better be prepared to pay for it. Altenatively you may just want to be like everyone else and settle for the cheapest you can lay your hands on in which case you can't expect the best. Having said that, your images are more likely to be soft becasue your technique is wrong and not becasue of any short comings of the lens.

Dan Fromm · Oct 20, 2015

RobC said:
True symmar designs are good for close ups but most LF Symmars aren't true symmars. Every lens is slightly different design and not all by far are symmars. (Symmars are Double Gauss types).

Why do you say that? I ask because Symmar is a Schneider trade name, not a design type. According to Schneider's propaganda early Symmars (so badged) are six elements in two groups dagor types and later Symmars (so badged) are six elements in four groups plasmat types. Plasmats aren't double gauss types.

Monk, why don't you just tell us what you're trying to accomplish? If closeup work, what range of magnification do you want to work at?

Oh, and by the way, there are books on close up photography. Lester Lefkowitz' The Manual of Closeup Photography is one of the best, you can buy a used copy from vendors on, in alphabetical order, abebooks.com, alibris.com, amazon.com, muchoslibros.com, ...

RobC · Oct 20, 2015

Dan Fromm said:
Why do you say that? I ask because Symmar is a Schneider trade name, not a design type. According to Schneider's propaganda early Symmars (so badged) are six elements in two groups dagor types and later Symmars (so badged) are six elements in four groups plasmat types. Plasmats aren't double gauss types.

Monk, why don't you just tell us what you're trying to accomplish? If closeup work, what range of magnification do you want to work at?

Oh, and by the way, there are books on close up photography. Lester Lefkowitz' The Manual of Closeup Photography is one of the best, you can buy a used copy from vendors on, in alphabetical order, abebooks.com, alibris.com, amazon.com, muchoslibros.com, ...

I'm no expert on lens design by far but I use the Rodenstock/linos/qioptic software for guidance. If you have Pre designer installed then click on systems tab and then the magnifier glass button. Then click in each of the lens elipses (such as double gauss) and see the typical lens element layouts for that type. Which one of those resembles a Plasmat?

As far as I'm concerned a symmetrical type lens is exactly that, a lens which has reflected symmetry between its front and back elements. Maybe Plasmats do, I don't know.

[edit]

did some checking and I think what you refer to as a Plasmat, the Pre designer software calls an Orthometar which may indeed be closer to a Schneider Symmar. But Plasmat and Double Gauss are both Symmetrical type lenses so I think Schneider are using a more generic terminology for symmetric lenses whereas there are in reality more specific design types within the "symmetrical group" of lens types by the look of it.

monk · Oct 20, 2015

RobC said:
Note:

For example, the very new schenider XL lenses are better performers than most older lenses so when you say you want maximum resolution and sharpness you better be prepared to pay for it. Altenatively you may just want to be like everyone else and settle for the cheapest you can lay your hands on in which case you can't expect the best. Having said that, your images are more likely to be soft becasue your technique is wrong and not becasue of any short comings of the lens.

nobody sad anything about having issues with soft images..
the schneider xl lenses are better than most older lenses but im pretty sure that the 300mm nikkor is a good performer too.(i see it every time).and i love to use the symmar too
but im not a line per mm counter..

monk · Oct 20, 2015

Dan Fromm said:
Why do you say that? I ask because Symmar is a Schneider trade name, not a design type. According to Schneider's propaganda early Symmars (so badged) are six elements in two groups dagor types and later Symmars (so badged) are six elements in four groups plasmat types. Plasmats aren't double gauss types.

Monk, why don't you just tell us what you're trying to accomplish? If closeup work, what range of magnification do you want to work at?

Oh, and by the way, there are books on close up photography. Lester Lefkowitz' The Manual of Closeup Photography is one of the best, you can buy a used copy from vendors on, in alphabetical order, abebooks.com, alibris.com, amazon.com, muchoslibros.com, ...

Dann,i just simply wanted to know "the limit" of my lenses.
"optimum magnification" as AgX sad so well(thanks for that
to know simply how "far can i go"
but than i realised that i should just give it a try and see myself what happens..
btw,the Lefkowitz book is coming back now the 6th time from different forum users,of different forums,so i think i should just get my hands on one of them..
Cheers!

how to determine the best working ratio for lenses

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