Jump to content
Mr. Ambiguous

77-75mm step-down, any ideas?

Recommended Posts

Hi,

I'm trying to find a way to mount the HardcoreDNA to the anamorphot 1.33x 50, but no one on planet earth appears to be making a 77-75mm step-down ring. Any ideas how to mount it?

Thanks

Share this post


Link to post
Share on other sites
EOSHD Pro Color for Sony cameras EOSHD Pro LOG for Sony CamerasEOSHD C-LOG and Film Profiles for All Canon DSLRs
33 minutes ago, Mr. Ambiguous said:

Hi,

I'm trying to find a way to mount the HardcoreDNA to the anamorphot 1.33x 50, but no one on planet earth appears to be making a 77-75mm step-down ring. Any ideas how to mount it?

Thanks

Yep, I don't understand why the Hardcore DNA doesn't have a standard size thread. Good thing is that some people are working on a solution to that problem ;)

Share this post


Link to post
Share on other sites
9 hours ago, Justin Bacle said:

Yep, I don't understand why the Hardcore DNA doesn't have a standard size thread. Good thing is that some people are working on a solution to that problem ;)

Indeed, 75mm appear to be the most incompatible front thread on the market. I'm seriously considering buying one and gluing it onto the anamorphot :)

Share this post


Link to post
Share on other sites
12 hours ago, Mr. Ambiguous said:

Hi,

I'm trying to find a way to mount the HardcoreDNA to the anamorphot 1.33x 50, but no one on planet earth appears to be making a 77-75mm step-down ring. Any ideas how to mount it?

Thanks

First use a 77-72mm step down ring, then add one or two 72mm uv filters with glass removed...making a shallow hood, giving enough thickness for the Core DNA to firmly clamp on the outside diameter of the 72mm step rings (as if it was a lens front).

Share this post


Link to post
Share on other sites
7 hours ago, Hans Punk said:

First use a 77-72mm step down ring, then add one or two 72mm uv filters with glass removed...making a shallow hood, giving enough thickness for the Core DNA to firmly clamp on the outside diameter of the 72mm step rings (as if it was a lens front).

Great idea! Thanks!

Share this post


Link to post
Share on other sites
Just now, Mr. Ambiguous said:

Great idea! Thanks!

From memory, that will work (with 72mm rings).

I have since machined out the rear of my Core DNA to accept two 77mm step rings to be clamped into the rear, works very well...the outer rear 77mm thread is now in the ideal position.

Share this post


Link to post
Share on other sites
1 hour ago, Hans Punk said:

From memory, that will work (with 72mm rings).

I have since machined out the rear of my Core DNA to accept two 77mm step rings to be clamped into the rear, works very well...the outer rear 77mm thread is now in the ideal position.

Sounds good! Did you use a lathe? In that case I guess there are no rear threads on the Hardcore any more?

Do you happen to have any pictures of the modification? :)

Share this post


Link to post
Share on other sites
Just now, Mr. Ambiguous said:

Sounds good! Did you use a lathe? In that case I guess there are no rear threads on the Hardcore any more?

Do you happen to have any pictures of the modification? :)

Yes, I used a lathe to open up the rear diameter a few mm's (enough to push a 77mm step ring inside snugly)...and the result? - no useless 75mm rear thread on the DNA anymore. In these pics you can see the mod I did on my DNA (original model) - I expect the Hardcore DNA has the same rear diameter as mine did before I enlarged the rear. Now you can see how I can just drop a 77mm with 72mm step down ring for 72mm lenses...or just keep 77mm step ring for 77mm lenses. The step rings just drop into the new recess, then clamp in tight with the nylon screws.

The larger opening (without step rings installed) now allows me to use the DNA on my larger Kowa inflight 1.75x lens and get the optics way closer than the original design..

IMG_2977.jpg.cc50217e1082603fcb5ed11c54c1e4f6.jpg

IMG_2978.jpg.e7841ca3ddffaeb978325177f5d92585.jpg

IMG_2976.jpg.a0cc5bd13207c31594bc8963497d0fdd.jpg

IMG_2979.jpg.3404fdfe382e09d1ad56bd6c8235c390.jpg

Share this post


Link to post
Share on other sites
4 hours ago, Hans Punk said:

Yes, I used a lathe to open up the rear diameter a few mm's (enough to push a 77mm step ring inside snugly)...and the result? - no useless 75mm rear thread on the DNA anymore. In these pics you can see the mod I did on my DNA (original model) - I expect the Hardcore DNA has the same rear diameter as mine did before I enlarged the rear. Now you can see how I can just drop a 77mm with 72mm step down ring for 72mm lenses...or just keep 77mm step ring for 77mm lenses. The step rings just drop into the new recess, then clamp in tight with the nylon screws.

The larger opening (without step rings installed) now allows me to use the DNA on my larger Kowa inflight 1.75x lens and get the optics way closer than the original design..

Thank you so much! This is great! I have no experience what so ever using a lathe... Did you do it yourself our did you go down to the local metal shop? I guess you found a way to remove the glass? Sry for the millions of questions but I'm so curious. I just bought a Hardcore DNA thanks to you ;)

Share this post


Link to post
Share on other sites
10 hours ago, Mr. Ambiguous said:

Thank you so much! This is great! I have no experience what so ever using a lathe... Did you do it yourself our did you go down to the local metal shop? I guess you found a way to remove the glass? Sry for the millions of questions but I'm so curious. I just bought a Hardcore DNA thanks to you ;)

Taking the DNA apart is easy, there are instructions that are supplied when you receive it. You just need a cheap precision screwdriver set to get the small screws out without damaging them and a small hex key to unlock the focus ring. Or whatever the hardcore version needs to open it up (may be slightly different from original DNA design). 

I did the work myself, but if you have no experience with a lathe, I strongly advise you find a local metal/machine shop to do it for you. Once you disassemble the lens, removing the rear optic is easy and you are left with the rear section of the DNA body that just needs the rear opening to be enlarged. If you supply the machinist with a 77mm step ring and basically say ' I want this ring to snugly fit inside this hole' - they cannot really go wrong. The only thing they need to be sure of is not to go any deeper than where the housing diameter steps down to where the retainer ring is to hold the rear optic in place - once you have the part in your hand, it is very obvious where the lathe needs to stop removing material.

If you look at my first example picture, you can see that the metal is removed right up to the point that the housing has an internal thread - to allow rear optic to be screwed in with a retainer ring. Once lathe work is complete, spray the area with some acid-etch black primer spray paint to give a hard wearing matte black finish to cover the bare metal...this will eliminate any unwanted reflections to the rear optic and make the lathe job look 'factory'.

You may not need to lathe the rear diameter if you clamp 2 x 72mm empty rings with 77-72mm ring (to effectively give DNA 77mm male rear thread), but you may find that the optic distance and vignette might be too much for your needs, in which case, the lathe method is the way to go...especially when wanting to use DNA on larger lenses.

Share this post


Link to post
Share on other sites

This is great information! Thanks a bunch! If you don't mind I think I'll also show the person who'll be working the lathe your pictures from this thread, it doesn't get any more obvious what to do than that, but I'll of course bring a 77mm step ring too.

5 hours ago, Hans Punk said:

You may not need to lathe the rear diameter if you clamp 2 x 72mm empty rings with 77-72mm ring (to effectively give DNA 77mm male rear thread), but you may find that the optic distance and vignette might be too much for your needs, in which case, the lathe method is the way to go...especially when wanting to use DNA on larger lenses.

I was thinking about this regarding the potential vignetting issue, does it actually help to lathe in order to fit 2x 77mm rings instead of 2x 72mm rings? Judging from the pictures it looks like it's going to be the ring closest to the glass that'll be responsible for the vignetting in that case since you won't be able to get the DNA closer to the adapter, or am I missing a piece from the equation? :) I understand the benefits of being able to fit your anamorphic adapter directly "inside" the DNA. It would be nice to fit the Anamorphot directly inside as you did with your Kowa Inflight, but I think it'd be a bit of a stretch...

5 hours ago, Hans Punk said:

...this will eliminate any unwanted reflections to the rear optic and make the lathe job look 'factory'.

Great tip! Everything looks 10x more professional in matte black.

1 hour ago, Hans Punk said:

Just found this guy who makes adaptor ring for DNA front and rear use...quite decent designs, but still does not address vignette issues or allow larger lenses to be attached easily.

I'll look into it!

Share this post


Link to post
Share on other sites

The outer diameter of the Anamorphot 1.33x - 50 is 82.6mm

The outer diameter of this 77mm ND-filter is 79.9mm

Judging from your pictures, removing another 2.7mm in diameter (1.35mm on each side) seems risky. Do you think it'd be possible or do think you'd run into the holes for the nylon screws? It would be neat to clamp the DNA directly to the anamorphot though...

IMG_2097.JPG

Share this post


Link to post
Share on other sites
1 hour ago, Mr. Ambiguous said:

The outer diameter of the Anamorphot 1.33x - 50 is 82.6mm

The outer diameter of this 77mm ND-filter is 79.9mm

Judging from your pictures, removing another 2.7mm in diameter (1.35mm on each side) seems risky. Do you think it'd be possible or do think you'd run into the holes for the nylon screws? It would be neat to clamp the DNA directly to the anamorphot though...

IMG_2097.JPG

It should be fine, 83mm would be the largest I'd recommend though. Apparently from the press release of the Hardcore DNA, there is now more material on the rear section to accommodate people who want to mod with a lathe, yet maintain strength in the aluminium. Maybe take a 77mm step ring and something that is 83mm diameter with you to the machine shop and see what the guy/girl feels more comfortable in doing to try and preserve the nylon screw holes.

(Sure thing, show them my pictures if it helps).

Machinists like to measure everything themselves so if you have part 'A' (your anamorphot) and part 'B' (your HCDNA) they can use proper precision calipers and work out exactly the best method and final diameter. That will probably be the easiest and clearest way to explain things...with both parts in hand so you can say 'I need this to fit inside this, until it hits here'.

Share this post


Link to post
Share on other sites
18 hours ago, Hans Punk said:

It should be fine, 83mm would be the largest I'd recommend though. Apparently from the press release of the Hardcore DNA, there is now more material on the rear section to accommodate people who want to mod with a lathe, yet maintain strength in the aluminium. Maybe take a 77mm step ring and something that is 83mm diameter with you to the machine shop and see what the guy/girl feels more comfortable in doing to try and preserve the nylon screw holes.

(Sure thing, show them my pictures if it helps).

Machinists like to measure everything themselves so if you have part 'A' (your anamorphot) and part 'B' (your HCDNA) they can use proper precision calipers and work out exactly the best method and final diameter. That will probably be the easiest and clearest way to explain things...with both parts in hand so you can say 'I need this to fit inside this, until it hits here'.

Sounds good! I noticed just by looking at the pictures from the press release that the design is different, and yes you can see that the placement of the screws are further down and it seems that rear section is wider / thicker. I'll upload some pictures once I receive my unit.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...