[MF3D.FORUM:1198] Re: How much shift can be necessary toset the window?

["Michael K. Davis" <zilch0@xxxxxxxxxxxx>]

Paul,

At 12:41 AM 8/30/00 -0500, you wrote:
>
>With a mirrored viewer you could use virtually any format.
>Why stop at 50x63?

I hear you.  Good point.

>> 50x63 would offer a 13.75% larger diagonal vs. 50x50
>> 50x63 would increase area by 26.0% vs. 50x50 (3150 sq. mm vs. 2500 sq. mm)
>
>Use of diagonal and area probably overstate the significance of the
>difference.  Richard Rylander came up with an "immersion factor"
>formula the last time this subject was discussed.  I suggest studying
>the many messages in the late December-early January time frame.
>This can easily be done using the date-order index in the archives
>at Marco's site http://www.pauck.de/archive/mailinglist/mf3d/mf3d.html
>by date:
>http://www.pauck.de/archive/mailinglist/mf3d/mhonarc/idx_date1.html
>
>Also, John Bercovitz kindly created a spreadsheet that utilizes
>Richard's formula, and has it available for download at:
>http://www.angelfire.com/ca2/tech3d/techdocs.html
>(see the line near the bottom "What solid angle does your
>format subtend at your eye? Rylander calculation. (Excel file)"
>which points to:
>http://www.angelfire.com/ca2/tech3d//FormatImmersion.xls
>Note: this is one person's attempt at quantifying "immersion factor."
>I don't even understand it's working very well, and I'm not trying
>to present it as "gospel truth."  Something to consider, however.

Thanks for the links.  I've looked at them and don't quite follow the
immersion factor stuff either, for lack of accompanying text perhaps.

>> 50x63 yields the dominant, if not esthetically preferable, 4:5 aspect ratio
>
>I'm not even going to touch that one.  ;-)  I'm just glad you
>aren't trying to sell the 2:3 aspect ratio of full frame 35mm.
>I don't care for that format at all.  I like the 4:5 format,
>but I don't know whether it's my favorite, and I certainly
>won't try to make the decision for anyone else!

Oh, I wouldn't force any aspect ratio on anyone, but I do think I'm correct
in making the objective observation that 4:5 enjoys a dominant position.
I'll not stir this any further by stating my personal likes and dislikes,
except to humbly offer, "I can't stand square images!"  :-) 

>> 50x63 would allow a mix of portrait vs. landscape orientations
>
>As does 40x50.  Maybe that's one reason we also have 40x50 and
>50x40 mounts in the 80x132 size.  :-)

Hey, there's an easy fix for my square-itis, albeit at the loss of overall
size...

>
>> 50x63 would simply make the best possible use of a 6x7 frame
>
>I'd be tempted to utilize more of the vertical dimension than just
>50mm.  If you have a means of assuring good vertical alignment in
>the cameras, there is no reason to crop off a full 5mm from the
>height, if image maximization is the goal.  So you could use a
>format like 53x57 in lieu of 50x63.  It would achieve some of the
>same goals as your proposed format, come close on others, allow
>more window setting flexibility, and attain a slightly higher
>immersion factor rating under Richard's formula (as presented in
>John B's spreadsheet; there may be some kinks to work out yet,
>however).  Perhaps most importantly it would have a better chance
>of being compatible with other folks' viewers.

I also hadn't considered going "taller" - thanks again!

Mike