# Help: Canon 24mm f2.8 IS Vs. Canon 24mm f1.4L II for astrophotography



## Hjalmarg1 (Sep 27, 2014)

I am aware that these two lenses compete in different leagues in terms of build quality and IQ. 
I am planning to get into astrophotography and many folks have told me that my 24-70mm f2.8L (I) will not be good enough. 
There is a guy that is selling his 24mm f2.8 IS at a good price and the lens is in like-new condition, would you stay with the 24-70mm and give a try, or buy the 24mm f2.8 IS or keep saving and get the 24mm f1.4L II?

I am aware that there is a Rokinon 24mm f1.4 that seems to be a good option but I prefer to use canon. And my other current option will be my EF 15mm f2.8 (fisheye) lens.

If you go with any of the options, could you tell me why?

Thanks


----------



## dswtan (Sep 27, 2014)

Do NOT use the 24L II for astro. It is a complete waste of time. You will be frustrated, like others before you.

It has the most appalling coma (distorted stars in corners). This only shows up in astro. See: http://www.dpreview.com/forums/post/50949062 - there has been similar discussion in this Forum too, but that thread was the best I found.

I do not know how the 2.8 performs in this regard, but typically Canon seems to not have low coma in their priorities. I do have the 24L II and I have spoiled astro shots thanks to the coma - I made the same stick-with-Canon mistake as you. 

I now have a set of the Koreans dedicated for astro work. The Korean lenses are exceptional for astro. That they are so inexpensive is an amazing bonus. Manual focus is all you want at night. Live view to focus precisely. They are even sharp at full aperture. 

Buy your 2.8 if you need AF in daylight, this may be reasonable for your daytime purposes. But use the rest of your 24L savings and get yourself one of the Korean brands (Samyang/Bower/Rokinon) for night use. Seriously, they are just fantastic at night -- plus, it's at night. No one can see the brand you are using and we won't tell on you.


----------



## timmy_650 (Sep 27, 2014)

Use your lens. You got good enough lens to start in to asrophotography. After you take some picture decide what your lacking. The fisheye is fun but sometime too wide and the 24 might not be wide enough but you have the 16-35 f4 should do it. it would be better to be faster but they will be a bit nosier. Spend your money into getting into dark area and that will help the most.


----------



## Khalai (Sep 27, 2014)

24-70L II has very nice controlled coma, according to lenstip review. The new 16-35/4L as well, although f/4 can be slow for astro for some...

24/2.8 IS has some coma in the corners, worse than two lenses above: Lenstip review.


----------



## weixing (Sep 27, 2014)

Hi,
Most lens are not design for pin-point light source especially those wide angle lens, so if shoot at wide open and view at 100%, most likely you'll be disappointed... stopping down one or two stops might help.

Below is a website that might help you:
http://www.astropix.com/HTML/I_ASTROP/LENSES.HTM

Have a nice day.


----------



## Hjalmarg1 (Sep 27, 2014)

weixing said:


> Hi,
> Most lens are not design for pin-point light source especially those wide angle lens, so if shoot at wide open and view at 100%, most likely you'll be disappointed... stopping down one or two stops might help.
> 
> Below is a website that might help you:
> ...


Thanks you all! 
Common sense is to use the lenses I have and try something later. 
Lenses I was considering rated really bad in coma so, I will start trying with my 24-70mm f2.8L (I) and my 16-35mm f4L IS. I will then see if what I need. Now, I will save my money later.
Astropix.com also gave me some good references (indeed bad results).


----------



## Jim Saunders (Sep 27, 2014)

Here is what I got the other night with a 16-35 f/4. Please keep in mind that I don't do much of this.

Jim


----------



## Jim Saunders (Sep 27, 2014)

A close-up of the North star from the previous. I wouldn't have zipped them but the forum doesn't allow tiff. The only adjustment made to the image is the lens profile in LR5.

Jim


----------



## Mr Bean (Sep 27, 2014)

I'll throw a curve ball here. For astro work, I'd use a Zeiss 21mm f2.8 lens.
- Yes, it's manual focus, which doesn't matter for astro work.
- It has an infinity hard stop, meaning, just turn the focus until it stops, and its in focus for you. No fiddling around with Live View.
- It's tack sharp at f2.8 across the entire frame.

I have the 24mm f1.4 lens and its fantastic for terrestrial use. A beautiful lens. But, not one I'd use for astro work, as others have mentioned (lacking in sharpness).

I used the 21mm a couple of years back for some astro and landscape work. Even though I have the 24mm, I'd consider getting the 21mm for specific things.


----------



## neuroanatomist (Sep 28, 2014)

Khalai said:


> 24-70L II has very nice controlled coma, according to lenstip review.



Thanks for that bit of info! I'm going to try some night sky shots next month, sounds like my 24-70 II will be my best choice.


----------

