minimum image circle / coverage for each format

[tenderobject]

Hopefully, i've posted this in the right place..

I've been searching and searching about minimum image circle/coverage for each familiar formats from 4x5, 5x7 to 8x10. was looking if there are some sites that have charts for this so i would know what lenses i can use for either of these formats.. i'm just really curious, since i've read some type of lenses can cover this type of format some lenses can either cover both formats.. thats where i'm confused.. IE: some 90mm lenses can cover 4x5 to 5x7 some other 90mm can only cover 4x5 becuase of its image circle/coverage.. can someone point me to a site where i can read more info about this? chart would be great as well! an extra info for ULF too :). how much (minimum)coverage does have a lens to cover a format. i think that would be my question.. sorry for my bad english and my stupid questions. :)

[Ron Marshall]

This is one of the spreadsheets on the front page of this site that shows the excess coverage of modern lenses on various formats; in this case 4x5. The film diagonal, the minimum image circle required, (153mm for 4x5) is shown at the top:

http://www.largeformatphotography.info/lenses/LF4x5in.html

[percepts]

Think Pythagoras. The square on the hypotenuse is equal to the sum of the squares on the opposite sides.

i.e. for 8x10 image circle = √(8² + 10²) = 12.80 inches. Any more than that gives you room for shift.

[Dan Fromm]

Percepts, remember that for sheet film actual image size is smaller than the nominal film size.

[percepts]

Percepts, remember that for sheet film actual image size is smaller than the nominal film size.

I included a small margin of error ;)

[tenderobject]

thanks ron marshall, percepts and dann..

@percepts : thats kinda new to me ack!