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Best Way To Set Focus on Infinity?

wchettel
Frequent Contributor

I am using a Canon EOS Rebel SL2 with a Canon EF-S18-135mm f3.5-5.6 IS STM lens. Is there an easy way to set the focus on infinity when I'm using MF mode on the lens? I just want to set it and forget it.

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Walter
in Davie, FL
1 ACCEPTED SOLUTION

" I just want to set it and forget it."  " I occasionally like to take pics of the moon and stars ..."

 

That is one way to shoot nighttime stars. Set the lens to MF.  Use the widest aperture.  Focus in the day time on something you can see that is very far away and put a small piece of tape on the focus ring.  In the dark use your Liveview option to focus.

EB
EOS 1DX and 1D Mk IV and several lenses!

View solution in original post

47 REPLIES 47

Ray-uk
Reputable Contributor

I assume you are using it for astro-photography, if so then set your focus using the moon.

In normal photo conditions just focus on something as far distant as you can find, although I don't understand why you would want your focus fixed on infinity for everyday photo situations.

wchettel
Frequent Contributor

@Ray-uk wrote:

I assume you are using it for astro-photography, if so then set your focus using the moon.

In normal photo conditions just focus on something as far distant as you can find, although I don't understand why you would want your focus fixed on infinity for everyday photo situations.


Ray-uk, It's not for everyday photo situations. I live just off the flight path of Fort Lauderdale-Hollywood International Airport. A few times each day there's a flood of planes either landing or taking off. I'd just like to take some pics of the planes without worrying about the focus.

 

And, I occasionally like to take pics of the moon and stars but I usually do that using a tripod and remote control using the app on my phone.

--
Walter
in Davie, FL


@wchettel wrote:

@Ray-uk wrote:

I assume you are using it for astro-photography, if so then set your focus using the moon.

In normal photo conditions just focus on something as far distant as you can find, although I don't understand why you would want your focus fixed on infinity for everyday photo situations.


Ray-uk, It's not for everyday photo situations. I live just off the flight path of Fort Lauderdale-Hollywood International Airport. A few times each day there's a flood of planes either landing or taking off. I'd just like to take some pics of the planes without worrying about the focus. ...


Well, that's what autofocus is tor, isn't it? I would think that your camera, like other recent Canon DSLRs, must have at least one motion-sensitive AF mode that would suit your purpose.

Bob
Philadelphia, Pennsylvania USA


@wchettel wrote:

.

 

And, I occasionally like to take pics of the moon and stars but I usually do that using a tripod and remote control using the app on my phone.


Different types of light sources can focus in different ways.

 

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

 

Notice the red dot on the focus ring next to the vertical white line on the focus ring?  Both are infinity focus marks.

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

"Doctor told me to get out and walk, so I bought a Canon."

kvbarkley
Honored Contributor

Uh, no. The red dot is the infrared focus mark. RTFM.

"Uh, no. The red dot is the infrared focus mark."

 

It may take more than 10K for some folks. Smiley Very Happy

EB
EOS 1DX and 1D Mk IV and several lenses!


@kvbarkley wrote:

Uh, no. The red dot is the infrared focus mark. RTFM.


Uh, there is a lot of infrared in the night sky.  If you focus on visible light, then the infrared will be OOF.  One mark is infinity focus for visible light.  The other mark is infinity mark for infrared light.  Practice what you preach.

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"Doctor told me to get out and walk, so I bought a Canon."

kvbarkley
Honored Contributor

The "infinity mark" is the L mark in the distance scale. The line and red dot are the indicators of where focus is set. It has nothing to do with infinity.

 

If you want infinity focus you put the line or mark (as appropriate) on the L mark. If you want to focus at, say 5 feet, you put the dot or indicator at the 5 foot mark.

 

And while there is a lot of infrared in the night sky, I don't know if it is at the same wavelength of IR film.

The red dot is used to adjust the focus if you're shooting using an infrared filter.  Nowadays it doesn't have anything to do with IR film.

10,001 anybody? Smiley Happy

EB
EOS 1DX and 1D Mk IV and several lenses!