Please help with lens coverage database

darinwc · Apr 20, 2006

I'm working on a database of large-format lens data.
When my webserver is abck up I will webify the data for all.
Of course I will have all the usual data, including lens type and elements/groups.

I will have a field to account for different versions of a lens, like "pre-war" "linhof", "multicoated" etc.

And I will have separate fields for 'coverage' and 'illumination'.
Should I include a field for light falloff?
Should there separate light falloff fields for the edge of coverage vs edge of illumination?

donbga · Apr 20, 2006

darinwc said:
I'm working on a database of large-format lens data.
When my webserver is abck up I will webify the data for all.
Of course I will have all the usual data, including lens type and elements/groups.

I will have a field to account for different versions of a lens, like "pre-war" "linhof", "multicoated" etc.

And I will have separate fields for 'coverage' and 'illumination'.
Should I include a field for light falloff?
Should there separate light falloff fields for the edge of coverage vs edge of illumination?

You may find this link helpful.

http://www.bostick-sullivan.com/Alt_cameras/large format lenses.htm

David A. Goldfarb · Apr 20, 2006

There are also tables like this mostly for modern lenses at lfphoto.info.

darinwc · Apr 20, 2006

I have those lists, thank you. My goal is to combine the modern list with the classic list.
Then I will make a cross-reference table of the diagonals of most formats.
This will allow people to quickly answer questions like: what lenses cover 7x17?
Does this lens cover 10x12?, etc.

Also, we talk alot about the manufacturers specs vs. what is acceptable and vs. the illumination. I would like to see some of that listed in my database.

Oren Grad · Apr 20, 2006

If you're looking for features that might distinguish your effort from the existing lens tables floating around, you might consider including separate fields for image circle at f/22 and at f/45, to capture transparently the behavior of the many process lenses and classic lenses that continue to gain usable coverage as you stop way down. If you do that, you should also distinguish between values obtained from manufacturers' specifications, and values obtained from user report.

df cardwell · Apr 20, 2006

You might check manufacturer's data against the existing tables: many are simply recycled and contain some... flaws.

That's the problem when you introduce photo lore to a data base: bad data becomes even more difficult to weed out.

Thankfully, there are primary sources. PLEASE, use them.

Capocheny · Apr 21, 2006

darinwc said:
I have those lists, thank you. My goal is to combine the modern list with the classic list.
Then I will make a cross-reference table of the diagonals of most formats.
This will allow people to quickly answer questions like: what lenses cover 7x17?
Does this lens cover 10x12?, etc.

Hi Darin,

Take a peek at this link as well...

http://www.egksystems.com/lenses/

Cheers

darinwc · Apr 21, 2006

Capocheny said:
Hi Darin,

Take a peek at this link as well...

http://www.egksystems.com/lenses/

Cheers

blech! those colors are hideous, like crab juice or something. Heh, well that list is a start. but they have the diagonals for the film wrong, and they dont include any panoramic formats.

darinwc · Apr 21, 2006

df cardwell said:
You might check manufacturer's data against the existing tables: many are simply recycled and contain some... flaws.

That's the problem when you introduce photo lore to a data base: bad data becomes even more difficult to weed out.

Thankfully, there are primary sources. PLEASE, use them.

Yes of course. I will probably add tags to the coverage data so as to show manufacturers data vs reputed coverage. (thank you for the suggestion Oren!) Maybee in the future I will allow people to vote on certain data or something.

AllenR · Apr 21, 2006

I have a LF lens database that contains around 2000 entires for older optics. It's been in the works for several years and the data comes entirely from catalogs and advertisements that I have in my posession. Each entry lists the source of the data. I had a html-only test version on the Center For Photographic History & Technology server for a while, but that site is being restructured, so it went away. I will try to get this text version up on my server in the next few days. Longer term, the data needs to be ported to MySql and a direct database interface crafted, however this is not very high on my priority list at present.

Allen

darinwc · Apr 21, 2006

Thats awesome allen! I've allready started the database structure and php code.
This is going to be fun project!

Capocheny · Apr 21, 2006

Darin,

Well, I do apologize for posting that link... I didn't suggest that it was complete nor did I suggest the colors would fit into any "desired" palette preference. It was merely a suggestion!

Cheers

jp80874 · Apr 21, 2006

Thank you for doing this and making it available.

John Powers

darinwc · Apr 24, 2006

Friends,
I'm still having trouble trying to represent coverage in the database.
There are many details that cannot fit into one or even two fields. There is advertised coverage vs. experienced. There is coverage wide open vs. at optimal aperature vs. stoped way down. There is sharp coverage vs. illumination. Coverage at infinity vs. coverage at 1:1 (this can be calulated on the fly though).

Please help us decide how to store and present the various coverage data. What do you want to see?

argus · Apr 27, 2006

darinwc said:
Friends,
...There are many details that cannot fit into one or even two fields...

Example?

Why should you limit the rows to only 2 colums? It's better to have a well-defined scheme that's not so human-readable than cluttered data that is unsearchable.

darinwc said:
... What do you want to see?

As much as possible

G

Steve Hamley · Apr 27, 2006

Darin,

I suggest 3 coverage columns to elimnate any confusion. These columns would be headed "Coverage, manufacturer", "Coverage, if buying", and "Coverage, if selling".

Steve

Ole · Apr 27, 2006

What is "sharp"?

In my quick informal comparison of two 90mm Angulons of different vintage, it became obvious that "sharpness" must be defined before it can be referred to.

The newer lens har a larger sharp image circle at wide apertures, which increases a bit on stopping down. The older one has a much smaller (sharpish) image circle wide open, which increases a lot when stopping down. At f:32 the older may have a larger sharp image circle, depending on how you define "sharp": Dead Link Removed

colrehogan · Apr 27, 2006

I have to agree with Ole here. I did a little test of my own last year to see what the Kodak 203 mm f/7.7 Ektar would look like on an 8x10 (mostly because I love this little lens and it wasn't getting used much since I moved up to 8x10). I suspect there are a lot of other people out there who have done stuff like this.

donbga · Apr 28, 2006

darinwc said:
Friends,
I'm still having trouble trying to represent coverage in the database.
There are many details that cannot fit into one or even two fields. There is advertised coverage vs. experienced. There is coverage wide open vs. at optimal aperature vs. stoped way down. There is sharp coverage vs. illumination. Coverage at infinity vs. coverage at 1:1 (this can be calulated on the fly though).

Please help us decide how to store and present the various coverage data. What do you want to see?

You should be able to create as many fields as neccessary to include all the characterristics of the lenses that you have data for. It sounds as though you maybe confusing display data with real data. Define your data dictionary first and worry about presentation later.

darinwc · Apr 29, 2006

It looks like the best way to accomplish this is to split out the coverage data into a separate table. This will let me specify the accompanying data of each coverage measurement without adding 12+ fields.

The database is going slower than I would have hoped, mainly due to honey-do lists that have filled up my free time. But it is progressing, and should be ready in a few more weeks.

donbga · Apr 29, 2006

darinwc said:
It looks like the best way to accomplish this is to split out the coverage data into a separate table. This will let me specify the accompanying data of each coverage measurement without adding 12+ fields.

The database is going slower than I would have hoped, mainly due to honey-do lists that have filled up my free time. But it is progressing, and should be ready in a few more weeks.

My question is why? 12 fields in a single table shouldn't be a big deal. After all you are thinking about putting them into a seperate table. Am I missing something here? What database are you using?

I'm just curious about this since I'm a database administrator.

EKeck · Oct 31, 2006

Tut tut!

darinwc said:
blech! those colors are hideous, like crab juice or something. Heh, well that list is a start. but they have the diagonals for the film wrong, and they dont include any panoramic formats.

Hello Darinwc!

The list was formulated from existing data. The author of it allowed others to do as they wished with it.

The diagonals are for the full sheet at its nominal size, not the area cropped off by the film holder, and the image circle required diameter; however that makes it darned close I'd say.

The whole point was to QUICKLY recognise a go-no-go situation and identify a lens that might not have enough stated coverage. The list has checked out well for many lenses, in spite of the fact that coverage stated is often on the conservative side.

The colors were chosen to make the different categories of coverage stand out, and no attempt to beautify things or make them fancy was made. It was just another way to organize a chart.

The link was shared with others as a starting point and another way to look at the data, certainly not as some kind of "know it all", super-duper project as you might wish to create.

It is odd that you would elect to put others down and make yourself all high and mighty when the list's intent was just to casually share, for fun and for free, a point of view that has been useful.

It is also odd that you didn't write to those nefarious "they" guys to point out your issues and concerns and alert them to the fact that anyone is even interested in the topic. Most charitable and community spirited of you I'd say.

Meanwhile, I'll advise those nefarious bad guys to take down the page at that link because you have complained about it and offered to replace it with a better product.

Good luck with your version though, and hopefully, you'll find all the data you need to make it go well.

Mark Sawyer · Nov 29, 2007

Just bumping this thread, wondering if the database ever came to be?

Uhner · Oct 17, 2008

Bump.

Please help with lens coverage database

darinwc

donbga

David A. Goldfarb

Moderator

darinwc

Oren Grad

df cardwell

Capocheny

darinwc

darinwc

AllenR

darinwc

Capocheny

jp80874

darinwc

argus

Steve Hamley

Ole

Moderator

colrehogan

donbga

darinwc

donbga

EKeck

Mark Sawyer

Uhner

Please help with lens coverage database

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