[Dewman]

What is the general consensus of having a resource available on the PF for lenses, both Pentax and third party, that lists the macro magnification of each?
I realize that many aren't true macro lenses, but listing them AND close-focusing lenses would be very helpful. Maybe even go so far as listing the magnification AFTER adding close-up filters and/or extension tubes.


Many of you who are deeply into macro already know about such things, but it would be a real boon to those of us who are neophytes on the subject.


Who knows, maybe there already is such a resource. Just a thought as I suffer through another long night of insomnia.


Dewman
SW Idaho

[old4570]

Lens Magnification and Depth of Field Calculator Here is a calculator

Macro Extension Tubes & Close-up Lenses

Macro photography: Understanding magnification: Digital Photography Review

Hope the links help ...

[Dewman]

Well Matt.... what I had in mind was a page you could go to.... like the lens review section..... look up the lens in question, and viola! .... there would be the macro/close focus magnification ratio, along with the lens review. I suppose that could be incorporated into the already-existing lens reviews.


Dewman
SW Idaho

[savoche]

Well Matt.... what I had in mind was a page you could go to.... like the lens review section..... look up the lens in question, and viola! .... there would be the macro/close focus magnification ratio, along with the lens review. I suppose that could be incorporated into the already-existing lens reviews.

For some lenses that is already included, like for the DA 50/1.8. So if somebody volunteers for doing the calculations it shouldn't be impossible to update the info.

[Adam]

Well Matt.... what I had in mind was a page you could go to.... like the lens review section..... look up the lens in question, and viola! .... there would be the macro/close focus magnification ratio, along with the lens review. I suppose that could be incorporated into the already-existing lens reviews.


Dewman
SW Idaho

Our lens database should already have the magnification and/or reproduction ratio specs for each lens

[Na Horuk]

Our lens database should already have the magnification and/or reproduction ratio specs for each lens

I was just about to say that! The only problem is, it is inconsistent. Sometimes the format is ratio (1:7) other times its multiplicator (x0.11). Best would be both, of course.
The lens reviews need to be updated anyway. For example, I think the description of FA 50mm says its the only 50mm in production, but this ignores DFA 50mm macro and DA 50mm f1.8

[Dewman]

Our lens database should already have the magnification and/or reproduction ratio specs for each lens

Some do, most do not.


Dewman
SW Idaho

[Adam]

Some do, most do not.


Dewman
SW Idaho

If there's a genuine Pentax lens missing the spec, shoot me a PM or post in the site help forum and I will add the info. Third-party lenses will be fixed up later on, but I'd be happy to add the info to those as well if you know it.

[Pentax Bob]

For me, the choice of lens and accessories for Macro work depends on a lot of factors. Not the least of these is practical working distance. I have never seen a chart or data that compares the working distance ( lens to subject distance ) at 1:1 magnification. It makes a world of difference depending on what you are attempting to photograph. Live creatures usually require more distance than stationary object. Any ideas where I can find this type of information ? The lens data base would be wonderful.

Pentax Bob

[Dewman]

For me, the choice of lens and accessories for Macro work depends on a lot of factors. Not the least of these is practical working distance. I have never seen a chart or data that compares the working distance ( lens to subject distance ) at 1:1 magnification. It makes a world of difference depending on what you are attempting to photograph. Live creatures usually require more distance than stationary object. Any ideas where I can find this type of information ? The lens data base would be wonderful.

Pentax Bob

Perhaps combine THAT information with what I was asking about? That would be one heck of a useful resource!


Dewman
SW Idaho

[Not a Number]

The bellows manuals have tables with this information but they only cover up to the "A" series manual focus lenses.

Here is a spreadsheet that can be used to calculate this data.
Macro lens calculations

The problem with these and the above calculator is that the principle focal planes (often called the optical center) of the lens should be used. This can be seen by looking at the tables for 50mm lenses f/1.4 vs f/2.0 vs f/4 macro or the f/4 100mm bellows macro vs 100mm prime. The bellows manuals tell you to contact Pentax or your Pentax dealer to get the actual principal plane data for your lenses. Lots of luck with that 30 years later.

[old4570]

Well Matt.... what I had in mind was a page you could go to.... like the lens review section..... look up the lens in question, and viola! .... there would be the macro/close focus magnification ratio, along with the lens review. I suppose that could be incorporated into the already-existing lens reviews.


Dewman
SW Idaho

I was addressing the 2nd part , close focus filters and macro tubes , as such information usually needs to be calculated by the user ( so many variables in equipment )