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Author Topic: Rokinon 14mm f/2.8  (Read 13253 times)

joshmurrah

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Rokinon 14mm f/2.8
« on: October 25, 2012, 09:10:45 AM »

I dug through the forums here, and I didn't see a dedicated thread (there was some good info in the 12-24mm thread tho).

I'm looking into this lens mostly for astrophotography, so I can shoot a wide view of night skies, milky way mostly.

I tried this out with my 24-105 for the meteor shower last weekend, and found that I need something faster, and something wider, so the Rokinon seems to satisfy both of these needs.

I have two big questions:

1)  does anyone have any experience shooting at infinity @ f/2.8 with this lens, does it have a fairly flat field of focus?
2)  Has anyone had experiencing correcting the strong distortion in ACR 7?  Is there a profile for a FF camera plus this lens in it that works well?

And of course, any general opinions about this lens would be great.

Thanks in advance!!
gripped 5DIII, 70-200 f/2.8L II, 24-70 f/2.8L II, 16-35 f/2.8L II, 8-15 f/4L, 50 f/1.2L, 85 f/1.2L II, 2x III, 3x 600EX-RT, ST-E3-RT

extremeinstability

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Re: Rokinon 14mm f/2.8
« Reply #1 on: October 25, 2012, 10:01:18 AM »
Number 2 first, I found one I believe in here:  http://www.adobe.com/products/photoshop/extend.displayTab2.html#resources  In the profile downloader area.  There was just one for the lens.  In the profile list I think it was listed as canon and not samyang/rokinon/etc.  Works great to remove the crazy distortion.   There so much resolution everything is still highly sharp after the correction. 

I haven't tried the Milky Way yet as the real good parts aren't high up now.  I wonder how well it will work as there is a lot of vignetting and light loss at F2.8.  May not matter given the brighter parts of the Milky Way get put in the middle.  It just has a way of not feeling like F2.8 I guess. 

Edge to edge is pretty sharp at F2.8 infinity.  It doesn't seem you even gain much more sharpness by stopping down than from where it starts at.  But I haven't used this lens all that much yet.  And my new/used 5D II also has a flange to sensor plane difference that needs fixed, but even on that it's good to go. 

Brand B

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Re: Rokinon 14mm f/2.8
« Reply #2 on: October 29, 2012, 03:56:07 AM »
I bought one a couple of weeks ago and shot some various test shots with it (5DIII) prior to leaving on a trip, and got pretty good sharpness, but I concentrated on F5.6.  Have not had a chance to do much with it at 2.8.  I shot some night shots, but there is so much light pollution where I live they were't worth keeping, not a hint of the Milky Way.

I bought PTLens and am correcting the distortion externally that way, but I use Aperture.  It has a plugin for LR and PS, but not for ACR.  It does correct the distortion quite well though.

I hope to do some shooting with it this weekend, and will post more conclusions.

tron

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Re: Rokinon 14mm f/2.8
« Reply #3 on: October 29, 2012, 07:34:54 AM »
Number 2 first, I found one I believe in here:  http://www.adobe.com/products/photoshop/extend.displayTab2.html#resources  In the profile downloader area.  There was just one for the lens.  In the profile list I think it was listed as canon and not samyang/rokinon/etc.  Works great to remove the crazy distortion.   There so much resolution everything is still highly sharp after the correction. 

I haven't tried the Milky Way yet as the real good parts aren't high up now.  I wonder how well it will work as there is a lot of vignetting and light loss at F2.8.  May not matter given the brighter parts of the Milky Way get put in the middle.  It just has a way of not feeling like F2.8 I guess. 

Edge to edge is pretty sharp at F2.8 infinity.  It doesn't seem you even gain much more sharpness by stopping down than from where it starts at.  But I haven't used this lens all that much yet.  And my new/used 5D II also has a flange to sensor plane difference that needs fixed, but even on that it's good to go.
Can you please get a picture of the night sky with the lens fully open and see how the stars show at the corners? If the lens has coma (which even Canon L lenses have fully open) they will look like ... seagulls!

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Re: Rokinon 14mm f/2.8
« Reply #4 on: October 31, 2012, 03:18:30 AM »

joshmurrah

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Re: Rokinon 14mm f/2.8
« Reply #5 on: October 31, 2012, 09:03:34 AM »
Price is the same at amazon (I imagine one of these two is matching the other).
gripped 5DIII, 70-200 f/2.8L II, 24-70 f/2.8L II, 16-35 f/2.8L II, 8-15 f/4L, 50 f/1.2L, 85 f/1.2L II, 2x III, 3x 600EX-RT, ST-E3-RT

extremeinstability

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Re: Rokinon 14mm f/2.8
« Reply #6 on: October 31, 2012, 10:42:14 AM »

Can you please get a picture of the night sky with the lens fully open and see how the stars show at the corners? If the lens has coma (which even Canon L lenses have fully open) they will look like ... seagulls!

I can but I have to be motivated enough to drag it out after dark lol.  I should have tested it for that before when I was testing all the other lenses.  I think I can chalk that up to not counting on this to be much of a night sky lens due to all the light fall off/vignetting.  I suspect there's enough vignetting at f2.8 with this lens that it will be hard to get bad coma issues with stars.  But now I am curious what the distortion would do to a star trail lol.  Anyway, I just kinda doubt the issue will be coma on a night sky with it F2.8 and as much vignetting as there is there(it's more than the 14L II...which also has winged stars/coma I guess).  I have to send my 5D II in to fix the mount to sensor plane issue, which might happen today, so it'd likely be after that returns. 

tron

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Re: Rokinon 14mm f/2.8
« Reply #7 on: October 31, 2012, 01:05:44 PM »

Can you please get a picture of the night sky with the lens fully open and see how the stars show at the corners? If the lens has coma (which even Canon L lenses have fully open) they will look like ... seagulls!

I can but I have to be motivated enough to drag it out after dark lol.  I should have tested it for that before when I was testing all the other lenses.  I think I can chalk that up to not counting on this to be much of a night sky lens due to all the light fall off/vignetting.  I suspect there's enough vignetting at f2.8 with this lens that it will be hard to get bad coma issues with stars.  But now I am curious what the distortion would do to a star trail lol.  Anyway, I just kinda doubt the issue will be coma on a night sky with it F2.8 and as much vignetting as there is there(it's more than the 14L II...which also has winged stars/coma I guess).  I have to send my 5D II in to fix the mount to sensor plane issue, which might happen today, so it'd likely be after that returns.
Thanks anyway! Even the vignetting information is useful. Unfortunately there is no such thing as a "free lunch". I' ll check vignetting in photozone.de and the-digital-picture.com
« Last Edit: November 02, 2012, 09:16:43 PM by tron »

cayenne

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Re: Rokinon 14mm f/2.8
« Reply #8 on: October 31, 2012, 02:20:14 PM »
FYI, price drop to $359 at B&H for this lens:

http://www.bhphotovideo.com/bnh/controller/home?sub=cpw&is=REG&Q=&A=details&O=productlist&sku=769532

Aside from the obvious price difference..how does this lens stack up to the Cannon 14MM?

http://www.amazon.com/Canon-Ultra-Wide-Angle-Digital-Cameras/dp/B000V5P94Q/ref=sr_1_1?ie=UTF8&qid=1351707415&sr=8-1&keywords=canon+14mm

The description for the cannon says it is "corrected for rectilinear distortion"....is the other lens?

Can someone give me a good definition (noob level) for what rectilinear distortion is? I'm guessing that is something to do with correcting fish eye lens looks?

Anyway, can someone compare on these? I was looking at the Canon...to mess with, but if this cheaper one is in the ballpark, might be a quicker way to play with a very ultra-wide lens...

I'd also seen some non-cannon, I think a Samyang (sp?) what was a 8mm?

cayenne

Drizzt321

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Re: Rokinon 14mm f/2.8
« Reply #9 on: October 31, 2012, 02:32:43 PM »
FYI, price drop to $359 at B&H for this lens:

http://www.bhphotovideo.com/bnh/controller/home?sub=cpw&is=REG&Q=&A=details&O=productlist&sku=769532

Holy crap that's tempting right now. Just got a couple of vintage m42 lenses off of ebay...so I'm going to avoid spending more money on lenses, even one this inexpensive.
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risc32

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Re: Rokinon 14mm f/2.8
« Reply #10 on: October 31, 2012, 08:45:21 PM »
I'm almost in the same boat as the OP, so i'd also like to hear what you guys have to say. I read a review somewhere, "lenstip?" that showed very little coma wide open. well below what my personal threshold would be for coma.  the other option is to get an "astrotrac", for a bit more money, then shoot away at nearly any f stop i want, but then it changes things once you start having your camera moving on even longer exposures.. ay well....

tron

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Re: Rokinon 14mm f/2.8
« Reply #11 on: October 31, 2012, 09:05:57 PM »
I'm almost in the same boat as the OP, so i'd also like to hear what you guys have to say. I read a review somewhere, "lenstip?" that showed very little coma wide open. well below what my personal threshold would be for coma.  the other option is to get an "astrotrac", for a bit more money, then shoot away at nearly any f stop i want, but then it changes things once you start having your camera moving on even longer exposures.. ay well....
I do have Astrotrac and I was able to take some nice wide field pictures of the sky. The problem is with Landscape Astrophotography where the camera has to be steady on a tripod. In addition I read many reviews where the buyers had exchanged their copies a lot until the got a good one (the main problem was decentering).

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Re: Rokinon 14mm f/2.8
« Reply #12 on: November 02, 2012, 09:41:26 AM »
The description for the cannon says it is "corrected for rectilinear distortion"....is the other lens?


The Rokinon is not.  However, PT lens, the correction utility, fixes the images quite well.

Axilrod

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Re: Rokinon 14mm f/2.8
« Reply #13 on: November 02, 2012, 06:16:15 PM »
I've heard nothing but great things about this lens and have considered ditching my 14L II for it.  I think the Rokinon is just as good in pretty much every aspect aside from distortion.  Pretty amazing that they can pump out such quality products for reasonable prices. 
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Drizzt321

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Re: Rokinon 14mm f/2.8
« Reply #14 on: November 02, 2012, 06:54:07 PM »
I've heard nothing but great things about this lens and have considered ditching my 14L II for it.  I think the Rokinon is just as good in pretty much every aspect aside from distortion.  Pretty amazing that they can pump out such quality products for reasonable prices.

Except, of course, for the weird and difficult to correct distortion :P   But I agree, it's fantastic they can deliver such great performance at such a price.

Now, the things we're lacking, is amazing build quality, and....I guess that's about it aside from the crazy distortion.
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