Best crop for both 5X7 and 8X10?

[deeman]

What aspect ratio should I use that would cause the minimum amount of cropping when printing the same image at both 5X7 and 8X10?

I am assuming that 3 by 4 would be the best ratio, but maybe there is someone out there with a better idea.

 

[kovacj]

If you normalize the aspect ration for 5x7 and 8x10 you get 50x70 and 56x70 - i.e. the 5x7 is skinnier than the 8x10 so I would crop to 8x10 and then you'll lose a few more pixels when re-cropping down to 5x7 (but width only, no height).
-jk

 

[Phil Rose]

The more I think about this question, the more I conclude that--as presently stated-- it has no good answer. There is too much variability involved with respect to composition of an image you might wish to print at both 5x7 and 8x10. How tightly was the main subject framed? Portrait or landscape, etc., etc.

So, might you be more specific: is your question in regard to a decision about buying a digicam based on its aspect ratio (with an intention to print at both 5x7 and 8x10 from each image)? I suppose 3:4 (1:1.33) would be a good intermediate aspect ratio but it means little if the image isn't composed properly to allow the multiple format printing you envision. IMHO, the aspect ratio is a pretty poor (or trivial) basis on which to make a decision about digicam choice.

Phil

What aspect ratio should I use that would cause the minimum amount
of cropping when printing the same image at both 5X7 and 8X10?

I am assuming that 3 by 4 would be the best ratio, but maybe there
is someone out there with a better idea.

 

[deeman]

Just to clarify, this has nothing to do with a camera purchase. This is the final cropping of an image that will be posted and could be printed as either a 5X7 or 8X10

So, might you be more specific: is your question in regard to a
decision about buying a digicam based on its aspect ratio (with an
intention to print at both 5x7 and 8x10 from each image)? I
suppose 3:4 (1:1.33) would be a good intermediate aspect ratio but
it means little if the image isn't composed properly to allow the
multiple format printing you envision. IMHO, the aspect ratio is a
pretty poor (or trivial) basis on which to make a decision about
digicam choice.

Phil

What aspect ratio should I use that would cause the minimum amount
of cropping when printing the same image at both 5X7 and 8X10?

I am assuming that 3 by 4 would be the best ratio, but maybe there
is someone out there with a better idea.

 

[danielsan1]

4:3 gives the least cropping for 5x7 (6x8 vs 6x9) whereas 3:2 gives the least cropping for a 8x10(8x12 vs 9x12). Pick your poison.

What aspect ratio should I use that would cause the minimum amount
of cropping when printing the same image at both 5X7 and 8X10?

I am assuming that 3 by 4 would be the best ratio, but maybe there
is someone out there with a better idea.

 

[Tricia]

4:3 gives the least cropping for 5x7 (6x8 vs 6x9) whereas 3:2 gives
the least cropping for a 8x10(8x12 vs 9x12). Pick your poison.

Actually, 4:3 would be better for 8x10 - precropping is 8x10.667.
3:2 for 5x7 is 5x7.52 and 4:3 is 7x5.25.

--
Tricia

 

[Driveguy]

Here are two diagrams - I propose that images with unimportant stuff...

on the sides use an 8x10 crop, so if it goes to 5x7, nothing important is lost

on the top / bottom use an 5x7 crop, so if it goes to 8x10, nothing important is lost

Not a universal answer, but something I need lately when I have event photos for sale - people can order a 5x7 or an 8x10 of the same photo

 

[gscotten]

What aspect ratio should I use that would cause the minimum amount of cropping when printing the same image at both 5X7 and 8X10?

I am assuming that 3 by 4 would be the best ratio, but maybe there is someone out there with a better idea.

Why would you crop it at all until you are ready to print, and only then crop for that specific aspect ratio? The next customer might want 4x6.

 

[NAwlins Contrarian]

Here are two diagrams - I propose that images with unimportant stuff...

on the sides use an 8x10 crop, so if it goes to 5x7, nothing important is lost

on the top / bottom use an 5x7 crop, so if it goes to 8x10, nothing important is lost

Not a universal answer, but something I need lately when I have event photos for sale - people can order a 5x7 or an 8x10 of the same photo

This thread is nineteen years old.

That said, the response above doesn't answer the OP's question.

What the OP supposed / suggested, that a 4:3 or 3:4 starting aspect ratio produces the minimum image loss when further crops to 5:7 and 4:5 are equally possible, is very close to correct. To be technical, the optimum is not 1.33:1 but 1.32:1.*

The purpose of determining such a crop is to deliver one file that the recipient can crop further for either print size with minimal loss. It has nothing to do with what crop is best for what composition.

*To determine the optimum, take the square root of the ratio of the aspect ratios, then multiply that by the lower ratio. SQRT((7:5)/(5:4)) = SQRT(1.4 / 1.25) = SQRT(1.12) = 1.0583; 1.0583 x 1.25 = 1.3229. If you crop to a 1.3229 aspect ratio, then either a 5x7 or an 8x10 will be a further 1.058x crop (94.5% retained) along the dimension cropped. This is the process by which the 16:9 aspect ratio was chosen for HDTV: it's very close to an equal crop between legacy 4:3 TV programs and 2.39:1 widescreen movies.