Imaging with the Samyang 135mm f2

[Simon Pepper]

Hi Steve 

I was able to find focus last night with how I put it together so must just be really lucky 😊

I did notice some CA or coma not sure which when zoomed right in on single subs seem to be worse too left side these were 30s at f2. I am new to this lens first time out was last night do people generally stop it down to 2.8 or even 4? Trying to understand the sweet spot. Also the bug star off to the left has some odd cylinders type of line through it. This is completely unprocessed and one 30s sun. I will post the processed result after work today. 

 

[Simon Pepper]

3 minutes ago, Space Oddities said:

Actually you have the correct spacing  The EOS adapter is actually 26.5mm thick, according to ZWO. With the 11mm ring and the 6.5mm of the camera, that makes 44mm, which is what the Samyang lens needs (for Canon). Just make sure you remove the 5mm spacer that comes with the adapter, this spacer is only needed with 12.5mm backfocus cameras (like the non-cooled models).

My setup is slightly different: the camera has 17.5mm of back focus, to which I added a 16mm thick filter drawer and a 10mm M48 spacer ring. Which puts me at 43.5mm. Since I use a 2-3mm filter inside, 1/3 of the filter's thickness gets me very close to the 44mm back focus distance required by the lens. My lens doesn't have a Canon mount, but a M48 threaded interface, by the way.

Hope that helps!

I just replied here oh I really did get lucky last night 😊

[Space Oddities]

Glad you found your focus!  

 

[nephilim]

49 minutes ago, Space Oddities said:

Actually you have the correct spacing  The EOS adapter is actually 26.5mm thick, according to ZWO. With the 11mm ring and the 6.5mm of the camera, that makes 44mm, which is what the Samyang lens needs (for Canon). Just make sure you remove the 5mm spacer that comes with the adapter, this spacer is only needed with 12.5mm backfocus cameras (like the non-cooled models).

My setup is slightly different: the camera has 17.5mm of back focus, to which I added a 16mm thick filter drawer and a 10mm M48 spacer ring. Which puts me at 43.5mm. Since I use a 2-3mm filter inside, 1/3 of the filter's thickness gets me very close to the 44mm back focus distance required by the lens. My lens doesn't have a Canon mount, but a M48 threaded interface, by the way.

Hope that helps!

 

Edit: actually I'm not sure which version of the lens you use, I assumed Canon. For Nikon, it's basically the same, but the adapter is thicker (29mm) to work with Nikon back focus distance (46.5mm). But in any case, ZWO adapters are made to give you the exact distance you need for the mount you're using, so you just need the adapter, the 11mm spacer ring and your camera.

Everything is explained well here: https://astronomy-imaging-camera.com/product/nikon-t2-adapter-suitable-for-all-asi-cameras

So I was right in a way (if the spacer had been 25mm 😂) plus he'll still need to account for the L-eXtreme?

Edited August 25, 2021 by nephilim

[nephilim]

Hi Simon,

I'm at work using my phone at the moment so I'm have to wait until I get home onto my desktop for a proper look. 

If you've read the whole of this thread (I have & it took a while 😂) there are few people who've mentioned the performance of this lens & although very good, no two lens will even be completely identical. Some people have had minor issues when shooting wide open @f2 & some have had to resort to f2.8 or even f4 due to coma at the edges or In the corners, I've never seen it just on one side though. Although mines fine @f2 I usually stick with f2.8 as it makes focusing easier (I use a combination of the ASIair Pro & a Bahtinov Mask but mainly rely on the mask)  

if it is due to the lens I'd recommend stopping down but also image slightly over to one side so you can crop in processing.

here's an image I took  with my 135 & ASI533. Although the stars arnt perfect, that's due to my focusing & inexperience with post processing 😂 For widefield AP I love this lens as it's an absolute photon hoover. This image was only 50x 180 seconds. I can't wait to start guiding so I can go longer.

Steve

7 hours ago, Simon Pepper said:

Hi Steve 

I was able to find focus last night with how I put it together so must just be really lucky 😊

I did notice some CA or coma not sure which when zoomed right in on single subs seem to be worse too left side these were 30s at f2. I am new to this lens first time out was last night do people generally stop it down to 2.8 or even 4? Trying to understand the sweet spot. Also the bug star off to the left has some odd cylinders type of line through it. This is completely unprocessed and one 30s sun. I will post the processed result after work today. 

 

 

[Simon Pepper]

Haha classic photon hoover not heard that one before! So here is my processed effort decided on the SHO bodge in PI as Ha in the red can be a little overpowering. I guess each to own preference in this area! So I have actually cropped off the left side of the image and did a rotate for better composition and without zooming right in its turned out alright I think! This was 185x30s wanted to keep the exposures low as going to bosh it in SGL 30s maximum exposure contest. I will go back and check the uncropped version but I reckon I will need to stop it down to 2.8 and if going for really long exposures I think perhaps even more. 
 

I will also go back through this thread and read it all could be interesting. That will be done with a beer in hand and on laptop none of this iPhone malarkey.

thanks 

[Adam1234]

Loving the images taken with this lens and the mounting solutions. I don't have the 135mm lens but I have the Samyang 14mm that I'm hoping to use with the ASI120MC - does anyone know of any ring mountings that would fit the 14mm? 

[Simon Pepper]

16 minutes ago, Adam1234 said:

Loving the images taken with this lens and the mounting solutions. I don't have the 135mm lens but I have the Samyang 14mm that I'm hoping to use with the ASI120MC - does anyone know of any ring mountings that would fit the 14mm? 

Hi Adam,

the 135 is slightly thicker and bigger all round to the 14mm. For the 135 I am using the redcat ring but another user from SGL noted a sigma ring that also works but will need a bit of felt or Velcro added as it is about 1mm to big. That was this: 71mm Tripod Collar Mount Ring 1/4" for SIGMA APO 70-200mm F2.8 II EX DG MACRO HSM Lens https://www.amazon.co.uk/dp/B07DVKZBXG/ref=cm_sw_r_cp_api_glt_fabc_9GWY361RF8KKMS66Y9PD?_encoding=UTF8&psc=1

I have just checked that ring on the 14mm and it fits snug over the aperture ring but obviously you will want it over the body and before the focus ring. See picture for guidance if I was a betting man I would say you probably want somewhere in the region of 69mm but I reckon the above options you could make work with a bit of diy tape, felt or Velcro.

 

[Adam1234]

11 minutes ago, Simon Pepper said:

Hi Adam,

the 135 is slightly thicker and bigger all round to the 14mm. For the 135 I am using the redcat ring but another user from SGL noted a sigma ring that also works but will need a bit of felt or Velcro added as it is about 1mm to big. That was this: 71mm Tripod Collar Mount Ring 1/4" for SIGMA APO 70-200mm F2.8 II EX DG MACRO HSM Lens https://www.amazon.co.uk/dp/B07DVKZBXG/ref=cm_sw_r_cp_api_glt_fabc_9GWY361RF8KKMS66Y9PD?_encoding=UTF8&psc=1

I have just checked that ring on the 14mm and it fits snug over the aperture ring but obviously you will want it over the body and before the focus ring. See picture for guidance if I was a betting man I would say you probably want somewhere in the region of 69mm but I reckon the above options you could make work with a bit of diy tape, felt or Velcro.

 

Thank you Simon, I will check that one out!

[Dinglem]

I've had this lens a while but not had much time lately to do any astrophotography. Last night we went babysitting to my sons out in the country, the forcast was pretty good, so I took my Star Adventurer, astromodded 450D with no filter and the Samyang 135, I could have framed it better but I did notice I'd polar alligned on the wrong star after about 10 exposures.

I managed to only get 35 60s lights, 4 darks, 30 flats and 30 flat-darks, I've just done a very quick process, it obviously needs more data and more time processing but it has potential.

[geeklee]

From 13th August (yeah, it's been that cloudy since!) the best 20 of 30 180s Ha subs (1 hour) of the Heart and Soul.  Taken while testing my Samyang + 183MM (~F2.4) on an AZ-GTI in EQ mode with ASIAIR Pro.  Not processed much except to reduce the stars.

Some nice detail for 135mm in the heart of the Heart:

[Budgie1]

I was imaging NGC6960 with my main imaging setup and the night was clear, so I thought I may as well get the Samyang 135 out with the modded EOS 1300D on a EQ5 and point it in the same area.

This is 75x 180s subs with flats, dark flats & Bias, stacked in DSS & processed in PI. I wanted to get this target with my ASI294MC Pro and L-eXtreme filter but the RedCat 51 mounting ring hasn't come back in stock with FLO yet. But this is still quite good for a basic, unguided, setup.

[Petrol]

Thanks to Olly for pointing me in the direction of this thread. Thanks also to everyone on here, it made setting this up easy.

[Simon Pepper]

Hi Guys 

Wondering if someone can assist here. I have noted that my starts are not quite pin point when zooming in around the edges  it seems worse in one corner of an image, but this one its top left. If looking bottom left they streak away bottom left as you come up to middle left they streak middle left and so on. I have seen this issue elsewhere but I don't actually know what it is whether its tilt, backspacing or some other issue.... I am new to the 135 so seeing here if anyone has had similar and been able to correct it? This was shot at f3.5 (stopped it down to see if it helped think it did ever so slightly but still apparent) 300s.

I have attached the raw fit as well.

 

Top left

Bottom left

Top right

 

Bottom right

Thank

Light_IC1396_300.0s_Bin1_0012.fit

[Space Oddities]

What kind of adapter are you using? Canon/Nikon to T2? Do you have a picture of your setup maybe?

[Simon Pepper]

26 minutes ago, Space Oddities said:

What kind of adapter are you using? Canon/Nikon to T2? Do you have a picture of your setup maybe?

Hi Pierre see below. I believe its the older version of this as it has slightly different disconnecting button. I may just have a dud 135 lens lol I know the quality control is not always top notch...

 

https://www.firstlightoptics.com/zwo-accessories/zwo-adjustable-eos-lens-to-t2-adapter-for-all-asi-cameras.html

[Space Oddities]

Honestly I think all Samyang 135's have one ugly corner somehow... But I think most bayonet adapters don't help. At least that was the case with my copy. When I replaced the Canon mount of my lens by a M48 mount (with this excellent adapter), I believe that my bad corner improved. It's also a much easier adaptation to astro cameras!

[Simon Pepper]

2 hours ago, Space Oddities said:

Honestly I think all Samyang 135's have one ugly corner somehow... But I think most bayonet adapters don't help. At least that was the case with my copy. When I replaced the Canon mount of my lens by a M48 mount (with this excellent adapter), I believe that my bad corner improved. It's also a much easier adaptation to astro cameras!

Ok I will check it out! Thanks 

[900SL]

First attempt at the Veil. D5600, SY 135mm, ambient 35C so thermal noise a big issue. No darks. Bit of a beginner with processing,..

 

45 x 120s subs at ISO 800 f2.8

 

 

 

Edited September 10, 2021 by 900SL

[powerlord]

On 31/08/2021 at 10:38, geeklee said:

From 13th August (yeah, it's been that cloudy since!) the best 20 of 30 180s Ha subs (1 hour) of the Heart and Soul.  Taken while testing my Samyang + 183MM (~F2.4) on an AZ-GTI in EQ mode with ASIAIR Pro.  Not processed much except to reduce the stars.

Some nice detail for 135mm in the heart of the Heart:

very nice. And I'm liking the mono.

stu

[900SL]

another SY 135, not sure if this was D610 or D5600, Saudi desert, Bortle 3 due to nearby town. Still a novice at processing so overcooked

Its sharp. Very sharp if focused correctly at f2.8

 

[powerlord]

lovely wide field. like that a lot. one to try in a few month here in blighty.

[Simon Pepper]

Agree with Powerlord great widefield shot there will have to try that on out 👌

[900SL]

Thanks! Only my second attempt at Orion so Im pretty chuffed with the way it came out.  Suprised to get the red nebulosity as my cameras are unmodded Nikons. 

 

 

Edited September 16, 2021 by 900SL

[Space Oddities]

Lovely details, well done! It does look a bit green on my screen though, but that should be easy to correct by realigning the channels slightly. 

Are you using Photoshop? There's also a very nice free plugin called Hasta la Vista Green, for Windows only, but it usually does a great job to remove that green tint.