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Samyang 135mm F2 ... poor performance in 3 units.

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33 replies to this topic

#26 garret

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Posted 23 March 2020 - 01:57 PM

Many good examples of the Samyang135mm F2.0 out there, some not so good, some really bad. But one user with 3 lemmons is a little bit suspicious

The package delivery company/ person maybe. (rough handling)



#27 Alen K

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Posted 23 March 2020 - 07:03 PM

The package delivery company/ person maybe. (rough handling)

I can believe that. 

https://www.boredpan...era-lens-canon/


Edited by Alen K, 23 March 2020 - 07:05 PM.


#28 SandyHouTex

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Posted 23 March 2020 - 10:46 PM

This is Ap though, you dont need af, is, auto aperture, or magnesium lens bodies for shooting handheld in the hot sun. You just need glass that corrects well. The samyang 135mm does just that. Its made of glass fiber plastic and is all manual. Its unquestionably less sturdy than my 135mm Elmarit, but optically the Samyang is unquestionably superior. The point here is that you really need to learn how to troubleshoot your gear and it sounds like the camera is the issue here imo.

I would be interested in knowing how you have concluded that “...sounds like the camera is the issue here...”?



#29 SandyHouTex

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Posted 23 March 2020 - 10:48 PM

Sensor tilt at F2 can be a real pain.  My ASI183 produced good images at F6, suspect images at F4 (but very useable), but at F2 were completely unusable (ZWO kindly swapped it so all good).  Point being at F2 dont blame the lens until you 100% certain its not sensor tilt.  Also the Samyang is very easy to mod so it can focus slightly past infinity..google it.

If it was sensor tilt it would be consistently bad in the same corners for all of the 3 lenses tried.  I believe the OP said that wasn’t the case.



#30 Swordfishy

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Posted 24 March 2020 - 07:14 AM

If it was sensor tilt it would be consistently bad in the same corners for all of the 3 lenses tried.  I believe the OP said that wasn’t the case.

How are you securing it to the camera? Is it a native flange or an adapter? Only issue I have come across has been from that, slop in the adapter, I got it close by using aluminum foil to shimmy it, but it was inconsistent. Thus I bought the native one for my camera. Same lens as you and it is really good, save for SLIGHTLY larger stars in the extreme right corner. However, it is so minor and so isolated that I couldn't care less about it. I have plenty of real estate and for $400 it is superb.

 

 That is my .02 cents on it bud. Here is a sample with only the stacking artifacts cropped, essentially nearly the full frame is there.

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#31 SandyHouTex

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Posted 24 March 2020 - 10:03 AM

How are you securing it to the camera? Is it a native flange or an adapter? Only issue I have come across has been from that, slop in the adapter, I got it close by using aluminum foil to shimmy it, but it was inconsistent. Thus I bought the native one for my camera. Same lens as you and it is really good, save for SLIGHTLY larger stars in the extreme right corner. However, it is so minor and so isolated that I couldn't care less about it. I have plenty of real estate and for $400 it is superb.

 

 That is my .02 cents on it bud. Here is a sample with only the stacking artifacts cropped, essentially nearly the full frame is there.

Actually I’m not the OP.  See post 12.


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#32 Joepie

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Posted 25 March 2020 - 06:12 AM

The lens is great, although not every lens has it's lenses aligned perfectly. Quick and dirty edit of an image I took at the end of 2019 with my D800E and 135mm Samyang at F/2.0. No sharpening applied in any way. Focus wasn't perfect. Just cropped 5 pixels from every side, applied levels and curves in Photoshop and then saved to jpg @ 60% quality. I've unintentionally smacked this lens against a hard surface before and I had to send it to a repair center that realigned the lenses and did a great job as you can see:

 

MS7Kpuci207MAkYsoesp9Uis.jpg



#33 Poynting

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Posted 25 March 2020 - 09:19 PM

I have had some odd performance once before with my 6D and Rokinon 135mm where I definitely had some tilt between the sensor and lens. It showed up as half the image having slightly red halos and the other half having slightly blue halos. This was at f/2 where focus is critical. I recently took this image at f/2.8 and it shows no issues in my eyes. I'll try again at f/2 again someday and see how it performs.



#34 calypsob

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Posted 26 March 2020 - 08:32 AM

I would be interested in knowing how you have concluded that “...sounds like the camera is the issue here...”?

Well unfortunately we have not really arrived at a resolution. Op would need to share samples taken with other optics to rule out either the camera or lens.

F2 at 135mm is very unforgiving and microns of tilt or misalignment mean the difference between good and bad stars.

Edited by calypsob, 26 March 2020 - 08:34 AM.

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