Canon Community Canon Community
 


Reply
Highlighted
Occasional Contributor
Posts: 5
Registered: ‎08-05-2019
Accepted Solution

canon 35mm f2 is usm

can anyone tell me what the fixed marks 22 11 and the red dot on the focus ring indicator signify

VIP
Posts: 8,471
Registered: ‎08-13-2015

Re: canon 35mm f2 is usm

[ Edited ]

The numbers are an aperture settings.  They are showing the approximate depth of field at those aperture settings.  As you vary the focus, you can read off of the focus ring how deep the DoF would be.

 

26B1D035-9104-4720-8725-49875F4FB858.jpeg

 

The lens in the image is focused at the hyperfocal distance.  I am not sure about the red dot.  

----------------------------------------------------------------------------------------------------------------------------------------------------------

"I don't rent software. I use Photoshop CS6, ACR 9.8 and Lightroom 6.8 ."
Occasional Contributor
Posts: 5
Registered: ‎08-05-2019

Re: canon 35mm f2 is usm

Thanks
Honored Contributor
Posts: 5,040
Registered: ‎06-25-2014

Re: canon 35mm f2 is usm


@Waddizzle wrote:

The numbers are an aperture settings.  They are showing the approximate depth of field at those aperture settings.  As you vary the focus, you can read off of the focus ring how deep the DoF would be.

 

26B1D035-9104-4720-8725-49875F4FB858.jpeg

 

The lens in the image is focused at the hyperfocal distance.  I am not sure about the red dot.  


It appears to me that the lens is focused at infinity, not at the hyperfocal distance. I think that the two numbers to the left of the vertical bar point to the hyperfocal distances at f/22 and f/11 when the lens is focused at infinity.

Bob
Philadelphia, Pennsylvania USA
Esteemed Contributor
Posts: 3,466
Registered: ‎02-17-2016

Re: canon 35mm f2 is usm

[ Edited ]

The red dot is for infrared focus, because the wavelength is different, you need to focus at a slightly different point. It does not mean much for a DSLR. 8^)

VIP
Posts: 11,491
Registered: ‎12-07-2012

Re: canon 35mm f2 is usm

Now for the correct answer.

The white lines are the DOF, or hyper focus, you use the hyper focal distance scale to know which parts of your image will be in focus at different aperture settings.  The red dot is used to adjust the focus if you're shooting using an infrared filter. When set to infinity the focus ring is turned slightly to the left so that the infinity marking appears in line with the red dot. For 99% of us it is useless. The side ways "L" is a variable infinity because infinity can come at slightly different places depending on several factors.

EOS 1DX and 1D Mk IV and several lenses!
Respected Contributor
Posts: 1,075
Registered: ‎11-19-2017

Re: canon 35mm f2 is usm

[ Edited ]

Red dot on hyper focal distance scale.

 

Good questions.

 

Its the infrared focusing mark.  Believe its a carry over from days gone by.  With infrared film you actually had to focus at a different place than normal because the infrared spectrum of light is different than what we see with our eyes.  No idea how to replicate digitally, but I guess it can still be done. 

 

*****All 3 of us posted over one another  LoL

Rick
Bay Area - CA
~6D2 (f/w 1.0.4) ~16-35mm f2.8L II, 50 f1.8 STM, 85 prime USM, 70-200 f2.8L IS II ~70-300 USM II ~Sigma 24-70 f2.8 Art (f/w 2.02)
~Sigma 150-600 C + TC1401 1.4x (f/w 2.00) ~Speedlite 430 EX II ~DxO PhotoLab Elite ~Windows10 Pro1903 ~EVGA RTX 2080 FTW3 Ultra
VIP
Posts: 11,491
Registered: ‎12-07-2012

Re: canon 35mm f2 is usm

"*****All 3 of us posted over one another"

 

It would seem so. Smiley Happy

In fact most lenses don't have many marks on them at all anymore.

EOS 1DX and 1D Mk IV and several lenses!
Occasional Contributor
Posts: 5
Registered: ‎08-05-2019

Re: canon 35mm f2 is usm

Thanks everyone. Appreciate your help and knowledge
Esteemed Contributor
Posts: 3,466
Registered: ‎02-17-2016

Re: canon 35mm f2 is usm

The cool adaptive LCD display on my 70-300 II does not have an infrared mark. 8^)

 

I am hoping for a firmware update so that it will show the hyperfocal distance.

powered by Lithium

LIKE US on Facebook FOLLOW US on Twitter WATCH US on YouTube CONNECT WITH US on Linkedin WATCH US on Vimeo FOLLOW US on Instagram SHOP CANON at the Canon Online Store
© Canon U.S.A., Inc.   |    Terms of Use   |    Privacy Statement