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 Post subject: Parfocal direct projection to a dslr on an M420
PostPosted: Sat Oct 20, 2018 7:13 pm 
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Note that you can also buy a premade version of this on eBay from seller mmalkin15, which is where I got the idea from: https://www.ebay.com/itm/M420-Wild-Leic ... 2811185124

Hello everyone. This is a mini-project I recently completed and I figured I should share the steps here so it'll be a bit less work for someone else in the future. I didn't take enough pictures as I was going but I think there's enough information here to make it work.
As it comes, the M420 is mostly convenient for adapting to a modern dslr, at least one with an APS-C sensor--there's a nice tube on top and with inexpensive adapters readily available. You can just attach your camera with no intervening optics and get going on pictures, but you'll soon find that you can't quite make your camera parfocal with the eyepieces--it's close, but the tube is just a bit too long. It's not a huge deal, but it's annoying to have to crank the scope up and down all the time--and if you didn't care about convenience and ease of use you would probably be using lenses directly connected to a camera in the first place. So it's fairly important to get this right.
Yeah, you could take a hacksaw to that Wild tube, but you won't.
So now for the obvious solution, which is to replace the tube entirely. Fortunately the entire top plate of the m420 is very easy to remove, with four flathead screws holding it on. Inside you'll see a lens (I'd note this lens was filthy when I got my m420, but thankfully was very easy to clean). The tube is connected to the top plate of the M420 with three 2.5mm hex screws. You'll need to remove the entire plate and reach down through the top of the tube with a long hex wrench to unscrew them. Once you get the tube detached from the top plate, you'll see the bottom of the tube looks like this:
Image
It sits down in a little round recess in the top plate of the M420. So to make an adapter here you'll need something round with the right diameter to sit down in the recess, a bit of meat to drill holes in for the screws, and optionally that also fits into the central hole to keep centering. The answer to this is a simple female M420 to male C-mount adapter:
Image
I used this one (actually a T-2 to c-mount adapter), which is very thick and well-made, perfect for this task. Pictured here after I marked it with the approximate location of the screw holes. You'll need to drill holes in it big enough for the screws to fit through, but small enough for their washers not to fall in. Marking the locations exactly is difficult, but fortunately you can get it a little bit wrong.
Image
I screwed up a bit but it doesn't matter at all, just moved one hole a bit.
Image
The other thing you have to do is file down the c-mount threads a bit, since the hole is a bit less than an inch in diameter. I used a grinder for most of it and coarse sandpaper for the corners.
This adapter is rough but nobody will see the ugly parts. And even though I bought two adapters to give me some room to mess up it worked perfectly on my first try.
Image
From here it's just a matter of adding a t2-to-m42, a male-male M42 adapter and spacers of the appropriate length to get the camera parfocal. I started out using a cheap Chinese helicoid to get the spacing perfect, but they have a lot of jiggle room and aren't suitable (though I suspect a bit of superglue would make them more rigid and keep them at the right length if you wanted to go that route). Fortunately I found once I'd gotten it parfocal that the helicoid was exactly the same length as one of my cheap Chinese spacers so I could remove it and be perfectly parfocal.

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 Post subject: Re: Parfocal direct projection to a dslr on an M420
PostPosted: Sat Nov 24, 2018 1:03 pm 
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I have just finished converting a Wild M450 to a photomacroscope and with a somewhat similar methodology.
I used my M420 as the template for machining accurately the position of the chimney in the locator plate. This became the position for a 50mm od tube with an iso38mm id.It was located in the holding plate by machining a small sleeve to fit, then machine screwed in position.
Since I use both a Leica DFC camera as well as a Canon dslr, I manufactured an adjustable
chimney to c-mount or T2 mount that will slot into the iso38mm tube.
Its a simple matter of adjustment then to have parfocality with both Leica and Canon cameras.
My next project is to plagerise a diagnostic instruments PA1-35a using either a Nikon cf pl 2.5x or Olympus nfk 2.5x.
A Nikon 2x or Olympus 1.67x would be preferable, but they tend to be megabucks.
If anyone is interested, I will post some images.


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 Post subject: Re: Parfocal direct projection to a dslr on an M420
PostPosted: Sat Nov 24, 2018 6:02 pm 
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Awesome! Yeah, having a full-frame solution publicly posted would be really nice, especially one that doesn't require the apparently vanishingly rare snoot lens from the m400. Even if there isn't a direct response having this stuff posted publicly is helpful.
I've been doing a similar conversion to my m420 on the m400 head I recently got--looks like it should be even easier than the m420.

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 Post subject: Re: Parfocal direct projection to a dslr on an M420
PostPosted: Sat Nov 24, 2018 7:45 pm 
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Stephen Challener wrote:
Awesome! Yeah, having a full-frame solution publicly posted would be really nice, especially one that doesn't require the apparently vanishingly rare snoot lens from the m400. Even if there isn't a direct response having this stuff posted publicly is helpful.
I've been doing a similar conversion to my m420 on the m400 head I recently got--looks like it should be even easier than the m420.

I assume that you got that off flea-bay last week, I was toying with the idea of purchase.
I don't think that I will pursue the current M400, the quoted shipping at $600 is atrocious and should not be more than $150 to blighty.
I have tried both my Canon's 450d and 5d in the set-up.
The 450 set up is a dawdle, but the 5d needs a relay lens to solve the vigneting.
I am attracted to the idea of using a Nikon teleconverter lens TC14b, but may try some vivitar left-overs that I have.
If i find time, I will post some photos.


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 Post subject: Re: Parfocal direct projection to a dslr on an M420
PostPosted: Sat Nov 24, 2018 10:31 pm 
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Yup, that's the one. I already had a base it would fit on (since the M420 I bought had a bad focus block and I ended up adapting it to an olympus stereo mechanism and putting it on an olympus bf/df base), and it's one of the few upgrades left to make to my system. Now I just need to think about how easy it will be to swap it onto my frankenscope...

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 Post subject: Re: Parfocal direct projection to a dslr on an M420
PostPosted: Fri Nov 30, 2018 3:54 pm 
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Somebody picked up a bargain on flea-bay.
A Wild M400 plus photo stand etc for 250gbp.
I would have placed a bid, but the dealer wanted $600 for shipping.
He was clearly maximising his profit margin this way.


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 Post subject: Re: Parfocal direct projection to a dslr on an M420
PostPosted: Tue Dec 11, 2018 3:27 pm 
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amhosib wrote:
Somebody picked up a bargain on flea-bay.
A Wild M400 plus photo stand etc for 250gbp.
I would have placed a bid, but the dealer wanted $600 for shipping.
He was clearly maximising his profit margin this way.

I have just got my hands on a M400 with a standard makrozoom lens, in the UK.
It comes with x0.5 and x2 objectives and is mounted on a Leitz Aristophot stand.
Lots of scope here for various mods.
Cant decide whether to machine for full frame or cropped, any comments anyone.
Best Scientific ltd make direct couplers for both full and cropped frame (1.9x or 1.3x resp.)
These are also the units sold by Martin Microscopes of Carolina.


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 Post subject: Re: Parfocal direct projection to a dslr on an M420
PostPosted: Fri Dec 14, 2018 7:28 am 
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Stephen Challener wrote:
Note that you can also buy a premade version of this on eBay from seller mmalkin15, which is where I got the idea from: https://www.ebay.com/itm/M420-Wild-Leic ... 2811185124

Hello everyone. This is a mini-project I recently completed and I figured I should share the steps here so it'll be a bit less work for someone else in the future. I didn't take enough pictures as I was going but I think there's enough information here to make it work.
As it comes, the M420 is mostly convenient for adapting to a modern dslr, at least one with an APS-C sensor--there's a nice tube on top and with inexpensive adapters readily available. You can just attach your camera with no intervening optics and get going on pictures, but you'll soon find that you can't quite make your camera parfocal with the eyepieces--it's close, but the tube is just a bit too long. It's not a huge deal, but it's annoying to have to crank the scope up and down all the time--and if you didn't care about convenience and ease of use you would probably be using lenses directly connected to a camera in the first place. So it's fairly important to get this right.
Yeah, you could take a hacksaw to that Wild tube, but you won't.
So now for the obvious solution, which is to replace the tube entirely. Fortunately the entire top plate of the m420 is very easy to remove, with four flathead screws holding it on. Inside you'll see a lens (I'd note this lens was filthy when I got my m420, but thankfully was very easy to clean). The tube is connected to the top plate of the M420 with three 2.5mm hex screws. You'll need to remove the entire plate and reach down through the top of the tube with a long hex wrench to unscrew them. Once you get the tube detached from the top plate, you'll see the bottom of the tube looks like this:
Image
It sits down in a little round recess in the top plate of the M420. So to make an adapter here you'll need something round with the right diameter to sit down in the recess, a bit of meat to drill holes in for the screws, and optionally that also fits into the central hole to keep centering. The answer to this is a simple female M420 to male C-mount adapter:
Image
I used this one (actually a T-2 to c-mount adapter), which is very thick and well-made, perfect for this task. Pictured here after I marked it with the approximate location of the screw holes. You'll need to drill holes in it big enough for the screws to fit through, but small enough for their washers not to fall in. Marking the locations exactly is difficult, but fortunately you can get it a little bit wrong.
Image
I screwed up a bit but it doesn't matter at all, just moved one hole a bit.
Image
The other thing you have to do is file down the c-mount threads a bit, since the hole is a bit less than an inch in diameter. I used a grinder for most of it and coarse sandpaper for the corners.
This adapter is rough but nobody will see the ugly parts. And even though I bought two adapters to give me some room to mess up it worked perfectly on my first try.
Image
From here it's just a matter of adding a t2-to-m42, a male-male M42 adapter and spacers of the appropriate length to get the camera parfocal. I started out using a cheap Chinese helicoid to get the spacing perfect, but they have a lot of jiggle room and aren't suitable (though I suspect a bit of superglue would make them more rigid and keep them at the right length if you wanted to go that route). Fortunately I found once I'd gotten it parfocal that the helicoid was exactly the same length as one of my cheap Chinese spacers so I could remove it and be perfectly parfocal.

This is a request for help re Wild M400 that I have purchased.
It is in excellent condition, but I need to make some "mods"
a, how can you remove the in-built camera focusing graticules. The L tube has a retaining ring that with the right tools is probably removable.The R tube also has a retaining ring but with no apparent removing notches.
b, how do you remove or alternatively adjust the tubes for vertical image placement on the graticule (I don't mean the dioptric adjustment). They clearly don't unscrew, but there must be an easy way. Perhaps Tim can respond or any other that have managed the change.
Thanks in anticipation.


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 Post subject: Re: Parfocal direct projection to a dslr on an M420
PostPosted: Mon Jan 21, 2019 4:23 pm 
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Quote:
This is a request for help re Wild M400 that I have purchased.
It is in excellent condition, but I need to make some "mods"
a, how can you remove the in-built camera focusing graticules. The L tube has a retaining ring that with the right tools is probably removable.The R tube also has a retaining ring but with no apparent removing notches.
b, how do you remove or alternatively adjust the tubes for vertical image placement on the graticule (I don't mean the dioptric adjustment). They clearly don't unscrew, but there must be an easy way. Perhaps Tim can respond or any other that have managed the change.
Thanks in anticipation.


Sorry for the lay.

a+b in one go I think: Never had the urge to remove the reticles :) I'd approach 'm from the back... Remove the entire front plate and remove the tubes. Depending on what generation M400 yours is you'll find some screws holding the tubes or they unscrew (I think - I'm getting rusty, it has been a while - all my scopes are boxed up - I have been living in a WWI battlefield the past two years - renovating & microscopes don't mix well).

Just out of curiosity... Why do you want to (re)move 'm?


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