First Light with new ASI585MC Pro.
Not the 135 but similar I would think.
The click stops are created by this spring loaded ball pressing against a set of serrations on the aperture ring :-).
Pretty smart, but pity the people on the assembly line :-)
Chen
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Aha, this is the last plastic ring, with just the stainless bayonet plate removed.
There may be a way to attach a M54 interface to it.
PreciseParts can do a "bolted" version of EFW mounting that converts a flat flange to a M54 tube. An aluminum plate can go on instead of the bayonet plate,and a precise part can be bolted to it. This is one of my PreciseParts "bolted" adapters (to M54); picture from PreciseParts:
But the backfocus is still pretty short though. The EF bayonet plate is 3mm thick. So, about 40mm to 45mm worth of backfocus to play with (not enough backfocus for both a CAA and a filter drawer). But at least we don't have to deal with flakey ZWO camera adapters. I'll look into adapting the Rokinon this way.
Heck -- I should look at the Sigma 40's Nikon bayonet plate to see if I can do a direct M54 connection. The key is going to be how short can PreciseParts make a bolted adapter to M54. I'll do anything to avoid flakey ZWO parts.
Chen
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w7ay I should look at the Sigma 40's Nikon bayonet plate to see if I can do a direct M54 connection.
Hmmm, may be easier said thann done -- the Sigma 40 Nikon bayonet has electrical contacts.
However, since I don't use the lens on a real camera, I can probably just cut all the wires off, or remove from that internal connector. Darn lens appears to work when not attached to a camera.
Just from the bayonet, the build quality of the Sigma appears miles ahead of the build quality of the Samyang. Again, you get what you pay for (and difference between Japanese engineering and Korean engineering).
Chen
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Kevin_A N
OK, this is the shortest "bolted" interface (to M54 male thread) from PreciseParts... 3mm.
Another thing that can be done (cheaper than PreciseParts) is to look for M68 to M54 male adapters and see if they can be bolted to the Samyang.
If you don't care about aperture rings and such, you can probably mount a plate deeper into the Samyang, to get more backfocus and also bolted to metal instead of plastic, like to here:
Yeeha, this one might work (and I have one on hand):
Chen
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Looks do-able:
The removed plastic parts and the EF flange accounts for 17.5mm. The ZWO plate is 2mm thick. By bolting the ZWO plate to the metal part of the lens, we potentially have a backfocus of 44mm + 17.5mm - 2mm = 59.5mm, and with no plastic in between!
P.S. The screw holes on that metal part appear to be separated by 53mm (there are four 90º apart that can be used. The M54 make thread won't allow any bolting. So, I will need to use an intermediate transfer plate (from the Seattle machine shop) to go between the Samyang and the ZWO plate.
Now, if I can find a similar M48 instead of M54 plate, it may have enough clearance. The exit glass is about 30mm, so even an M42 hole may be good enough.
Chen
w7ay with these electronic lenses you just hook them up to a Nikon camera, adjust the aperture wide open and remove the lens with the camera still on. That keeps the lens at whatever aperture you had it at when you removed it. You could order a Nikon camera from amazon, set the lens wide open then return the camera or just go to a camera store and ask them to see a camera and do it that way. No aperture ring tabs on those lenses.
Kevin_A N
Frankenstein, just as a test (note the 1.6mm scews are just holding on to the edge of the Stellarview stop ring):
A StellarView stop ring holds a 5mm M42 spacer (4mm would be better, but I don't have many M42 stuff anymore). The four Samyang M1.6 scres hold the stop ring on the lens. a M42 to M48 zero length adapter is then screwed to it.
Finally, a 48mm-54mm zero length adapter goes over everything to provide an M54 make interface. This hack gives perhaps 58mm worth of backfocus.
Here it is with a 13.5mm CAA, a 20mm filter drawer, 17.5 camera flange, with a few mm to spare :-).
I will look into this for mounting the Rikonon to get rid of DSLR camera flanges (and ZWO camera adapters, which I don't trust for tilt) completely.
Chen
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Kevin_A You could order a Nikon camera from amazon, set the lens wide open then return the camera or just go to a camera store and ask them to see a camera and do it that way.
Nah, as a capitalist myself, I would never do that to someone else. I don't return products I end up not liking; I just donate stuff I don't like. Trashed a few scopes and lenses that way. (Held AAPL stocks since 1988, so I can afford to do that today.) If the Sigma 40 don't work out, it will just go to Goodwill.
I treat others like I want to be treated myself. Golden rule my mother taught me.
Chen
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Kevin_A have you tested the 40mm lens to make sure it is a good copy yet?
No. I want to properly mount an EAF first. In any case, I am in no big rush when it comes to wide camera lenses. Not my highest priority. As you know, I neither have enough sky between the trees nor dark enough skies to make good use of camera lenses. Thus lack of interest. If the lens has lots of coma, I can always just use it as a meteor camera (am using the Samyang XP50/1.2 currently; absolutely horrid coma to use as a wide field scope).
I might get back to playing with filter gratings again, and a wider camera lens could be useful too since the regular OTAs are too long to find meteors. I was just earlier exchanging email with Tom Field of Field Tested Systems -- turns out he is also a radio amateur. I kinda lost interest a couple of years ago because most of the gratings are meant for DSLR mounting, but I stumbled on a 1.25 mounted one from Field Tested; so I can use it on an astro camera.
Right now, I am most anxious if I could mount a filter drawer within the 72mm portion of my FSQ. That is so that I can simply refocus after changing a filter, without having to readjust backfocus between its flattener and where a normal filter holder would be. It also allws me to stack filters with two drawers.
I have a M72-M54 adapter, and tried a ZWO M54 drawer, and it looks like it might work. So, I am now waiting fopr a PreciseParts adapter to go from the ZWO drawer to a female M72 thread, where the flattener goes. The assembly replaces a 2" M72 Takahashi part that is currently on the scope.
PreciseParts adapter coming mid June -- looks like business is picking up foprm them again. The lead time went down to 1 week at a point last month.
Chen
Ah... that YouTube video shows that there are screws on the outside that are holding the lens assembly. I see a couple on my sacrificial Samyang 135:
Looks like the screw head has already been pre-stripped :-). I'll take a look tomorrow to see if this works. The assembly is a bit different from the video. My rear glass elements is on the inside, and if you remember, I have not yet been able to remove it. His was protruding to the back (and was loose :-).
OK, I just need to change 5 or 6 holes, and the Sigma 40 base plate will be ready to go. It uses the same floating EAF plate, so I just need to resubmit that for fabrication.
Chen
w7ay sending stuff back to amazon does not hurt anyone. The return shipping is already priced in and it goes back, sent to the distributor, looked over and sold again. Like I said… then go to a camera store and just ask them to look at a camera…. then set it and remove it… no harm done! I am not sure how you will set it wide open other than gutting it…. but it’s ur call.
Maybe you have a friend who can set it wide open for you as it just simplifies your project. I would send you one but ur in a different country and that’s customs complicated! Haha
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w7ay it is too bad telescope spacing and flange related parts are crap or non existent, outdated and basically have not been improved upon since the 1970s. Every project turns into a Frankenstein job. Speaking of crap… one of the biggest astro pundits just released a video on the Asi585mc pro touting it as an excellent deep space camera for 5 minute subs… Trevor Jones of Astrobackyard… I had a good laugh when I saw his bloated oversaturated stars due to the too small FWC. Just another pundit selling lies!
So my thoughts of capitalism are a bit different when I see a zwo and a pundit influencer pushing a crap product to the masses… as the masses cannot return the cameras when they find out it is a crappy DSO camera that was just meant for lucky imaging! That’s what my mother instilled in me… as long as no one innocent gets hurt. The guilty and gluttonous be damned only!
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Kevin_A Maybe you have a friend who can set it wide open for you as it just simplifies your project.
No need to do that. The SIgma 40 comes wide open. Same as the other EF mount ART lenses that I have. I think they just designed it that way. And as long as I don't apply power to it, I don't think it is going to close. If it does, I will just buy a refurbished (I never buy refurbished stuff to actually use) cheap Nikon model. My ethics.
OK, I managed to remove the rear lens element of the Samyang by doing a close focus :-). The rear part then pops out. And since I have already loosen it with a lens spanner, comes out nicely.
There are sure a lot of parts associated with focusing on the Samyang, that we don't need. In addition to the plastic stuff around the bayonet, there are focus rings, etc, that I will never put back, to reduce the weight. There are fewer loose pieces on the Rikonon Cine, though.
I have submitted the Sigma-40 base and floating EAF plates to the web machine shop already. If there is nothing wrong, they should be able to start work tomorrow, and I might get it back before the weekend.
Trevor Jones of Astrobackyard…
That is the same genius who touted the Radian (OPT's house brand) rebadge of the SharpStar refractor, as something he personally designed :-). Typical shill. I wonder who is paying him now that OPT has gone bankrupt. One of the stores must still be sending him free stuff. I wonder if it is Highpoint. It is amazing that after the Radian fiasco that he has the gall to still make YouTube videos.
BTW, the guy who started Agena (also an immigrant :-) got his Masters degree in optics from U of Arizona. The same place that Katie Schwertz and a bunch of other good optics people come from. Used to be you can ask him to open the box of an OTA up to inspect collimation. I don't know if he still does that since Agena has gotten so large. But Agena must at least still have the optical bench to do it; something you would not expect from Highpoint.
the masses cannot return the cameras when they find out it is a crappy DSO camera that was just meant for lucky imaging!
Just buy Takahashi or Vixen. They don't pay shills. The Japanese don't usually do things like that (when they do, their CEO commit seppuku :-). And that is why you do not see Taks and Vixens touted on YouTube. How often have you seen Astro-Physics or 10Micron touted on YouTube? I don't think I have seen a single. Even PrimaLuce is sedom mentioned on YouTube. YouTube just have things like ZWO and SVBONY.
ZWO tried to bribe me many years ago, but I kept refusing, so they don't even try anymore. Except last year, they tried to bribe me with mooncakes instead of their products (I think they know I can't stand their junk hardware). I told them politely that I don't want to pay taxes for foreign bribes. I wonder at times if the YouTube shills actually report the bribes in their taxes.
The Chinese companies have definitely made this hobby less honest.
Chen
