Lens length

[David Lindquist]

Can anyone explain the Kodak Ektars engraved 127mm & 203mm (great little lenses).
Pete.

I have a hunch Kodak's reasons for that are lost to the mists of time. Just checked my Kodak lenses:

The 1948 Wide Field Ektar is marked "250 mm." and in parentheses "(10 in.)"
The 1958 Commercial Ektar is simply marked "14 in.", with no metric equivalent
The 1959 f/7.7 Ektar is marked "203 mm." with no inch equivalent.

Not exactly a consistent pattern here.
David

[Jack Dahlgren]

*sigh* i wish the USA switched when they threatened to do so in the 70s. fractions suck bad! inches, feet, miles, pounds, all suck bad!

1 liter of water weighs 1Kg. how nice is that....and then all is divisible/multiply by 10.

oh the simpleness it could be.....

A pint is a pound, then all you need to do is divide by 16. :-)

[domaz]

A pint is a pound, then all you need to do is divide by 16. :-)

And a mile is 5280 feet. Of course! How elegant...

[Leigh]

1 inch = about 2.54 cm

Nope.

1 inch = EXACTLY 2.54 cm, by definition.

- Leigh

[Brian C. Miller]

A pint is a pound...

<joke> Could one of the lads over in the UK please go down to the pub and verify a pint? I see it's reportedly that way in Ruddles, but they might've downed a few before reporting in. </joke>

[Jim Jones]

And a mile is 5280 feet. Of course! How elegant...

And a mile is also 8 furlongs, 320 rods, 1760 yards, 5280 feet, 21,120 hands, and 63,360 inches. The first four were commonly used in rural America when I was growing up. I've only seen hands used to measure the shoulder height of horses, and never seen inches used for really long measurements. Surveyers also used chains and links. There is more logic to the English system of measurements than is immediately apparent, just as there is some logic to the characters used to write Chinese. However, the Chinese could be very elegant in their caligraphy.

[Ernest Purdum]

Thomas Jefferson advocated use of a decimal system of measurements. We didn't follow his suggestion, so now everybody is out of step except us.

When I was making metal things for a living, we had to keep the ability to work in both centimeters and inches. If I was working to customer design it was usually inches, unless the customer was an auto maker. If my own design, it was to metric dimensions.

I think Americans are afraid of having to constantly convert. You don't. You just lay a metric rule on the object to be measured.

[Leigh]

I just can't fathom all the different units of measurement.

- Leigh

[Pete Watkins]

Leigh,
You need to think more deeply (:-))
Pete.

[Helen Bach]

...There is more logic to the English system of measurements than is immediately apparent...

I agree, as long as you stay with one property (dimension). It's a natural sort of a system, with units being matched to their practical use at one time or another - an acre is a chain by a furlong, and this recalls a relationship with working the land before industrialisation.

Where it falls apart is in its failure to be systematic - when you start to combine fundamental properties (mass, length and time) to make others (power, force etc), and to compare. Then the advantages of SI (not just 'metric') really help with calculation and comparison.

Best,
Helen