EF-S 18-135mm f/3.5-5.6 IS STM - Best Way To Set Focus on Infinity?

[wchettel]

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.

[ebiggs1]

"...that's what autofocus is tor, isn't it?"

I would say let the camera do its thing with AF for distant airplanes, too.

[ebiggs1]

"...Canon EF-S18-135mm f3.5-5.6 IS STM lens."

Some lenses do not do a very good job at night sky photography and you have one that doesn't. If you really want to get good shots of the sky look for a more suitable lens for that purpose.

[ebiggs1]

Oh, BTW, the particulars were...................

EOS 1DX, Canon EF 16-35mm f/2.8L II USM Lens.
30sec, ISO 3200, f4.

And, yes, I know, I know this isn't the best choice lens for night sky work either but it is a typical sample and settings if you don't have dedicated astro gear.

[wchettel]

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@ebiggs1 wrote:

"...Canon EF-S18-135mm f3.5-5.6 IS STM lens."

Some lenses do not do a very good job at night sky photography and you have one that doesn't. If you really want to get good shots of the sky look for a more suitable lens for that purpose.

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Got any suggestions for a more suitable lens? I also have a Canon EF 75-300mm F4-5.6 III lens that came with my kit.

[robgilmo]

If the lens isnt marked, point at a star, focus ring all the way out, then bring it back a little.

[ebiggs1]

"I also have a Canon EF 75-300mm F4-5.6 III lens ..."

That would be a worse choice.  Typically you want a lens with a low f-ratio like the 16-35mm I used.  ALso you typically want a lens that has a fast aperture like f2.8 again like the one I used.  Of course this advice is for stars and the Milky Way type objects.  If on the other hand you wanted to do a Moon shot then you might give your "EF 75-300mm F4-5.6 III lens ..." a try.

Stars are so far away that a 300mm camera lens wil not make any difference in magnification. A super great lens for a Rebel camera is the Sigma 18-35mm f/1.8 DC HSM Art Lens. Another is the Canon EF-S 17-55mm f/2.8 IS USM Lens. Not only would they do an admirable job on the night time sky, they are excellent normal general use lenses.

[Waddizzle]

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@wchettel wrote:

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@ebiggs1 wrote:

"...Canon EF-S18-135mm f3.5-5.6 IS STM lens."

Some lenses do not do a very good job at night sky photography and you have one that doesn't. If you really want to get good shots of the sky look for a more suitable lens for that purpose.

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Got any suggestions for a more suitable lens? I also have a Canon EF 75-300mm F4-5.6 III lens that came with my kit.

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Your 18-35mm can do a perfectly satisfactory job of capturing landscape shots with the Milky Way in the sky.  All you need is [a] sturdy tripod that won't wiggle in a breeze, and maybe a wired remote shutter release.  The shutter delay built into the camera works, [too], instead of buying a remote.  

Using Manual shooting mode, you would want to use the the shortest focal length and the widest aperture, 18mm at f/3.5.  Ernie used f/4 in his example.  You can capture a good exposure using a 15 second shutter speed.  The way to determine shutter speed is to use the 500 rule.  This rule is a guide to determining the longest exposre you can capture before you start seeing star trails.  

It works by dividing 500 by the focal length you are using.  Except, 500 is what works for a full frame camera body.  With a crop sensor body you could use 300, or you could multiply the 18mm by the camera crop factor and use 500.

Setting the ISO is another matter.  Depending upon how much stray light is in your night sky, you can use anywhere from ISO 800 to ISO 6400, or higher.  I recommend starting at ISO 800.  The higher your ISO, the more noise will be present in your images.  Noise can be reduced [through] image stacking in post processing.  But, for a single shot I recommend ISO 800 as a starting point.  Try higher ISO values, and determine if the shots are too noisy for your liking.

Good luck.

[wchettel]

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@Waddizzle wrote:

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@wchettel wrote:

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@ebiggs1 wrote:

"...Canon EF-S18-135mm f3.5-5.6 IS STM lens."

Some lenses do not do a very good job at night sky photography and you have one that doesn't. If you really want to get good shots of the sky look for a more suitable lens for that purpose.

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Got any suggestions for a more suitable lens? I also have a Canon EF 75-300mm F4-5.6 III lens that came with my kit.

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Your 18-35mm can do a perfectly satisfactory job of capturing landscape shots with the Milky Way in the sky.  All you need is [a] sturdy tripod that won't wiggle in a breeze, and maybe a wired remote shutter release.  The shutter delay built into the camera works, [too], instead of buying a remote.

...

Good luck.

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Just curious? Did you mean to say my 18-135mm lens?

[Waddizzle]

Yes, that is a typo.  Your 18-135mm can do a more than adequate job set to 18mm.

[ebiggs1]

Here is why it isn't the best choice for night sky photography the other don't seem to know about or understand.

Distortion is one issue, that is to be expected from a zoom lens of this range and type.  It is acceptable for average daytime snapshots but not so much for night sky work.  This lens also vignettes the corners which means it illuminates the edges of the frame less brightly as the center of the frame.  Again not a big deal for normal photography.  Lastly it suffer from CA which again is more sever at the corners and is worse at 18mm. CA becomes pretty good above 18mm but 18mm is what you want.  Some of this can be corrected in software like PS/LR and done so nicely for day time work. However, the stars will be comas or curves instead of dots and have odd coloring for night sky work.

I know of no serious night sky photographer that uses a longer zoom lens for good night sky work.  Here the prime lenses rule. And fully manual primes are a real good idea. If you just want a night sky shot and don't care if it is really high IQ, shoot away. It will take a picture!

A lens like the Rokinon 14mm f/2.8 IF ED UMC Lens, fully manual, which is about $250 bucks is a much better choice, IMHO, of course. There are others too but that one is a best buy.