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

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#1 elakrab

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Posted 17 March 2020 - 11:03 AM

Some months ago, while I was in an observatory in Arizona, I bought an unit of the Samyang 135mm F2 for my Canon 6D (Full Frame) and I got a lemon. Amazon offered to exchange it, and I got another lemon. Not believing my bad luck, this last week I bought another unit in Amazon Germany, thinking that maybe I was just unlucky and got two units of a bad batch ... well, does not look like it, I got a third lemon and enough to say that Samyang QC is just plain horrible. Even more, by default it does not focus to infinity, but maybe to 50-100m max (it can be adjusted, but you have to disassembly it, not really that nice).

 

It is also interesting to note that it is not sensor tilt, as in different units the corner that looks the worst changes.

 

I cannot but strongly suggest you to stay away from the Samyang/Rokinon lenses, in particular this well reviewed 135mm F2. 

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Edited by elakrab, 17 March 2020 - 11:05 AM.

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#2 RichCO

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Posted 17 March 2020 - 02:33 PM

This is why I gave up on third party lenses (although they have gotten better in general).

 

Manufacturing lenses consistently perfect is hard - and is a big factor in manufacturing cost and retail price.  Same with telescopes I guess.

 

Great lens when you get a good copy though.



#3 Tapio

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Posted 17 March 2020 - 03:06 PM

Might have worked with APS-C camera.
Anyway, there's a significant price difference compared to better QC.

#4 Erik Bakker

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Posted 17 March 2020 - 03:25 PM

There is a price to pay for good quality plus a significant bonus for consistency. If that is what you want, be prepared to pay for it.

Prices will be lower on a good used sample.



#5 t-ara-fan

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Posted 17 March 2020 - 04:29 PM

 

I cannot but strongly suggest you to stay away from the Samyang/Rokinon lenses, in particular this well reviewed 135mm F2. 

That lens is about half the price of real Canon L glass.  IF it was half as good, that would be fair. But your examples were garbage.

 

Also, that lens is not a refractor even if it refracts.
 


Edited by t-ara-fan, 17 March 2020 - 04:30 PM.


#6 rgsalinger

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Posted 17 March 2020 - 06:01 PM

There's a fixed cost to making a lens (in China), materials, packaging it, shipping it, marketing it, followed by possible even 2 markups before you get it. So that 500 dollar lens may really be a 200 dollar lens. Take the same (more or less) 300 dollars of ingredients and overheads out of the 1000 dollar Canon and you're starting with a 700 dollar lens. I've made this point in the past about equipment generally, there may be a non linear relationship between even massed produced similar goods and their prices.

Rgrds-Ross 

 


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#7 hoof

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Posted 17 March 2020 - 08:15 PM

That lens is made in Korea ;)

Sorry you got bad copies. I got the Samyang 135mm F/2 years ago and its sharp sharp sharp. It’s also something rare with camera lenses: truly apochromatic. If you can get a good copy, it’s optically one of the best 135mm lenses ever made.

That said, mine mostly gets used nowadays attached to my Night Vision device.
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#8 calypsob

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Posted 18 March 2020 - 05:59 AM

You just made a multi paragraph post slamming a lens without comparing other lens data collected by your 6D. 

Does other glass do better on your camera? 

Did you have the lens supported or was the bayonet supporting the weight of the camera?

any sensor tilt?

 

also what does an entire frame look like?


Edited by calypsob, 18 March 2020 - 06:02 AM.

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#9 Kevin_A

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Posted 19 March 2020 - 10:37 AM

That lens is made in Korea wink.gif

Sorry you got bad copies. I got the Samyang 135mm F/2 years ago and its sharp sharp sharp. It’s also something rare with camera lenses: truly apochromatic. If you can get a good copy, it’s optically one of the best 135mm lenses ever made.

That said, mine mostly gets used nowadays attached to my Night Vision device.

+1

mine is sharp corner to corner with perfectly round stars and zero coma on a fullframe Nikon.... but saying that, i did buy and return the first one and the second was optically fabulous at f2.0....you just have to buy where you can return multiple times but in the end its worth it to get a good one.


Edited by Kevin_A, 19 March 2020 - 10:42 AM.

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#10 Traveler

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Posted 19 March 2020 - 10:49 AM

That lens is made in Korea wink.gif

Sorry you got bad copies. I got the Samyang 135mm F/2 years ago and its sharp sharp sharp. It’s also something rare with camera lenses: truly apochromatic. If you can get a good copy, it’s optically one of the best 135mm lenses ever made.

That said, mine mostly gets used nowadays attached to my Night Vision device.

+2 My Samyang is a very nice lens.

 

 

+1

mine is sharp corner to corner with perfectly round stars and zero coma on a fullframe Nikon.... but saying that, i did buy and return the first one and the second was optically fabulous at f2.0....you just have to buy where you can return multiple times but in the end its worth it to get a good one.

+1

Go to a nice photoshop with some personell who knows what they sell. Some do understand what you are looking for and act in a good way.

 

Good luck..



#11 erictheastrojunkie

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Posted 19 March 2020 - 05:23 PM

My goodness, I can't imagine you'd get 3 copies of this lens that is so poor, I've gotten 2 copies (one an F-mount and one an E-mount) and both are bang-on perfect corner to corner. 


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#12 elakrab

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Posted 20 March 2020 - 08:31 AM

You just made a multi paragraph post slamming a lens without comparing other lens data collected by your 6D.
Does other glass do better on your camera?
Did you have the lens supported or was the bayonet supporting the weight of the camera?
any sensor tilt?

also what does an entire frame look like?


It is not that relevant. I tried rotating the last one, supporting it in the body, in the lens, with both hands. The differences trial to trial where negligible compared to the absolute loss in definition.

The last one I did not even bother to try at night, as it would require opening it to modify the infinity focus stopper (again) so that it focusses at infinity. But the first unit I got was absolutely terrible. I tried to stitch together two frames to do a mosaic and needed to cut more than 50% of each frame so that the stacking software could actually stack on the stars, otherwise the deformation required would be unacceptable.

My 6d sensor could be tilted of course, but again that would show up with the same corner working equally bad with the different samples, which is not the case. And finally, yes, some lenses perform better. My 70-200L f4 (I know, at f4) keeps the corner a bit better, or at least less assymetric. The first samyang I tried, even at f~5 was really mediocre. The others I did not test that extensively as they seemed to be pretty bad too.
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#13 Jon_Doh

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Posted 20 March 2020 - 09:02 AM

I've been involved with semi pro photography for years and have a lot of expensive stuff (Canon 1D camera, Leica, Canon L lens, etc) and every Samyang lens I have ever seen has been garbage.  These days you don't have to pay an arm and a leg to get a high quality lens like you did in the old days.  The build quality on many consumer lens is below pro quality, but many are very sharp.  You just have to know which are which.  Sigma Art series is a good example of high quality third party lenses with fast apertures.


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#14 calypsob

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Posted 20 March 2020 - 10:54 AM

It is not that relevant. I tried rotating the last one, supporting it in the body, in the lens, with both hands. The differences trial to trial where negligible compared to the absolute loss in definition.

The last one I did not even bother to try at night, as it would require opening it to modify the infinity focus stopper (again) so that it focusses at infinity. But the first unit I got was absolutely terrible. I tried to stitch together two frames to do a mosaic and needed to cut more than 50% of each frame so that the stacking software could actually stack on the stars, otherwise the deformation required would be unacceptable.

My 6d sensor could be tilted of course, but again that would show up with the same corner working equally bad with the different samples, which is not the case. And finally, yes, some lenses perform better. My 70-200L f4 (I know, at f4) keeps the corner a bit better, or at least less assymetric. The first samyang I tried, even at f~5 was really mediocre. The others I did not test that extensively as they seemed to be pretty bad too.

Yea somethings not adding up. Both of my samyang 135’s test well on my Sony A7riii using an ef converter. Ive personally worked with 3 samyang and 1 rokinon 135mm f2. All have done what they should. It would seem to me that testing your camera at f2 with another 135mm lens is needed to establish a clear picture of this scenario.
Btw Is your 6D modded?
If you have more image samples we can probably do a better job trouble shooting.

Edited by calypsob, 20 March 2020 - 10:55 AM.

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#15 Swordfishy

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Posted 20 March 2020 - 11:24 AM

I bought 2 copies, both were spot on, one I sold here... The adapter was the issue so I bought the E mount version of it and I am sharp corner to corner... That is also that I bought it from Ebay used at random... Both times actually and both were optically great, even wide open at F2.0. 

 

 Maybe you just got really unlucky, or you have tilt due to a loose lens adapter which is where my money would be.


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#16 calypsob

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Posted 20 March 2020 - 12:28 PM

It is also possible for the dslr bayonet flange to wear out and no longer hold the lens tight
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#17 Kevin_A

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Posted 20 March 2020 - 12:29 PM

I have had good luck with all brands of lenses but i can also honestly say that over the last 6 years or so all manufacturers assembly quality have dropped.

I just returned a pro level Tamron and a Sigma Sport ($2000) lens due to lens de-centering where 1/4 of the image was blurry.

In the past i have also returned Nikon as well due to quality issues so its hard to say if its manufacturer specific or just a sign of the times. 

 

I do buy most of my Samyang/Rokinon lenses thru Amazon so I can quickly return n replace n return if required without concern. Pro level glass I tend to go thru dealers so i know that the warranties are legit.



#18 calypsob

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Posted 20 March 2020 - 12:35 PM

I've been involved with semi pro photography for years and have a lot of expensive stuff (Canon 1D camera, Leica, Canon L lens, etc) and every Samyang lens I have ever seen has been garbage. These days you don't have to pay an arm and a leg to get a high quality lens like you did in the old days. The build quality on many consumer lens is below pro quality, but many are very sharp. You just have to know which are which. Sigma Art series is a good example of high quality third party lenses with fast apertures.


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.
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#19 elakrab

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Posted 21 March 2020 - 05:01 PM

My 6d is modded, so sensor tilt can be an issue, I know. But this would made all the units go wrong in the same corners in the same or similar way, not the case it looks to me. There is no adapter, it is the canon version of the samyang. Still annoying, even if it was optically good, that they don't let the lens focus slightly past infinity.
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#20 james101

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Posted 21 March 2020 - 06:55 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.



#21 calypsob

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Posted 21 March 2020 - 10:58 PM

My 6d is modded, so sensor tilt can be an issue, I know. But this would made all the units go wrong in the same corners in the same or similar way, not the case it looks to me. There is no adapter, it is the canon version of the samyang. Still annoying, even if it was optically good, that they don't let the lens focus slightly past infinity.


Did you replace the highpass filter glass with clear glass after the mod? If not, the backfocus will be wrong and af impossible.

#22 calypsob

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Posted 21 March 2020 - 11:00 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.


Did you have the zwo ef adapter? If so, you have to add shims behind the compression flanges to stop sag.

#23 whwang

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Posted 21 March 2020 - 11:58 PM

I have read enough bad stories about SY lenses like this one.  This really doesn't surprise me.  Of course there are people who are lucky with SY lenses, and there also exist excellent images taken with SY lenses.  But you can probably assume there are equal number of bad images or unlucky ones who never become visible on internet.  Now you had tested your luck and got an answer.  Time to move on to a different brand.  Life is short and time is limited.

 

If you really have budget constraints and have to stick to SY lenses, the first thing to do is to fix the infinity focus issue.  Then if the distortion of stars is caused by a loosen lens mount, or if it turns out to be a tilt (either the lens, or the sensor), you can get some adhesive aluminum foil to either tighten the mount or to compensate the tilt.  This is a cheap fix that I occasionally had to use.  The worst scenario is that the distortion is caused by misalignment of multiple lens elements in the lens.  Then there is no way for you to fix it.

 

You said it doesn't look like a sensor tilt.  I tend to agree with you.  It doesn't look like sensor tilt to me.  But I don't think this can be completely ruled out at this stage.  It will be worthwhile to keep investigating the sensor tilt part.  If at the end you decide to go to a different brand (which likely costs more), you want to first be absolutely certain that there is no sensor tilt before you spend the money.

 

Good luck.



#24 Traveler

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Posted 22 March 2020 - 01:03 AM

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. 



#25 elakrab

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Posted 23 March 2020 - 07:19 AM

Did you replace the highpass filter glass with clear glass after the mod? If not, the backfocus will be wrong and af impossible.

 

Yes, it has the baader filter.




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