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Millicam MFR-5 And Mod 3?

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#1 Eddgie

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Posted 16 May 2019 - 11:13 PM

Has anyone tried the Millicam MFR-5 or other Millicam reducers with their Mod 3 or Micro?

 

These reducers appear to be a much better design than the inexpensive .63 reducers and are made with CCTV mount in mind, and since the Mod 3 and Micro are CCTV spec, it might be a good match (though these cameras don't have the same size area as the image intensifiers do).

 

With a 1.25" filter up front, the clear aperture would be about 24mm or 24mm (filter retaining rings eat up some inner diameter) so with a .6 reduction, this would suggest a decent 25mm fully illuminated circle, and if one chose to accept some falloff, a .5 reduction would still provide about a 12mm fully illuminated circle.

 

I am in the process of buying an 80mm f/7 refractor which is going to be primarily used as a Solar H-a scope with a Quark filter, but if someone has experience with the Millicam MFR-5 on C mount NV, I would be very eager to hear reports.   

 

Thanks!



#2 Shelldawg

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Posted 17 May 2019 - 07:38 AM

I use the mallincam filters with my Mod 3 ... works good ... think it is the mfr 5 but not sure as I have many of them as I got 2-3 over the years as he made them for different cameras ..... works in most scopes as is ...but only one half works in my big 30"f3.3 dob (there are two lenses that screw together) so I had  Siebert make me a bottom half to better match my needs and it works better than the bottom half that came with it ... think I have some pics of Eagle where I show the unreduced image and then the reduced image with a couple quick and dirty iPhone hand held snaps ... will see if I can find and post later ... thinking I have no reducer, one half, and two halfs with Siebert Mod ....



#3 Vondragonnoggin

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Posted 17 May 2019 - 07:55 AM

I’d be curious to know if there is noticeable vignetting.

 

Years ago I bought an AVS Varioreducer which is the same principle as the MFR-8 system which incorporates the MFR-5 and uses various width spacers to get the different reduction amounts. In the Varioreducer, everything was still using a 1.25” focal reducer, a c-mount to 1.25” thread spacer, several 5mm 1.25” spacers. The main problem was that the reducer  lens was still constrained to a 1.25” size housing. I tried in my pvs-7, Litton M942, and NVD Micro and all the same results for c-mount sized opening - vignetting in all of them.

 

Maybe the Mod 3 is different, but the c-mount opening in the housing of the NVD-Micro and M942 are very close to the optical input window of the Intensifier so theoretically should give least chance of vignetting.

 

The MFR-10 would be the only one I could use with my monoculars without vignetting. Looks like an interesting product as it states it also has a field flattener built in.

 

Eddgie - if you want to try my AVS varioreducer on your mod 3, PM me. It sits unused since 2015. I’ll send it to you to try out if you want.

 

The AVS Varioreducer:

 

http://www.astro-vid...ll-systems.html

 

They state 26mm clear aperture on the website.


Edited by Vondragonnoggin, 17 May 2019 - 08:05 AM.


#4 mclewis1

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Posted 17 May 2019 - 08:49 AM

The MFR-10 would be the only one I could use with my monoculars without vignetting. Looks like an interesting product as it states it also has a field flattener built in.

Rock doesn't appear to build his reducers for any specific scope flattening characteristics (so for example his MFRs are not SCT specific flatteners or anything like that). It does appear however that a good focal reducer also flattens a little of the field curvature present in most scopes.

 

The MFR-5 consist of three pieces. An MFR-6 which is a C-mount reducer (something in the .6x reduction range), a spacer with a 1.25" filter thread on the front end, and an MFR-8 which is a 1.25" threaded reducer that delivers an approximate .5x reduction. The -8 also has a 1.25" filter thread on it's front end. With the spacer in between the two lens packages the MFR-8 front end isn't running at .5x reduction so the combination of both the two reducers (the complete MFR-5) will deliver about .5x reduction.

 

If you are looking at buying an MFR-5 I'd look for the -II model as it has better coatings which helps with reflections off of the closely spaced lens elements. Also be on the look out for the model that has the rear lens element of the MFR-6 part extending down below the lens carrier. This could interfere with other optical surfaces if they are positioned very close to the front surface in a C-mount camera (usually this would be an optical window or filter on the camera).

 

Edit - fixed the -10 vs -8 confusion on my part.


Edited by mclewis1, 17 May 2019 - 09:37 AM.

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#5 Vondragonnoggin

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Posted 17 May 2019 - 09:01 AM

Rock doesn't appear to build his reducers for any specific scope flattening characteristics (so for example his MFRs are not SCT specific flatteners or anything like that). It does appear however that a good focal reducer also flattens a little of the field curvature present in most scopes.

 

The MFR-5 consist of three pieces. An MFR-6 which is a C-mount reducer (something in the .6x reduction range), a spacer with a 1.25" filter thread on the front end, and an MFR-10 which is a 1.25" threaded reducer that delivers an approximate .5x reduction. The -10 also has a 1.25" filter thread on it's front end. With the spacer in between the two lens packages the MFR-10 front end isn't running at .5x reduction so the combination of both the two reducers (the complete MFR-5) will deliver about .5x reduction.

 

If you are looking at buying an MFR-5 I'd look for the -II model as it has better coatings which helps with reflections off of the closely spaced lens elements. Also be on the look out for the model that has the rear lens element of the MFR-6 part extending down below the lens carrier. This could interfere with other optical surfaces if they are positioned very close to the front surface in a C-mount camera (usually this would be an optical window or filter on the camera).

Why is this the description for the MFR-10 then if you say it is a 1.25” threaded reducer?

 

”MallinCam MFR-10, 2" Large Format Focal Reducer

 

The MallinCam MFR-10 (MallinCam Focal Reducer-10) is a breakthrough in optical performance only from MallinCam. You can now have a focal reducer for your larger size (up to 28.4mm diagonal) CCD or CMOS sensor astronomical camera. The large format focal reducer has a 2" (48mm) thread on either end, and comes with a T-to-2" adapter to allow use with all T-mount type cameras.  Reduction for a 17.5 mm back focus camera is 0.46X. The 3 element multi-coated system has a built-in field flattener crucial for RC type telescope and SCT as well. The MFR-10 will  make your telescope F/ ratio faster when using a CCD or CMOS camera, cutting exposure time by up to 5X”


Edited by Vondragonnoggin, 17 May 2019 - 09:02 AM.


#6 mclewis1

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Posted 17 May 2019 - 09:36 AM

Sorry ... it's the MFR-8 ... not -10 

 

Thanks for the catch, I'll correct the post above.


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#7 mclewis1

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Posted 17 May 2019 - 09:45 AM

Oh, and I was going to mention in response to Eddgie's original post that folks might try just the MFR-6 on an NV (or any setup for that matter) where they want to reduce vignetting with the reduction. The MFR-6 does have the smallest internal aperture (bad) but it mounts so close to the C-mount threads (good) that it can sometimes offer less vignetting than a 1.25" threaded reducer/spacer combination. The downside is less reduction ( something in the .65x range) on a 17.5mm C-mount setup.


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#8 mclewis1

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Posted 17 May 2019 - 09:54 AM

Another reducer option similar to the MFR-6 is this Agena Astro reducer https://agenaastro.c...ducer-0-5x.html

 

This product looks similar to an earlier product from AA that was advertised as a .6x C-mount reducer ... one difference appears to be that this new reducer has 1.25" filter threads on it's front end. There is also a possibly confusing statement in the description.

 

"Native reduction provided is 0.5x when reducer is directly coupled with C-mount cameras (slightly more with CS-mount cameras)"

 

"slightly more" would be in the number, but that would actually be a decrease in the amount of reduction (less aggressive so objects would be slightly larger with the shorter CS-mount spacing).


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#9 Vondragonnoggin

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Posted 17 May 2019 - 10:13 AM

Yes, a reducer directly coupled to the c-mount and a nosepiece placed after the reducer as well as using 2” filters on the diagonal would probably eliminate vignetting for my applications.

 

Not sure about the Mod 3 housing, but I imagine it would be the same. Thanks for those suggestions Mark!

 

would fix an issue for me of the battery cap on the NVD Micro protruding out too far to allow fully threaded 2” nosepiece where I put my 2” reducer. I can get enough of the threads in to make it secure, but still not fully threaded in. That would allow me to use a 1.25” nosepiece instead and still use a reducer without vignetting.

 

For most of us, there is not enough back focus to use a reducer screwed on a diagonal so we screw them on the nosepiece. An option to use reducer first, then nosepiece is good.

 

Good information.


Edited by Vondragonnoggin, 17 May 2019 - 10:15 AM.


#10 Eddgie

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Posted 17 May 2019 - 12:15 PM

Well, geometry suggests that if you start with a clear aperture of 25mm and you compress it by .5x, you are going to wind up with only a 12.5mm fully illuminated circle so any C mount NV device (and from my measurements, the Mod 3 and Micro are midway between CCTV and C mount.  Now at reasonable effective focal ratios (maybe f/4 and slower) the vignetting outside of this circle would probably be gentle, so getting a pleasing result over the entire field is probably possible.

 

 

I’d be curious to know if there is noticeable vignetting.

 

Years ago I bought an AVS Varioreducer which is the same principle as the MFR-8 system which incorporates the MFR-5 and uses various width spacers to get the different reduction amounts. In the Varioreducer, everything was still using a 1.25” focal reducer, a c-mount to 1.25” thread spacer, several 5mm 1.25” spacers. The main problem was that the reducer  lens was still constrained to a 1.25” size housing. I tried in my pvs-7, Litton M942, and NVD Micro and all the same results for c-mount sized opening - vignetting in all of them.

 

Maybe the Mod 3 is different, but the c-mount opening in the housing of the NVD-Micro and M942 are very close to the optical input window of the Intensifier so theoretically should give least chance of vignetting.

 

The MFR-10 would be the only one I could use with my monoculars without vignetting. Looks like an interesting product as it states it also has a field flattener built in.

 

Eddgie - if you want to try my AVS varioreducer on your mod 3, PM me. It sits unused since 2015. I’ll send it to you to try out if you want.

 

The AVS Varioreducer:

 

http://www.astro-vid...ll-systems.html

 

They state 26mm clear aperture on the website.

The Mod 3 has the same geometry as the Micro and PVS-7 C mount.   All have about 14mm to 15mm from the flange to photcatode (which is 1.8mm behind the front of the glass as I understand) so if it vignetted with the other 1.25" reducers, it would probably vignette with the Millicam stuff, though I would think that at .63x, the vignetting would be very mild.  

 

Thank you for the offer but I think that this suggests that it is not going to work without vignetting for anything other than rather mild focal ratio reductions.




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