Lens language

[rhadorn]

I have newly a Canon 24-105 lens. I did not get any user guide with it and did not find any on Internet. I suppose some of you can answer two rather basic quesitions of mine.

On the distances scale, the infinity mark has a l___ sign on its left. I suppose infinity should be on the 'l' and the ___ beyond is the headroom needed by the focus mechanism to focus on infinity. Is this assumption correct?

Right of the distance mark, there are red engravings with the following numbers: 50, 35, 24. I suppose these allow for setting the focus on the hyperfocal distance at full aperture for three focal lengths. Is this correct?

If the above is correct, is it of any use?... I tend either to select the focus point depending on the picture I take or (actually seldom) to use a chart with hyperfocal distances.


Reto

[Geoff F]

I also bought that lens this year, but I can't remember if there was a booklet with it. I can't find one with my other camera instruction leaflets.

However I will quote from the 28-135 booklet:

'To compensate for shifting of the infinite focus arising from changes in temperature the distance scale can be rotated past the normal infinity focus mark. To ensure accurate focus, look through the viewfinder and check the focus before shooting.

The figures in red above the distance scale are the infrared index. The infrared index is used when black and white infrared film is used. After achieving focus, shift the current distance setting of the distance scale to the infrared index mark.'

But in reality, I just look through the viewfinder and focus as required.

A good quality well built lens I find.

[arith]

Canons site is horrendous; I can't find anything but did come across this:

http://www.canon.co.uk/For_Home/Prod...nouncement.asp

[rhadorn]

I was not aware that some people still shoot on infrared film. Of course, I had similar marks on all my lenses from wet times...

My lens is a UX something.

Thanks to both of you.


Reto