Re: Pop Photo Resolution Lines Per ? MATH

[Roger Eichhorn <eichhorn@xxxxxx>]

It's handy to regard unit conversions as though the units were  
algebraic symbols.  They can then be cancelled.  For example  2.54 cm/ 
in X 12 in/ft = 30.48 cm/ft.  Inch is in the denominator of the first  
and in the numerator of the second.  The two cancel.  Take the last  
result and multiply by 3 ft/yd and you get 91.44 cm/yd as ft cancels.   
Take he reciprocal of this last result and you  get 0.1094 yd/cm.  It  
avoids a lot of errors.

Roger

On 14 May 2008, at 4:11 PM, PhotoRoy6@xxxxxxx wrote:

> So Jim, Michael is right
> ( Further, your math is wrong. 2100/25.4 = 82 lines, which  
> translates into
> 41 lp/mm. Keep in mind that these tests are at full contrast (i.e.  
> Black lines
> on white background) so comparison to normal 50% MTF is difficult.
> )
> which makes digital APS-C no where near to 35mm film in terms of   
> resolution.
> Thanks,
> Roy
>
>
>
> In a message dated 5/14/2008 8:48:08 A.M. Eastern Daylight Time,
> jimth@xxxxxxxxxxxxxxx writes:
>
> Your understanding of conversions between metric and  imperial  
> measurements
> is decidedly limited.
>
>
>
>
>
>
>
>
>
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