Please examine this sharpness test on my new Rokinon 16mm/f2

Navman said:

Hi Rudy, I've seen worse. Another way that I've tested this is to take an infinity focused landscape shot which I've then repeated with the view framed the same but with the camera inverted. Alternatively frame something - I use the pylons across the road from my house - so that it is located in the same relative position in each of the four corners of consecutive images, and compare those. I've had two lenses replaced after this sort of test, and one was a Loxia 21 - the NZ Zeiss agents were very good about it.

-John

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Navman said:

Hi Rudy, looking again, are you sure that this isn't field curvature? You don't say what aperture that you shot at, but I would also compare with an image focused on the corner. And if your intended use is astro, I'd be doing it at infinity, ie, close to your intended us.

-John

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Navman said:

You don't say what aperture that you shot at,

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Member said:

but I would also compare with an image focused on the corner. And if your intended use is astro, I'd be doing it at infinity, ie, close to your intended us.

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Member said:

-John

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RudyPohl said:

Hi There,

After a year of giving up trying I broke down and bought another Rokinon ultra-wide angle lens, the Rokinon 16/f2.

I did a preliminary sharpness test by shooting a flat screen of aluminum mesh screen, critically focusing on the center and then checking throughout the frame, especially in the corners.

I have cropped a section of the center and laid it onto the upper right corner. It looks to me that the corner is very unsharp compared to the center.

- What is your opinion?

- What do you think the issue, simply a soft corner or decentered lens? Note that the right=hand corners are noticeably sharper than the left side.

- Do you think I should send the lens back to the store?

Thanks,
Rudy


Center/corner sharpness test - Rokinon 16/f2

Here is the entire frame 6000 x 4000 pixels shot on a Nikon D5500


Sharpness test - Rokinon 16/f2

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RudyPohl said:

The results this time were much much better. I think I might be keeping this lens provide the actual field test on real stars work out well.

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TJL LTFF said:

RudyPohl said:

The results this time were much much better. I think I might be keeping this lens provide the actual field test on real stars work out well.

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That result looks really good. As a follow up it would be fun seeing your stellar lens test photo.

good luck and have fun

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chris gunn said:

If you want to use it for star pics, I recommend doing a star pic test.

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Will B Milner said:

Looks pretty good to me Rudy. Can't wait for some of those epic farm-scapes.

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BlackgumNate said:

Rudy! I wish I'd known you wanted this lens, I mighta given it to you. I recently sold mine after being listed for some time. It was a new one they sent me as my first was decentred.

Agreed, you want it for stars, test on stars.

Don't make me regret getting rid of that little thing

nate

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RudyPohl said:

BlackgumNate said:

Rudy! I wish I'd known you wanted this lens, I mighta given it to you. I recently sold mine after being listed for some time. It was a new one they sent me as my first was decentred.

Agreed, you want it for stars, test on stars.

Don't make me regret getting rid of that little thing

nate

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Hi Nate,

Yea, too bad we didn't know what the other was doing... oh well c'est la vie!

I did manage to get the thing on sale for $130 Canadian off the reg price, ended up paying $450 for it which will be all well and good if it does the job. I will continue working on my 35mm mosaic pano technique this season, but I want a fast ultra-wide with good coma control and sharpness for shooting single frame wide Milky Way.... here's hoping.

Rudy

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1llusive said:

RudyPohl said:

BlackgumNate said:

Rudy! I wish I'd known you wanted this lens, I mighta given it to you. I recently sold mine after being listed for some time. It was a new one they sent me as my first was decentred.

Agreed, you want it for stars, test on stars.

Don't make me regret getting rid of that little thing

nate

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Hi Nate,

Yea, too bad we didn't know what the other was doing... oh well c'est la vie!

I did manage to get the thing on sale for $130 Canadian off the reg price, ended up paying $450 for it which will be all well and good if it does the job. I will continue working on my 35mm mosaic pano technique this season, but I want a fast ultra-wide with good coma control and sharpness for shooting single frame wide Milky Way.... here's hoping.

Rudy

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I'm in the same boat. I want to get the Sigma 35 1.4 this year to do some pano/mosaic images because of the increased detail and better perspective it will bring. Another wrinkle going against my 16 f/2 is that a lens that wide and fast will struggle with interference filters like UV/IR around the edges of the frame. So, the 35 is very likely in my future.

The 16 is a great lens, though. I wouldn't be surprised if it ends up being the sharpest lens you own at nearly any aperture and you end up doing daytime landscapes with it as well.

I even used it hand-held when I needed to photograph really large objects in a dim hangar.

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RudyPohl said:

1llusive said:

RudyPohl said:

BlackgumNate said:

Rudy! I wish I'd known you wanted this lens, I mighta given it to you. I recently sold mine after being listed for some time. It was a new one they sent me as my first was decentred.

Agreed, you want it for stars, test on stars.

Don't make me regret getting rid of that little thing

nate

Click to expand...

Hi Nate,

Yea, too bad we didn't know what the other was doing... oh well c'est la vie!

I did manage to get the thing on sale for $130 Canadian off the reg price, ended up paying $450 for it which will be all well and good if it does the job. I will continue working on my 35mm mosaic pano technique this season, but I want a fast ultra-wide with good coma control and sharpness for shooting single frame wide Milky Way.... here's hoping.

Rudy

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I'm in the same boat. I want to get the Sigma 35 1.4 this year to do some pano/mosaic images because of the increased detail and better perspective it will bring. Another wrinkle going against my 16 f/2 is that a lens that wide and fast will struggle with interference filters like UV/IR around the edges of the frame. So, the 35 is very likely in my future.

The 16 is a great lens, though. I wouldn't be surprised if it ends up being the sharpest lens you own at nearly any aperture and you end up doing daytime landscapes with it as well.

I even used it hand-held when I needed to photograph really large objects in a dim hangar.

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Hi Eric,

Nice image in the hanger. Regarding mosaics, I have struggle with them for two entire Milky Way and I'm still no bloody good at them, and I'm not normally photographically or technically challenged. It just seems that one thing or another messes them up so that I end up with nothing.

The 16/2 is a backup solution so that as I continue working on my mosaic shooting I will know that before the end of my session I can haul out my Rokinon and still come away from the evening with a nice usable image. This is especially the case for the next few months when the Milky Way will still be low enough in the sky that I can get a full arch composition which is my aim.

I live in an unbelievably light-polluted area and to get a location that will allow a full arch comp is extremely hard to find... if we head too far east of Ottawa, since the MW is in the eastern sky, we head right into the Montreal light dome. Anyways, all together there's not much room for error and not much time for messing around if you want to come away with a full arch, especially in February where it is visible for less than an hour and really only decent for half that.

Rudy

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