Beginner Help setting infinity

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Ellie Mac

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Lorna
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Beginner to photography can anyone let me know how to set infinity ? want to be ready to capture the northern lights, thanks
 
Believe it or not a cannon 5D mark III (indulgent Husband!!) feel a bit silly asking this very basic question but I just cannot get it right, thanks
 
Just put the camera into manual focus and turn the aperture ring on your lens to the infinity sign, its a bit like a sideways figure 8, not all lenses have the infinity setting by the way, apparently it is something to do with damaging the ultra sonic motors or something like that, I seem to remember reading somewhere.
 
Check with live view and mark the setting, most autofocus lenses will go past infinity and back to focus, so infinity could be anywhere from the start of the symbol to the end of the 'L' shaped marking after it.
 
You should Not set your lens to infinity by using the infinity sign on the lens as most such marks are inaccurate. As correctly stated above you switch you lens to manual, switch on live view, point camera at a bright star, focus camera ( manually), press the magnify button which magnifies the live view field and refine your focus once again. All this needs to be done on a tripod.
If you are preparing to shoot the northern lights I suggest you first practice getting ultra sharp shots of stars ( which are basically at infinity), at home, before you make your trip. There is nothing worse than being fa ed with a fantastic aurora and not knowing what you are doing !
If you need more help you can always email me.
James
 
As above, practice on stars or even the moon. The smallest of movement on the focus ring can make the shot sharp or out of focus, and the infinity mark is not accurate. Even the old lenses with infinity stop are often slightly off and need to be backed up a bit from the stop.
 
jbw said:
You should Not set your lens to infinity by using the infinity sign on the lens as most such marks are inaccurate.
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snerkler said:
and the infinity mark is not accurate
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I'm not saying you're both wrong but I would check the infinity mark first before dismiss it completely, on my Tamron 17-50 its spot on :)
 
sk66 said:
"Infinity" varies with the wavelength of light and temp; in fact, all focusing does... any preset marking can only be an approximation.
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I'm asking this because I'm keen to learn ;) ...........Surely when set to infinity the depth of field is so great, that wouldn't matter?
 
sk66 said:
"Infinity" varies with the wavelength of light .
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True for a some ancient camera camera with only one simple lens if front of but all ( without exception) modern lenses are compound lenses that will bring the two ends of the spectrum to the same focus - I expect you have heard of apochromatic lenses etc ?
 
Perhaps your husband could explain it to you, much easier to be shown first hand
 
sk66 said:
Well, the DOF *in front of* the focus point is great, but not beyond it.
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Well according to this, unless I'm missing something, that's not correct. A quick Google and I found this............and I'm not here to argue with you, just to clarify things ;)

In addition to closing down the diaphragm (i.e., smaller aperture), we can also focus at the hyperfocal distance. If a lens focuses at infinity, the depth of field starts at somewhere in front of the lens and extends to infinity. More precisely, from that point on, the scene appears sharp, and subjects between that point and the lens are out of focus. The distance from the lens to that point is referred to as the hyperfocal distance. In the figure below, the hyperfocal distance is marked with a thick red line.



hyperfocal-1.jpg
 
Phil-D said:
Well according to this, unless I'm missing something,
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I think you are... where is the point of focus in that diagram? It's on the right side...

One would think that "infinity" cannot have a limit... that's what it means right? And how can there be any DOF beyond infinity? But by that same principle an object cannot be at an infinite distance. I think it's better to consider the infinity range as meaning "unmeasured/uncalibrated."
Anytime you focus beyond the HFD the far DOF limit is infinity and the near limit is never less than the HFD... but that's DOF and not "focus." Anyone who's ever tried to take pictures of the moon or stars has seen that just having "infinite DOF" does not mean the moon/star is actually in focus.
 
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sk66 said:
I think you are
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Well, what ever it is I'm missing, when shooting in the dark, manually setting the lens to infiity, works for me ;) :)
 
I don't do astro photography; landscapes and people mostly, but on my 5D3 with 17-40, and 24-105 I've had the best results when you turn the lens to infinity, but then pull it back to just before the end of the little "¬" shape to the left of the infinity symbol. Also, make sure stabiliser is off. As mentioned already manual focus is without doubt the best option and use live view and magnify so you've got the best possible view.
 
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