Hi
i have this lovely lens from 1 year ago. Till now i used whit my last 294mcpro but now i have zwo 2600mcpro+2600mmpro attached to efw filter wheel. The backfocus for this lens is 44mm (canon mount) so i removed the 2600 tilter+efw+m48 adapter (10mm) so i have the perfect backfocus. The problem is when i want to use my 2600mmpro because my filter wheel is m42 so the adapters for this lens to ccd overpass 10 mm so it, s not possible focus anything. So please anyone who has this setup, what adapter do you use for m42 efw or cameras?
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Copy the URL below to share a direct link to this post.
This post cannot be edited using the classic forums editor.
To edit this post, please enable the "New forums experience" in your settings.
Since you have the Canon version you could replace the lens flange with a M48 thread one. Firstlightoptics sell them, made by metal. Otherwise the ZWO 2" EFW adapter is the perfect fit - but only if you have the 2" EFW of course. With the smaller ones it becomes a bit more difficult, so I'd opt to replace the Canon mount and install the M48 threaded one which perhaps could give you just enough room to make it fit. I have two myself but I have the Nikon versions and a 2" EFW, I decided to go with 2" partly because of the Samyangs I own. What I will add though, is that the "perfect backfocus" is not 44mm in your case, especially not with the larger IMX571 sensor. Filters need additional spacing (1/3 of the filter thickness apprx). Then possibly minor adjustments to dial it in, especially if used wide open which is extra demanding - even more so when using larger sensors. So long story short, you would need either a 2" EFW and the appropriate adapter or replace the camera mount with something like this which would be the cheapest option.
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Copy the URL below to share a direct link to this post.
This post cannot be edited using the classic forums editor.
To edit this post, please enable the "New forums experience" in your settings.
I have the Canon version of the Samyang 135 and use it with the ASI 2600 MM bolted to a ZWO 36 mm EFW with 2 mm thick Antlia filters installed. I replaced the EF flange with the FLO M48 version that Jan Erik mentioned. Then I added an M48/T2 6 mm adapter (from Teleskop Service, product no. TSM48i-T2a), a T2 5mm extension (also from TS, product no. TST2V55), and finally a 0,6 mm spacer. That brought me to 44,1 mm. I think I need a bit more distance in order to reduce star distortion at the edge of the frame, but thanks to BXT it works ok.
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Copy the URL below to share a direct link to this post.
This post cannot be edited using the classic forums editor.
To edit this post, please enable the "New forums experience" in your settings.
Not exactly the answer you are looking for, but might be useful once you figure out the adapters:
Even if you sum up the distances from the devices you have, sometimes there is error small errors in the distances that can screw up the backfocus.
A trick to get it right, is to use use the lens in a canon camera and focus on infinity. After that, dont change the focus, detach the camera from the lens and set up your astronomy gear, if they are in perfect backfocus, the image should be in focus, if not you will need to play with spacer until the fixed infinity focus matches.
In mine I had to add approximately 2 mm of spacers.
Also, linear elongated star on the corners means you the sensor is too close (solvable with spacers) and circular elongation patterns means the sensor is too far…
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Copy the URL below to share a direct link to this post.
This post cannot be edited using the classic forums editor.
To edit this post, please enable the "New forums experience" in your settings.
hi, thanks for your responses.
i have the 2600mcpro with 2" efw and goes well with samyang and 10mm adapter m48 to canon lens.
The problem is in 2600mmpro because i have 36mm filters, so efw is m42. There is no adapter that i have found that works with backfcous distance. I mounted to m48-canon lens a ring adapter from m48 to m42- 0.75 mm and i can´t find focus that way. Maybe it be an thin adapter for canon to m42
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Copy the URL below to share a direct link to this post.
This post cannot be edited using the classic forums editor.
To edit this post, please enable the "New forums experience" in your settings.
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Copy the URL below to share a direct link to this post.
This post cannot be edited using the classic forums editor.
To edit this post, please enable the "New forums experience" in your settings.
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Copy the URL below to share a direct link to this post.
This post cannot be edited using the classic forums editor.
To edit this post, please enable the "New forums experience" in your settings.
As mentioned above, you have to remove the EF flange and replace it by the FLO M48 type. Then you have enough space left to work your way from M48 to M42 and stay within the required 44 mm backfocus distance.
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Copy the URL below to share a direct link to this post.
This post cannot be edited using the classic forums editor.
To edit this post, please enable the "New forums experience" in your settings.
Sorry for my ignorance, but i don´t know how change m42 side of efw 36 mm filters to m48 . It´s fit on the side of efw m42 and then you attached the m48 adapter to canon, right?  |
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Copy the URL below to share a direct link to this post.
This post cannot be edited using the classic forums editor.
To edit this post, please enable the "New forums experience" in your settings.
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Copy the URL below to share a direct link to this post.
This post cannot be edited using the classic forums editor.
To edit this post, please enable the "New forums experience" in your settings.
Lutz Kirchner:
This is what I use:
1. Flange fpr Samyang 135 -> M48, 44 mm left (https://www.firstlightoptics.com/adapters/astro-essentials-samyang-lens-to-m48-adapter.html)
2. TSM48i-T2a adapter from TeleskopService -> M42, 38 mm left (https://www.teleskop-express.de/en/adaptors-10/adapter-t2-m42x0-75-122/ts-optics-adaptor-from-m48x0-75-to-t2-6-mm-optical-path-length-10401)
3. TST2V5 extension tube from TeleskopService -> M42, 33 mm left (https://www.teleskop-express.de/en/ts-adapter-39/adapter-extensions-124/ts-optics-t2-extension-m42x0-75-5-mm-length-2261)
4. 6 mm spacer, 32,4 mm left
5. EFW -> M42, 12,4 mm left
6. ASI 2600 MM Pro without tilt plate, -0,1 mm left
Example image: https://www.astrobin.com/bm8tn5 Thanks for the explanation. Something i m doing wrong i have: 1-ASI 2600MM whithout tilt plate-12.5 mm 2-EFW filter wheel-20 mm 3-m48-m42 adapter - aprox 4 mm. 4-Canon lens m48 adaptor-10mm So total backfocus 46.5 mm, with this way i can´t focus stars 100% .  |
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Copy the URL below to share a direct link to this post.
This post cannot be edited using the classic forums editor.
To edit this post, please enable the "New forums experience" in your settings.
You need 44 mm without filter, a bit more with filters. 46,5 mm is way to much. It seems that you use the Canon EF flange that came with the lens. That thing has to be removed and replaced by the M48 flange in order to stay below 44 mm. The optical path of your Canon adapter is too long.
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Copy the URL below to share a direct link to this post.
This post cannot be edited using the classic forums editor.
To edit this post, please enable the "New forums experience" in your settings.
Lutz Kirchner:
You need 44 mm without filter, a bit more with filters. 46,5 mm is way to much. It seems that you use the Canon EF flange that came with the lens. That thing has to be removed and replaced by the M48 flange in order to stay below 44 mm. The optical path of your Canon adapter is too long. Thanks. i will try whit that adapter
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Copy the URL below to share a direct link to this post.
This post cannot be edited using the classic forums editor.
To edit this post, please enable the "New forums experience" in your settings.
